Chapter I:

INTRODUCTION by

AHMET GURSOY Parsons Brinckerhoff Quade & Douglas, Inc. U.S.A.

PAUL C. VAN MILLIGEN Stmkton Betonbouw The

Tunnelling and Underground Space Technology, Vo|. 8, No. 2, pp. 119-121, 1993. 0886-7798/93$6.00 + .00 Printed in Great Britain. Pergamon Press Ltd 1 19 Chapter 1: Introduction

1. TECHNOLOGY--AN INTERNATIONAL PERSPECTIVE

2. HISTORY OF THE WORRING GROUP

3. CONTENTS OF THE REPORT

4. ACKNOWI.EDGMENTS

120 TuN~.v.~a ~m UI~'D~GZOUNVSPACE TZC~OLOaY Volume 8, Number 2, 1993 1. Immersed Tube Tunnel Since thon, the WorkingGroup mem- herein can offer solutions for cro~ings Technology =n International bers have met ahout a d~ tJm~witifin invery deep waters. Terhni~lly speak- Perspective the past four years. In addition to ing, the floatgug t,,-n,d options wrAm. sped_',bpurpose meetings, the Gnmp ined in tK~ section offer weU-known It is with great satisfaction that we met during ITA Congress mean n and techniqu~ from off-shore constmctmn, present herewith our report on various during various speciality conferem~. as well as from immm~od tube t]lnnel aspects of ;~,-m~ed tube tunnel tech- Duringthe 1989meet~Bgin ]Mr- n~-k,~- construction. We believe that the ~me niques, based on worldwide input of ter, England, slx toplcs wore adopted for to put such construction into practice bmnel experts from the U.S.A.; from future publioatloxL Five of these topics has arrive~ various European countries, including were selected for publication for the Swedon, , D~nm-~k, the United 1993 ITA meeeng in Am.terd.m It is 4. Acknowledgments Kingdom, The Neth__~lands, , hoped that the ~ma;ning topic, the Bel~m~ and Italy;, and from Japa~ mAintonance ofimm+~13edtl~lnneJ~, Wi]] The work presented in this publica- We trust that this report will con- be e~amined and a report publishod in tion represents the reeults ofthe Work- tribute to a better understanding ofthe the near future. ing Group's tireless efforts, conducted conditions under which +~m,~ed tun- From the beglnning~ the Working on a truly global scale. Credit is due to nels are designed and constructed, as Oronp members displayed great inter- the principal authors and collabora~-g well as the condithmsunder which float- est in reviewing the state-of-the-art authors (listed separately for each sec- ing b,nne]s will be built in the future. characteristics of immersed tube and tion), who perfmwned the work with flOStJng t.nn~l~. For immersed tube dedication and care. 2. History of the Working Group ~tlnne]B, the ~mmlnation of the two Teclmical editing was performed by Mr. ~h~t Gureoy, and overall editing The report h aa been prepared by the major constructionmethods--one prac- ticed in Europe, the other in the United of the material on submerged floa~_ng WorkingGroup on T'mmm'8~ and Float- t,mnels was performed by Mr. D. R. ing Tllnn~ of the International Tun- States--was the focal point in setting the Group's agenda. Culvorwell. International coordination n,~ll;ng Association. The Group was of the preparatory work was provided establ~hed in 1988, at the ITA'si con- by Paul Van Milllgen. Publication coor- ference in Madrid. Mr. V. L. Molenaar 3. Contents of the Report dination, layout, copyrediting, and final served as the Group's ,~-im~teur for This report includes discussions on productionwork were performedby Ms. one year, aRer which Mr. P. C. Van the state of the art of floating and im- DonnaAhreas, )4---~-gEditor of Tun- Milli~en assumed th~ posistion. The mersed tube I~,n-els, with sped_'A] em- nellin8 and Under, round Space Tech- Group's Tutor from 1988 to 1991 was phasis on basic features of steel and nology. Official 1TA representatives to Mr. B. Pigorini, who was succeeded by concrete tube t~mnel global construc- the Working Group, from 14 countries, Prof. A. Glenm~ tion practices. are listed in Appendix ~. Work for the report has been carried Chapter 2 e~nm;nes structural de- The Animateure of the Working out by various Sub-Working Groups, sign features of steel and concrete im- Group wish to extend their deep appr~ managed by Sub-Worki~_~ Group lead- ~ tube t:l 1n ne]B, inc~l ai n£ co][li~;z11c- elation to the Working Group members ers under the coordination of the tion stages, accidental loads, load fac- and to the members of the ITA Execu- ~tnlmatettr~. tars for combinations of losdln~s, and tive Cotmcil for the~ contilo-;ng sup- The first meeting of the Working material spedfi~tions. port during the last four yeare. The Group was held in Manchester (United Chapter 3 provides general discus- growing enthusiasmwithin the ITA and Kingdom) in 1989. At that meeting, sions of construction techniques for im- within the Working Group toward the the Group decided on the Sub-Working mersed tube t.nn*lq, induding l~pocial ~global sharing oflmowledge" is a Hying Groups for each topic. Each of the five attention to data~ollection methedol- testJnmuy to the dedicated proLe~___'on- groups establishod at the Manchester ogy, dredging te~h-;ques, enviromnen- alism ofits members, and a credit to the meetinghave produced a section ofthis tal impacts, and floating transport. civil engineering profession. report. Chapter 4 deals with specific details for steel and concrete blnne]B to obtain watortightuess, concentrating mainly on the various joints for steel t~,--els and on membranes, coating techniques andjoints for concrete t~mnels. Thelast pert ofthis chapter brieflydiscusses the subject of maintenance in relation to eventual leakages; it is hoped that this topic will be addressed in detail in fu- ture publications. Chapter 5 comprises a catalogue of immersed tube t~InneIB, both Istee[and concrete, starting with the first Detroit b,nnelin 1910, and continuing through to very recent tllnne]B that are under constructio~ Chapter 6 covers a very special ject--floatlng t-nnels. Although thla type of t~mnel has never been con- structed, it has been su~ciently re- searched to provide details on po~i_"hie ~GmsoY PAUL C. VAN ]M'nss~ floatingb,--e1~tion~ Thetech- Animateur (Chairman) nically feasible techniques presented Viee-Animateur (Vice-Chairman)

Volume 8, Number 2, 1993 T~.TJlqG ~ U~D~m~D SP*CZ TECm

STRUCTURAL DESIGN OF IMMERSED by

JAN SAVEUR Van Hottum en Blankevoort The Netherlands

WALTER C. GRANTZ Parsons Brinckerhoff Quade & Douglas, Inc. U.S.A.

Contributions and comments by:

D. R. CuIverwell U,K. C. Th. van Doom The Netherlands A. Glerum The Netherlands A. Gursoy U.S.A. Chr. J. A. Hakkaart The Netherlands K. Hestner P. C. van Milligen The Netherlands S. de Ronde The Netherlands E. A. Szmnsen T. Tamotso

Tunnelling and Underground Space Technology, VoI. 8, No. 2, pp. 123--139, 1993. 0886-7798/93$6.00 + .00 Printed in Great Britain. Pergamon Press Ltd 123 Chapter 2: Structural Design of Immersed Tunnels

1. INTRODUCTION

. OVERVIEW OF IMMERSED TUNNEL PRACTICES 2.1 Tmmersion Inst~llAtion 2.2 Fabrication 2.3 Joints 2.4 Watertightness 2.5 Cress-section Types 2.5.1 Steel shell tunnels 2.5.2 Concrete t~mnels 2.5.3 Miscellaneous

o WATERTIGHTNESS 3.1 General 3.2 Steel Shell Tunnels 3.3 Concrete Tunnels 3.4 The Expansion Joint Concept for Concrete Tunnels 3.5 The Waterproofing Membrane Concept 3.6 Protection of Concrete Against Chemical Attack 3.7 Longitudinal Prestressing

. DESIGN OF TYPICAL TUNNEL SECTION 4.1 Interior Geometry 4.2 Typical Composite Steel Shell Cress-Section 4.3 Typical Concrete Box Structure 4.4 Weight and Balance

. LONGITUDINAL ARTICUI~TION AND JOINTS 5.1 Steel Shell Tnnnels 5.2 Concrete Tunnels 5.3 Shear Transfer in Intermediate Joints 5.4 Intermediate Flexible Rubber Joint Design 5.5 Expansion Joint Design 5.6 FinAl Joint of Concrete Tunnels

. STRUCTURAL ANALYSIS FOR CONCRETE TUNNELS 6.1 Transverse Analysis 6.2 Longitudinal Analysis 6.2.1 Longitudinal hydrostatic compression 6.2.2 Concrete stresses by temperature deformations 6.2.3 LongitudinAl bending 6.2.4 Temporary construction loads 6.2.5 Longitudinal reinforcement 6.2.6 Permanent longitudinal prestress

7, STRUCTURAL ANALYSIS FOR COMPOSITE STEEL S~lfl~.t.T, TUNNELS 7.1 Stage 1: Fabrication and Laun~hlng 7.2 Stage 2: Internal Outfitting with Concrete 7.3 Stage 3: FinAl Condition after Baclrfilllng in Place

So LOADINGS 8.1 Loading Combinations and Allowable Stress Increments 8.2 Accidental Loads

9. TYPICAL MATERIAL SPECIFICATIONS

124 Tu~.t.r~G AND UNVP.m~OtU~VSPACE TEC~UqOLO~Y Volume 8, N-tuber 2, 1993 The purpose of this report is to de- these codes relate to structures which are floated to the site; installed velop an un~di.~ ofthe state-of- designed for different structural one by one; and connect~ to one an- the-art structural design for ~n~reed performance and generally more other under water. An ;mmmcsed tun- road and railway t~m-els. The report sevea~ envirolunental exposure than nel is generally instmltmd in a trench covers commnu and specific aspects of ilmn~'sed t.nn~lm= The layout and that has been dredged previously in steel shell b,n-els and concrete ttm- design of an ;,-.-..~ed t---el is very the bottom of a waterway between nela. It is the first time that engineers much related to coz.~t+~don oppor- structures constructed in the dry. fTom Europe, the U.S.A., and Japan tunities and site conditions. The The space between the trench bet- have collaborated on a report of th;~ state of the art described in this tom and the so~t of the t,,-nel can be kind for imm~rsod blnne~l. report covers different practices a prev/oualy prepared gravelbed, or This report is very timely in that, in that serve the same goal: namely, sandbeda;- S pumped or jetted under- recent years, a longstanding tradition to produce watertight and durable neath the t-,,-el. has begun to fade. No longer are steel immersed tunnels. Piled foundations are sometimes ~ll-]~e~ the on/y types oft~mnels An important issue for concrete tun- used, where soil conditions require construct~ in the United States, and nels is the difference in practices for them. As CO~LCtiOa proceeds, the concrete box t,mn~ls the only type of providing watertightnees and durabil- bmnel is backfilled. The completed tim nels uusedin Europe. The steel shell ity agA/-~ aggressive groundwater. tl m n el is usually covered w/th a protec- was a serious contender in the coml~- These practices cannot be evaluated t/ve layer over the roof. tition for the Great Belt ~,,,nel in properly without an understandln~ of Den,---k, while the concrete box will the influence of the longitudln~! per- 2.2 Fab~cation be used for the Fort Point ChA-nel formAn~e of the b,nnel structure. This Tunnel in (, topicsis disc.ssedin so~e depthhe~in, b,nnAi e]mlle~ts are U.SJ~), currently under design. using numerical examples. fabricated inside drydecks or specially The history of :immel"Bed t-nnel For the structural design of steel constmcted castingbasins. Sometimes practice began in 1910, with the con- ~eH t111MIlr~,the thr(~ basic construe- the cofferdam for the approach ramp struction of a two-track railroad tun- tion ~ges require separate and diffor- structure is first used as abasin for the nel across the Detroit River between ent design analyses. These are de- fabrication of the tamnel elements. the United States and Canada. For scribed and the assumptions are de- ~ sh~l]t~mnAl elemea~ are usu- the next thi~-ty years or so, virtually tailed for each case. ally fabricated in a shipyard. Aitor the ~11 imm~rl~gd t.~]n n e|B were conl~ruct~d element is launched, most of the inte- rior coucrete is installed while the ele~ inthe United States. Duringthis time 2. Tunnel Practices a rather specific steel shell technology merit is floating. The element is then emerged--a technology that has con- 2.1 Immersed Tunnel--Definition placed in the trench. Steel shell tun- tinued largely tmchanged up to the An ;mmarsed b,nnel consists ofsev- nels have also been fabricated and present. In 1941, construction of the oral prefabricated tunnel elements, partly concreted in dry'dock& Maas Tumnel in (The Neth- erlande) began, marking the begin- ning of the use of+mmorsed ~ln ne]B in Europe. Shallow river crossings with mul- Definitions tiple-lane requirements led naturally Tunnel Element: to the concrete box scheme, a very A section of the tunnel that is fabricated and immersed as one whole unit. different method of desiga and con- struction from the steel shell A con- Intermediate Joint or Immersion Joint: siderable number oft~mne]s were con- The joint between two tunnel elements. structed in Europe with this method; Terminal Joint: and, as a result, engineers in The Neth- The joint between the terminal structure (e.g. ventilation building) and the erlande, Germany, Sweden, , immersed tunnel. Belgium and Denmark adopted the concrete box method exclusively. This Final Joint or Closure Joint: tradition persists today. The last tunnel element to be immersed must fit in between two ends of the Meanwhile, Japan was buildingtun- previously immersed elements, or between a previously immer~d element nels ofboth types. The authors believe and the terminal structure. At one end them can be a regular Immersion Joint. that Europe and the United States, as At the other end there must be a marginal gap to allow tt~ element to move well as other countries, would do well in its slot. to follow Japan's example. It is hoped that th;~ ITA Report will Expansion Joints: encourage mlgmeor8 in m~irlng equal Special watertight vertical joints between segments of a tunnel element, use of beth of these b~m:¢ technologies. allowing limited movements between the segments. (used in concrete Both have unique advantages and tunnels) llmltationB, depending on the site. The selection of method should be made by Tube: engineers on the basis of job site In croas-section a tunnel can be structurally compartmented in vadous tubes conditions--not because of any lack (sometimes called "bores'). of understanding of either method. Gallery or Service Gallery: A compartment of the cross-section used for services and/or pedestrian 1. Introduction passage. Even though immersed t-nnels are des~ned and constructed worldwide, Ventilation Duct: special codes for ;~morsed t...Al~ do A compartment of the cross-section used for ventilation air supply or not exist. ~andard codeo for highway discharge. structures are ofl~n used, although

Volume 8, N.mhor 2, 1993 Tt~n~z.mO~_~D~SPACZ ~ 125 2.3 Joints There is a wide range of cross-sec- shape is often used because ofthe obvious All joints are gasketed and tightly tion configurations, depending on the advantage for transverse load transfer. However, the shape most oRen used closed. The immersion joints between intended use of the tunnels. In deter- mining the ult.lm~te shape and size of for double- and multiple-tube concrete the tllnnel ele11~ents Can be pE~/A,ta~- ently flexible rubber compression the tunnel cross-section, the designers traffic t,m-els is the rectangular box, gaskets, as is oi~m the case for concrete must consider, for example, whether which may have to be widened with ~nnels. These gaskets are pre-installed the tunnel is to be used for railway or extra cells for ventilation air supply at one end of each tunnel element. motor traffic; whether it will be a single and services. The box shape best ap- Intermediate joints can also be made tube, double tube, or multiple tube; proaches the rectangular internal clear- rigid. This is done at the inside of the what the ventilation requirements will ance required for motor traffic, with temporary immersion seal by welding be; and what construction practices good conformity between resistanceand lapplates to the shells of steel tunnels will be applied. weight. The box shape also permits or by placing concrete for concrete practical concrete construction prac- tslnnels. 2.5.1 Steel shell tunnels tice. When longitudinal ventilation would be sufficient,all of the services The final joint must always be For steel shell tlm-els, a circulur- made in-situ. can be kept within the traffic tubes-- shaped section for a single tube or a that is, along the roof and inside the binoo_~l~rshape for a double-tube cross- ballast concrete underneath the road- 2.4 Watertightness section are most economical for exter- nal pressure loading, as most sections way or walkway. Often, however, a Immersed t~mnele have a small of the structural ring or rings are in special services gallery is preferred or, n-tuber of in-situ joints. With regard to sometimes, required by the fire depart- compression at all times. An addi- ment for emergency escape. watertightness, this is quite an tional benefit lies in the fact that the advantage over most bored tunnels. space between the roadway slab and ET-mpIes of cross-sections of con- Tmme~l~N:~ tllnne]lS are des~ted to be crete immersed tunnels are shown in watertight. Standards for the invert and the space above the Figure 2-2. acceptable suspended ceiling, if applied, can be leakage rates that are state-of-the-art for bored tunnele have no meanlng for used for air supply and ~.xhaust for transverse ventilation. These spaces 2.5.3 Miscellaneous immersed tllnnelS. can also be used for services. Low-point drainage sumps have to Steel shell tunnels are watertight For larger vehicular tunnels, the be provided within the confines of the by virtue of the quality of the many usual configuration involves one or structure. welds of the shell made in the fabrica- two tubes, each having two roadway In binocular double-steel-shell tun- tion yard and by virtue of the quality of lanes. The structure consists of a nels, the sump can be placed between the in-situ joints. the tubes. In single-steel-shell and The watertightness of concrete tun- circular steel shell stiffened with steel diaphragms. A reinforced concrete concrete t3;nnelS, the sumps have to be nels depends on the quality ofthe joints placed underneath the roadway. The and on the absence of full-depth cracks ring installed inside the shell is tied to the shell and acts composite with the presence of service galleries is helpful in the concrete. in positioning the pumps. concretet.-nels are provided shell and the diaphragms. This is the Many main structure, designed to resist ap- Generally, for given crose-sectional with watertight enveloping mem- plied hydrostatic and soil loadings. requirements for vehicular space and branes. In addition to providing wa- ventilation, the concrete box section tertightness, this membrane is some- Welded to the exterior flange plates of the diaphragms is a second "shell", can be made shallower than the steel times needed to shield the structural section. However, for the same condi- concrete against agreseive chemical the form plate, which contsln~ the ballast concrete partly placed as tions, the steel section is generally a agents. There are distinctly different narrower section. views among design engineers about tremie. This ballast weight provides the necessity of such membranes. the required negative buoyancy. This type oft-nnel is called a =double-steel- 3. Watertightness shell tunnel". 3.1 General 2.5 Tunnel Cross-section The single-steel-shell concept is used for tunnels with one or two relatively Although watortightneas is one of The selection of the typical cross- the pr*-,~ objectives otany;m--,-~l sectiongenerally is determlned by pref- narrow tubes, such as Umnels for metro t~,--el design, the design would be ds~- erences based on successful previous railtransportation. The stoelshellison dent if the consequences of incidental experieQacein the specific region or coun- the outside and acts composite with the concrete. The ~m.. leakages were ~ On the try, as well as local site constraints (as internal ring ballast con- large perimeter surface of a bin-el ele- crete,which isproportionately less th-n witnessed by the practice in the U.S.A ment, the possibility of an ofselecting steel shelltunnele;in north- for the larger double-steel-shell tun- pinhole in a steel weld or an undetected west Europe, of selecting concrete tun- nets, is placed on top of the element to co--on imperfection of the con- nels; and in Japan, where beth con- keep the shell as small in section as creto or wa~ ~ can- cepts are applied). Recent interna- possible. For single tubes, a circular tional immersed tenders in Europe shape is preferable; sharp corners are not be ruled out completely. Suitable repair methods exist and have included alternative options for avoided. Single-steel-shelltunnAls have steel tun-els. little allowance for internal ducting. must be specified in the dm~. The The structure of steel shell tunnels Examples of steel shell tunnel crOSS- build-up of water pressure within the consists of relatively thin-walled com- sections are shown in Figure 2-I. b,-,el wall system must be av~dsd by posite steel and concrete rings. The provision of proper drainage into the steel shell provides the water barrier. t~m-el drainage mymte~ Seepages of 2.5.2 Concrete Tunnels this kind are very small and do not The ballast concrete is placed outside For concrete t~,nnels, circular shapes require extra drainage and sump of the shell in pockets formed between have also been used for single tubes (in the structural diaphragms. capacity. Concrete tunnels are monolithic combination with transverse ventila- structures in which most of the fine] tion) and for relatively narrow service 3.2 Steel Shell Tunnels weight is incorporated in the struc- tunnels. For railway ~uneis with two For steel shell b,nn~l elements, wa- tural components. slngle-track tubes, the near binc¢~)l-= tertightness is provided purely by the

126 TUNN~.T.mOAND U~-vE~Otn~ SPACE TZCH~OLOGY Vol,,me 8, Number 2, 1993 1~L87o, 266o,

e,

r I ° 1 l 12260 .J I-- I DOUBLE STEEL SHELL SECOND TUNNEL. 1978, t ;

BN.t.ASTCONCRETE 12400 _1 2 2oo I o _1 -{- I

DOUBLE STEEL SHELL FORT MC - HENRY TUNNEL ,1984

1. ,,,o ..1 SINGLE S~1E~3. SHELL, .~q-FRANSISCO TRANS--BAY 11JNNEL, 1970

Figure 2-1. Examples of cross.sections of steel-shell tunnels.

steel shell itself. The watertightness member will cool off to the ambient There are basically two different relies on the quality ofthe large n.ml~r temperature. The resulting contrac- concepts regarding control of leak- ofwelds. The concrete in,de the shellis tion of the now-hardened concrete is ages for concrete box tunnels: trAnwTersely under compression. subjected to restraint. This occurs when 1. The expansion joint concept in- casting the walls above the horizontal volves avoiding longitudinal stresses 3.3 ConcreteTunnels joint with a base slab that was cast at that can cause cracks, thereby relying an earlier stage. The result of the For concrete t~m~els, leakage is on the watertightness ofthe uncracked cooling contraction of the wall con- concrete. related to the development of cracks. nected to the rigid base slab is com- Therefore, an understanding of the 2. The waterproofing membrane pression in the base slab and longitudi- concept involves enveloping the con- different structural behaviours in nal tensile strain in the bottom part of the tranaverso and longitudinal di- crete t, nnel element in a waterproof- the walls. ing membrane. rections is important. Unless proper measures are t~ken, In the transverse direction, box- vertical full-depth cracks can occur at Each of these concepts is discussed shaped reinforced concrete t.~mnels al- about 5-m intervals. Satisfactory in more detail below. ways have zones in the roof and base processes have been developed to avoid slabs that experience bending teusion, these construction cracks, namely by 3.4 The Expansion Joint Concept for notwithstanding the transverse com- using concrete with relatively low Concrete Tunnel Waterproofing pression. The tamnel section is de- cement content and forced cool~n~in the signed so that the resulting cracks can The expansion joint concept in- lower part of the walls (see Fig. 2-3). volves achieving watertightness by only parti_'_ally penetrate, leaving the So~ thla iS done in combination concrete in the compression zone suffi- avoiding tranaverse craeklng of the with insulatien and heating of the base concrete. ciently thick to avoid leakage. slaba If cracks nevorthe!_~s~_are found, In the longitudinal direction, the A bmnel element 100 m long or remedial grouting appears to be morels doaignedwith expansionjoints. stresses are of a much lower magni- effective. tude than in the transverse direction. The length between the expansion Effective control of differential heat joints is determ;nad by the practical The basic stress is ma-ginal compres- development largely depends on the sion. Secondary effects that can cause length of a complete concrete pour, heat of hydration of the concrete. This which is in the range of 20 m. The partial tension should not lead to full process, in tttrn, is a direct function of depth cracks. Thermal shrinkage vertical joint between two segments is the amount of cement in the mix. basically an unreinforced cold joint cracks are a typical secondary effect. Therefore, the use of typical concrete In thick concrete nmmbers, the heat provided with a cast-in flexible mitres with high cement factors (taken waterstop. In this way, the tamnel of hydration causes substantial heat- from highway structures codes) can be ingofthe member. Aiter some thne the element can be subjected to flmmral counterproductive in this respect. deformations without developing

Volume 8, Number 2, 1993 Ttne~z.~OAsDU~aOVI~SPACZTecHSOLooY 127 24770 29800 I-- --I IDI j t, ,~

MAASTUNNEL 1940 VLAKE TUNNEL 1975 ROTTERDAM VLISSINGEN

108qO 500 26180 ,11 EXTERNAL BALLAST POCKETS CTC 20 m 2 t, 2 RAILWAY TUNNEL 1992 I PARANA TUNNEL- SANTA F'E 1968 ROTI'ERDAM

I_ 12680 _ I 30000

II II -~I 11 II KEY YO UNE TUNNEL 1980 TINGSTADT TUNNEL 1968 DAIBA GOTHENBURG

39700

I_ 103O0 _1

METRO TUNNEL 1985 TAMA RIVER TUNNEL 1984 SPIJKENISSE (THE NETHERLANDS) TOKYO

I_ 24100 I- "1

SERVICE TUNNEL 1973 SERVICE TUNNEL 1986 CONWY TUNNEL 1991 HOLLANDSCH DIEP PULAU SERAYA WALES (THE NETHERLANDS)

F~gure 2-2. Examples of cross.sections of immersed concrete tunnels.

12R Tum~.v.mG AND UNDEP~a~OUNDSeA~ TECHNOLOGY Volume 8, Number 2, 1993 longitudinal tensile strain between Figure 2-3. the eal~ansion joints, which can cause Thermal cracking of the concrete. shrinkage Great care must be taken to assure problem and that shrinkageofti~malcrg~ki~ does solution. not occur in the asgments and that any cracks which do occur are sealed prior to floating the element out of the cast- ing basin. During transportation and in.hA. tiou, the segme~llts of such a t~mnel element must be structurally coupled in the longi~z~J~A! directio~ This can be done by tempormT coupling rods, with 114[ UE 0f O~Ut~ ~O or without prestress; or by temporary longitudinal prestressing tendons over the full length of the b, nnel element. The temporary prestressingtendons are usefully cut after installation. How- ever, they are sometimes maintained An alternative method is to apply 3.6 Protection of the Structural permanently--gor example, when flex. the steel roof plates after concret- Concrete against Chemical Attack ural bending of the bmnel is not ex- ing the roof. Steel rail, are partly The direct exposure of the struc- pected, as may be the case with a piled embe~ed in the top of the concrete. foundation. tural concrete oflmmersed t~mnels to Steel plates will be welded to these their external Ambient envir~nmAut is rails and any voids will be grouted much less severe th~ the exposure of afterwards. 3.5 Waterproofing Membrane Concept highway structures to the atmosphere. When a waterproofing membrane is Steel plate membranes (typically Observations in the course of dura- 6 mrn thick) are anch~ into con- used, the tl,nnel elements are made the bifity investigations have attested to monolithic, using regular vertical crete by welded studs, usually four studs per square meter. Because the the long-term reliabilityof reinforced construction joints with continuous concrete structures pe~mansntly im- longitudinal reinforcement. The thin plates are rather sensitive to tem- in seawater. perature deformations, much care is mersed waterproofing membrane is made In seawater, chloride ions will required to keep the plates flat. The continuous over the full length of the diffuse into the concrete, thereby t~mnel element. Full-depth transverse bond between the steel plate skin and depassivating the concrete. Corrosion concrete cracks can develop, especially the concrete should not be relied upon, of the steel reinforcement can begin in the vertical construction joints. In notwithstanding the use of the studs, when the depassivation front has this concept, full reliance is given to because the stoel plate membrane does reached the reinforcement. However, the membrane waterproofing that not provide a structural contribution the corrosion of the reinforcement at envelopes the element. to the concrete structure. the outside face of the concrete will not To protect the steel plate mem- The following options are used for be effective, because of the very scarce waterproofing membranes: branes agAJnAt corrosion, impressed supply of oxygen. The type of cement current cathodic protection can be • Steel plate below the base, with used and the density of the concrete installs& Sometimes coating of the are important factors for the penetra- bib~mlnous or plastic membranes steel plate is also specified, but it is tion rate of chloride ions and oxygen. on the walls and roof. practically impossible to provide it • Steel plate below the base and on The chloride diffusion front may never without some local deficiencies (e.g., penetrate to the inside face of the the sides, with bit~,mJnous or at splices). Nevertheless, the coat- plastic membr~e on the roof ing, although imperfect, will reduce concrete. only. Sulphate attack in seawater is not the direct current deman& accompanied by expansion of the con- • Steel plate all around. Obviously, a wator~Rn~ mem- crete because of the presence of cldo- • Plastic membranes all arouncL brane must be fully continuous around rides. Gypsum and sulpho-a]-mln Atos, the whole of a ~ulnnel element. The which are soluble in chloride-rich envi- Bit~mlnous or plastic membranes emphas~ for steelplates is on the qual- must be protected against mechanical ronments, are leached out. Therefore, ity of the Welds. For bib~mln~as and special sulphate-~cementis not damage. This protection is usually plastic membranes, the emphasis must provided by a concrete layer, which needed; and, moreover, would in- be on providJn5 the proper application; crease the sensitivity of the con- must be permanently held to the struc- observing the proper l~mltetious for crete to chloride penetration. ture. Unfor~,n~ely, th~Aarrangement weather conditions; andprevim-~good requires ~nehorsto penetrate the mem- The inside face of the concrete, overlaps over the upstand of the steel especially in road t~mnele, is gener- brane. Other necessary penetrations membrane. are for bellard- and fender connections, ally exposed to chloride attack in an Sometimes the trA-Aition area is oxygen-rich environment where the access AhAt~S, and certain Jmm,~rsion also clamped. A small leak in the equipment. air may be aggressive. Further- membrane can cause water to flow more, in many tunnels, passing Steel plate ~irln~ applied on the sides underneath the membrane to weak for waterproofing are also used as stay- vehibles bring in d~l,~ salts, which spots in the concrete at other loca- add to the depassivatiou of the con- in-place formwork for the walls of the tions, thereby mA~,~ the source of element. For steel membranes across crete by carbonation. The steel leakage dlt~eult to trace. reinforconamt also could be subject to the roof area, holes can. be left in the A combination of the two meth- corromon. practical plates for placing and vibrating the Again, the best ods--i.e., using both waterproofing protection is good concrete density and concrete. The holes are dosed up later. membranes and the expAnRion joint sufficient concrete cover. This method is more complicated for a methodDis not considered cost-ef- fiat roof than for an arched roof. fective or advisable.

Volume 8, Number 2, 1993 Tvm~z.wo+~DUsDmemou~SPAC8 T~msoLo~ 129 Because the steel reinforcement in the dry and are part of the com- 4.3 ~ of Typical C,orcre~ Box is more sensitive to corrosion at the posite structure, along with the con- The "concrete box" tunnel can inside face of the concrete than at crete ring inside the inner shell. The be considered as a monolithic frame the outside face, the protective exterior concrete on the sides, which comprising base, walls and roof. membrane waterproofing method is is poured under water, serves to There is a horizontal construction not used. restrain buckling of the diaphragm joint between the base and the walls. flanges and acts as ballast. Waterstops are sometimes provided 3. 7 Longitudinal Prestressing The interior steel shell is provided in these construction joints (they on the inside with J-shaped steel hooks are not used in The Netherlands). It To avoid uncontrollable full-depth that are stud-welded to the shell plate. cracks, the longitudinal working ten- should be noted that the application of These hooks tie the ring concrete and a waterstop may obstruct the easy sile stress should not exceed the tensile its reinforcing steel to the shell to pro- strength ofthe concrete. Normnllythi~ placing and compaction of the con- vide the composite action. crete, which is not the case on a clean requirement can be satisfied in the The steel assembly is built on land design of concrete t~mnels. If needed, fiat surface. Generally the weight and launched sideways or longitu- and downward forces in the whole of a fairly small rate of longitudinal pre- dinally, with the bottom part of the stress can substantially increase the the wall provide enough pressure to exterior concrete in place. This make the joint watertight without allowable range of loading that causes esssmbly is considered a =keel" for tensile stresses. For example, for con- special provisions. stability during towing. The ring The walls and slabs for a traffic crete with a tensile strength of 2 Mpa concrete inside and remaining outside and 1 Mpa longitudinal prestress, the tllnnel are us, Any at least I m thick. concrete ballast are placed when the To increase the resistance for shear range of loading causing longitudinal assembly is afloat. tensile stress could be 50% higher. and hogging moments, hatmches are The structural loading during the provided underneath the roof slab. subsequent construction stages is quite When designed without haunches, the 4. Design of Typical Tunnel complex~ The stresses in the shell are base slabis up to 1,5 times thicker than Section more severe during launching, towing the roof, with the top following the 4.1 Interior Geometry and outfitting with interior concrete cross-fall of the roadway. This ar- than when the element is finally im- The interior geometry ofimm'~ed rangement not only is attractive for mersed. The interior shell is about 8 construction, but also provides mass tunnels depends largely on local, state mm thick and is stiffened with exter- or national highway design standards stability to the Umnel element. nol longitudinal stiffeners. The form Sometimes the floating condition applicable to the type and volume of plate usually is 6 mm thick. traffic for which the blnnel is designed. may require a thinner base with For double-shell design, a compos- haunches in the corners. Base Interior clearance envelopes for c~llng ite steel concrete t~mnel is achieved by height and width of lanes are set by haunches require special attention for covering the steel shell all around with concreting. The ballast concrete is these agencies. Other requirements a thick concrete cover, which provides may involve ventilation equipment; placed on top of the base. mechanical and corrosion protection Allowance for services in concrete overhead sign clearances; safety and for the steel shell. The double- access walkways; placing of services; tunnels. The main electrical feeders steel-shell element end detail shown are usually placed in conduits in the and use of suspended ceilings, curb in Figure 2-5 illustrates the typical details, etc. hal l~At layer and/or are suspended from structural steel arrangement. the roof. The services inside the tubes Roadway drainage, superelevation, The single-steel-shell type ofi~mnel sight distance for horizontal, and can be reduced to local distribution if a is ~mpler in concept, although also sub- special services gallery is used. The vertical curvature may also play a part ject to more critical steel shell stresses in the interior geometrical design. The exterior walls in the latter case would in the launching stage, when the inte- not require large panel recesses, which vertical clearance should be extended rior concrete is not yet inst~lled. To to compensate for expected (unequal) can act as crack initiators. The same stiffen and stabilise the element in the could apply if the size of the low point settlements and d~m~n~ioneli~g:cura- launching stage, the base ofthe interior cies. The horizontal clearance may drainage sump would require deep re- coucreteringis instMled prior to launch- cessing into the base slab. have to be extended for horizontal ing. The steel shell is stiffened with inaccuracies. stiffening plates and temporary trans- verse spiderweb frames. For double- 4.4 Weight Balance 4.2 Description of Typical Composite tube single-shell elements, a verti- The design of the croes-sectionel Steel Shell Cross.section cal longitudinal steel truss is con- geometry is very sensitive to varia- Figure 2-4 shows a typical cross- structed in the center. This truss tions in the density of the water and section of a double-steel-shell t-nnel, will later be absorbed in the interior the construction materials; dimen- which consists of an interior steel shell concrete and partly removed where sional inaccuracies; and the weights of made composite with the interior rein- cross-passages are required. Fig- temporary equipment needed for forced concrete ring inside. The ure 2-1 shows an example of a single transportation, temporary instal- exterior steel, called the "form steel-shell element. lation and the permanent condltio~ plate, ~ envelopes the interior shell Cathodic protection is sometimes A concrete bmnel element must be in an octogonal shape up to the el- required for singls-steel-shell t~lnneis able to float with all temporary imm~. evation of the crown of the interior if the tunnel passes through a zone of sion equipment on board. The free- shells. The shell and the form plate stray currents, such as a subway sys- board should be ~ to redu~ t~ are interconnected by steel plate tom or an industrial facility. In such Amc~mt of permanent and diaphragms at 4- to 5-m centree. cases, provisions are made to measure ballasting. The ~m'7 on~ Exterior concrete fills the space be- the currents at test locations. These we~ht, with the water ballast tA,,~ tween the shell and the formplate and tests will determine the required level filled, must be su~ident~ For the W- covers the shell. of impressed current needed to pre- reagent con~tion, it must be ~an- The bottom part and the roof part vent loss of steel section. teed safe against uplitt with the fixed of the exterior concrete are poured bAl!~t in place.

130 Tumc~J.mG AND UNWm~gOU~ SPACE T~mNOLOGY Volume 8, Number 2, 1993 I_ 12260

~6001870 2660 2660 1870160"~ I_ _ i ; _ _ t -I_ _ I ~ ~/- K Ir¢1 CONCRL~I[ • #iaphroqm

STEEL SHELL ~ 6,30 6,3o ~ FORMPLATE va/ves form

Figure 2-4. Typical cross-section of a double-steel.shell l aliqnment tunnel. wedge

The roof is usually covered with a protective concrete layer that is also Figure 2-5. DoubIe-steel-sheU element and detail, and used for trlmm';ng purposes. When typical structural steel arrangement. Formplate is only ]:fi.t~mJnouswaterproofing membranes partially indicated. are applied to the walls, protectivewood covor or concrete cover is also applied to the wails, as cast~in-plaes or precast These factors are nsed to determine For concrete tlmn~la, the thiclmess panels. The roof edges are usually the required geometry. The actual of the structural concrete is genorally bevelled, to reduce the risk of hooklng safety factor may be slightly higher or sufficient for the strength. The deter- ship's anchors. lower, depending on the actual as-built mlnAt;ion of the ~ geometry is more The mJnJmu2n factor of safety for dlmAu~OIX$. complicated because the ballast con- the permanent condition of immersed For example, a part of the stable crete is on the JnRide. Variation of the tlmnelsis~ specifiedas 1.10,based type of roof protection, such as rip internal ballast volume affects the in- on the following conditions: rap, may be allowed to be included in ternal geometry. 1. Uplip fore~: the safety factor of 1.10. Some- • Buoyancyby the water at the times a mum safety factor of 5. Longitudinal Articulation mATimnnl expected density 1.06 is appl/ed for concrete t~m~e]s and Joints with only the structural concrete and according to the theoreti- Tmmer88d O, nnsjI8 are rigid struc- cal displacement. and ballast concrete as stabilising factors. For steel shell t~,~nAl% 1.07 tures in the longitudinal direction. The • Hydraulic lag, if applicable in is applied, exnluding the contibution stresses with which the structure tidal waterways. of the side walk concrete. would respond to axial tensile strain 2. Stabilizing loads: The minJmmn temporary safety (temperature) and longitudinal bend- • The theoretical weight of the factor during installation is usually ing strain (unequal settlement or structttral steel, concrete and 1.03 after release of the j,-me~_ien large surcharge discon'tmuities) de- reinforcementsteel, a~l,ming equipment. pend on the material properties and a remKt~dc density for the con- Sometimes allowanco has to be the longitudinal articulation. crete that will not exceed the made for uplift caused by hydraulic actual density. gradient. A hydraulic gradient can 5.1 SteelShell Tunnels • The fixed per..,--ent ballast be caused by tidal lag of pie~ometric Steel shell l~mnAlS have approxi- concrete, inside or outside. height underneath the t~mnel, which mately the same longitea;,,*] flerdral can occur with silty or clayey ba~'.kR1] in • The weight ofprotoctivemem- rigidity as concrete t-,,,,els. However, tidal waterways. Anothor cause of by virtue ofthe inherent ductility ofthe branes and cover concrete. hydraulic gradient is the suction caused * The roadway pavement, sus- steel shell, they have a larger lougitudi- by the squatting of ships passing nsl strain capacity, and are therefore pended roadway slain, or fx~d- over; however, this factor is only track support eooere~ less sensitive to foundation discon- considered in the installation stage. tinuities and temperature ~tions 3. Factors not considered as stu- For steel shell O,-~els, the total than concrete bmne]& The concrete bilizing are:: amount of concrete needed for the part of the ¢ompomte structure inmde * Backfill surcharge and weight balance Amply exceeds that re- the steel shell is not co~trolled in the downward friction. quired for strength. Tbe ~al bel- design for transverse crs~t~-g under • The weight of mechanical last concrete is the variable factor for hmgitudinal tensile strn~n= It will not equipment and suspended the weight balance. affectthe hoop resistance ofthe compos- ceilings. ite ring.

Volume 8, Number 2, 1998 ~LnCO,~DUZmmmm~SPaC~'I'SCmNOLCX~ 131 steel bulkhead ~NT SZC~ON O~ CONCRETE ~,N~ BULKHEAD PLATE / CONCRr~ RING ~ ~]oint filledwith ~-- ~ / DRAINTUBF" \\

exhaust: ~ "~",%.-"~.bulkhead~ t. I ,',tat,* airducl ~X~ I r "

f' ~ "~-d~d p~, ~ top l~ ::::::::::::::::::::::::::::::":,:'.'~'-';;;,';" ~L-:-'-" • ..... "'"::'i:!::"':!""

£XTERt0R / BULKHEADPLATE / ~ULKHEADPLATE J CONCRETE. INBOARD / OUI~OARD / SIJ~NG JOINT

Figure 2-6. Typical tremie conerete joint for a double-sheU Figure 2-7. Intermediatsjoint with sliding arrangement steel tunnel. for a double-steel-shell tunnel.

Generally the steel shell is made the permanent watertight gasket. They gasket, is considered to be the main fully continuous between the t~mnel can also be ~ed prior to placement seal. The space between the Gina gas- and with special joints at the terminal with provisions for in-situ adjustment. ket and the Omega seal is usually structures (e.g., as for the BART rail- Shear transfor for AreAl| shear forces drained offto the inside of the ~m-el way bmnel in San Frands~); or with can be accomplished using shear keys An~mple ofanintermediateflex- sleeved joints, as recently developed or longitudinally movable dowels in ible joint dmign for concrete ~mnels is for Boston's Third Harbour ~mnel. the base slab area of the joint. shown in Figure 2-8. The continuity joint is often made Settlement discontinuities often oc- This type of joint can also be used by a bayonet-type fitting of the shut- cur at the termlnaljoint. Shear fixity for steel bm~els, when flexible joints ring ends of the interior shells, which is desirable, but the shear force and are required. are lapped by plates welded to them on resulting bending moment can become The Gina-type gasket acts am a the inside. Temporary watertightaese very large. To reduce the shear, the flexible joint under c~pre~, and is achieved by tremle concrete between following solutions, or a combination can practically be considered as a hln~e the shell and a cofferdamformed by the thereof, can be applied: in longitu~nAlmomanttr~-~. Shear ~damplates ~ and side closure plates. * Ground imnrovement, in the case reslsfam~ can be ignored, becanse it This type of joint is called the ~tremie of soft upper layers. has a tendency to slip a]m~ its base concrete joint ~ (see Fig. 2-6). under shear deformation. For this * Delaying the shear connection until a part ofthe settlement has reasen, sheer ~ ac~se ajoint 5.2 Concrete Tunnels taken place. is not ~,~tsd by propertiee of the Gina Concrete t-nnels are us, Ally pro- guket~ but rather bythe allowshle shear * Readjustment of the tl,nnel el- strain Of the Omega gasket, espedally vided with permauant flexiblejoints to evation with rei~eetion of bed- reduce restraint to temperature con- with regard to its corner section. cling sand. The extra,or rubber gAAkAt should be traction and to reduce flexural bend- • Preloeding by internal floodln~. ing. However, there is an example of placed as much as possible to the out- side ofthe structure, inorder tokeep the a concrete tunnel made monolithic over 400 re, but with flexible term~nMjoints. 5.4 Intermediate Flexible Rubber Joint recess between the side and the outside The type of solid rubber gaskets Design of the gR~ AIkAIlOW. ~ arrange- generally used between concrete im- The type ofsolidrubber gasket seine- meat prevents back~ matedal from mersion unite normally can provide times referred to as the =Cdna"gasket accumulating gradually and obstruct- enough flexibilityfor this purpose with- is used for pragtically all concrete tun- ing the proper movement of the joint. out losingtheir sealing capacity. These nels. It is used as a temporary seal at rubber gaskets only transfer compres- the instal|ation stage and remAinA as a 5.5 Expansion Joints sion effectively. To prevent shear de- flexible compression joint for the per- These joints are applied in concrete formation in an intermediate joint, torment stage. The facing t~,nnel ele- t~mnel elements at the location of the which is desirable for the alignment ment ends are lined with steel plates vertical construction joints. They are and for seAllngpeformanco, shear keys that are matched as parallel planes basically cold joints without steel rein- are require& An example of an inter- within ~5 mm tolerance. The gasket is foreement, provided with steel-rub- mediate joint for a double-steel- clamped at its backside. The speci- ber flexible waterstope. Special shell tJmnel is shown in Figure 2-7. fications for material characteris- provisionB are made to enable pressure tics and geometry are um~ny based grouting acce~ around the waterstop 5.3 Shear Trartster in Intermediate on the l~manent m-~%grequirement the mA~ structural co~crete is Joints under ~ leng-tmm decompres- hardened. A typical Dutch expansion sion and ~iAyAtlon ofthe gasket. Nev- joint is shown in Figure 2-9. Transfer of large shear forces in ertboLe~__,a second ~ble rubber wa- When the t~mnel in its permanent intermediatejoints canbest be achieved ter barrier is installed at the inside of comiit~m is subjected to lc~'udinal by shear keys in the walls that are a curved-slab-type rubber gasket. This curvature, these joints will open at the made in situ in front ofthe inner face of gasket, often referred to as the "Omega" ~ausion ~ side. However, tension can-

132 TUNNELLmaAND UNDEm~ROUNDSPACE TEC~tNOLOGY Volume 8, Number 2, 1993 not be tranafered through these joints. gradually in that direction, the frames pressure distribution. In the case of This relieves the concrete between the can be analysed with balanced loads. hard subsoil, it is advisable to investi- exp~nmion joints of longitudinal ten- However, in areas of heavy sur- gate the sensitivity to the spring con- sion transfer. charge, such as embankments, and, stant, becauso the spring constant can- especially, near discontinuities of sur- not precisely be deter~ed and may 5.6 Final Joint of Concrete Tunnels charge, as well as in aroas of expected vary in time. redistribution of soil reactions, the ex- The final joint cannot be made with ternal vertical loads acting on the plane 6.1.1 Structural Resistance the intermediate rubber compression frame are not balanced. The shear Under some national codes, only joint that is used in the regular forces between the adjacent frames intermediate joints. Wedges are used the Ultimate T.~t State (U.L.S.) is need to be analysed for these condi- checked, using the appropriate load inside the temporary watertight tions. An elastic beam analysis can be and material factors. In U.L.S., the enclosure to maintain the longitudinal conducted to determine the longitudi- compression. nal distribution of the vertical subsoil reinforcement is yielding. Other codes also require the control The joint can be made monolithic, reaction, and the longitudinal shear with shear trAnAfer provision to the of crack width at the Service Limit distribution. Theshear forces can then concrete on one side of the joint and be entered as vertical loads acting along State(S.L.S.). At this state, most ofthe with a flexible waterstop on the other the vertical members of the frame. loads are factored by unity, and the side. In this way, the joint will re- The application of hydrostatic pres- reinforcement is not yielding. The eemblethe action ofthe expsn~ionjoint m~dmum allowed crack width varies sure and surcharge loads is straight- in the different specifications; 0.2 mm described in Section 5.5, above. forward. The magnitude of the lat- An example of a final joint for is usually speeiRed. Protective mem- eral soil pressure and possible wall concrete t~m-els is shown in Figure caused by backfill can- branes are not used, in order to allow friction the for greater crack width. 2-I0. not easily be determlnecL It is best to assume lower and upper bond val- A distinction should be made betweenlongib~dinnl cracks caused by 6. Structural Analysis for ues to find extreme bending in differ- Concrete Tunnels ent members of the frame. trAnAverse bending, and transverse cracks caused by longitudinal action. In numerical analysis, it is practical 6.1 Transverse Analysis The transverse cracks will cause to model an elastic foundation for the leakage. For the transverse analysis, a con. base with a given spring constant. For crete t~,nnel can be considered as a An important contribution to the the soR soil case, the effect on trans- transverse bending moments in S.L.S. series of plane frames. When the loads verse moment distribution is practi- are the restraint moments caused by a and soil reactions are constant in the cally the same as a ,lnlforln. ground longitudinal direction, or vary only temperature gradient across the thick- hess of the slabs and walls. The tem- perature gradient effect is not factored for the U.L.S. conditio~ Its contribu- tion to the reinforcement steel stresses

~4m Q~t/r ~f ~ mtJ~ 00tP~$~ OA~LW should be taken into account. Special cases of concentrated loads have to be examined. Ex- amples include temporary jacking pin supports, the effects of shear dowels, and discontinuities of cross- section that occur at the joints.

6.2 Longitudinal Analysis for Concrete Tunnels The understanding of the longitu- m$~ R~ II4RF.A~D ~ / dinal performance of concrete tun- nels is important in view of the rela- IIMI~q~E~AT[ ~NT tively low tensile strength capacity of I i the concrete and the desire to avoid ~WAV ~J~ V m~Jm~o~ Jawr .'L,/ i

I ..... J~'\\\\\'~ i

i I"- .... kx.\\\\\\\~ o __ I__ m mmN~ | I

Figure 2-8. Intermediate flexible joint for concrete Figure 2-9. Typical Dutch expansion joint. tunnels (Dutch solution).

Volume 8, Number 2, 1993 TtmN~.WO~'~DUI~Sm~OUSDSP~ ~ 133 Figure 2-10. Example of about 10 mm of joints positioned at of the final joint for 100-m intervals. / concrete tunnels. A n-merical example ofconcrete com- pression, based on the use of a rubber compression joint, is shown below: for D (avg.) = 20 m: ~fc (avg.)= 20 x 0,024 = 0.48 Mpa long4~anfc(avg.) = 0,5 x0,48=0~4Mpa* for D (avg.) = 6 m (near shallow end of a tunnel): long-term fc (avg.) = 0,5 x 6 x 0,024 = 0,072 Mpa* *the factor 0,5 is estimated It is notedthat the compressive stress in the concrete by the hydrostatic com- pression, although very Sma11~is suffi-

I dent to keep the joints sealed. Because the rubber joints are flex- ible, the restraint to longitudinal strain of the tunnel elements is practically eliminated.

6.2.2 Concrete stresses by yempereture deformations The relevant temperature changes l 1 ofthe concrete are of a seasonal nature. At the time ofinstadlation, the whole of the structure canbe assumed to be the same temperature as the surrounding water. The temperature changes ofthe con- transverse cracks. It has been shown Losses of the fixed hydrostatic com- crete areu~,a"y specified in two parts: that these cracks can indeed be avoided. pression. Losses ofthe fixed hydrostatic 1. An overall increase or de- The effects of hydrostatic compres- compression are caused by tinm4iepen- crease, relative to the ambient sion, temperature stresses and longi- dent relaxation of rubber compression ground water, with a range ~om tudinal bending on the longitudinal joints and short~nlng of concrete, caus- 15°C to + 10°C. concrete stresses are explained below tug decompression of the joint. 2. A so-callad ~gradient" over the with numerical examples. The degree of re]sTation of the rub- thickness of a wall or slab, which is a bet compression joints varies with the linear temperature variation from 0°C 6.2.1 LongRudinal hydrostatic characteristics of the selected type and on the outside to ± 1O°C on the inside. compression the range of compression. Generally This gradient can be split in an overall The longitudinal hydrostatic com- the loss will be about 50% of the initial increase or decrease of S°C, to be added comprl~Bslon. pression force in any vertical section of to (1), above, and a linear variation Typical performnn~e rates for flex- the tunnel is equal to the water over the thickness from -5°C to +5°C, ible rubber compression ga~kete used pressure that would act at the aver- or vic~versa. age depth, D (avg.), of that section as intermediate joints are shown in The overall increase or decrease of Figure 2-11. times the gross area of that section. the temperature of the structure With the simplified assumption that Shortening of the concrete can be will lead to longitudinal deforma- caused by shrinkage and tempera- the ratio between the gross area and tion. For tunnels with monolithic the concrete area is equal to the ture deformation. Creep of the con- intermediate joints between the ter- ratio of the densities of concrete crete can be practically ignored. minals, this could lead to concrete and water, a simple expression for The concrete codes do not provide stresses in the range of the tensile proper parameters to determine the the average concrete stress is: strength or yielding of the vertical shrinkage strain for thick-waned con- joints. fc (avg.) ffi D (avg.) * 0,024 Mpa, (D in m) crete members of immersed concrete "l~mnels with intermediate flexible The longitudinal hydrostatic com- tamnelS. If calculated according the compression joints are not restrained pression force will follow the changes FIP-CEB model code, a very small to longitudina! deformation of the con- in water depth (e.g., by the tide), as strain is found. The shrinkage strain crete, but the flexible joints will react long as the immersed part ofthe ta~n. el is not restrained when flexible inter- with a minor increase or decrease of has a free end and friction between the mediate joints are u~lim~l, but the common. free end and the section under consid- resulting decompression ofthese joints The linear temperature variation eration can be ignored. will cause a m;-or loss of the locked-in over the tl~ekn~_ of a wall or slab of The hydrostatic compression will be compression force. +5°C to-5°C willcauasbending stresses fixed as soon as the t~mnel is closed In The Netherlands, the ghrinka~ varyingfrom-l.O Mpato+l.0 Mpaover between the terminal structures. strain is ignored for t~m-els in which the thickness of a concrete wall or slab. The compression is assumed to act the concrete is directly exposed at the Although ~mAll, these S~ are a at the center of the structure when outside. magnitude larger than the hydrostatic flexible intermediate compression Temperature deformation caused by precompression. On the outside, there joints are used. a temperature decrease of the t~mnel will be tension in the summer and by 10°C. would cause a demmpression compression in the winter.

134 Tumv~a.mG AND UNDmamOUNDSP~Z T~amOLOOY Volume 8, Number 2, 1993 The stress diagrams of Figure 2-12 MA~dmum bending manco. However, special attention deady showthatthetomperetore varh- stress: fc (~a=) = should be paid to the watertightness tions will not cause transverse cracks. 2.04 Mpa of the construction joints of mono- lithic t~,nnel elements, as is also the This simple calculation shows that a 6.2.3 Longitudinal bending case for expansion joints. In addition, range of 50 mY- of such ~tisl watertight enveloping membranes Discontinuity of surcharge and dis- settlement can cause nmnolithic t-nnel may require special attention at the continuity of settlement have the s~me elements to crack transversely. These construction joints, to keep them wa- effect. They cause longitudinal bend- cracks wenld be full-depthover thethick- tertight in case of yielding of the con- ingofthetunnel, which canbe analysed heSS of the base slab and the wails. ~h-ction joint. as a beam on elastic fo~datio~ While it is preferable to prevent The large beam stiffness of the tun- forced deformations ofsuch m%~nituds, nel leads to high shear force and bend- sometimes it c~-not be avoided. Con- 6.2.4 Temporary construction loads ing moment response to longitudinal troll;ng the width of such cracks by The effects of temporary construc- bending. This is illustrated by the longitudinal reinforcement will not tion loads are of a temporary nature following theoretical example for a provide ductility of the t~nnel element only. The tnnnel elements are not monolithic t1~nnel element (not seg- as a whole; furthermore, it is not eco- ,mJformly loaded during the transpor- mented) that wants to settle 50 mm~ nomical. However, tranverse cracksin tation and Jmmorsion stages. but has shear restraint at one end the concrete can be avoided by provid- The tsmporary bey d Jn~ mommlts for (which could be the terminal joint). ing ductility at the construction joints. a t-nnd element 120 m long for the The joint is flexible for rotation. The Because the vertical construction given ezample are in the range of 50 to main variable is the spring constant of joint c~nnot transfer concrete t~n~le 100 MN/m, catud~ cc~crets stresses in the subgrade reaction. stresses, it will crack at an early stage. the range of 0,15 Mpa to 0,30 MI~ The For this example, Ko ffi 2 MN/m a is The longitudinal reinforcement longito,];-~| bena;n~ would increase used, corresponding to a deflection of through the joint should not yield with ;ne~esed t.~,nn,d element length 0,05 m under a pressure of 0.1 Mpa (or within the expected bend~g range, and by long waves, in the case of sea 10 t/m~, as could be caused by heavy which should be safely below the bend- transportation. surcharge). ing capacity of the tmcracked concrete. For monolithic ~m.el elements, i~gure2-13 shows ane~,~le di~gi. Beyond that range, the joint should the steel reinforcement stresses m~.AI a-~tysis for the response of c~- yield, and thereby provide sufllcient must be safely in the e|A~dc range. crete b,nnets to unequal settlement. rotation capacity to avoid an increase For bmnel elements with expansion in tensile stresses in the uncracked joints, temporary longitudinal pre- Example calculation: concrete. The resistance ofthelongitu- stressing is usually applied at the External dinal reinforcement will not be condition that the concrete will not cross-section: hf8m, mob'dised, except in the joints. The receive tensile stresses. b=30m concrete will not craclL Modulus of Inertia: I = 1.200 m' If the spring constant in the above 6.2.5 Longitudinal reinforcement Section modulus: S = 300 m s ~A~le were four times higher, or if it The longitudinal concrete stresses Elastic modulus: E = 2.10~ Mpa were the same but the undisturbed are very ~all~ The necossm7 ductility Spring constant: K=koxb Mttle~xe~t was lJmJf~ to 25 ram; the should be provided by the intermedi- =2x30 mA~mum bending mmnent would enly ate joints and expR-~onl or construe- = 60 MN/m = be 300 MN/m and the ~-~d~un con- tionjoints. If, instead, the longitudinal Characteristic length: 1o = 35.5 m crete tensile stress would be 1.0 Mpa. reinforcement of the homogenous Thereinforcomentthrenghtheconstruc- sections would have to be activated Undisturbed tion joint could then be 0.2~ % of the settlement: Yo ffi 0,05 m for the longitudinal ductility, the concrete area, without yield;n~ of the concrete of these sections could be M~dmum shear joint. force (at fixed end): subjected to full-depth cracks. Vm~t ~ Monolithic concrete tunnel ele- The longitudinal reinforcement is 2 E1 x Yo/lo s ments can be designed with a rela- =53MN designed to act as secondary relnferc~ tively low amount of longitudinal re- ment to the main transverse rein- M~=imum bending moment inforcement (~Jmi|ar to concrete tun- (at 3/4 le from fixed end): forcement or as m;nJrnu.ul 1-e~.~orce- nel elements with expansion joints), ment for two-way slabs and wA]]a, M ffi 0,322 loxV ffi without the risk of concrete cracks in compliance with the applicable ffi 612 MN/m resulting from the in- situ perfor- concrete codes. This usually re- sults in a longitudinal reinforcement of about 0~ percent of the total con- crete area, for a reinforcement yield Figure 2-11. Typical stress of 500 N/ram=. This same per- performance of flexible contage, applied to the construction rubber compression joint, would limit the v~nYJmtuntAn~|e gaskets used for stress in the concrete lz~wesn these intermediate joints. joints to about bMfthe ultimato tensile strength.

I //lJ , L-- 6.2.6 Permanent longitudinal prestress

- 111 11~l~. I~IIENT Longitudin~ prestressing is not an effective way to economJRe in the de- sign of the cross-section of concrete jn~n'tm'sed t~lnnA1R) aS it is for many 2 3 4 II II 7 • • other structures. It must be applied -~;formly over the depth of a bmneL

Volume 8, Number 2, 1993 Ttro~.mo~vU~mov~SPAcz T~msoLoo~ 135 C~NCL~11[ $'i"tq~ ll~ 11~mN~L ZTIT~IEZ3~'T1E 11E~PERA~JI~ 11DA~B~KIN[AN0 ~N. i I

...... I

m

i

~ -~.o ~ ,, ~ ¥ m~ * L~

Figure 2.12. Diagrams of concrete temperature and Figure 2-13. Examples of longitudinal analysis of the stresses for summer and winter, valid for tunnels with response of concrete tunnels to unequal settlement. flexible intermediate joints.

As can be seen from the previous filled without myth difference in the However, in this t~l--A1 the design was example of longitudinal bending basic structural sectio~ In contrast, based on a launched A!~t because analysis, the prestress levels re- the fabrication of steel shell elements the expectation had been that the ele- quired would be very moderato. The involves a structure that undergoss a ments would be co~troztsd in the con- longitudinal prestress can be used series of stages, each involving a basi- ventional way with outfitti~bei~ done to allow higher loagituai-~! bena~ng cally different structure. in flotation. Boston's Third Harbor loads, causing tensile stresses. If The description below applies to ~mnel is currently being considered concrete tensile stresses are not double-steel-shell type structures. The inthe same di-ydock, slthou~very]itt]e allowed to occur, as is often speci- structural concept is simpler for the of the interior concrete will be placed fied in the case of prestressing ap- single.hell type t-nnAl because there prior to floatl-g out. plication, more prestress would be is no exterior concrete, other than bal- During fabrication, each steel bin- needed to compensate the tensile last concrete on the roof. However, the ool]A,.ormonoc-lR,.module (about eight strength of the concrete in the operat- singl~-shellt-~-elundergoes the modules per element) mtmt be sup- ing condition. same stages ofbasically different struc- ported adequately to avoid distortion Longitudinal prestress should be tures. Bocause this type of shell has no or local buckling. In some cases, applied to increase the tension and exter~ diaphag~, temp~ary inter- interior aspiders ~ may be required bending capacity of the vertical con- hal spiderframes are u~l;~L In the to maintain the roundness of the shell structlonjoints, in particular, to a level case of double-tube shells, tempo- plate. Accurate roundness must be where these joints will not open under rary longitudinal trusses also are maintained to assure a --~form thick- certain extreme conditions such as utilised in the middle. hess of the interior ring concrete. This earthquakes. The homogeneous con- The structural stages are: is critical to the eventual structural crete sections are always stronger than Stage 1: Fabrication and launch- integrity of the elements when it is the construction joints because of their ing. bacir611ed. inherent tensile strength. Stage 2: Internal ontfiWmg with A portion of the exterior concrete A typical ,~,mgle of longitudinal concrete. about 1.5 m thick, ~lled the ~zeel," is prestressing is Tokyo's TAmA River Stage3: Final condition after placed in the bottom of the formplate rr~'nnel, which i8 located in an active back~llJng in place. prior to launch. This provides protec- earthquake zono. The t, mnelelements tion for the bottom of the element dur- Each of these stages is described in were longitudinally prestressed in ad- ing launch, as well as stability during detail below. dition to the longitudinal reinforc~ towing. After this concrete is placed, ment. Special prestressing tendons the loads of the element are trans- were installed and stressed in-situ 7.1 Stage 1: FabficaUon and ferred tolaunchJn~ sleds or, in the case to act as a flexible tie across the Launching of end-launching, fore and aft poppets intermediate joints with rubber During Stage 1, the loads on the prior to launching. The shell and dia- compression gaskets. The Tama structure are largely a function of the phragms may require reinforcements River ~m-el is also provided with a method of support and launrhin~, if in either case. watertight enveloping membrane. the element is to be construet~ on The keel conorete is considered to be shipways. It may be launched side- a longitudinal beam acfin~ with the 7. Structural Analysis for ways, or end-launched in either a con- stiffened shell plate and diaphragms. Composite Steel Shell Tunnels trolled or uncontrolled launching. The water pressures, both static and dynamic, which will occur during The design of steel shell im-~sed As a recent e~Ampla, the elements of the 1-664 r1~Innel in Hampton Road, launch must also be determined and b In Ir-~la(11"~]B¢ fronl concrete b(~ b In n A]B (U.S-~) were co~ in a accounted for. because ofthe -~--~r oftheizconstruc- drydock and flontedont. In thJa case, all While the basic design of the ele- tio- Conorete box b,-,mls ere cast in a ments takesinto account sc~ne expocted basin, floatod, andth~ ~ emdback- of the interior concrete was prior to in~.altln~ the end ]~allbheads. Is.n~hJng loads, the contractor must

136 Tum~.~.mo AND UNVZSa~OVNDSPAC~ TZCSNOLOGY Volume 8, Number 2, 1993 be made responsible for checking the ment sequence; it generally becomes facilitate otherwise very difficult, or element det~ih for the preposed methed most critical during the placement of perhaps even impossible, calculations. ofsupportln~ and launching, and must the heavy haunch sections. Thank~ to the availability ofrelativaly provide whatever additional rein- Longitudinal loads are resisted by inexpensive, accurate, and easy-to-use forcement that may be required. the shell plate and the radial stiffen- computer so,ware such as ~AAD M, Towing may impose longitudinsl ers. Stress enalysis for critical com- STRUDL and others, the structure may stresses on the steel element. Ofl~n pressive stress for buclrlJn~ of curved be modelled to the exact shape of the the practice has been to tow the ele- panels under nnlform compression are proposed t, mnal. Because the location ment under its own flotation, because used to determine moment capacity ofthe frame line, the cross-section area, the drait of an element not outfitted al~er applying a suitable safety factor. and the moment ofinertia are allinter- with interior concrete end the remain- The local buckling of the shell is related and affectthe results (moments, der of the exterior concrete is only investigated for leading in torsion end shears, axial loads end deformations), about 2-3 m If the dements are to transverse shear. Bucklln~ofthe arch an iterative design approach is neces- be towed in ocean waters, the height between stiffeners is investigated. sary. Using such an approach, a series of long periodic swells becomes im- The shell plate end longitudinal stiff- ofcomputor ~InA are made, each using portant, because the swells impose eners are considered as a cylindri- information from the previous run, to signlficent longitudinal bending m~ cal shell spanning between dia- modify frame line location and mem- ments. Unless accounted for, these phragms. The shell plate alone can ber properties, thereby converging on bending moments could cause buck- resist water pressure as a ring an accurate and economical solution. ling of the top shell. structure and a cylindrical beam. For the prellmlnary design, the to- Recently the practice has been to Assumptions are made regarding tal thickness of tlmnel walls may be tow elements on large offshore con- how these loads are distributed be- based on previous experience or very struction barges in order to reduce thiA tween the shell and the stiffeners. rough hand-calculations. The t~mnel effect, when ocean towing is required. The diaphragmis designed as a ring is drawn accurately and the frame line structure, with its ends RYed in the is laid out by "eye" or judgment, more 7.2 Stage 2: Intemal Outfitting with keel concrete. The effective width of or less along the mid-thickness of tun- Concrete the shell plate, which acts with each nel walls, discounting exterior tremie diaphragm, is dete~rnlned as a func- concrete. During outfitting, the losaln~ condi- tion of the centerline radius of the shell Coordinates ofselected ~joints" along tions on the shell change with each end its thickness. the frame line can be very conveniently concrete placement. At first, the ele- obtained if the work is done by CADD ment is supported nnlform]y as it floats drafting. Using the resnlts ofthis first with a constant drait. The end bulk- 7.3 Stage 3: Final Condition after Backfilling in Place run, the design engineer can propor- heads are quite heavy end impose a tion steel end concrete depths end thick- hogging moment on the element. As Th~ final transverse analysis stage nesses based on stress analysis, end sections of the interior cencrete are considers that the ~Inn~ is completed obtain new section properties. These placed, additionalmoments areimposed and fully back~lled end is subjected to data are used in turn as input for a on the shell. The sequence is designed a series of loading combinations, second, more refined computer analy- to counteract the hogging effect and listed below. sis, wherein the frame line is located at reduce its deflection so that at the Bending moments and direct the center of gravity of the gross end, the element is as straight as stresses are computed on the basis of composite section and member proper- possible. six superimposed loading conditions: ties are based on the same. As the concrete weight is added, the 1. Uniformly distributed loading-- This process is repeated until the element sinks lower in the water, top. designer is sa~Red that changes re- thereby imposing transverse mo- 2. Uniformly distributed loading-- suiting from further refinement are ments on the shell plate and diaphragn~ side. negiigible. Theoret~tlly, the final com- The formplate does not take any of this 3. Triangl,IAr side leading. puter run should be based on a frame load, as the water is allowed into the 4. Loading from exterior upper line correepond;n~to the center ofgrav- pockets between the shell end the form quadrents. ity of the cracked section, end member plates. The only exception occurs at 5. Buoyancy forces. properties, area, end moment of iner- the end pockets between the dam plate 6. Water surcharge. tia are based on the same. (extension of the b,dkhead) end the It should be kept in mind that the first diaphragms. These pockets are Generally, the effect of these load- composite three-dlm~nsional ~lnnel filled with structural concrete, placed ing combinations results in a moment structure with variations in leadings is in the dry, to help resist the large forces diagram with negative values (tension extremely complex. The goal of the that act on the joint during dewater- on the outside) near the center wall on enalysis should be to determine an ing. Typically the shell plate is de- the top end bottom end in the central envelope ofmi~mmnmoments, shears signed to take the water pressure as portion of the exterior walls; and posi- end RffiJRIloads so that all possibilities the outfitting progresses. tive values (tension on the inside) in of overstress are @lJmln~ted. For ex- The placing sequence is deterTnlned the regions in between. This is some- ample, gross section properties may by the engineer as a reasonable volnme what Rimilar to the moment diagram result from maTimuln effect at one that can be placed while limiting the for a two-cell rectangular box loaded location end mlnimqm effect at en- moments and shears in the exposed top and bottom, as might be expected. other, whereas thecracked sectionmay shell plate. The concrete placement Axial thrusts act in addition to the show the reverse. This approach, in- should be symmetrical about the moments end are caused by overbur- conceivable in the past, is not at all transverse end longitudinal center- den and side pressures. These have difficult today with the help of clever lines of the element. As the head of the effectofredu~n~the tensile stresses computer programming, water increases on the shell plate, the caused by bending, while increasing Future enalysis methods may make ciro,meerential moments must be re- the compressive stresses. use ofthre~;n~nmnual finite element sisted by the diaphragms and shells Before computers became readily modeling. This will be partio,lnrly in- embedded end, therefore, fixed in the available, the t~lnnel configuration terea~n~ in the nn~lysi8 of ]oadJn~8 keel concrete. This condition must be assumed for analysis was simplified to such as ship collision, enchor dragging, ckecked for each stage of the place- circular or elliptical shapes in order to

Volume 8, Number 2, 1993 ~s.mo~Uzm~tovNvSPAC~ ~ 137 and internal explosion. The longitudi- For reference II, only the ultimate- crete to avoid mechanicaldsmage to the nal distributionof these loads is other- limit state factors are given. However, structural concrete. Dragging anchor wise very difficultto determine. service-llmlt state verificationis also loads ofthis m_agnitude normally can be donein view ofwatertightness require- resisted by the available friction of the 7.4 Field Measurements ments; for example, temperature re- foundation. straint has to be considered. The final assessment of any design as complex as that for immersed ele- 8.2.3 Flooding of tunnels ments can only be made on the basis of 8.2 Accidental Loads The probability of internal flood- field measurements. To our knowl- Accidental loads to be considered ing is very small during the opera- edge, this has never been done for steel may include: tional life of the blnnel. However, it shell tunnels in any sophisticated way. I. S~lnken ship loads. makes sense to investigate this type of It has been proposed that strain 2. Dropping or dragging ships incident in the light of possible unde- gauges be attached to the diaphragms anchors. sirable settlements. and interior reinforcing steel of the 3. Flooding of the tnnnel. Third Harbor Tnnnel in Boston, Mas- 4. Internal explosion loads. 8.2.4 Internal explosion loads sachusetts (U.S.A.) at various loca- The probability and extent of inter- These loads are subject to dif- tions, representative of the wide nal explosion loads depends very much ferent probability for each project. range of imposed loading conditions on how the tunnelis to be used. Arecent They are usually specified as deter- that exist for this tunnel. If this example is a t.llnnelin Belgium, located mlnlstic loads, corresponding to an program goes forward, the results near an industrial area, which has obtained will increase our under- excedance probability of 10 4 per been designed for an internal expl~ standing of the structural action of year. Increases in working stresses slon pressure of 4 bar. This require- steel shell ~innels and could lead to are usually allowed. ment substantially increased the better, more economical designs in The discussion ofearthq-Mce load- amount of transverse reinforcement the future. ingis considered to be beyond the scope needed. In the future, where unique condi- of this report. Tmrnersed tllnne18 have tions exist or, in general, where value withstood major earthquakes success- can be gained from similar measure- fully. Ample experience with earth- 9. Typical Material Specifications ments ofthe action oflmmersed tlmnel quake design for steel shell and con- 9.1 Structural Concrete for Concrete elements, there may be merit in in- crete tunnels exists in the U.S.~ and Tunnels clnding test programs of this type in Japan. the construction bid packages. Although specifications vary con- siderably worldwide, a distinction 8.2.1 Sunken ship loads can be made between two main 8. Loadings For imrnm~Jed toxmels in sof~ grotmd, groups of specifications. One group 8.1 Loading Combinations and the tunnel may respond more rigidly of contractors tends to use highway Allowable Stress Increments than the adjacent bae.kRlL This can be structure codes, which usually specify accounted for in the load to be speci- An indication of the types of loads high-grade concretes, with character- fied, usually as a uniform load over a istic strength in the range of 40 Mpa, and their comb/nations used for the mlnlmuln area. For the design of an design oflmmersed elements is given in and with durability requirements immersed tnnnel across the Great Belt associated with sulphate attack. The Table I. The table, based on data pro- in Denmark, which is an international latter requirements generally lead to vided from the U.S.A., Japan, and The waterway used by very large vessels, the use of sulphate-resisting cement or Netherlands, isnot exhaustive. Itshould the specification was 100 kN/m~ over Portland cement to which pulverised be noted that the factors given in the 250 m 2. table are based entirely on the specific fly ash (p.f.a.) has been added. project conditions and requirements. The use of silicafumes with p.f.a. The reference projects in the table 8.2.2 Dropping and dragging and Portland cement concrete is relate to t~lnnels of widely differing anchors being considered in some countries. The other group, of which The structural nature. They are intended Tmmersedtnnnels aregenerallycov- to provide an understanding of the ered with a protective concrete layer on Netherlands are typically representa- range of values for loading conditions the roof. For navigation conditions, tive, use lower-grade concrete, with that are encountered in immersed tun- protective stone cover is also applied. the emphasis on construction crack he1 design(s). The energy of an object free fall- avoidance, low permeability, and chlo- The three reference projects used in ing in water has to be absorbed by ride penetration resistance. Water- the table are: the stone cover and partly by the crush- tight membranes are not used. ing of the concrete cover layer. The A typical concrete specification I: A steel shell traffic tunnel for Dutch irnme~ted tunnels is: (Third Harbor ~mnel, Boston, structural roof load is related to the Characteristic Massachusetts, U.S.A.) impact pattern. This factor can usu- ally be accommodated without addi- strength: 22.5 Mpa Ha: A longitudinally prestressed tional reinforcement. Cement types:Dutch blast furnace reinforced concrete traffic tun- The lateral load of a dragging an- cement (more nel with waterproofing mem- chor hoolr/n~ bahlnd the edge of the than 65% slag) brane (Tama River Tunnel, tunnel roof can be derived from the Japan). Max. cement effective anchor-rope-breaking content: 2 75 kg/m 8 Hb: A reinforced concrete railway loads. For large vessels, the load can tunnel with waterproofing Max. water/ be in the r~nge of 3000 kN, actln~ as cement ratio: 0.5 membrane (Keyo-Line Daiba low as 4 m below the rooftop, de- ~mnel, Japan). penRin S on the type of bottom mate- Permeability: Less than 20 ~m in HI: A typical Dutch reinforced con- rial. The upper part of the walls penetration test, crete traffic t~mnel ('I%nnel De should be provided with cover con- according to DIN Noord). 1048

138 TUNNY.T.TJN(~AND UNDF.][~,OU~'DSPAC~ TF.C~;]NOLOGY Volume 8, Number 2, 1993 Table 2-1. Indication of allowable stress increments or load factors for loading combinations~

Type of Structure

Ill (F): I (S): Steel II (S): Reinforced Reinforced shell traffic concrete tunnel concrete tunnel with waterproofing traffic tunnel Stress Increments (S) or Load Factor (F) (U.S.A.) membrane (Japan) (Netherlands)

A. BASE LOADING 1.00 1.00 1.5* Unfavorable combination of: • Dead load • Backfill • Surcharge and live load • lateral earth pressure • Water pressure at mean high or low water

B. TOTAL STRESS INCREMENT FOR COMBINATION OF BASE LOADING WITH ANY OF THE FOLLOWING: B1. Extreme high water 1.25 1.5 m B2. Anchor dragging or dropping 1.25 B3. Sunken ship load 1.25 B4 Temperature restraints B5. Unequal settlements 1.00 1.30"* B6. Temperature restraints and unequal settlements 1.15 B7. Intemal explosion 1.0 B8. Earthquake, unequal settlement 1.50 B9. Earthquake, temperature restraints, unequal settlements 1.65 BIO. Erection condition 1.30

NOTE: A dash Indicates that this aspect is known not to be reviewed, or Is not critical. * Refers to Dutch practice: the load factor used for the ultimate limit state is 1.7, reduced for the material factor incorporated. ** The factor 1.30 also Includes extremely high water. **• 1.4 * A + 1.15 * B1.

9.2 Matedals for Steel Shell Tunnels Cement Fly ash: will be substi- Typical material specifications for content: 565-610 lbs/yd, a tuted for 5% of structural concrete and structural Water~cement the cement for steel, as presently used in the U.S.A., rat/o: 0.48-0.50, de- all concrete. are: pemd~ng on size Structural steel: ASTM Grade of aggregate A36 (mild steel Structural concrete: Slump: 2 in.-5 i~ with 36,000 psi Strength: 4,000 psi (also for Permeability: 2,000 coulombs YP) tremie concrete) per 6 hours, Reinforcing Cement: Portland Cement: where tested per steel: AASHTO M31 AASHTO M85, Type AASHTO T-277 Grade 60 (60,000 I orH p=yp)

Volume 8, Number 2, 1993 Tu~w3.~o~mU~SPA~ T~mNo~Gv 139 Chapter 3:

CONSTRUCTION TECHNIQUES

by

V. L. MOLENAAR Ingenieursburo Ir. V. L. Molenaar The Netherlands

Contributions and comments by: W. C. Grantz U.S.A. A. Gursoy U.S.A. Chr. J. A. Hakkaart The Netherlands P. C. van Milligen The Netherlands G. H. van Raalte The Netherlands

Tunnelfing and Underground Space Technolog% Vol. 8, No. 2, pp. 141-159, 1993. 0886-7798/93 $6.00 + .00 Printed in Great Britain. Pergamon Press Ltd 141 Chapter 3: Construction Techniques

. EXECUTIVE SUMMARY

. INTRODUCTION

2. CHARACTERISTICS AND TYPES OF IMMERSED TUBE TUNNELS 2.1 Concrete Tunnels 2.2 Steel Tunnels 2.3 Comparison 2.4 Floating Tunnels

3. EXTERNAL ASPECTS AND CONDITIONS AFFECTING CONSTRUCTION METHODS 3.1 Introduction and Set-Up 3.2 Hydraulic Aspects 3.2.1 Data collection and methodology 3.2.2 Current velocity and directions 3.2.3 Specific gravity 3.2.4 Tidal effects 3.2.5 Waves, swell and surf 3.2.6. Sedimentation 3.2.7. Other river and/or sea characteristics and obstacles 3.2.8. Hydraulic models 3.3 Meteorological Aspects 3.3.1 Data collection and methodology 3.3.2 Wind 3.3.3 Temperature 3.3.4 Visibility 3.3.5 Other meteorological matters 3.4 Shipping/Navigation 3.4.1 Ship movements during marine activities 3.4.2 Suction caused by ships 3.4.3 Navigational depth and clearance requirements 3.5 Soil Investigation 3.5.1 Data collection and methodology 3.5.2 Trench dredging 3.5.3 Settlement 3.6 Seismic Aspects 3.7 Fabrication Sites

4. DREDGING AND RELATED ECOLOGICAL AND ENVIRONMENTAL IMPACTS 4.1 General 4.2 Geotechnical, Hydraulic and Environmental Conditions 4.3 Criteria Related to the Trench 4.4 Evaluation of the Dredging Process; Technical Options 4.5 Selection of the Optimal Solution

. AVAILABLE TECHNIQUES FOR CONSTRUCTION, IMMERSION AND FOUNDATION OF TUNNEL ELEMENTS 5.1 Construction of the Tunnel Elements 5.1.1 General considerations 5.1.2 Steel option 5.1.3 Concrete option

142 Tu~uc~.T.ma~ UNvm~zou~v S~xcz T~m~o~Y Volume 8, Number 2, 1993 5.2 Fini~h;-g Jetty 5.3 Transport of the ~1-nel Elements 5.4 Immersing 5.4.1 General matters 5.4.2 Vertical control 5.4.2.1 Steel tunnel elements 5.4.2.2 Concrete tunnel elements 5.4.3 Horizontal control 5.4.4 Other equipment-related options 5.5 Positioning 5.6 Tunnel Foundation 5.6.1 General information 5.6.2 Screeded gravel bed 5.6.3 Sand-jetting foundation 5.6.4 Sand-flow system 5.6.5 Cle~nlng of the trench

6. GENERAL MATTERS 6.1 Quality Control 6.2 Risks 6.2.1 General considerations 6.2.2 Time schedule 6.2.3 Costs 6.3 Project Management 6.4 Project Financing

Volume 8, Number 2, 1993 Ttml~x.wa~UNDm~mOtmDSP,~.CE ~ 143 O. Executive Summary mentation ofthese data. A snmmary of less the same way. This chapter does A number of techniques are avail- required data and relevant techniques not provide extensive details on the execution offloatingt~mnels, but rather able for the construction of t~mnels. In is given in Section 5, which discusses comparison to bored tllnnels, immersed construction techniques. deals with construction applications tube tunnels have a number of advan- The availabilityof sufficient data, on existing projects. tages. The construction time can be techniques and skilledpersonnel, sup- A special section on dredging and shorter, and the risk in terms of time ported by a strong organisation and its environmental impacts (see Section and cost overruns may be lower. Delays good commujnication, is an additional 4) is included because of the increasing can be neutralised, for example, by ac- factor in determining the success of a awareness of the interaction between the ecological process and dredging ac- celeratlngcertain activitiesor by using project. Whatever the legal and con- tivities. Examples for predicting and additional equipment--measures that tractualrelationships between the par- are dlitlcult, if not impossible, to use in ties involved, the organisation on the controlling these environmental im- construction of bored tllnnels. site must be direct and open. All main pacts are given. This chapter does not deal with all As the constructionoflrnrnersed tube parties involved should have access to tunnels has increased considerably relevant information and should have relevant construction techniques. Watertightness and structural aspects, worldwide, the Dumber of parties in- input in the decision-making process. for eTample, are covered in other chap- volved in such construction has in- When the guidelines described in ters of the report (see Chapters 2 and 4, creased proportionally. For those in- this chapter are properly followed,the volved for the first time on such projects, result should be a successfuloperation respectively). the specific implications of this technol- for all parties involved, resulting in No judgment of the various tech- ogy may pose difficulties. This situation few, ff any, cost and time overruns. uiques has been made, because such can lead to an increased risk of acci- judgments are beyond the scope of this dents, delays and cost over~m~ 1. Introduction report. Construction techniques can be judged only when all conditions, This chapter snmmarises many key The construction of immersed tube aspects of immersed tube tnnnel tech- criteria, and requirements for the spe- tunnels is arguably one of the most ciilc project are known. A stated pref- nology. An integrated design and con- fascinating civil engineering achieve- erence for a specific technique may struction process is essential to the ments, because of the wide variety of lead to the wrong conclusion for a par- success ofthe project,as is the involve- construction techniques that are used ticular project. ment of experienced and capable staff. and the many challenges posed by ex- The construction techniques are ternal conditions. very much influenced by the specific The construction of concrete or steel 2. Characteristics and Types of environmental conditions and require- tunnel elements of high quality and Immersed Tube Tunnels ments of the project. This means that accuracy, the necessity for" precise 2.1 Concrete Tunnels great care must be given to the investi- dredging, the preparation of the foun- The two basic types of immArsed gations and survey of environm~.ntal dation, and a number of sophisticated tube tunnels are concrete tunnels and conditions, e.g., hydraulic conditions, marine operations for placing the tun- steel tunnels. weather conditions and geetechnlcal he1 elements require professional en- Concrete immersed tube ~unels conditions. Often the effects of these gineering skills and experience, as well have their roots in Europe. More than conditions are interrelated and, thus, as sophisticated equipment. The con- half a century ago, the first European decisive for beth the construction meth- struction techniques selected often immersed tube tunnel was built in ods and the design. have an important effect on the design The dredging and backtilllng of a of the tunnel. Rotterdam (The Netherlands). Since then, the construction methods have trench constitute an essential part of Within the scope of the report by the considerably been simplified and the construction oflmmersed tube tun- International ~1~mnelling Association' s optlmi~d. Today, about three dozen nels. The effects of this work on the Working Group on Immersed and Float- concrete tunnels have been built all environment may temporarily change ing Tunnels, this chapter covers the over the world. The majority of con- the ecological and biological conditions various construction techniques related crete immersed tube tnnnels have been on the site, or even elsewhere. These to the different types oflmmersod tube built in Europe, and half of those in effects can be positive or negative. In tunnels. The various conditions that The Netherlands. any case, the impact ofthis activity can may be encountered, and the various The muin principle of a concrete be controlled by proper preparations options available to deal with these Jmmerse~ tunnel is that the tunnel and an intelligent selection of dredging conditions, are discussed. No specific techniques, adapted to the circum- recommendations are made with re- elements are made of reinforced concrete, which serves for structural stances and criteria for the particular gard to the working methods to be project. On a nnmher ofrecent projects, selected under various circumstances, purposes as well as for ballast. Although most immersed t-nnels built the presumed contnmlnating effects of because every project is unique and no recently do not have a watertight dredging have resulted in the choice of general rules can be devised. membrane, older tunnels (as well as bored tnn nels---a decision that accepts For the engineering principal, this some more recent ones) typically used higher risks in time and cost overruns. chapter offers an overview of the prob- a watertight membrane of steel or So-called unforeseen conditions lems that may have to be faced and, asphalt bitumen. have caused delays and cost overruns therefore, must be considered on such Most completed concrete tunnel el- in a number of recent immersed tube a project. For those who have some ements consist of a number of seg- tunnel projects. Could these have been experience and know-how, the chapter ments, limited in length to approxi- foreseen and properly implemented may serve as a checkllat for imma,~ed mately 20-25 m, llnkad by during the design and construction of construction. together bmnel flexible joints. Because each segment the projects (a process which, as noted The material herein covers the main is a structural entity, it is easier to above, relies on the skills, experience techniques that have been used to date control the concrete placement and to and know-how of professionals in the on immersed tube . limit the structural forces in the ele- field)? The answer would depend on Construction of tunnels that depend ments. A few concrete t~mnels have the collection of required data and, upon the principle of ~floating~ (see stiff tunnel elements. above all, proper judgement andimple- Chapter 6) can be dealt with in mere or

144 ~r.Lmo ASD UND~.P~aOU~ SPACE T~mNOLOOY Volume 8, Number 2, 1993 2.2 Steel Tunnels tedmiqnss willlead to overall improv~ ]ic conditlcms alreadyis av-ilgb~e. Long- The first steel bmnels were built in monte in optimi-~ag the~ term information (i.e., data collected North America at the beginnln~ of the The remainder of this chapter com- over a period of five to ten years) is twentieth century. Steel bmnels are pares some specific differences in the desirable because the more that is designed as a composite structure with various aspects of steel and concrete known, the less likely that unforeseen steel and concrete. The steel serves as solutions. events will occur. a watertight membrane and makes a In additien, considerable experience significant structural contribution. 2.4 Floating Tunnels and skfllis required to lmow what infor- mation is critical or vital, what informa- The concrete is used primarily to take Thus far, no floating (a,nnels have compreSsion forces and as ballast, and tion is important, what informatic~ been constructed, although a number could be of ur~ and how to deal with also contributes to the structural of StUdieS for such ~lnneba have been requiremente. the information. 'I'he answer to the reported. As noted above, this chapter latter question will depend upon the Thecomplstedbmnelelamentsform does not deal with the construction a monolithic structure that has some specific requirements ofthe project. For details of projects not yet executed. mmmnle,transportin~ a(amnelehment flexibility, thankato the elastic charac- However, based on the floating ~mnel teristics of steel. Thirty-three steel over sea requires a different approach projects being stUdied, it can be re- from tranaporting an element over in- tm~e]s have been built all over the ported that the main marine construc- world, but mai,ly in North America. land waterways. Th__e;mmA~g of ele- tion techniques are much the same as mentsin a river can be entirely different those for existing imm,msed t,--ds. from immm~ag them in a canal. Tidal 2.3 Comparison of Concrete and Steel For floatlng tamnels, the dredging influe~es may create not only opportu- Tunnel Techniques process is replaced by the anchoring of nities, but hazards as well the floating t~mnel, which involves en- Until recently, the concrete and the The engineer also has to have a tirely different assumptions regarding steel options were considered to be fe~lln5 for the behaviour of the river, buoyancy. Data collection and judg- different worlds, divided by the canal, or sea strait during the execu- Atlan- ment of environmental impacts, execu- tic Ocean. Only receatly have the two tion oftheworlr What will bethe effect tion techniques, etc., are comparable to of the trench? Willit cause sedimenta- techniques competed on the same those for normal imrn~sed talnnall~. projects and compared properly. Such a tion; will it collect bottom transport? Readsrs arereferredto Chapter 6, which comparison must take into account all What will be the effect of the shape of incorporates various data and tech- the trench? Willit cause a decrease in oftheir aspects. Without being exhaus- nique8 regardln~ floating tamnela. tive, a few comparative notes are given current velocity? below. The level of detail of the informa- In addition to the different tech- 3. External Aspects and tion can also reflect the View~ of the niques used to construct the elements, Conditions Affecting the contractor about the methodology and the marine techniques for concrete and Construction Methods equipment to be used. In general, it is steel tunnels require different ap- 3.1. Introduction and Set-up wise to design the work;-~ method and proaches. These differences are re- the equipment use to allow for some lated to the principleS of the different External aspects and environmen- extra capacity, should unforeseen cir- materials, as well as to the contractors' tal conditions are factors of major im- cumstances demand it. techniques, which have developed in- pertance for the design end construc- Problems with tnnnel projects dependently of one other in the differ- tion of an immersed ~lnneL AB such, in the past have often resulted f~om ent environments. they must be known in detail in order ins-m cient inform ~tion,judged by Each application has a different to understand what conditions can oc- ,naktlled personnel impact on the time schedule, the con- cur. Moreover, these conditions must Too often we have been faced with struction of the approach ramps, the be monitored and predicted through- the remark that unforeseen conditions casting yard and/or fabrication yard, out the various phases ofthe execution occurred that cost the client and/or the etc. Time, for example, is of critical of the project, in order to avoid unfor~ contractor large ~,mq of money. In importance for privately financed seen and nasty situations. many cases, these ~nforeesen condi- projects. It may even result in the It is therefore essential to collect tions ~ could have been avoided by in- acceptance of higher direct costs. and properly~udge the data available, volving skilled spe~M;_~ in evaluat- With regard to cost, it cannot simply and to be sure that these data will be ing the conditions at an early stage of be said that concrete is more costly registered and reported as the project the project. .~ than steel. For a~r~mple, because proceeds. Dependlngupon the specific The following section t-,mma~ess environmental requirements may conditions, these data can have an im- marine conditions that influence the increase the cost of a specially pact on the methodology; and, in many construction to~hnlques and~ subse- constructed cas~n~ yard for concrete cases, may be decisive for the method, quently, the design of the project. Al- b mnelelenlents, a steel tam nel solution equipment, and timing of the various though this summary may be used as a maybe choson ~d. The immereed activities. basic che~kllat, specific site conditions part of a steel t~lnnel may be longer An ~mple ofa schemeincorporat- must always be kept in mind. than that of a concrete t~m-al, thus ing proper data collection and report- shortening the /n-s/tu approach ing is shown in Figure 3-1. 3.2.2 Current--velocity end ramps--a factor that may influence directions the overall comparison. 3.2 Hydraulic Aspects Currents significantlyinfluence the The roasons for the differencesin the 3.2.1 Data collection end selection of the towing and construc- American and European approaches methodology tion technique for ;mm~,sing the ele- have their roots in scientific and politi- The collection of data depends upon ments. The tamnel element to be towed cal development~ However, in general, and ;m,,~-~.~l is exposed to the cur- history h~ preven that the end results- the local c(mditions, the specificrequh~- meats of the project, and the informa- rent. To maintain control ofthe bm nel in terms ofquality, watert~htnese, life- elennmt, the tow capacity and immp~s- time, reliability, m~inten~nce, etc.-- tion available. Manylmm,n~edt~mn~lq are built in areas where considerable ing equipment and provisions in the does not d2_~f~er. Only the futu~ will tell element must take into account the whethe~ a combination of the ~iat;n~ infmm~ation about the specific hydrau-

Volume 8, Number 2, 1993 Ttn~r~Lwo~vU~WDSPA~T~m~ 146 data collection check process report

hydraulic > site 1 dock _ waves _ current check > site 2 trench _ densify

_ etc. dual I [ > other sites central computer > dredging meteorological system ~> immersing _ pressure

_ wind > towing _ rain check

_ temperature > etc.

_ visibility _ etc. > shipping

from > storage

station 1 station 2 check station 3 etc.

Figure 3-1. ~cheme for data co/~ect/on prior to and during a marine operation. forcos resulting from the correct. These me~t more than 120 m long will re- ciple of buoyancy, it is important to forces are: quire ~l~al procedures. know the specific gravity precisely. • The outcome of the current The directions of the current are However, the specific gravity can velocity. also important considezation& A tun- r han~e over time with regard to placo, • The ~hape and size of the t~mnel nel befit in a tidal area offers opportu- depth, scale--ration, and tempera- element. nities to make use of tldal effects dur- lure. Because it is not always possible ing ~---port. However, during the to be entirely sure about these varia- • The width, depth and shape of ~ f~n the tnmap~ ~h-~ to tions, a marsin of error for must be the rive: or current-atfectsd area. the ~mm~zi'w~ alld oth~ man~l.Ve~, a aszeed upon in advance. In the past, these forces were-- very precise and good prediction ofthe P,ega~na time aspects, it should and, in many easco, still ar~--predicted current behaviour is~ In many be noted that seasoul variatio~ in the by tests performed in hydraulic csmm, it is advisable to set up a system specific gravity may occur. This varia- laboratories. that meammm the current velocity A~a tion may resu~ h~n ~ in tsm- If the conditions at hand are not too registers the current directions during perature, as well as from se~,~nta- dflferent f~om throe encountered in the the mJ_,~ne operations. lion, which may vary by seaso~ pas~ the forces can be e~/m-ted based in ~ we~t for upon previous eaper~mco, and test r~ 3.2.3 Specific gravity freah water versus salt water may be suits can be compared with real infor- The h,mAl~n~ of huge t,mnA! ele- critical with re~Be~ to placement of mation available from past project& ments is very often controlled by the the elementa This aspoct, of ~au-se, Current veloclty and available space availability and use oflocal equipment depends on whether the t~m-el is for maneuvering are often llmi*in~ fac- and know-how. ~mnel elements located at or cime to the ma cr inland. tors for the length ofb,,~-~ elements. ~weq~. tnwre than 48,000 tons have However, the water inland is not ~,...; .l..-,..ts 280 mleng have been and tr~ for ~r- neemur~ frm& The heavier ealt ~m-,-~ed in c=-I~- where there is al- laon at a dimmt lo~tion---a procedure water may go inknd, _a,~-~ upon n~tnocur,~ ~hastau~ht that cma be accomplished only by m*~- the local ~, the ~-~ of that tam n~I e~l~lnlmts are llmltegl to 140 i~ use of tl~ buoyu=y caused by the water o~m~n~ ~ ~i.n~, the water m when current velocities are as high water. level at ua, etc. All of thme matte~ as 1,6 m/sec. Hisher current velocities, Because the dwign of an immm-md e.g., greater than 2 m/sec., have been bm~el is directly related to the prin- ~ie~leond/t/onL Itmaybeadvisable-- dealt with successfully. A t~mnel ele- and, in mine cams, ~s~t/sl--to ]mow

146 Tum~.T.mo AND U~I~aOUNV SP,,.c~ ~OLO~ Volume 8, Number 2, 1993 the relationship between the waves and/or suction from passing 3.2.70Uler fiver and/or sea meteorological and hydraulic ships can have an enormous effect on oharaclBrlMi~ and ob~aoles conditions. the forces on the ~,nnel elements. In the desilpl and pinnning of an The specific gravity will vary over immersed tube bmn~i, the ran-round- the wator depth se well. This var/ation 3.2.6 Sedimentation h~ra.~ ¢o.~t~ m~t be in- can be caused by a n-tuber of factors. vestigstsd ¢arofu]ly. Not all condi- For ~nmple, the water temperature Most rivers pese specific problems with regard to sedimentation, silt, tions have been mentioned horein, and can vary over the depth of the water each sits may present anoth~ sur- body--e.g., the heavier salt water will mudflows, and/or transport of mate- rial over the bottom. These conditions prise. This report touches on only be near the bottom, while the fresh can affect the maintenance of the e~eptional situstians, such as those water will be at the surface. A compll- trench, the quality of the foundation, involving ice(bergs), seaweed, and cated system of current~velocity and and the quality and ce,A-tity of the nh~all~.,h (or other fish). ~ condi- direction also may be caused by these l~nA~t system to be inst~ed. tions may i,¢1,,~,~ the location meth- in spee~ we~h~ Experience has shown that sedi- ods during the im,,~,,'sins operations. Thus far, specific gravities r~noing mentation is different for every fiver, Other unforeseen conditions also from 0,9850 to 1.003 have been experi- and depends entirely upon the local may occur. For example, obstacles--- enced on various projects in different such as wrecks--at the location where locations; or on the same project, with situation. These aspects have to be considered in advance. When this is the trench is to be dredged present an variations occurring over time. done and possible outcomes are known, additional sedlm~tation need not be a problem, 3.2.4 Tidal effects if proper precautions have been taken 3.2.8 Hydraulic models The influence that tidal effects can withregsrdts, e.g., d~-;-~the trench In order to invest~ats and deter- have on the current velocity has been and the system for plating the final mln~ the effects ofthe hydraulic condi- noted above. Tidal effects also cause foundation. tions on the censtruetion methedology, differences in water height. These Five main causes of sedlrrmntation hydraulic tests performed in a labora- effects can influence the choice and/or are given below. In many cases, a tory will provide comfiderableinforma- the design of the casting yards. In n.mhor of individual aspects alone or tien (see Fie. 3-2). In the meantime, addition, both the transport of ele- together influence the sedlm,~utation. m*ny tests have been performed by a ments over waterways and the im- 1. A sudden decrease in the llm~ted n-tuber d q-mHRew:l,laborato- mersing process are influenced by the current-velocity in the trench may zies. The results of these tsst~ can be height of the water. The length of the cause sedimentation of the materials used to estimate the forces acting on immersed section is influenced by the beingtransported by the fastor-flowing the t~mn~l element and to forecast the tide and by the water levels. water. behaviour of the t~-~l element in the Thore may be an optimum period of 2. Sediment suspended in fresh specific conditions of the given sits, tidal ~, ranging from spring water, when ,~d with salt water, emm without perfocs~-m teats. to neap tide. At spring tide, the water will flo~alats aud mgtle on the bettom, ~ the ¢vastmetm of tom~ can reach its maxinmm height (and formln~ a thin mud layer. As subse- in the lamt, the data remdt;ug fi~m the m;n;,m,m height as well), whereas at quent tides deposit more layers on top hydra.l~ med~ tsm and the thm~- neap tide the current velocity will be of it, consolidation may occur as a re- cal ~ have hem ¢mnpszvd with lower. Theseph~ mayresultin sult ofdeveloping wsight-premm~. The the real dat~ ~ese mmpari~ have categorizing a number of days as sy~z for amt freq~cy of trench the q~,~ty of the ~- presenting the best, or required, cleanin~ may need to be adapted, de- not only regar&~nz the ;m~ circ,,m~t-~n~es for the marine opera- pending on the rats of the se*llm~nnta- of the elammt~ but also ¢o-~-;-~the tions. These periods are called the tion and consefidatio~ as well as the oondltio~that will be enmtmtsred dur- "tidal windows'. n.ml~- of tides to which the dredged ~ the tow~ of the faunal e~entL tre-ch is effipo~l. The forces of the water on a ~n-el Waves, roll and surf 3. In a waterway characterised by are given by the formula: In many cases, h, nnels are built in high flows and high currents, ezisting F - 1/2 "A'r "V2" Cd relat/vely protected areas, where the materials may be carried by bottom waves have very little effect on the transport This material will settle where tunnel elements. In such cases, only readily in dredged t~ache~ AIS the exposed surface of the element pea-pendlcul~ to the the effect of waves going over the tun- 4. Under certain cenditians, the ac- nsl ~-~t daring the towing and current. tivL~_'_~_ for the project or in the envi- ris the specific gravity of the im~'~ operations may need be rons of the project can increase the taken into _~:~unt. However, under sedlm,mt.~tlon. For ~mple, placing water. relatively effipo~d ¢onditio~ o~e, Vie the rdative vdocity, i.e., the the foundation underneath the b,-~el d~eran~ ~ the speed the effect of waves and swell san be of may affect the concantratian of comdderable im~ to the trane- psnded sedlnmntinthermn-inln~part of the ~ andtha water. port and ~ operation: =ud, CA is the frk~_'_~_ ~t (drag- oftha tren~ sing ~r~ient). consequently, ts tbe desiga itself. For 5. In gsnernl, the occurrence of izu~m~wwioutfatk, the su_-fwillhaveto mudflows and se~tatien in rivers This frictian ~ factor dif- be taken into considerati~ as well can be foreseen, although the q~,atlty fers with tim cire,~-t~ of the sps- Anothor aspectthat m~t be coz,,dd- and the quantity of this material is (~f~ i~r~ect~ It is affetCed by the tbape ored ~ the ~ of the tmmel ~ to predict. In this regard, the ofthe t---el element, the d~ape ofthe elomm~ itself in relation to the pos.. advice of specialists is important be- river and the layout of the trench, the fmquend~ of warm or swdl re- cauas these matters can be of major size of the ~ in tlm water-filled sult/ng fl~n wind, offshore cenditions, impm4m~e to the su___~ess ofthe execu- space, and the ~ factor of the and/at ~. Espscla~ when tion of the project, as well as the qual- ~ in tho rl~r. the t-,,n~l dmmmt is moored at an ity of the foundation. This ~is tho entvome oftbe outfitting quay in a vulnerable place, laboratory tests and will vary accord-

Vohtme 8, N, mhor 2, 1993 ~wwxmo~~SP~~ 147 ing to the location of the t-nnel ele- • Ice may m~ke it impossible to to be built in a busy harbour, because ment in the river. In past projects, work with the equipment, ropes, every (unforeseen) hour that the these values have been compared with etc. harbour is blocked has its price. reality, and the comparison has shown In connection with the hydraulic con- that the tests have yielded relatively In most cases, meteorologic data ditions,the possibilityof hydraulic "win- realistic outcomes. To demonstrate collection is no problem. Long-term dows ~ should be noted. Hydraulic win- how important this factor can be, it data on weather conditions have been dows represent the period of time dur- should be noted that Cd values ranging collected and are available in most parts ing which conditions are acceptable for from 0,75 to 5,2 have been recorded on of the world where the construction of the towing and immersing operations. one project. The latter value resulted ;mm~d t--nels is being considered. The same principle applies to weather in a decision to completely alter the In many (although not all) of these "windows ~, i.e., the period during which operation in order to avoid these high locations, the influence of the weather weather conditions are acceptable for forces. This aspect concerns the trans- conditions on the hydraulic behaviour pefform;n~ the towing and Jmmersi'nz, port oftimnel elements, as well as the is known or can be known, when skilled In practice, consideration of both types immersing procedure. specialists investigate and compare the of windows is required. data on weather conditions with the hydraulic conditions. When these data 3.3. Meteorological Aspects are not known, additional survey work 3.3.2 Wlnd 3.3.1 Data collection and will be required. As mentioned above, wind can have methodology During the operations, it is neces- a strong influence on the hydraulic sary to be well-informed as far in ad- behaviour as well as on the operations, Because they normally affect ma- vance as possible about the conditions dependin Z upon the equipment used. rine conditions, weather conditions that are occurring as the operations Wind also has a positive effect on must be taken into account. Weather proceed. The sensitivity of the mA~ine v~b~ty. conditions also can have an important operation methods and the eventual direct effect on the mArj~ae operations. risks related to a delay and/or sudden For eYAmple: 3.3.3 Temperature postponement of the immersing may * Too much wind may be risky dur- The temperature can be a problem even justify setting up a weather fore- when it falls below a critical point in ing the immersing. casting station at the site. Such a • Alack of visibility may frustrate relation to h-m;dity, thereby causing solution might be worth the invest~ poor visibility. When frost occurs in the location methodology of the ment, for example, when a t, mnel has operations. conjunction with the low temperature

Figure 3-2. Testing a model of a tunnel element in a hydraulic laboratory.

148 Tum~.,.~o AND UNDnme~UND SPACB T~a~OLO~'Y Volume 8, Number 2, 1993 ofthe water, ice may form on the equip The wori~-g methods fir dredging can be ~ with regard to the poe~- merit, anchor and mooring lines, creat- works on the trench can be adapted b/Utyofns~aea~-gya~L ing difli~tdties. through the use of, e.g., floating pipe- this ssldam win be a prob!m for steol linm, split or other bargse, and e~avat- bmnAia, ll~'ni precautions may have 3.3.4 Visibility ing eq~pmsn~ m~,~zod dredg~ to be taken for eon=ote t--neem. companies are quite capable of a--u.g Poor visibility, one of the most difl~- with the sps~ec project ~ts. cult and unpredictable situations, can 3.5 Soil Investiga#on frustrate the positio-ing systems. Al- During the +mm-rsing operation, 3.5.1 Data collection and though it is possible to use the systems shipping often must be halted for a methodology certain period. During transport, de- under poor visibility conditions, the A proper soil survey must provide cost of doing so may be very high com- pendinguponthe space available, ship- ping traffic may or may not have to be information about the soil conditions pared to the benefits. These costs de- that will be encountsred. These soil pond upon a nl~mher of factors, such as: stopped temporarily. Itis wiseto avoid all sudden movements in the water conditions may influence the bearing • The frequency of poor vim'bility. near the t-nnee elements while vital capacity ofthe soil. Because the tnnned • The number of t,'"nel elements activities are t~irlng place, such as: itself weighs less th, n the soil that is to be installecL being replaced by the t3m-el, the crite- • The risks and the results related • The eventual takeover ofthe tun- ria for the required soft conditions are to a delay or postponement of nel elements from the tugs to the not too strict~ m~,~ne operations for the project anchor lines; or The methodology to be used can itself. • More importantly, the moment best be defined by the institution ex- of placing the bmnel element • The economic effects of a sudden ecuting the survey. Questions to be agai-~t the previous element and answered will include the following: delay or postponement on the closing the joint. surrounding ares. * What is the geological history of Ifcomplets blockage ofshippingtraf- the area? 3.3.5 Other meteomloglcsl matters fic should be required, it can be lim;ted " What works that have been per- Although most of the vital meteoro- to a period of 12 hours or even less, formed in the area could affect logical consequences have been dealt depending upon the methodology used the soil conditions? with, other phenomena specific to the and the experience of the ;,-m~sing * Are there rock formations? site will have to be considered. It is contractor. A number of techniques are avail- In principle, the soil problems are always wise to talk to local sal]ors or not much different for imm~+~d tun- pilots about these matters. able for the foundation work. Some techniques may influence shipping, nees than for other civil engineering Local conditions also may influence construction activities. the accuracy of the positio-;-g system while others will not influence it at all. u~i, or Inay fl-uJstrats commtlnications, 3.5.2 Trench dredging This can be the case with high and 3.4.2 Suction caused by ships heavy steel structures or with high- Shipping movements can influence To determl-e the shape ofthe trench voltage electricity cables in the sur- the %.nnel elements as well. On a and the dredging methodology, tests rounding area. w,mher of occasions,ships passing over for slope stability should be performed. a t~mnee element have created a suc- Aiber deciding on the trench slopes, the additional effects of the current veloc- 3.4 Shipping~Navigation tion effect with the ¢,,mee elements. This phenomenon depends upon the ity in general and the specific condi- 3.4.1 Ship movements dudng size of the ships; the size of the t~-mee tions that will be encountered during medne sctivltles eel.meats; the navigation speed of the the immersing must be considered, Most immersed tube b~nnees are ship; and, most importantly, the space because a sudden slopefall during the built in waterways where there is heavy between the ship and the tunnel imme~-g operations c~--ot be fished. shipping. Hi-drances that the marine element. In addition, the stability of the founda- operations present to shipping move- The,~n~mum forcestJ~at have been tion and its material api-At currents ments, especially in busy shipping wa- measured are lifting forces up to 100 or tidal effects should be vedfied. terways, must be avoided or kept to a tons. If it is found that such high forces A proper survey of the mineral, or. mln;mllm Options for deal;- Z with could occur, they must be taken into gsnic and biological composition of the this situation depend upon the local account during the various phases of soil is required in order to select the conditions and requirements. the immersing. The possibility of such optimal dredging technology and to The marine operations that affect forces occurring will also affect the identify the effects that the dredging ship movements are the dredging ac- design criteria. process will have on the environment. tivities; the transport of the b,nnel Another phenomenon is the These effects can be negative as well as elements; the immersing; and, possi- that suctions and waves caused by ships positive. See Section 4 for a discussion bly, the foundation work and the back- can have on the t.~Innel element moored of dredging and its ecological effects on ~;lll.g. In the first design phase of the at a jetty. Under certain conditions the environment. t~,-nel, prior to the preparation of the related to the local situation, this a~._on tender deeuments, the shipping au- might increase the movements of the 3.5.3 Settlement thorities and the pilots must be con- t]mnee element in such a way that the It must be kept in m;nd that when sulted. This consultation should be anchor lines or mooring lines would the b,--el is placed in the existing done with the help of an ;reminding break, if such a situation has not been bottom, it replae~ a volume ofseil that spe~aliRt who is able to judge the influ- foreseen. However, such effects can be is much heavier than the t,,--el ele- ence ofthe requirements on the project est;m-ted. ments, with an overweight of approxi- poseibilities and the cos~ In reality, mateey 10~ of the weight of the soil and in most (if not all) eases, it is 3.4.3. Navigational depth and vohune. Depe~dlng upon the design possible to find an acceptable solution clearance requirements methodology regardi-~ the use of flex- for all parties involved at no or mini- ible joints or rigid constructions, some mA| COSt. The avnil-ble depth in the river used for the towing of the t~,nnel elements settlement is allowable. However, un-

Volume 8, Number 2, 1993 Tt~r~x.moJa~vUm~mov~SPacI~ 149 der very poor soil conditions,unaccept- The above are only a few alterna- the bottoms of canals and rivers. New able risk may occur. To resolve this fives. Here again, experience will fa- technical solutions are and will be avail- potential problem, a n, mher of tun- cilitate selection of the best option. In able for the future. A properjudgment nels have been placed on long piles. general, it can be said that steel tun- of the environmental results of these Except for the abovementioned ex- nels offer more options for overcoming techniques for the specific site condi- tremely poor conditions, geotechnical environmental limitations. This ~]ex- tions is important. Part of the effort conditions rarely, if ever, cause settle- ibility may compensate for accepting focused on the results of dredging con- ments. However, settlements do occur the higher costs of steelt~,n-els versus cerns not only creation of the trench during the ballasting and bacl~lllng of concrete t, mnels. On the other hand, and bacl~lllng, but also control of the the t.~mnel elements. This settlement the longer transport routes are no prob- environmental effects. is caused by compaction of the founda- lem for either of the options, provided Experience has shown that the tion layer (discussed in more detail in that the water depth is sufficient. More dredging process for a t-nnel has only Section 5.6). The setUement might aspects related to the fabrication site a temporary impact on the environ- also be caused by the effects of the are discussed in Section 5, deMing with ment. The environmental conditions dredging and cleanln~ of the trench the construction of t~nnel elements. are greatly influenced by seasonal ef- (see Section 4 and Section 5.6.5 for fects, which oiten are greater than the further discussion). 4. Dredging and Related effects of dredging. Ecological and Environmental To overcome the resistance of inter- 3.6 Seismic Aspects ested parties (e.g., fishermen and envi- Impacts ronmentalists), it may be possible to The structure of both steel and 4.1 General Matters combine the construction of a t~mnel concrete tnnnels allows for seismic with measures to improve the ecologi- movements. Dredging will affect the environ- ment at the site. There has been some cal cirolmRtances, e.g., by: With regard to the execution meth- • CleAnlng the bottom of the canal odology, if fluidisation of the founda- misunderstanding about the degree of disturbance of local conditions, due to or river. tion underneath the t~nnel element • Placing layers of stones on top of occurs, it will cause upli~. However, ff a misunderstanding of the options for the dredging process. The degree to the tl~nnel. When this action is a sand foundation is used and if the taken, measures for protecting work is well executed, the characteris- which this process will affect the site depends upon the local environmaut, the t~nnel can be combined with tics of the sand will prevent liquefac- measures to improve the environ- tion from occurring. In some soft characteristics, dredging tech- cases, niqnes and equipment used, and bud- ment, allowing for the develop- cllnk~r is added to the sand under- get available to mlnlm/Ae environmen- msnt of new biological activities. neath the t~ln nel in order to strengthen • Inst~ 11~ng air i~oction equipment the structure of the foundation. tal impacts. In the past, there has been a lack of in the t~m nel to improve the qual- awareness, know-how and vision con- ity of the water flowing over the 3. 7. Fabrication Sites cerning ways of dealing with dredging. t~mnel, aRer the l~mnel has been The construction sites for the vari- In some cases, severe restrictions have Rni~hed. ous techniques are ~,mmA,~din Sec- been imposed without knowledge of tion 5, which deals with the construc- their effects on the specific site condi- 4.2 Geotechnical, Hydraulic and tion of the b,--el elements. However, tions. The result has been high costs to Environmental Conditions the choice of fabrication site not only the principal, often without achieving depends upon the construction meth- a proper solution to the problem. Occa- The following data are required for odology, but is also very much influ- sionally, concerns about dredging have a proper judgment of enviranmental enced by environmental restrictions. resulted in a bored t~mnel rather than effects related to the advised or pro- The restrictions noted below should be an immersed t-nnel---a choice that in- posed dredging methodology. kept in mind in selecting a site in volves higher risks for the principal. Regarding the soil in the trench: relation to the systen~ The approach required for suocess- * Mineralogical composition. The There may be restrictions in obtain- ful dredging comprises the following nature and extent of turbidity ing port--ion to install a casting yard steps: differs for different ml-erals and with a dewatering system. Because i. Investigatethe geotechnical and the absorption of the contami- such an arrangement may affect the enviro-mAutal quality of the soil. nants of the mineral. environment, it can be rejected. Should 2. Investigate the hydraulic condi- • Granular composition. Coarse thin be the case, it may be possible to tions of the river, CanAl or sea. particles are less susceptible to make a casting yard for all t.~mn,~l ele- 3. Investigate the various options resnspension than fine particles. ments without the need for dewater- for dredging technology and the affects The occurrence of CODt~m;nJntS ing. Although such a solution neces- of thi~ technology under these specific is greater in fine fractions be- increases the cost considerably, sarily ciro, m~nces. cause of the greater specific area it can be competitive, especially if the and loading differences for clay site can he used more than once. 4. Specify criteria for the dredging mineral particles at the molecu- Another solution might be the con- process, based upon the requirements lar level. struction ofa 8mAllm"yard fur jnst one for the environmAntal and ecological effects and the requirements for the • Density and the existence of stiff or two elements. While this solution material, which interacts with construction of the ~m-eL might decrease the cost of the casting the dredging metho~ 5. Check the propoasls ofthe dredg- yard, itwill increase the thne required • Consistency of the soil related to ing firms on the criteriaspecified. for the construction of the t~,nnel ele- strength, cohesion, viscosity, and ments and, therefore, the ovorall cost Major dredging firms have invested degree of commlidation. as well. Additionally, the fabrication considerable amounts of money in de- • The nature and degree of con- process will have to be interrupted. veloping solutions to deal with the eco- tamination. Another option is to construct the logical and enviren~ntal effects of tunnel element(s) in the entrance • The suspension of organic mat- the dredgingprocess. Many t~'hnt"_'Ues ter, which depends upon the con- ramps. However, this may only be have been developed to avoid polluting possible for very short t.~mnels. tent of the organic matter.

150 Tt~.7.mo AND U~D~ SP~ TeCHSOLOOY Volume 8, Number 2, 1993 * The chemical nature end gas cen- In addition, the trench bottom must be impact, the soil conditions, the ship tent of o~rse rubbish. dean before the bmnel element can be pi~ in tha area, etc. . Other data, as needed. phu~. Th~ r~p~em~t ne~__'_tates For the e~avatiou, known toch- additional care in the dredging of the niqu~-e.g., those involving a butut With regard to the hydrodynamic deepest ~t oftha t~h, a~lin~- dredger, a mttor or suct/m dn~l~er, or conditions: ing the trench to avoid ~ntatlon a sreb ~ S~i l~=.a~ti~ In . Thenatureandextentoftheflow, and consolidation of Sedlm~"t in the addition to the critoria listed in Sectim~ dispersion and suspension be- trench. 4.3, snd ecououfic facto~ t~ mlection haviour. The norm~l tolerances for the bot- of ezcav~tion techniques depends upon • Wave effects. tom ofthe trench are +15 cm. Because the envirmunentel requirements. * Flows resulting from wind. there is a mln~m~]~ requirement re- A cutter dredger stirs the mate. * Water depth. lated to the space underneath the tun- r/al te be di~d (see 1~. 3a). ~, • Silt and bottom transport. hal el~ent, a tolerance l~ween +0 process can have a negative effect on • Other data, as needed. and -30 an is required. tbe envlroument` Howevor, it invelves closed vor~cal and, ev~tual~, hori- Regarding water quality: 4.4 Evaluation of ~e Dredging zontal tr~n,,nport, when a floating pipe • Density variations, which in- Process.-- Technical Options is us~. Althou~ stirring will not fluence the sedimentation of cause problmmmwith dean, coarse ma- material. To properly evaluate the dredging terial, it may be a disadvantage when process, the various activities that . Aerobic or anaerobic state of the slightly cohesive materials are present. must take place prior to and after the layers. This condition has an Incentrast, a bucket dredger does important impact. placing of tunnel elements are not stir the mfl very much. However, identified below. theve~_caltransportofthe d~dgvr, in • Temperature, as it relates to vis- The m~lHng of the trench involves cosity and density. addition to the ov~w resulting from the following phases: d,,mping the sellin barges for the hori- In order to be able to predict the I. The cutting and excavating of zontal transport, may catlse cont.,,ml- effects of the project on the ecology at the soil. nation- This _~-h~que dees not present the site, the details of the ecological 2. The vertical transport of the a problem for cohesive and ~L-Se ma- and biological processes t~Irl- S place material. terials; howev~, it could be a disad- must be know~ This information is 3. The horizontal transport of the vantage when seit and cohesive mate- not limited to the site, but also includes material. hal is present. other areas affocted by the activities at 4. The depositl-~ of the material. A ~d~ ¢m'mne immmmte muah the the site. Thus, an inventory of the same envln~,M-*~.! ~v~te~m as ecological process has to be made in In principle, the mainte~_~-es and a b-_ck~ dredger, although the problem close cooperation with biologists aware baclrRllJ~ of the trench follow the same ten be pertly selved by udag a dosed of these local conditions. sequence, although the material and grab. The,,,-~- disadventa~ of a grab Below is a ~mm~y' of the ecologi- the related dredging techniques may is the uneven bottom that results. Be- cal conditions that should be know~ be different. cause this situatleninflmmces the foun- Physical conditions: The t~h~ical options for these ac- dation, the use of a grab crane may tivities numea-mas. • Tempera~re. are The t~.hnlque require additional precautions. selected has to take into consideration The effects of each of thcee tech- • Light int~Judty and penetration. the requirements specified above or niques are very dependent upon the • Sediment characteristics. elsewhere in this chapter. These re- condition and characteris~__'~ ofthe soil • Sheltering areas and/or hiding quirements are related to the struc- andthe 1o~i hyd~ulic cendltimxs Sl~/- place~. ture of the t-~nel, the envlre~v,~utal fied above. In lese- or non-cohesive fine • Currents and wave energy. Chemical conditions:

• Oxygen concentration. • Nutrients. • Toxic substances. • Flocculation. Biological conditions: • Food relationships. • Accompanying species.

4.3 Criteria Related to the Trench The trench serves a special purpose with regard to the placing of/~'""al elements and the foundation under- neath. Some requirements are related to the shape of the trench~for ex- ample, the trench being dredged must be ~tly wide and deep, with stable elopes. The bottom of the trench should be relatively fiat, Too much difference in ~:i:i:~:~i:~!~i~;i:~.i:i:!:~:i:~:i:!:~!i!~i! ii!;:'i:!;~: ':::'-' ?i'"!':~ /i! ;ii!.:i~:::::;ii:.!!V;~:~':!i'iii!i!ii:i~!~iiiiiii!~::ili:!:':!i':!~::!':'ii"i:!:'::i: '::': :7 :: :~: :: : IL:. i! depth underneath the t~mnel element will increase the cost of the foundation F~gre 3-3. Scheme showing the principle of turbidigy generation around a and may cause differential settlement. cutter suction dredger with 50, 100, and 250 mg/ l concentration of suspended solids.

Volume 8, Number 2, 1993 Tv~mrz.woAm>~SPAcZT~mN~o~ 151 materials,contamln~tionwillbe great, • The accuracy and selectivity of which deals with stxcctural design of The use of a dustpan dredger, with an dredging for the various layers. these bmnels. Therefore, this section entirely closed transport system for • Use of modifications to limit the briefly 811mmav~Jes the n~in aBpectBof the removal of this layer,may prove to turbidity. the construction methodology of these be the best wayto avoid negative envi- • The awareness and quality of techniques. ronmental impacts. the staffinvolved in the prepa- In reality, a numher ofdifferent tech- rations and the operation of the 5.1.2 Steel option uiques will have to be used in ecologi. dredging process. cally sensitive areas, because of the Steel shell tnnnels are composed of a structural steel shell lining, which chin ~ag charactedst~ ofthe soil. New 4.5 Selecting the optimsl solutions techniques, such as the use of an forms a composite structure with the envi- A number of environmental, eco- disc bottom cutterhead, concrete and also serves as ballast to ronmental nomic and technical aspects influenc- w~mwheel or auger suction dredger, the structure. A n-tuber of different ing the choice of techniques have been have been developed to avoid the disad- construction methods and sequences discussed above. However, optlmlaing can be used with the steel option. vantages ofthe options described above. the choice in terms of effects and cost To begin with, all or part ofthe steel For horizontal transport of the involves careRdly weighing the vari- shell is cons~. Some keel con- material, the main options are the use ous options. This process is influenced of a closed circuit with pipelines, or the crete may be added to the structure to by proper judgment of the ecological increase its stability and rigidity. Sub- use of barges. Shipping near the site, effects of the dredging operation on the sequently the steel structure can be in relation to the available space at the general characteristics of the specific put afloat and the remaining part of site, has an important influence on the body of water. the structure can be installed afloat. choice oftransport technique. Although pipelines will avoid con-tsmlnation In a canal or river where there is This construction technique allows around the line, the overflow from the little, if any, real biological or ecologi- for the use of a shipyard, shipways, cal activity, the conditions will not shiplii~s, dry docks and/or a temporary depot could cause a problem that would worsen as a result of dredging. In fact, construction basin. The tubes can be require additional precautions. If barges are used, the local conditions can be improved launched sideways or end-launched. contamination through the removal of polluted soil. This guided launching must be con- caused by the overflow and at the Many rivers have a regime that is trolled by using properly levelled guided dumpsite has to be taken into affected by the seasonal cycles. In these structures (winches and jacks, chains, consideration. cycles, heavy rainfall or the influx of A number of systems have been de- etc.). melting water may cause mere siltation veloped for cleaning the trench. Nor- AROr the tunnel element has been mally a dustpan dredger is used. This andcont~m/n~tionthandoesthe dredg- put afloat, it is towed to an outfitt/n~ ing Ofa trench. The self-hemlin~ effects is a suction dredger with a special type jetty for the finlahln~ ofthe steel struc- in mest rivors are enormotm, oftea -limi - if required; and the placing of all, of opening at the end of the pipe that ture, ree~mhles the head ofa Hoover vacunm= aating the effects of the dredging work or the remaining part, of the concrete. within one or a few seasons. The execu- The dredger is moved over the bottem In addition, specificrequirements for tion ofdredging activities can be planned ofthe trench at intervals defined by the the mav~.ne operation- r.uch as tem- quantity of sedimentation and the risk to work in harmony with beth these poraryl~Ikheads,joint structures, and seasonal effects and the cycles of bio- of consolidation. It is not possible to access sha.fl,s---~e installed. logical activities. clean the trench underneath an al- Additional ballast--concrete and/or ready immersed tunnel element be- In cases involving a sensitive area gravel--is placed on the tubes prior to immersing. cause of the characteristics of the silt. nearby (e.g., oyster beds, lobster nurs- eries, etc.), it is oRen possible to benefit If there is any concern that this space The design of the tubes willhave to may fill up with silt, special precau- from the current, which can be nsed te be adapted to the fabrication method- direct the siltation caused by dredging tions willbe required, depending upon ology and sequence. However, the de- away from the sensitive area. sign must allow for some flexibility in the foundation methods used. An accurate description oft_hhedrodg- order to optlmlae the construction in For baekRlling of the trench, sev- ing works to be executed and a proper relation to the fabrication capabilities. eral options are available as well. The type of material used is of crucial im- definition of the dredging limitatiOns portance. Clean, coarse material will in place and time, coupled with ad- 5.1.3 Concrete option equate eacecution, not cause any contamination, regard- controlduring should Smaller concrete croes-ssetioas can less of the technique used. A spreader suffice to limit the environmantsl ef- be launched or built on a shiplif¢, or a diffuser will limit the exchange of fects of the dredging operations, beth shipways, or other structure. This pro- in immediate project area and in material with the water in the river. the cess is more d;m~ult for bigger cross- the surrounding areas. Other possibilities for ilmJtln~ con- sections, for which existing docks and The poesibility that the construe- e~cavatod casting yards normally are tamination include the use of silt tion of the t~mnA1 will permanently screens, or sedim~nt~ation basins to hold used. change the hydraulic circumstances, the overflows of the deposits. in terms of the cross-section of the The following additional dredging- 5.2 Finishing Jstty related aspects may influence the im- river, must be taken into consideration. These effects could result in compensa- Tho criteria for these doeks are dic- pact of the dredging process on the tion elsewhere. environment: tared by the draught of the bin,,! el~ ment~ For eonc~m tunnA] elo~e~ts, • The production level and/or the 5. Available Techniques for the depth of the ce~ging doeJg ehould be capacity of the dredger. Construction, Immersion and equal to the height of tnnn,d elements • The technical conditions of the Foundation of Tunnel Elements below low water. If this is a problem dredger. because of the pemibfliti~ related to • The reliability of the methodol- 5.1 Construction of Tunnel Elements the yard or the depth Ofthe river where ogy and equipment under vary- 5.1.1 General the tu,-,-1,d,~-~will havetobetrans- ing conditions. The various aspects of the con- ported, the depth ofthe~ Z yard can • The turbidity and spillage from struction of steel and concre~ tunnel be~iftbetummldmmm~are the dredger. elements are discussed in Chapter 2, not entirely ~n~ Sq~om of the

152 Tum~J.mo Am) Ummmmot~v Sp, az TBc~ou~Y Volume 8, Number 2, 1993 concrete in the roof and, eventually, in av*~lAbleto give instructions to the tug As an affiaraple: for a tow operation the bottomcan be cast at a lator stage at capt~JnR and to correct the position of under average conditions in a river, the ~n~hi~jetty, near the imm'm~'~ 5 the bin-el element~ This is important with bm~el elements w~i~h~ 30.000 In othor case~ it has bee~ pm- because the huge ,nA~ of the tunnel to 40.000 tons, a total tow capacity of sible to increase the water level in the elements causes a considerable delay 10 to 20.000 HPwith four tup, eventu- canal temporarily. in any corrective reaction that may be any with pu~ pmsibt~tim, win be Because of the growing number of required for the t~,nn,d elements. requir~ This ~ amumm that restrictions regardln~ the dewatering In this regard, the type, the num- 1000 HP resulte in a tow capacity of I0 of the castln~ yard, additional provi- ber, the capacity and the layout of the tons. DepenA~n~ upon the m*neuver- sions may be necessary to avoid the tugs must be considered. In principle, ability, two or three t~ the theoreti- disadvantages of dewatering. These it is preferable to limit the n, lmher of ca/capacity may be required to control provisions may, in turn, ~ the tugs in order to l~mlt the problems the the position oft,he bm~el element. costs of the casting yard. Tlds problem operation will present to the mAneu- The tow operation ,,z,~ be sched- h~A been solved by using mri~t;,~ cast- vorability ot the total syeten~ Ul~ to WnA]rAmATimsl rn Ulmoflo~l tidal ing yards, where problems with dewa- When the system passes a lock or a conditions, changes in water height, tering either have not occurred or have bridge with limited space, it may be and current velocity and directic~ been solved, at locations far from the advisable to use winches. If the trans- imm,q~ing site. In such cases, the port from the fin~ahJ~ jetty to the 5.4 Immersing transport of the huge t-,reel elements ~mm~ug place is short, only winches iS limited only by the required m~neu- can be used. Transferring the bm~el 5.4.1 C~neml nmtters ~ng space. element fromthe tugs to the winches is The Jmmm-~g ofta~rtrlA1 e]elnenta A/ter the t~mnel edement8 have been an operation that must be properly is a risky part of the job. Perhaps fabricated and ballasted, including planned in accordance with the site because those involved in these opera- many of the provisions for i,-marsing, conditions. tions are aware of the rl,kA, few acci- the dock is flooded and the bmnel ele- Transport over sea is entirely dif- dents or failures have occurred, al- ments can be put aflcat. Thisis donsby ferent from transport in a river or ca- though some 500 or more bmnel ele- removing the ballast water. The tun- nal. As noted above, sea transport meats have been Jmm,qluxl thus far. nel elements are connected with an- requires that the struchxre of the tun- The technology involves working with chor points and put afloat in a well nel be capable of handlJn~ the forces huge elements under relatively d~/~. controlled way, in order to avoid driit- resulting from the swell cult conditions, where much ofthe work ing of the b,-~el elements. The bm~el The transport of a t~mnel element is done without a direct view of the elements are then towed to the RnJ-h- afloat has been dealt with above. Dur- activities. Therefore, it is crit/cal that ing jetty. tug part of the transport, depandinS the wor~" upon the size ofthe elements, whether • Be as simple as possible; and 5.3 Transport of the Tunnel Elements they are steel or concrete, and/or the •Bensfit as much as possible from the type of equipment used, the t~mnel the natural capabilities ofwater. In transport:mgthe t,.~ ,~el elements, element may be connectod to a piece of the following matters are important: equipment that also serves for immors- Succeesfully~l]ahin~ imm~s- • The conditions to be met (see ing. In this case, the bin-el element ing work requires having information Section 3). most oiten is already ballasted for the about the various anvironnmntal con- • The behaviour of the b,nnel ele- jmmm3~g operation. ditions (as specified earlier), as well as ments under the specific condi- Because transport ofhuge and com- the s killa, ~'ence and lenow-how to tions at the site. plicated structtL,~ or structures com- be able to interpret and apply these • The space avAJ!~ble in the navi- posed of more segments (such as a data to the operations as pl~. It is gation channel t~mne] element connected to the im- advisable to wock with an ovea~apacity • The type and capacity ofthe tugs. mersing equipment) has become more in the equipment, and with sufficient safety ,-A-sins. • The location system and the way commouplace, a computer model has been developed to forecast forces on An integral part ofthe preparations that these results are presented for ~mm~dng is a proper risk analysis to the operation leader. andinthe structure (see Fig. 3-4). This so-called Ships Response System can of the operations, with ~t back- • The org~nlaation of personnel up facih'ties for the equipment. It is and equipment involved in the be used for complicated situations. transport operation~ As~,mJ~ that the conditions that may be encountered and the effects these conditions will have on the tun- nel element during trAn~xt are well understood, the methodology to be used during transport can be defined. The capacity of and the ~,mher of tugs depend upon the resistance of the tun- nsl element in the river, canal, or at sea, as well as the space awJl~ble for m~n,mvoring. Anothor decisive may be the fleet available for the spe- cific locatio~ When the available space is narrow, an accurate and fast-working navi- gation system is required to provide information about the position of the t~mnel element in the available space. The fastor the system, the mm~ time is Figure 3-4. Computerized projection of the positions of a tunnel element in a river during transport.

Volume 8, N11mher 2, 1993 ~.mmmzmo,*,svU~SP,*,cz~ 153 advisable to make the operations re- 5.4.2.2. Concrete tunnel elements element, and on temporary struts at versible and to foresee the possibilities Vertical control of concrete t~mnel the free (or secondary) end of the tun- of performing the various operations elements may be different from control nel elements. The final positioning is step by step. of steel elements. After these tunnel done withjacksin these struts, thereby Figures 3-5, 3-6, and 3-7 illustrate elements have been built in the casting allowing for correction of settlement, immersing operations for steel tun- yard, they are ballasted with water in misplacement, etc. nels, concrete tuuneis, and pipeline order to remain at the bottom of the tunnels and outfalla, respectively. dock, while it is filled with water. 5.4.3 Horizontal control Tmmersing under normal, protected The ballast water is pumped out of The horizontal control of the tunnel conditions is a rather straightforward the tunnel elements to make them float. element normally is created by winches, process for the experienced tunnel The equipment most often used con- anchor lines and anchors in the water builder, and need not be too difficult to sists of pontoons adapted for the job. prepare, ffthe criteria specified below or ashore. These winches cau be placed These pontoons are placed on top of the on the pontoons. However, when the are followed. t-nnel elements, either before the ele- current is fairly strong, it is import.ant ment is put afloat, or at a later stage by to have direct control over the move- 5.4.2 Vertical control floating cranes. The pontoons are ments of the element. This can be 5.4.2.1 Steel tunnel elements equipped with winches to anchor both achieved by placing the winches in Prior to immorsing, the tunnel ele- the tunnel elements and the pontoons, towers on top of the t~mnel elements. ments are attached to the immaTsing or the pontoons only. Alternatively, the winches can be pontoons. These pontoons normally After the tunnel element has been placed ashore. moored to the anchors, the ballast tan 1¢g consist of a set of two or four pontoons Att.qiuiug horizontal control involves with bridges in between them. The are partly refilled with water until the the following steps: t-nnel element has sufficient negative tunnel element is suspended from these 1. The t, nnel elements are towed bridges. buoyancy. If additional ballast is re- quired during the immersing because or winched to the im~ site. In order to increase the weight of 2. While the elements are still the steel tamnel elements, they can be of a change in density, water can be added. afloat, the tugs are replaced by winches ballasted by additional concrete and/or connected to anchors in the river or by gravel. This ballast is placed on top Another option is to use additional floating bodies or towers with ashore. of the tnnnel element when it is sus- stability 3. During the lowering ofthe t~m nel the tunnel elements. The stability tow- pendsd f~mthe immersing equipment. element, the horizontal position of the The immersing takes place when ers, which are placed on top of the tlmnel t~mnel element is checked continuously. the tnnnel elements are lowered with elements, need to have both 4. Subsequently, the tunnel ele- sufficientfloating capacity and a suffi- winches on the pontoons. When the ment is placed with the prlm_A,Tend on tamnel element is dose to the bottom, it ciently large cress-section at the water a guiding structure on the secondary is lowered against the previOUS ele- level. The combination ofstability tow- end of the previous tunnel element. ment before being placed on the gravel ers and the ballast water provides ex- 5. The tremendous water pressure bed foundation. Temporaryjointing is cellent control of the t~,nnel elements. When the tlmnel elements are near pushes the tunnel element firmly accomplished with rubber gaskets; per- against the previous elAment, at the manent joints are made afu~ the tem- the final position, they are placed on a temporary structure on the previous same time dictating the direction of porary bulkheads are removed. the axis. The final axla of the t, mnelis very much dictated by the precise mea- surement of the end rings of the t~mnel elements containing the Gins profile.

5.4,4 Other equipment-related options The working methods described above have become commonplace in imersed tube bmnAlllng, thanlr 9largely to the availability of equipment and the experience with this method gained over time. Another option, which involves the use of %pud', or self-elevating, pon- toons, offers several advantages. With this type of equipment, the im~ operations on-site can be limited in time, and the intervals between the immersing of each t~Innel element can be limited as well. To date, sequences of one t--nnel element every 24 hours have been achieved. The choice among ~ and other options depends upon a combination of considerations, such as the n-mimr of t~,~el elements, site cenditi~s, time schedule available, specific require- merits from the diant, and equipment ~wure 3-5. Model of a lay barge used to place the steel tunnel elements for the available. Selectiug the best optioa is a Bay Area Rapid Transit (BART) system's Transbay Tunnel in San matter ofeconomy, te~hniqne and, Francisco, California (U.S.~). (Photo source: 'l~mnel Engineering of all, experiealco, tairilla and kllow-how. Handbook).

154 TUNN~s.r~o Arm UNDRROm3UNVSPACE TECt~OLOGY Vohxme 8, Number 2, 1993 "--.~..

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..;,.~ 7 / .~ ..~. | // --

f ~_~. ~ .-,~._

...... ::~ ...... , . ~ _ :, l Figure 3-6. Standard immersing system for concrete tunnel elements.

5.5 Positioning be lowered on the ~nR1 foundation. crete or steel slabs, placed in the trench The system that precisely defines The temporary foundation at the pri- prior to the ;~ma,~g of the ~,--el the location of the t--nel element in n~qTy end---i.e., the end connected to element. Attached to the bmnel el~ the river and/or the trench has under- the previous b, nnel element--is the ment and located above these slabs gone important changes in the past guided suppor~ of the b,--el element is a steel structure consisting of 20 years. These changes are the on a structure connected to the previ- bars and jacks connected to the tun- result of new technology in the pos- ous element~ nel element. This system allows for sibilities for survey above, as well The temporary foundation at the correcting the position of the ele- as under, water. Thanks to these secondary (or free) end consists of con- ment during the fonowing phases. developments, the period required for the ;mm~ of a tnnnel ele- ment is considerably shorter, and the risk of surpassing the t/me avail- able has decreased. The importance ofa fast eau-veysys- tem during transport has been noted. During the imma~fing process, the ac- curacy of the system is paramount. We must attend to the accuracy and vuinerability of the tunney system for external, as well as internal, eondl- ti(lll& Activities prior to the immer8.. ins mnst be controlled in detail.

5.6 Tunnel Foundation 5.6.1 General Information Three different foundation sys- tenm are available. In Europe, the sand-jetted and sand-flow systems are eo~m, ly umd. In the U.8A., the semeded 8ravel bedis ec-,,,~ praY_'_,-_~ For a sand fotmdation, the p~.~l element is temporarily founded di- rectly aP,er the ;=,,~ersing, until it can Figure 3-7. Immersing system used for pipeline tunnels and outfalls.

Volume 8, N.mher 2, 1998 ~z.wo.,.m)~Srxcae~ 155 5.6.2 Scmeded grovel bed This foundation type is generally used in North ~merica, with steel shell tnnne]s. Following the dredging of the trench, a layer of coarse sand or gravel is placed on the bottom of the trench. The gradation of the material must be related to the hydraulic conditions:the stronger the current, the higher the gradation. The layer will be approxi- mately 0,70 m thick. Careful attention must be paid to accurate levelling of the gravel bed. The required accuracy is +.q cm, de- pending upon the local conditions, the gradation of the materials, and the equipment used. Levelling is done with a screed, suspended from winches on a carriage rolling on tracks sup- ported on two pontoons. The rig is anchored above the sur- face to be levelled. The scresd suspen- sion can be adjusted to compensate for Chsang~ ill tide level. In order to ex- clude influences from the surface to the greatest extent possible, special equip- ment, based upon the principle of semi- submersibles, can be used. This method permits the screed to be directly con- nected to anchor blocks. Figure 3-8 shows the screed~n~rig used fur San Francisco's TransbayTube. Figure 3-9. Principle of the C&N sand.jet syster~ a: gantry, mombte along the tunnel axis. b: pipe system for sand supply, c: temporary 5.6.3 Sand-jatting foundation foundation, d: jetted sand. The first system used to create a sand foundation was the C&N method, which uses a gantry of steel ~,..i.~ around a vertical axis allow the the se-callad ~l-flow method has over the t~m-el element. Connected to entire space underneath the tunnel been developed (see Fig. $-10). this gantry are three adjacent pipes. element to be coverod. A space of With t~ system, as for the ~d- This system of pipes leads to the space about 1 m for moving the pipes j~t~~ a~~is underneath the tzmnel between the underneath the t-~nel elements is p,,,,,.,.,,.ml th.,,o,~..,h ~ to tim mpam, bottom of the t~,-nel and the bottom of required. tm&rmmth tim t-nnel +'~"m~+* (see the trench. The sand must be clean. The aver- Fig. 8-9). In+~- mum,~dd'twi~ The biggest pipe is in the middle. age grain size of the ~md is appr~- a movaifle symm, a n.mhet, of otmm- Through this pipe, a sand/water m;T. mat~ 0,6 ram. The co~tratian ~ m czzmd m me ~ dt~ ture (the composition of which is well- and the exit velocity of the sand/ t--nel element. Them op,~,,,p are controlled) is pumped underneath the water m~ffi,ture, which are directly ~-..-,.'tml to pi~ ~ ~ hwMe tunnel element. The two pipes on ei- related to the dianmter of the pan- or out,~le the ~,,,,.+,,,d du:mmts (the ther side of the large pipe suck the cake, must be well-controlled. water back. This creates a flow ping ~, ~ ~, action that settles the sand under- 5.6.4 Sand-flow system and preferenou of the contractor). When the pipes run from ashore neath the b~nnel element in a well- In order to avoid the use of a defined and well-controllod pattern. gantry, which might obstruct ship- ~-:m~tZe ~me£tot~0im~to be filled, thereis~oh~n~,'An~ at alltothe The gantry on the b,--el element traffic, and in order to place and the possibility ofturning the pipes foundations under deeper t~,n-els, mmdlwat~ -.~.,,'+ is, p--+.,ed through the ~ in tim .~,,,,,,.el element+ The sand nil-. the space ~ ~ tzmz~ ekmmt until the "crater" touches the bottom of the ~t. ~, ~ ~l~d-

~n in the lmm~ mqmmm a pre- ~~ ~Y, the n~t " " and the

The _-,;_maml the imt~'a oftlm open- i~, t~ ¢bz,rl,~ of the land, tho ~thofth.t.m~th,~t Figure 3-8. Model of a screeding rig used for the . (Photo ofthe ~ aml ~b~ ~ect~ ere source: T..nel Engineering Handbook). ~uterr-~te~ Tkk methodis very fast

156 TUNN~.,.ma AND UNVr~a~OUNV SPACE "I~c~ou~ Volume 8, N-tuber 2, 1993 and can fill the entire space undor- undor ~!...1 elements having a bet- The joints between the various neath a tunnel element withi. 24 tom surface of 3500 mS can be filled segme~s of the/~m~i elemeQts re- hours, thu~ avoiding the risk of silt- within a 34-hour peri~L quire special care. A variety of ation a/for the ele~nents have been With the C&~ eaud-jettln~ sy~ methods havo bern d.n~k~d to check placed. tern, the capacity of the system to and control the q,,.~ty of the joint& remove the silt is limited, as is the Quality control of the marine- 5.6.5 Cleaning of the trench capacity to fill the entire space un- related activities requires conaid- orable attention. Proper testing of The cl~-;n~ of an open trench was derneath a t~,--~! element. There- fore, the matter of sedimentation the system and equipment used for mentioned in Section 4.4. Siltation of must be givml special care if a sand- monitoring cenditions and for IX~i- the trench has been a problem on a jetting system is used. tioning is esse~_ti'_,tL For wrJmple, it nzlm]~a- of projects. B4~atlse the de- is very important to measure prop- of these problems are outside the erly the depth of a trench, the silt- scope ofthis report, the remake herein 6. General Matters ation, etc. The ability to perform are ~;m;ted to the conclmdona that can 6.1 Quslity Control be drawn from these ezperiences. these measurements successfully It has been emphasised that the is very dependent upon the condi- I/there is a riskofee~-~-tation by quality control for an ;--.~! tube tioM of the project and the capabil- bottom trensport and/or eiltstionin the t~mnAl must pay specific attention to ity of the equipment to deal with rlve~ in the space underneath the tun- nelelements, eet~eus ~ti~ n.l~t a n.mhor of ma~__A~e. In addition to specific circumstances. be given to the solutic~ In general, it the standard procedures for con- crete and other related activities, can be stated that removing siltation 6.2 Risks from undenxeath a bmnel element is special attention must be given to watort~tnm= of the concrete, for 6.2.1 General considerations extremelycostly. Tberefore,it is essen- concrete t-nnels, and of the steel The risks on a multi-disciplinary t/sl to avoid t~]~ type of sedlm~ntatio~ shell, for steel tunnels. Steel will project such as an ;,~! tube tun- When a gravel bed goundati~ is have to be X-rayed, while concrete nel can be distin~hed as thcee re- used, the risk of such se~tation will have to be checked for crack& httsd to tochniea] matters, to time is nil because there is no open space schedule, and to eeet. The risks for underneath the tunnel element~ With It is possible to check the wator- tightness after the graving dock has these types ofprojects are not basically a sand-flow system, which involves been flooded. Although repair of even- different from the risks for other civil ~ansport through pi~ and open- tual leaks at that timeis ezpeusive and engineering projects. Th~ statement inge in the b.-~ bottom, these prob- best avoided, it is techn;cally feasible. assumes, however, that the most im- lems can easily be avoided as well The weight of the bmnel elements portant requirement= ".e., regarding The system allows for very rapid in relation to the slze and lmoyancy of input based on experience and know- fi11;.~ of the space underneath the the t, mnel elements must be closely how--are ~,!Rl1~ on the project. t~nnel elements. The entire space monitored.

/ / j ~

= - .-'-r~. "r ~ T

P~ure 3.10. Principle of the sand-flow system, which uses a pattern of openings underneath the tunnel.

Volume 8, Number 2, 1993 Tmu~z~OZ~D~SPxcz~ 157 The history of immarsed tube tun- overruns for immersed tunnel struction process must not be nels does not reveal any major accidents projects is considerably lower. The worked out in too much detail prior or events that have had an impact on time required for the construction to the tender of the project. the projects themselves or on third par- of a bored b~nnel depends very much 4. This type of project is perfect for ties. The reason for this might be that upon the production outcome of the design-and-construct schemes. How- much efforthas been invested in proper tlmnel bering machine. It is difficult, ever, in order to limit the cost for the preparation of the project activities--- if not impossible, to improve this design as much as possible and to allow for ex-mple, in terms of risk ~nalyses rate during the course of the project. maximum competition, the client must (long common to these type of projects), An immersed tunnel offers much put the ma~dmum information avail- extensive survey work performed in ad- more flexibility with regard to time able at the contractors' disposal. This vance, and back-up facilitiesincluded scheduling. information must be collected by spe- in the systems. c/-!iats familiar with the local ~cum- Compared to other big schemes, an 6.2.3 Cost stances and by specialists in immersed immersed t~ n n el project may be viewed As noted above, some immersed tube tnnnelllng. as a relatively safe and sound system. tunnel projects have had consider- 5. The team must operate inde- Highly dramatic events have not been able cost overr~na. These overruns pendently of the contractual ar- associated with these types of projects. may have resulted from an exten- rangements between parties. However, a number of projects have sion of the work needed because of 6. Communication with third par- experienced considerable cost and time additional requirements or result- ties must be well organised. Especially overruns. Although these were often ing from unfor~seen environmental justified as the result of "unforeseen during the marine operations, good circumstances. communications are required in order events ~, this does not necessarily mean In all levels of the organlaation-- to avoid problems that could have cata- that these events could not have been design as well as construction--where strophic results. foreseen. A project under water in skilled personnel are involved, the cost difficult conditions is indeed not easy 7. Each party must be informed of overruns should not exceed 5% of the all available information and must have to perform; but here again, it is a mat- value of the project. Moreover, experi- access to this information. ter of properly investigating the exter- enced people can properly es~/m-te the nal conditions, taking these into ac- amount required to cover eventual cost count in designing and building the OVa. 6.4 Project Finance t~mnel, and properly controlling all rel- Recently, an-mheroflm~tun- evant aspects of the project. 6.3 Project Management nel projects have been built with pri- With regard to quality control, rlsk~, The above discussion underscores vate financing. Altho-~h details ofpri- and the structure ofthe organiRation of vats ¢;nA.~ng are outside the scope of the project, clients must be aware of the multi-disciplinary nature of im- mersed tube tunnels. In addition, the this report, this type Of~---~-Z should the importance of both the decisions be mentioned because it will have im- they make about technical aspects, and construction normally takes place at locations where other activities may portant implications for future im- the parties they select to be involved in mersed t~l--el tschniques and projects. the design and construction process. interferewith it. For immersed tlmnel construction,various sitesare created, The time schedule is a major influ- ence on privately fmanced projects: the 6.2.2 Time schedule each shore has an approach ramp, and the madno operationstake place in the bmnel must be built in the shortest The construction of an immersed area between these ramps. The ele- period possible. The optimal period t~mnel can be divided into a n-tuber of ments are constructed at another loca- should be determined on the ba_m_'s of separateprojects. Theapproachrampe, tion. All of these activities must be the results of a cost-benefit analysis the construction ofthe t~ nnel elements, pl-nned to mesh perfectly. comparing the investment in rapid con- the marine activities, and the finishing These aspects emphasise the need struction techniques, equipment, etc., of the works--civil as well as electro- for excellent cooperation between the with the savings in interest. mechanical--are essentially different personnel and parties involved in the A tight time schedule should not be projects, often performed at different project. When cooperation fails, a prob- established at the cost of the q,,a~ty of locations. This division of the project lem at one location may result in a the work. Experience and know-how will result in a number of activities disaster at another. are needed to define the op~m-! sched- being performed in parallel. They will Therefore, it is vitally important to ule for a partic~dar project. Further- have to mesh technically, as well as in establish perfect cooperation between more, a tight time schedule will mean the planning stage. all parties involved, guided by a skilled that the design must be optlmlged to Some parts of these tasks involve and experienced group ofpeople. Some take advantage of possibilities for sav- repetitive activities--for example, guidelines are given below: ing time °n vari°us aspects °fthe Project" construction of the t~m-el elements The almculty with private fiuancing and parts of the approach ramps, and 1. All relevant parties must be de- oiten is that the politician- acting on the immershxg process. Therefore, fined at an early stage of the project. behalf of society are neither ~llln~ to the negative effect of a sudden set- Their specific requirements, Airillq and nor capable ofd~Rnln.~thereq~ts back oRen can be neutralised by in- contributions must be known to all regardl,~ the. total package of design- creasing the number of forms; by parties involved and all aspects oftheir construct~finance-and-operateprojects. adding equipment; or by perf~ing work must be covered. This mean R that the authorities extra works at night, during the 2. A team of responsible key people advising the politicians in the interest weekends and on holidays. must be establL-h,~l at an early stage of of society must be capable of properly Purthermore, if there is a known the project. This team should include deR-in~ the te~h-lcal and additional risk associated with the functioni-~ skilled specialists for each discipline requirements of that society. of a particular piece of equipment, and must be guided by an experienced It is vital that all related parties be back-up equipment--or at least fast t~m-el specialist. identified prior to the real start ofthe and proper replacement of key equip- 3. Because d_~i_'_gnand construction work, for the entire scope ofthe project. ment---can be planned for. are closely related, early input from These parties must be capable of iden- In comparison with bored tunnels, the construction company regarding tifying and judging all risks--whether for example, the risk of time the design is advisable. The con- technical or financial---and of covering

158 TUNN~J.-~OAND UNDE~mOUND SPACE TECBNOLOGY Volume 8, Number 2, 1993 these risks.

Reference Bicke], John O. and m~eael, T. R., e~. 1982. Tunnel ~n~,,~cing Handbook. : Van Nostrand Reinhold.

Acknowledgments The author, a consulting engi- neer, has made an inventory of the various construction techniques used thus far in immersed tube t-nnel- ling. The result of his survey has been amended by a number of spe- cialists. In particular, the author thAnkA Mr. Ahmet Gursoy, Ix. P. van Milllgen and Ix. Gerard H. van Raalto for their advice.

Volume 8, N~ 2, 1993 Ttneam~.nqOaSV~SpACZ~ 159 Chapter 4:

WATERPROOFING AND MAINTENANCE

by

WALTER C. GRANTZ U.S.A. Parsons Brinckerhoff Inc.

G. LIONG TAN The Netherlands Bouwdlenst Rykswater-staat

EGON A. SORENSEN Denmark COWl Consult

HANS BURGER The Netherlands DHV

Contributions and comments by: A. Glerum The Netherlands Chr. J. A. Hakkaart The Netherlands

Tunnelling and UndergroundSpace Technology, VoL 8, No. 2, pp. 161-174, 1993. 0886-7798/93 $6.00 + .00 Printed in Great Britain. Pergamon Press Ltd 161 Chapter 4: Waterproofing and Maintenance

1. INTRODUC~ONANDBACKGROUND

2. STEEL TUNNELS 2.1 Recent Joint Evolution 2.2 Waterproof Joint for Immersed Tunnel Elements 2.2.1 Typical joints 2.2.2 Contingency method for sealing typical joints 2.3 Closure Joints 2.4 Termln~l Joints 2.5 Underwater Connections to TerminAl Elements Constructed in Rock 2.6 Seismic Joints 2.7 Concrete Requirements 2.8 Cathodic Protection of Steel Elements

3. CONCRETE TUNNELS 3.1 The Concrete Structure 3.1.1 Membranes 3.1.1.1 Steel membranes 3.1.1.2 Bit~lmlnc~s membranes 3.1.1.3 Polymeric sheet membranes 3.1.1.4 Liquid-applied membranes 3.1.2 Chilling the concrete 3.2 Joints 3.2.1 Ass-mptions for joint design 3.2.2 Immersion joints 3.2.3 Termin~! joints 3.2.4 Closure joints 3.2.5 Dilatation joints 3.2.6 Construction joints

4. MAINTENANCE 4.1 Experience with leakage in Steel Shell 'l~mnels 4.2 Experience with leakage in Concrete r~mnels 4.2.1 Leakage ~ tunnel structure 4.2.2 LeakAge through joints

162 ~.~.r~o AND UNDmm~OUND SPACE "l~mNar,ooY Volume 8, N,,m~r 2, 1993 1. Introduction and Background the two tubes. The joint was made in Vancouver, British Columbia This chapter deals with eusurL~ watert~ht by belting it tight and then (Canada), which used an inflatable watertightness of immersed tun- grouting the space between the two rubber gasket for the initial seal and nels; and, specifically, with the gaskets, in a manner not too-nlJkA the water pressure to effect the final soal. methods used to ensure watertight Boeton sewer built some 16 years pre- ~, the Gina and Omega integrity of i,-,-~d tunnels. Ma- viously. The shellwas 9.5-ram riveted profiles came into prevalent use in terial in the chapter covers both steel, lapped and ship-caulked. European countries, as well as in steel shell b~nnels and concrete box The next immn~rB~ tllnnel Was oniy Japan; and were recently intro- b~els. one element long. This was the La duced in for that country's For concrete ~:~,nnela, the twO basic Salle St. railroad b,n-el in Chicago, first imm,~md b,n-el, which is un- watortightueso design philosophies are constructed in 1912. The ands of the dar construction in Guanszhou. described. The first uses applied exto- element tied directly into cofi~rdAm~ rior 6reel and/or bitnmlnou8 membrsme. Again, the shell consisted of riveted, 2. Steel Tunnels ship-caulked and lapped construction. The second uses no exterior water- 2.1 Recent Joint Evolution ~glayer, butrathor accomplishes With the third immecsed tnnnel, the Tunnel in New Apart from certain special consider- waterproo/~ng by dividing the element into separate segments where concreto York, constructed in 1914, the de- ations concerning corroeion,which are shrinkage-cracklng can be prevented. sign of the joints between tubes took covered later in this chapter, the Because steel tube b,--~ls are com- a significant turn. The design no steel shell constitutes the basic wa- pletsly enclmed by the steel shell, the longer used a rubber gasket (per- terproof enclosure of all single- and issue ofwa~-z largely conc~ haps because of the difficulty an- double- shell steel elements. It is the dseign ofthejointbetween elements. ticipatod in mating the four tubes therefore mostly in the joint area The develolnnent ofthe methods for incorporated in these elements). In- that refinements in design details prodding watorUghtne~ in joints in stead, it used a riveted steel finer can be made. steel shellb,n-els over the past decades plate closure across a square-butted From 1930 through 1960, the de- sign ofthe joints in steel shell elements has been largely empiri_c~! and mainly joint after the exterior had been the result of in~porat~ the exp~- concreted with a tremie enclosure in the United States did not change enco gained on one t~,--~l in the design between elements. The space be- very muc~ The method of operation of the next. This proeees is ongoing in hind the liner plato was grouted. during placement r~ined bA~cally the United States. In the European This method was quito successful the same as it had been for the previous countries, however, dsvelo~aent has and set the pattern for all of the im- filty years. centered on concrete ~nne]s, con- mersed tnnnels constructed subse- The joint was mated and aligned structed with or without membranea quently in the U.S., until the Bay Area and then pinned with two heavy steel This chapter provides information Rapid Tr~n~dt (BART) Tran~bay Tun- pins. A form was installed on beth on current design practice for types of nel in San Francisco was constructed sides of the joint and a mas~ve tremie joints, membranes and watertight con- in 1970. The BART Transbay t~n-el concrete pour was made, which com- crete. It seems appropriate to begin was the first to use the double rubber- pletoly enclosedthe joint and hopefully this section on watertightneso with a gasketted joint now comn~uly used in sealed it suff~ently to allow the inter- brief history of its evolution in im- the U.S. The grouted steel liner plate nal liner plates to be welded in place mersed b,nnelling. detail (welded) was used on the BART without great difficulty. This was not The hlstoryofsubaqusousi mm~med rl~'nn'~| and continues to be used on always the case, however, because tunnels is about to attain its first steel shell b,nnel8 to ~ day. tremie concretois oi~on imporfect. The centonniaL In 1894, the flrstimmm'sed The Posoy Wl'nnel, coDsta'tlL÷t~dill joints would leak or, worse yet, the concrete would penetrate into the inte- tl~nnel large enough for a person to 1928 in Oakland, California, and the walk through was constructed. The Webster St, ~mnel--its near twin, con- rior of the joint and harden, requiring Boston Metropolitan sewer, beneath structod in 1962--are the oaly con- a time-cons-ruing ~m;.;.~" operation Shirley Gut in Boston Harbour, used crete bmnels without a steel shell ever to remove it. On the other h_-nd, the 15-m-long, 2.7-m-diametor elements constructed in the United 8tatoa Both tremie joint had one major benefit: it consisting of brick and concrete, with t~mnpJS were waterproofed with an ex- formed a rather strong structural con- temalbib~,-;n~m mmnbrane protoct~ nection between the elements. lO-cm-thick exterior wood shesthln~. Temporary wooden b.ikheads were with wood lagging, and beth used Although the gaskettedjoint is very instelled at both ends of each element, tremie concrete joints. effective in provJrl;-~ a more reliable and external flanges with rubber The ~ imm,~l, tnnnel to use working environment than the tremle gaskets were provided to permit the weldinu for its steel lining was the joint for the installation of the steel elements to be belted together. Thus, ])etroit..WindBorvehi£.'la[llelr trt n n el,con- liner plato, a disadvantage is that the the ~imm~l.t~lnnel tlBed rubber- struct~ in 1980. Only the longitudi- structure of the joint bec~m~ inher- ~etted joints. nal seams were welded; the cite-refer- ently weAk_.er. The former thick tremie In 1910, the Detroit River Railway ential sector were riveted, as in previ- concrete encasement, which helped to T-n-,d--consldoredto be the first ~ull- ons ~mnels. The first all-welded steel tie the elements together, was no lenger scale imns~d t],n nel~this 8alne shell was used for the elements of the used. In addition, in recent years the B-n~hAad thlckness ofthe struchxralinterlor con- metho& This t-n-el was unusual by rJ?llnnel,co~ in Mo- present-day standards in that it was of bile,Alsh,m,, in 1940. creto ring has been reducod, as higher- strength concreto and more sophisti- double-shell construction, placed on the By the time the ~ransbay T-nnel cated methods of analysis have come to bettom, with no concreto inside or out. for San Francisco's Bay Area Rapid The exterior concrete was then placed Transit (BART) system was de- be used. by tremie metheds. ~ all the ele- signed, concrete immersed t~lnne]S These changes have resulted in an ments were in place, the tubes were had long been ~ in Europe increasin8 problem with the effects of and Canada t~ng sinsle main gas- thermal expansion and contraction, accessed and the interior concrete lin- causln8 longitudinal movements in the ing was installed continuously, as a kets and mobili~-inu the water pres- m;nAd t~m--I would be lined. The sures to compress the gasket~ The first joints between elemeats and cra~l~ng spall;.~ of the interior Rnlahes of Detroit River ~,nnel u~ii-~d rubber such t,,-,,,el in North America was the and the bmnel. doublo-gaskettedjoints around each of DeasIslandt~-~nel, consh'uctedin 1959

Volume 8, Number 2, 1993 TtmNm~mOAm)U~SPACB T~mNOLOOY163 No leakages have yet been traced to these movements in any of the ttznnels ~ RubberGaskets where they have been observed (two bmnelsin I'l~mpton Roads, Va., U.S_A~, and the Fort McHenry ~lnnel in Balti- more, Md., U.S.~). However, there /----ll~out P/pe is concern that the liner plat~ ~he major llne of defense against even- tual deterioration of the main gas- kets--mlght begin to leak as a result of the seasonal joint centraction and compression; and, certainly, the ef- Shell P/ate fects on the wall tile are a serious " ~ ~ Shell P/ate maintenance consideration. In the case of the ~m,el for the Central Artery/Third Harbour Tunnel Project in Boston, the design of the Figure 4-1a. Joint detail for the Detroit River Tunnel (1910). joint detail has been revised to ac- complish two objectives: 1. To make the joint flexible, in order to prevent damage to the seal resulting from the motions that have been observed. 2. To provide a controlled location for the movement in the joint to appear in the surface of the wall. This new joint detail may be said to constitute the state of the art, insofar as it has been recommended for the ilot Pin aforementioned project by the two American consulting firms that have designed the large majority of the steel shell blnne]B ~0.the U.S.A~ Therefore, this discussion of water- proofing as it relates to steel shell ele- ments will use this most recent devel- opment as its m~in example for joint design. European designers will real- ize that this joint detail is very close to what is commonlyused on the Continent for concrete box elements. In fact, the Gma type of profile was Figure 4-1b. Joint detail for the Harlem River Tunnel (1914). specified as an acceptable alternative type of main gasket for the Boston Harbou.r ~mnel. displacements without struc- and down to a drA+--~e valve in the tural failure or failure in invert of the element. The valve re- 2.2 WaterproofJoints for Immersed watertightnoss. lieves the pressure and drains the TunnelElements Omega gasket into the lowe~ air supply Figures 4-1a and 4-1b show early du~ Although the Omega is rated for 2.2.1 Typical joints ~Amples of the ~ypieal joinff for the the ambient exterior water pressure, For the purposes of this discussion, Detroit River and the Harlem River the main gaskets do mo6t of the work; a %-ypical" joint is considered to be the ~+~nAls. F/gures 4-2a and 4-2b show only a slight seepage or trick~ might joint used between almost all of the an isometric and a plan section of a have to be intercepted by the Omega elements in an immersed tl m nel. Typi- typical tremie joint (a closure joint is gasket. cal joints are distinguished from cer- very -*-t]-- to this type ofjoint). Fig- The interlor s/ructural ring in the tain other special joints designed for ure 4-3 shows the current design ofthe joint area is mai, ly the tynlrcal struc- specific purposes, i.e.: typical joint for steel shell b",-nels that ture, ,:ompos.~ of the steel chell tied is prolmeed for use on the most recent * Closure joints, which are used com~to the mnorete. However, Boston Harbonr ~,--el ds~a. 60 mm of the joint ring osncrete over- when the last element is placed This new typical j~ut detail is d~ somewhere in the middle of the laps from one tube to the othee, to s~,ned to permit longit,,,,l+,',*l move,- ~o~af~lt~.tm~key~m~ immersed portion of the tunnel. merit generated by the temperature * Terminal joints, which are used element to ~mt~ This ov~iap per- variation during seasonal cycles. It mite relative ~ mot/on b~ between the shore ends of the is also designed to transfer shear imm~t~ t,,,mel and the land tweon elonmnts, by ,~t~e of the faet forces caused by ~n~e events, as that the concrete is ~ ~latsd portions. well as differential settlements, * Underwater joints into rock, be- from the eteel sheU in thls zaue by a which might cause Rms.ll rotational section ofjoint Kller that prevents bond- tween steel shell elements and movements in the joint. rock t~mnels. ing er j~ of the ~ ring as it The Omega gasket seals ag~i--t gradually moves in reqmnse to expan- • Seismic joints, which are de- water that m~ht eec__Jpeput the main sion and contraction. signed to absorb triaxial seismic exterior gaskets, and conduetsit around

164 TUNN~J.mO AND UNVgSm~OUNDSPAC~ TBCHNOLOaY Volume 8, Number 2, 1993 2.2.2 Contingency method for The closure joint provides roughly joint will usually be constructed in the sealing typical Joints h-1 fa metsr ofjoint a~t for the dry. The detail is relatively simple in All typicaljoints are equipped with accumulated variation in the length of t,hi~ case. If the termln.! structul~ vertical slots provided in the edges of the t~,nneis as they approach each are eoustructed first, then these struc- the b,d~h,quis to permit the installa- other. It is initially sealed by tremie tures must be provided with a built-in tion of curved form plates so that concrete contained within sheetpi]e elementjoint adaptor to which the first the joint can be sealed using concrete anelesures and kept out of the interior and/or last element can be attached, in the event that a seal c~--nt be ob- of the joint using enclosures with using norm.l placement procedures. tained in the usual manner with the overlapping top and bottom hoods, de~ * Se/sm~ mot/ons may control the gaskets. This curved form plate is signed to provide the range of joint design of the joint and its waterproof- identical to the one shown in Figure separation noted above. In contrast, ing detniling. The termln-! struc- 2a for the typical tremie joint. Al- the typical tremie joint does not pro- ture to which the end element must though thi~ provision is always made, vide for a range ofjoint separation. connect (e.g., a ventilation building) this second q_ine of defense"hse rarely, will usually have a very different if ever, been used. 2.4 Terminal Joints natural period of vibration, which will cause large relative movaments TerminM joints are the interfaces of the terminal structure with re- 2.3 Closure Joints between the portion of the bmnel cen- spect to the jmm,q~d b,--eL This These joints ere used at one end structsd bym~n, other th-n Jmmm~ed condition may require a fu~ seismic ofthe element that will close the gap in elements and the imma,~ed element joint with triaxial motion capabil- anlm-~'sedt~mnelbeing constructed portion of the t~mneL Ter~i--! joints ity. Such a joint was used for the fromboth shores. The other end ofthl, vary widely in design, dspen~-~ on Transbay ~l~,--el in San Francisco element is provided with a typical rub- certain b~_m_'cfactors, such as: (see Section 2.6, below). ber-gasketted joint. • The sequence of tube placement. • Anticipated expansion and con- If the elements are placed first, the tract/on between termJn,l elements and the terminal structaxrm. • Differential settlement between the Jmmp~sed tl,nnel and the te~,~;i--I ~ may be an important espeet in the joint design ifground conditions are rather poor. Some designs (e.g., Fort McHenry ~,--el in Baltimore, , U.S-A.) have attempted to avoid high stresses in the im~ elements by permitting d/fferential settlements at the joints. Other ds- signs (e.g., Second Hampton Roads ~mnel, Hampton Roads, Virginia, U.S~) have been dssigned to allow for expansion and contraction but no ver- tical movement.

2.5 Underwater Connections to Terminal Elements Consbucted in Rock For the 68rd Street ~,-nel (, U.S.~), two two-Almn_____ent ~mnels were placed: one befween the New York shore and Roosevelt Island, in the East R/vet, and the other be- tween the island and the shore. These tWO immersed tlmnel~ Figure 4.2a. ~ypical tremie concrete joint for a typical steel double- were joined at the island by a rock shell structure. tunnel At each end of the two immersed

/t ~ ._ tunnels, an und=water portal face and pocket was blasted in the rock I [," ." " iremie concrete FilI~ • " | Alter placing the element in this pocket in the rock face, the joint area wee tremied to form a tight seal. Subse- ~Ba~rete .)~ .~. i ? Top/Bottom Hood Plates- 7 .. " " , ". I ~.~" Ballast Concrete.~ " quently, the element was reached by rn~-~-~ through the rock and tmmie seal and removing the end b, ikhead. This joint was made watertight by a steel shell e~_~-mJ,m into the m~-ed 1~mneL

[ [ (Grouted/ P [Removed/ Construct/on Jo/nt ' I 2.6 Seismic Joints in Interior Concrete The only seismic joint design used to date in the United 8tares wu devel- Figure 4-2b. Section through a typical tremie joint. oped for the BART Transbay ~mnel in

Volume 8, N-tuber 2, 1993 Tum~;mo~vU~)u~vSpAcz TRamou)~ 185 Bulkhead P/ate , Omega Gasket Assembly 7 (Removed) ~I Drain for Omega Gasket-7 / ~-- Expanssbn Material

t ~. I .~ ~ ~ . ~.. !.- ~.- ~ ~ ,=. -/~ .. ~, ~'. ~.,,, ~, ,.,

b ~

7 ff.xferlOf ~.oncrele . c . - ) ~ . , ~..=.~ r . . " (Slrucrurnll -. ° . " ~.~ , ". ~', • .... " '

" " tern "

Bulkhead Plate ~ Bulkhead Plate -~ (InboardJ (Outboard)

Figure 4-3. Typical joint detail for Boston's Third Harbor Tunnel.

San Frandsco. The sel/am'~cjoint was flexibility in concrete tunnels are not for coai~g the steel shell with materi. designed to p~mit triaxial displace- required. It should be noted that this sis such as coal tar epoxy and/or the ments of :~8 cm in the longitud~nnl situation can lead to designer compla- provision ofimpressed current cathodic direction and +15 cm in any direction cency with regard to temperature and prot 'on in a vertical plane, while ma~nt~nln~ shrlnl~%~e controlin tha steel elements; Alternatively, stray current test watertight integrity. and thla can have the undesirable ef- stations may be speeiRed to permit The ~ and transvorse hodzon- fect of introducing excessive reflected periodic measurements at several tal motions are permitted by pre- cracking in 6nlnhed tile sm.facos. locations along the steel shell of the compressed rubber gaskets ~-~ on imm~zed tunnel. This arrangement radial Teflon bearing mxrfao~. The 2.8 Cathodic Pro~'tion of Steel permits flexibility in adjusting the longitud;-=l motion is taken by ~rn~lm- Elements extent of the cathodic protection to gaskets slidln~ on a clrolmfqurential the actual conditions encountered in Telton ~ mxrfaco. Both sets of It has not been the practice in the the completed project. In this byammed United States to provide special pro- regard, the intemal re~nforc~ug steel cables that allow the ~ by total. tection to the steel shell of im- and the steel shell must be carefully ing on T~lon~oatsd spherical bearings. mersed t~mnAl% unieas stray direct bonded electrically throughout the The assembly is protected from currents are detsrmlvmd to be present. t-nnel to prevent deterioration, or mud and the marine environment by Where stray currents do exist or are even accelerated localized corro- exterior rubber boot enclosures. expected, such asin an electrified rapid sion, in the presence of stray These assemblies were prefabri- transitbmnel, provim'ons maybe made currents. cated, assembled and tested as units before being attached to the ele- ~.Radia/ Teflon Faced ments. Four of these seismic joints Searing Surface were required for the Transbay Tun- nel. The joints performed well dur- ing the 1989 earthquake in San Frau- ..,.,,o, F.e ,,.ooe cisco. Figure 4.-4 shows the arr~-~e~ ment of this seismic joint.

2.7 Concrete Requirements j One of the basic advmztsges of stsel shell t=mn~Is lies in the fact that the watertightae~ does not rely heavily en the ab~h'ty ofthe concrete to withst,.,,d cracking, as it does for concrete box t~m-ela The concrete strength is im- © portant from the structural standpoint, and randmn temperature and shrink- age crg~t~ is a concern in this regard, however, from a l~=~e stsndpo~nt, Cable steel elements cau ~ate a great deal ¢rsankqn~ in ~ concrete Hnln~ than can concrete box elements. In addition, the concrete box is not as accommodating to variable ground Inside Face of Tunnel _..t settlAments asis the steel shell bm~el. As a result, intermediate joints ~m~lA~ Figure 4-4. Patented seismic joint used for the Tranebay Tunnel, San to those commonly used to introduce Francisco.

166 Tu~J.mo AND UI~m~tOUND SPAcz T~moLoay Volume 8, Number 2, 1993 3. Concrete Tunnels Severaltypes ofwate:proof~ mem- not overloade~ - situation that could Because steel is ez]>~-~ive on the branes havebeen used for the construc- c~ate cracks through the membrane. tion of;m~ concrete bmne]s: Although the concrete is placed Euro~__- mAinly,d, alternatives to the st~l sbell have been develol~cL Intbe • Steel membranes. ag-;-~ it, the steel membrane will not adhere to the concrete. The mparatlon past, problemm have occurred because • Bit~Im;nntl8 Inembranes. the concrete was not watertight, due to may take place in the casting basin • Polymeric sheet membranos. beeatme the temperatures ofthe mem- the lack of density of the concrete and • Liqu/d-applied membranes. cracks. brane and concrete are ~t. The Lenir-ge water can enter Each of these types of membrane is separation of steel and concrete will the t.,,nnel allow water from a leak in the mem- in two ways: discuased below. brane to find any leak in the concrete. 1. Through the concrete structure. In order to 1;mlt potable |Mkaees, con- 3.1.1.1 Steel membranes 2. Through the joints. sideration may be given to dividing the These types ofle~ knee are discussed This is the oldest method used for membrane into r~nor areas of per- below. preventing water from penetrating haps 10 x 10 m, ,Ring ribs welded into the t-nneL The steel lining onto the inner side of the membrane. encases the tunnel completely and Steel membranes have mainly 3.1 WaterLeakge through the has no stme~al functions. Gener- Concrete Structure been used at the bottom or the bot~ ally, the steel and concrete are not tom and sides of immersed t, nnels. It is very/mportant that the con- permitted to be considered as a The rem~ining part of the tunnel crete be impermeable. Possible composite structure. surface has then been covered with causes of cracks are climatic Normally steel membranes con- another type of membrane, umudly temperature fluctuations and hydra- sist of 6- to 8-ram-thick steel pla- a bi~IrnJnouB membrg~Le. The trail- tion heat during the pour. If the tes welded together. The connec- eition between steel and bit~m;=~ concrete structure cracks, water tion between the membrane and the membrane requires eomplez clamp- ]~Lk into the ~Inne]. Penetration concrete structure is provided by ing in order to ensure permanent of water into the concrete can cause shear studs welded to the mem- watertightness. corrosion of the reinforcement. brane. In addition to normal control A few concrete t~,n-els, including To prevent water from leai~,~ into of the welds, all welds between the 'l~ngstad '~,Tmml in ~gweden and the bmnA1 tJxrough the concrete, two plates are further tested for wa- the Dens Island 'l~,nnel in Canada, different measures are applied: t~ightness. This testin~ may be have been provided with steel mem- 1. Membranes. done rather simply by a portable brane all around. 2. Cooling the concrete to avoid vacuum box. Steel membranes have the follow- cracking. Because steel membranes are sub- ing advantages: ject to corrosion, protective measures It should be notod that no cmacrete is may be needed. If the bmnAl is we]/ • Geod ex~erJenes hae been gained with p,¢h ,,~-hranesinthe past. 100% watertight; some water seepage below the water surface and is sur- will occur eve~ thorugh a dense con- rounded by backfill, corrosion will oc- • It is a well-known tee~ology. crete. The water will not be visible, cur very slowly. • It yields savings in formwork because it evaporates at the inner face The following mi,imal measures * The membranos are robust~ ofthet--n,~l stzuctures, ffthewatoris must be taken in order to avoid local The disadvantages of steel mem- ~mHne, the salt will remain in the con- galvanic corrosion: crete and, a.eter some years, may have branes are: cont~mJnnted it to such a level that it • Light sandblasting should be • There is a risk of corresion and may cause corrosion of the reinforco- used to remove mill e~de from tbey requ~ pro~ the s~d plates. ment at the ;nnar side of the stmch~. • A leakage in tbe membrane may TbJs heus beem the ceme in the T.'iml~ord • Weld material should be ca- thodic, compared with the steel cause water penetration into the bmn~l, whore a combination of an im- b,nnel far from the leak in the membrane. perfect membrane, e~i;ne water, and a 100ue~mbral~e. concrete with m~ny fine c~tda~ hA9 al- For the Guldborgstmd ~mnel in * The membranes are quite co6tly. ready caused eldoride co~t~mlnation Denmark, the aforementioned mea- • A ]MkJee in the membrane can- above the critical level in some part of sures have been considered su_ffi- not be repaired. the b,-neL cient to ensure a llfetime of 100 years of the steel membrane, which is placed at 3.1.1.2 Bituminous membranes 3.1.1 Membranes the bottom and the sides tithe t~nnel. Membranes are provided on im- If the planned inspections show that Bib,m;naus membranes 8anerally are prefabricated mat~ reinforced by mersed tunnels to prevent outside furthor measures are req.m~, catho- water from entering the bmnal space. dic proted~on Aimilm" to that ~ on polyester or glass-fibre fabric. To achieve thi~ goal, the membrane steel b,nn~Is may be installed. They may be glued on with hot bitu- men or by warmin~ a bitumen layer must have a life expectancy .im~l.~ On the Conwy T,mnel in Wales and the Tingetad ~1---! in Sweden, the applied to the mat during fabrica- to that of concrete, and it must be tio~ The bitumen may be either hot- chemically and biologically resistant steel membrane has been protected blown or polymer-modified bitumen. to the environment. It also must be with both painting and cathodic Tbe latter h-A better ehu~ proportise able to resist forces from outside dur- protection. The shear studs mnnoctingthe mem- than the former, a factor that is impor- ing construction and in the perm~ent tant, e.g., in damping etrilm at the condition, and it must be ~tly brane with the concrete structure shenld elastic to accomm~u:]ate any crack8 that be designed so that they can tra,mnlt edges. the shear ~ from the soft. It should For t-nnel waterproofing, the poly- may be expected in tbe stnLeture. mer-modified bituminous membrane It is advisable that the membrane further be ensured that the nl,mher of studs is ~ent to limit difi~orential is preferable to the normal bib,mlnons adhere to the entre surface, thereby membrane because it reduces plastic eliminating the possibility of water movements between membrane and structure, so that individual studs are deformations and loss of pressure un- flow between the membrane and the der the clamping plates. The mere- concrete.

Volume 8, Number 2, 1993 Tu~mzmo~~SP~~ 167 REINFORCEMENT

TIVE CONCRETE

TIVE ROOFING FELT

OUS MEMBRANE

SCREW NUT Ai

CLAMPi

STEEL

~-- ANCHOR STRIP

Figure 4-5. Connection between steel and bituminous membrane. branes must fully adhere to the pz~-~d • They are cbeaper than steel. properly cured and is dry, t~i~ concrete surfaces in order to prevent • Their performan~ ha beon dom- ~ is on the =iaeal ~h. water ingression through IMi~ in the onstratod to be successful. Therefore, the H,,~,,~ between membrane to flow in the space be- • The membranes are relatively twasn the membrane and the concrete robust, if placed in two layers. in+ barn requt~ ck~ +oerd,ina- structure. • The membranes can bridge nor- tion with a speci~t subcon- Abit~,'m~ -,~Ls n~is ne~-11y malfissures. tractor. composed of two layers of bitumen- * The mem~anes can be applied • B~,m~.,~s ~ do not ~m~paatedmat~ Thematsareplaced on roofs, where steel membranes traa~r shear inthe with at least 100 ~ overlap and the are difficult to place. plane. joints in the two layers are staggered. • Special:arr~ at ~- In order to avoid water seeping The ~ving disadvanta~ ere ~ sion joints (steel ~ or ~m+. from behind the membrane, all free cisted with l~m~s ~: lar) may be required. edges of the membrane must be • The success oftbe membrane de- • A durable and complete adhe- clamped, e.g., by clamping strips of ponds on an ~ labour __m_n_ to tbe concrete surfaco is steel (see Fig. 4-5). for~ to ensure watertightness at ~m,m~ to obtain. A concrete slab 100 mm to 150 the edges and at anchor bolts for • A ~ in membrane may ~ ini~Al~y protoe~ the bitu- protection of the concrete. cause water to penetrate into m~mms nmmlnmm when it is placed • Because the application of the the tunnel far from the place on the t---*l roof. Because the Mtu- where the leak in the membrane mi-OUS membrane e~nnot transmit membrane can only be started aider the structural concrete is occurred. shear forces of long duration, it is ~ to anchor the prote~on slab (see Fig. 4-6). If the membrane is used on the t~lnnel sides, a allding layer of SOft bltumenis applied to reduco shear tran- sfer from the bs~kS11 (as was done JD at the Rupel T~m'nm] in Belgium), or CONCRETE protected by lO0-mm-thick con- crete plates bolted to the walls (as LATE at the Drecht ~,--el in The Nether- ROOFING FELT lands). At the b,--~l bottom, where it is difficult and complicated to secure the membrane to the con- crete, steel plate is still used. MEMBRANE Bi~,~ membranes at the tun- nel roof have often been combined with ~TE sty! .~hranes at the sides (and bot- tom) of the t~,'n,,,,l,+. T'Kis method has JO been applied to the Elbe T,,,,,,,~'i in Ger- m--y,f~he C~0nwy"Prm.a,1in Wales, and the ~ T,,',,',,,,,,,,1in D~,,~m"k.. Bit-mi',',ous membranes have the following advantages: Figure 4-6. Connection between structural and protective concrete.

168 'Ptmta~:u'm'o AND U~mB~ovNv SPAcz TeC~OLOOY Volume 8, Number 2, 1993 3.1.1.3 Polymeric sheet membranes based, can be applied by spraying or by each pour may be Hm';ted to approxi- Polymeric sheet membranes may roll.in~. The concrete surface must be mately 25 nL be thermoplastic ,,,At~rl,dA such as dean and dry in order to achieve geod This method of preventing cracks polyvinylchloride (PVC), polyethylene adhesion. If the membrane does not in the walls has been successfully (PE), chlorinated polyethylene (PEC), separate from the concrete around fis- applied in The Nethorlande since the and polyisolmthylene (PIB), or elasto- sures, the elongation of the membrane late 1970's. Belglum and GermAny merle materials as chloresulphanated own" a fissure formed after spraying have also adopted this method (e.g., polyethylene (CSM), polychloroprone will be ;-f;-ite. on the Liefkenshoekand Eros ~m-els, (Neoprene) (CR) and isoprone-iso- Sprayed membranes have not often respectively). buthylene (butyl rubber) (Ira). been used in the past, although re- Compared with membranes, the Thermoplastic materials may be cently a sprayed membrane was used cost of cooling is low and it reduces joined by hot air or plate we]dln~, which in the construction ofa t~nnelin Hong construction time. Even though are rather Aimple operations. Elesto- Kong. The membrane consisted of a cracks cannot be avoided totally, mer/c materials are joined by adhesion, 0.08-in.- (2.0-ram-) thick layer ofepexy those cracks that still appear can be while the rubber types (neoprene, bu- tar. Uai'ortunately, the first ~m.el injected prior to floodJ.~ the casting tyl, etc.) may be vu]cA-;,e~ Although elAments leaked because the coating basin. Injection must be done in the fairlyexpensive, vulcan; -~tion provides was not able to absorb the strain when absence of water flow; otherwise, a strong connection. cracking of the concrete occurred the crack will stay open and water These types of membranes are very after the waterproofing had been will continue to flow into the t~nnel. thin and, therefore, are very vulner- applied (Engineering News Record, able to mechanical damage during July 13, 1989). Later on the 3.2 ,Joints project, elemants sprayed with an construction. The following subsections discuss The butyl rubber membrane used improved membrane showed a bet- ter performance. requirements for joint design and pro- on DenmArk's T,Jmfjord ~l~mnel was vide ~Amples of joint layout. The glued on by a polymer-modified ce- Advantages of liquid-applied membranes are: following types ofjcints are normnlly ment slurry. 1Ltsed in 'imm~'wrsed concrete t~lnnelR: The advantages of polymeric sheet • They are low in cost. membranes are: • Intermediatejoint:usedbetween • They are continuous, i.e., with- ~,..el elements. • They aro low-cost, in cemparison out joints. to membranes. • Terminal joint: the joint be- • They may trRnRfer shear. tween the shore end of the • Fewer discontinuities in de- The following disadvantages are Jmrnm'sed t-nnel and the leJld tails, thereby reducing the structures. chance of errors. associated with these membranes: • D/fllculties in bridging fissures • Closure joint: the joint made in- • They are less subject to dAmAge s/tu after the last element has during and aitor construction. may occur ~ the membranes have been applied. been placed. • Better concrete quality can be • ~njo/nt: used within each maintained. • There has been little proof of their performance. individual t~m-el element, with- • They permit reduction in con- out continuous reinforcement. struction time. • A ltmkR~e in the membrane can- not be repaired. • Construct/on jo/nt: used with;- • They facilitate a clean and the individual h,nnel elmYlent, straightforward design. 3.1.2 Cooling the concrete to with continuous reinforcement. The disadvantages of butyl rubber prevent crocking • Joints~premstuni~forpre- stremed bmnAI ~JmnAnt& membranes are: Dunng the pouring of the walls on * Workmanship problems with the floor, the temperature in the Many t~mnAln have been designed the joinJ-~ of the sheets. walls increases because of hydra- without expansion joints. In such • If applied in only one layer, they tion heat. When the walls are cool- cases, the intermediate joints, ter- are very vulnerable, especially ing down, the shrl-k~ is obstructed minal joints and/or closure joints Jmmadiately after application. by the cool floor, creating tensile are normally ~ed as perma- • Degradation ofseAm~ occurs ovcr stresses in the cencrete. When the nent exp*nAion joints. Permanent time. tensile stresses exceed the ulti- expansion joints are arranged ap- • Embrittlement and degradation mate strength of the concrete, pro~mAtely every 25 m. Because of the sheets occurs over time. cracks will occur. these joints are generally difficult to execute, there may be a risk of leak- • Tensile and puncture strength To prevent the extreme rise in temperature that can lead to the age occurring at the joints. may be inadequate. A few t-n-sis have been designed • A durable and complete adhe- above scenario, low cement con- tents are applied (275 kg/cm*), and the as monolithic tllnna|S. The following sion to the concrete surface is descriptions deal mainly with im- d;mcult to obtain. cement that is used develops relatively little hydration heat (blast furnace ce- mersed concrete D1nnAl Rprovided with • A leakage in membrane may mentwithmorethA- 65% s!eg). More- waterproofing membranes. cause water to penetrate into over, the lower parts of the outer walls the t~mnel far from the place are cooled during the first days after 3.2.1 Assumptions for Joint design where the leak in the mem- pouring. This is done by pumping The purpose of a joint is: brane occurred. water through cast,in steel tubes. The • A leakage in the membrane can- controlled process results in a censid- * To connect individual castings not be repaired. e2-ab]yreduoed mA~irmlm oongrete tein- or prefabricated units. peraturejust above the floorslab, while • To allow for ~ caused by 3.1.1.4 Uquid-applied membranes a gradual temperature increase is ob- differential settlements, tem- perat.ze, eL~ep and shr;-~%~ Liquid-applied m~mhranes, which tained from this spot to the uncooled may be epoxy-besed or polyurethane- con~ete in the upper part of the walls • To facilitate construction. and the roof. In addition, the length of

Volume 8, Number 2, 1993 TUm~;.~O~NDUSD~e~aOUNDSPXczT~smV~ 169 ~-GINA GASKET GROUT - GINA GASKET i -- STEEL MEMBRANE ,I ! I

iiiiiii~ii~ili:i ! IVE CONCRETE ...... iI ?il]iiiiii!iiii~i~iiiiiiilil;iiiii!ili}i! ~US MEMBRANE i;!iii!i]!ii]ii!i!iiiiiiiiiiiii~i!i]!ilil iiiiiiiiiii!iii:iliiiiii:iiiiiiiiiiiiiiii~...... iiiiiii!iiiii!iiiiiiiii:i!iii......

iiiiiiiiiiiii~iiiiiii!!iiii~~ • i!!i!i!i'i:iiii!21/~:~ iiiiii!iii!ili!i!!i~

E EAST IN-SITU EONTROI.LINI~ 3HTNESS i

L. FOAM '~--OMEGA SEAL I I , =BEARING BLOCK PLASTIC ± SHEAR DOWEL Z OME[3ASEAL

Figure 4-7. Intermediate joint. Figure 4-8. Shear key of steel at intermediate joint.

Ajoint is a discontinuity in the nor- cast. The space behind the plates was will be sealed temporarily between the real homogeneous concrete structure. injected with grout. This method per- t.nnel element and the entrance struc- Therefore, one of the m~Jn tasks in mits very re,hAll tolerances to be met. ture. The permanent water-tightening joint design is to ensm'e watertight- inst~llJn~ the Omega seal, the Omega seal could be constructed as ness within the expansion limits for two t~mnel elements are connected by shown in Figure 4-10. which the joint should act. casting reinforced concrete in the r~ The possibility of differential In a brahe1 with a membrane, two mAJn;n~ space between them. This settlem~ts between the /n-s/tu con- waterproof barriers exist: (1) the procedure was used on ~ T,imi~ord structed part and the ]~smed tun- reinforced concrete, and (2) the and the Guldborge~d ~m-eis. nel part must always be considered. membrane. Alternatively, a perm~-~nt expan- With a sand-jetted or sand-flow foun- For the design of watertightness sion joint with shear keys may be car- dation, a certain settlement must be in the joints, it is important that ded out. The shear keys may be con- foreseen when the load on the tem- joint movements, alignment and tol- structod of reinforced concrete or of porary foundations is transferred to erance limits have been investi- steel. This method was used on the the sand foundation. gated and specified. The max-imum Conwy ~mnel, the Singapore Cable In Dutch t,,--eis, the shear keys water pressure for which the joint ~mnel, and the new Bilbao (Spain) in the floor are placed as late as should be watertight should also be Metro ~mnel (see Fig. 4-8). possible in the construction pro- specified. If the shear keys are of reinforced cess, in order to let the sand settle. It is essential to know the prop- concrete, which has been comman The shear keys prevent unequal erties of the joint materials, not practice until recently, access to settlement between the immersed only when new but also when aged, the Omega seal is hindered, whereas element and portal, while allowing as well as their lifetimes. Joints can access is retained if shear keys of for rotation when the opposite end only be replaced if this possibility is steel are used. The shear keys of of the immersed segment settles. foreseen in the design stage. Dutch t-nn~ls are installed only in the floor and are made of steel tubes 3.2.4 Closure Joints filled with concrete (see Fig. 4-9). 3.2.2 Intermediate Joints the last t,m-el (dement has Even when the joint is used as a Normally the intermediate joints been placed, a remalnJng gap, ap- permanent expansion joint, the are provided with a Gina gasket and proximately 1 m wide, normally movements are usually not large an Omega seal (see Fig. 4-7). has to be dosed. The closure joint is The Gina gasket is mounted on a and the Gina gasket stays water- located l~twsen the last b,--el ele- tight. This ~_~-~ that the Gina and steel frame at the pr*-n~y end of the ment and either a previously placed t-nnel element. After the t-nnel the Omega constitute a watertight bar- rierinthejoint. No serious leM~Ages of t~mnel element (as an in-situ.oast tun- elAment is placed, this end is drawn thJR type of joint have been repoi~ted. nel) or a portal structure. ARer clceure agAJnat the secondary end ofthe previ- panels have been installed all around ous t.nnel element, which has been the t--nel, the gap can be closed from provided with a match i-~ steel frRme. 3.2.3 Terminal Joints the inside of the ~mnel by casting In some early immersed t~lnne~ This type of joint is often identi- reinforced concrete. (e.g., the T,imfjord~mr, R1), the frames cal to the element joints, if the In order to facilitate placing and were made of U-profiles. Although portal has been built before the el~ watertightening of the panels, the end cast-in separately, the frames could merit is placed. In this case, the sea or ofthe last t~mnel element and the struc- not be adjusted, alter the concrete had river end of the portal l~Jldin~ is pro- ture to whish it shall be connected are been cast, to ensure suffidently accu- vided with a ~dirhead and a cast-in normally given a rectangular outer rate alignment. steel frame, like the secondary ends of shape. The two parts can be monolithi- The I~atch t,,--.4s and other recent the t~mn,d elements. cally connected, or a permanent ex- t~m -~!~ (e.g., the EJbe, Conwy and Guld- If the elements are built in the pansion joint can be ~ed. Figure borgsund T---els), have used an H- entrance, as for the Ouldborgsund 4-11 shows an example of a closure profile, and the end plates ofthe frames ~m~! and the Ptinses Margriet Tun- joint fer a ~mnel provided with a water- were welded atter the concrete had been nel (in The Netherlands), the joints proofin~ membrane.

170 Tt~u~.T.mo AND U~va~aaOWrD SPA~ TEc~moLo~ Volume 8, Number 2, 1993 ,~.,'2J, !

-- [ JOINT COVERPLATES

tMME TUNf PORTAL STRUCTURE t

Figure 4-9. Shear key in floor. •• ~ OMEfiA SEAL In the older Dutch bmnels, the clo. sure joints were provided with a so- csZ~a aoubleX)mega ~ (Ses~g. 4- ~_ TEMPORARY SEAL 12). TI~ type of joint can be very SHEET PILECUT - OFF wlnerable. In congm~don today, a segment of a normal cross- Pigure 4-10. Terminal joint at the Ouldborgsund Tunnel. sect/on of the blnnA| is built into the closure joint (see Fig. 4-13), while nor- mA! rubber-metal waterstops provide the watortightnsss. Temperature fluctuations cause the struction joints are made with con- joint to open and dose. When the joint tinuous reinforcement. 3.2.5 Expansion Joints opens because of shr~-k~ge, sand or Even though good adhesion be- soil can enter the joint. Then, when the tween the concrete at each side of the Depending on the local conditions, tlmnel section expands, the joint can- joint is achieved by sandblasting or the individual blnnA! elements may be not dose up again because of the sand watorjetting of the pr~mA~y concrete provided with'a number of expan- or soil in the joint. To keep the joint face, there is always a risk that a crack sion joints. clean, it is will arise at the joint~ Therefore, the In order to facilitate handl;n~ of provided with a rubber gas- v ket, as shown in Figuro 4-17. Because joints normally are provided with the tunnel elements, these joints it is di~ienlt to place the gA.Ik,~in the waterstops that act es a secondary bar- are fixed in the construction stage, bottom slab, theg~mkat is repleesd by a rier for ~,-n~ls provided with a mem- normally by prestressing cables or steel strip, as shown in Figure 4-18. brane, which is carried continuously rods (ses l'~g. 4-14). A/ter the element across the joint (see Fig. 4-19). is placed, these connections are re- 3.2.6 Construction Joints Another type ofco~o~joint is leased or cut in order to allow free the joint between procast segm ts of expnnAion. Construction joints may be de- prestressed t~--els. An example f~om The watsrtightness of the expan- signed as expn-~on joints; generally, a cable bmnel in Singapore is shown in sion joints is ensured by cast-in however, at least some of the con- 4-20. waterstops. The t.nnel membrane can be continued ace.s the joint in the form of a steel Omega profile, as was done at the Elbe and the Conwy ~,--ets (see Fig. 4-15). The design of the steel Omega pro- ~-- TEMPORARY SUSPENSION file, where the corners are especially critical, has been verified by full-scale ~--/BLOCK-OUT FOR SHEARKEY testing. Since the mid-1970's, all of the im- mersed t-nne]s in The Netherlands have been constructed in segments, with the lower portions of the walls cooled and the membranes omitted. The only waterstop in the expan~on joint is a rubber-metal waterstop. Be- cause the rubber is subject to defmwaa- /:ion by the water pressure, the met~ strip in the concrete is used to guaran- tee watertightness. This single waterstop must be of high q11nlity. To E SOIL ensure that the waterstop works prop- REACTION ON PANEL) erly,/x~ection tubes at the end of the ...... '~LOSURE PANEL~/ metal strap are provided, as shown in Figure 4-16. ~re 4-11. Cl~ure joint at bot~m slab.

Volume 8, Number 2, 1993 'llea~.n~oasvU~mmw~'vSP,,.c1~ 171 FILED WITH CONCRETE---~ I~EAR KEY ~-~3UL~( HEAD Temporary piping used in placing op- I erations must be cut off and sealed, with a cover plate seal-welded over the opening. Special details such as cross- passages between tubes must permit good welding accessibility to assure quality welding. Althoughthe experienco with water- tightness of steel shell t-nnels has been very good, given proper design and fab- rication procedures, if a leakage prob- lem arises, it tup~lly OCCURSat the ter- m~n~]joints with the land sections. The problem usually stems from the transi- DOUBLE OMEBA ~RCIFILE-/ tion from a tetally enclosing steel shell to a conventional exterior structure waterproo~sys*~ Inaddi~n, there Figure 4-12. Closure joint formerly used in Dutch tunnels. maybe problems in keeping the excava- tion area dry where the waterproofing is being installed. Therefore, proper l i i' det~lin~ at this interface is critical.

4.2 Leakage in Concrete Tunnels 4.2.1 leakage through the tunnel \ / structure Reports of leakages in concrete t~mnels in some Dutch t~,--els, beth with and without membranes, have mainly concerned minor leakages through the floor, walls and roof. In t.~mne]s with men~ranes, leak- RU~eER-~IETAL ~ATERSTOP TYPE19Ul "--/ ] I age through cracks in w~11~ or floor CL(~VRE PANELS----'''~ i is difficult to repair because it is ~Im~t imposmble to find the leak in Figure 4-13. Closure joint used on modern Dutch tunnels. the membrane. In such cases, the leakage is stopped by injecting all cracks. When leakage through one crack is stepped, water seeks, and will weld inspection and teats for water- 4. Maintenance appear through, another crack tightness during fabrieafion. 4.1 Experience with Leakage in Steel It is easier to stop leakage in tun- Shell Tunnels Perm~mt penetratimm ofthe shell nels without membranes, because the are to be avoided whenever possible in leakage point can be detect~ Le~kAoe in the im~ portion of the design. Where openings are pro- In beth caass, the inject/on has te be steel shell tunnels generally is mini- vided for access or concrete placement, done without a water stream. m~l Watertightnees depends to the great Dare nmst be takan toinspeet and greatest extent on the care with which There have been some leakage prob- test welds of the closure plates for lems at the T.imf~rd ~mnel in Den- the integrity ofthe shell is maintained watertightness. through design and execution. m~k. Thele~k~ mainlyhave occurred The soap bubble and vacuum box tr~n~se constructionjoints, Therefore, tunnel specifications test is a good watertightness test through must require suitable welder qualifica- which have not been provided with for smaller openings in the shell, waterstops. tion, as well as radiographic, nltra- atter the concrete has been placed. sonic and dye-penetration methods of

i -ANCHOR JOINT ±DYWlDA5 ROD. WRAPPED WITH BOND BREAKING TAPE --BLOCK-OUT FOR CUTTING OF ROD i iiiiiiii!iiiii!iiiiii \- STEEL MEMBRANE

Figure 4-14. Temporary reinforcement at expansion joint. ~sure 4-15. F_apansionjoint with steel Omega profile.

172 TLWS~.T.mOAND Um~m~OU~D SPACE ~]U~INOLOGY Vo1uule 8. l~mlwr 2. 1993 +,. o ~J~ I--ToPOF" BO"f'IO~ 51_^B //ZI~/' , I tl 7 ~I[~VE @1~/¢1

INJECTABLE: ~U 8B£..R - METAL ~ATERSTOP .~CME-PROF]LE IIPE ¢I,IE 20A

I 5rl I 25_1 t I E ,,' il I- I Figure 4-16. Injectable rubber-metal waterstop. Figure 4-17. Expansion joint in walls.

8

I I ,I ,00 I, ,+,0 .]

Figure 4-18. Expansion joint in floor. Figure 4-19. Construction joint.

The total amount of water l~k%oe i~ the t~mne/isa'ather re'troll---on the order of 50-100 l/hour (based upon -WATERPROOFING MEMBRANE - ts ofa m;-,~t area). How- PROTECTED BY PLYWOOD ever, even ~m~il amount8 of leakage through the concrete structure are unacceptable, as the water in the ~ord is s~li~e and therefore has caused cor- rosion of the reinforcement in the tun- ::~!~i~i~iC::!!iii::Ci~i~::Ci~iiiiCi~i~::~!~::~i~i~i~iiii~i~i::::!iii::::ii::iiiii::!,~ :i,!:~iiii!!~iiiii~!~::'------GROUTED JOINT nell. i~i i ~~~ ~ ~ i ~~~i~1!~i~111~i~iiii~i~i :::':': ...... i~ii~i~1i~!i~i:!:~:~:!~: ~ TUBE The .~1nine,| ill provided with a mem- brane of butyl rubber. Obviously, t~;- membrane is not watertight; and, be- ~ , ...... ,...... :..-- i:~:~:1.:.:.::::::::::::::::::::::::::: :i:i:i:i:: ':'~.~.:.:~.." " ~::::::::::::::::i::i:i::::::.:.!======cause the adhesio~ to the concrete is probably in~flqeient, the water may +++ + spread between the membrane and the structure. The l,~kn~ee began during the con- ...... ::::::::::..... GROOVE FOR struct/on stage. 81~ce then, more at- INJECTION PIPE temp~ have been made to stop the water seepage. Trial injections have been msde wim epo~, ~ and acrylic gel The lsU, er bare pro- Pigure 4-20. Joint between precast segments. duced #.he best; rem~ts, but in all cases

Volume 8, Number 2, 1998 Ttnm~,mozzmUm~mma~m~Sl,aczT~my 173 the leaks have started again some time 4.2.2 Leakage through joints This type of le~irRge occurs because after the injection has been performed. LeAlcAges through expansionjoints of the high positioning of the terminal It is assumed that the reason for this is are usually caused by gravel pockets joint, which lies just below the surface that because of the seasonal tempera- that formed under the rubber-metal ofthe water. During winter, when the ture variations, the long monolithic waterstop during the pour. LeRl~age river freezes, the Gina loses its elastic- t~Innel is alternately exposed to ten- problems are usually handled by injec- ity and the t~m nel shrlnkR, causing the sion and compression, causing move- tion; however, if injection is not suc- joints to open. The stiff CJ.na c~nnot ments of the cracks. cessfnl, the water must be directed to swell to keep the gap dosed. Other measures, such as internal the drain.. A survey of leAkAge of mdsthlg tun- membranes (polyurethane and fibor- In Dutch t~,n-els, a control systemis nels was performed within the Work- texture-reinforcedcement-paste mem- available to detect leakage through the ing Group. The responses indicated no brane) have been tested. The adhesion Gina gasket. During construction, a 1/2- serious leakages, and only some small of the polyurethane membrane to the inch pipe is embedded in the concrete, drippings, for both steel and concrete concrete was not sufficient, and the connecting the space between the Gina ;mmersed t-nnels. cement paste membrane was very ex- and Omega to the central gallery. pensive. Therefore, attempts to find a A leak through the Gina was de- References suitable repair method are continuing. tected at the Zeeburgor ~m-el. How- Reina, Peter and Nsoaki, Usui. 1989. ever, the water did not enter the tun- "Sunken tube tunnels proliferate. nel, which means that the Omega seal HowEng/z~eeri~ News Record, July 13, is watertight. 1989, 30-37."

174 Tum~.Tma AND U~m~OROT~V SPAc~ TE(~MOLOGY VO]Ulne 8, N.ml~r 2, 1993 Chapter 5:

CATALOG OF IMMERSED TUNNELS by

WALTER C. GRAN'I-Z U.S.A. Parsons Brinckerhoff Inc.

Contributions and comments by:

D. R. CuIverwell U.K. H. Duddeck Germany Chr. J. A. Hakkaart The Netherlands K. Hestner Sweden N. Rasmussen Denmark E. ~mnsen Denmark T. Tamotso Japan H. Wind Germany

Tunndling and Underground Space Te~hnolo~, Vol. 8, No. 2, pp. 175-263, 1993. 0886-7798/93$6.00 + .00 Printed in Great Britain. Pergamon Press Ltd 1~ Chapter 5: CATALOG OF IMMERSED TUNNELS

1. INTRODUCTION

2. REFERENCE TABLE OF IMMERSED TUNNELS

3. IMMERSED TUNNEL FILES

176 Tummr.T.mo~ U~mm~ov~w SP,,,cs Tsc~Nolo~ Volume 8,1~m~ 2, 1993 1. Introduction This catalog attempts to highlight t,,-~-la listed in the catalogue, During the early meetings of the the principal aspects ofeaeh project (a This report has been developed Tmm,w~ed and Floating~,--ml- Work. total of 91 projects are presented), as over the past four yea~ by sol~% ing Group ofthe International ~,...1. well as documenting both the earliest ing information from various mem- lingAssociafion(ITA), it was clear that methods used (seine of which are very bers of the 8ubwort~-u Group. This movative, even by today's standards) was done followin8 the ha~ f~at a catalog of immmv'sed tlm-Ole WOUld provide an important contribution to a and the most current techniquu. In prmented lmreia as a quasti_--~i~e. better worldwide understanding ofthe deing se, it is hoped that the engineers The research work involved in col- history and technology in this field of who are in the process of conceptualiz- lecting ~hl. information was a thne- ing new conp,mln~ altVleult undert~l~in~. We tl,--el e~n__eering. At its 1989 meet- a t~mnel crossing van use this ing in Toronto, Canada, the Group de- catalog as a source ofideas for develop- therefore are very grateful to our cided to develop such a catalog for tug their demgns. colleagues who have contributed to future publicatio~ The catalog also represents the the catalogue. This catalog, which focuses specifi- range of d~mA-elonal features of im- As the catalog has been reviewed by callyonthe ~m~ t~,-n~l s designsd mersed elements. the Subworlri~ Group members in draft form, interest has increased and for rail and highway t~,--els, is not Other aspects covered, where data intended to be complete, as a much were available at this writing, include more information has been forthcom- more comprehensive catalog of all ttm- methods offabrication, material speci- ing. While the inventory is not as nele worldwide is already published by fications, methods offoundation place- complete as might be desired, we feel it the ITA. Rather, the intent is to pro- me~t, e~vironmentalc~ditiem, safety is important that the inventorynow be vide a 8~,mmm'yof as much engineer- factors, and types off,n-eljoints used. printed so that it can reach a wider ing information as can be found in Finally, where data were available, audilNtll~. various papers and articles in a con- the owner, designer and construction It is hoped that readers will e=cuse cise, useful m..n.q- for the designers of contractors have been listod as a refer- any m~cns. In this regard, the Subworlrln~ Group will welcome any this type of t~,--eL ence, as well as an acknowledgment of Over the past century, fewer the work undertaken by then~ ~orcontributionsof~ than 100 railroad or highway tun- Also included in a nnmher of the informatio~ It is expected that the nals have been designed worldwide. catalogue ~ are one or more eros- catalog will be amplified and reprinted Two basic techniques have evolved: sectional drawings of the t~,-neL We from tl.m to t~.m to ~ new are most grateful to Mr. D. R. infonnstie~ Additional informe~o- 1. The steel shell method, com- Culverwell, who has granted permi~ maybese~ttothe author ofthlschapter monly used in the United States; and sion to reprint drawings used to illus- at the follewln8 addrms: Bechtel/Pa~ 2. Theconcreteboxmethod,usedin trate his ~World List of Tmma~sed sons Brindmrhoff, One South Station, Europe. Tubes', published in Tunne/s & Tun- Boston, MA, 02110, U.SA. nelUng in March and April 1988. New t~mn~la are started every year, More recently, these techniques Th,nim are also due to Mr. Nestor and new to~h-~quas will be developed. have merged in the Far East, Hong Rasmussen, of ChristiA,i & Nielsen A/ We hope that the reader will find Kong and Japan. S, for providing illustrations for other catalogue both interesting and useful

Volume 8, Number 2, 1993 Tum~=mo AND Um~mmOU~D 8~acz TmCENC~0~r 177 Table 1. Reference list of tunnels included in the catalogue of immersed tunnels on pages 174-258.

Reference Tunnel Country Year Completed No. (* indicates --l~nown construction start date

1 Detroit River U.S.A. 1910 2 La Salle St. U.S.A. 1912 3 Harlem River U.S.A. 1914 4 Freidrichshafen Germany 1927 5 Oakland-Alameda (Posey) U.S.A. 1928 6 Detroit Windsor U.S3t 1930 7 BAnkhAad U.S.A. 1940 8 Maas Netherlands 1941 9 State Street U.S~ 1942 10 Aji River Japan 1944 11 Washburn U.S.%. 1950 12 Elizabeth River U.S.A. 1952 13 Baytown U.S.A. 1953 14 Baltimore Harbor U.S~_ 1957 15 YIAmpton Roads Bridge T---~! U.S.A. 1957 16 HavA-- 1958 17 Dens Island Canada 1959 18 Rendsburg GermAny 1961 19 Webster Street U.S.A. 1962 20 Elizabeth River Tunnel No. 2 U.S.A. 1962 21 Bridge ~,--sls U.SJt 1964 22 Li]jeholm~viken Sweden 1964 23 Haneda (vehicularb~nnel) Japan 1964 24 I~neda (monorail tl, nnel) Japan 1964 25 Coen Netherlands 1966 26 Woliburg Pedestrian ~,--AtS C-erm-ny 1966 27 Benelux Netherlands 1967 28 Lafontaine Canada 1967 29 Vieux-Port France 1967 30 Tingstad Sweden 1968 31 T...AI. Netherlands 1968 32 Ij Netherlands 1969 33 Schaldt E3 (JFK ~,--el) Belgium 1969 34 Heinenoord Netherlands 1969 35 T.Jm~ord Denm-~k 1969 36 Parana (HernandJas) Argentina 1969 37 Dojlm- River Japan 1969 38 Dohtonbori River Japan 1969 39 Haneda (T-m- River) Japan 1970 40 Haneda (g~hJ. Ch-nnel) Japan 1970 41 Bay Area Rapid Transit ~,..AI U.S.A. 1970 42 Charles River U.S~ 1971 43 Cross Harbour 1972 44 63rd Street U.S.~ 1973 4 5 Mobile (I-10) U.S.A. 1973

continued on following page

1'/8~o Am> Um~mmot~v ~,~ffi Tsc~m~ Volume 8, Number 2, 1993 Reference ~m-e] Country Year Completed No. (* indicateo p]-,,-ed or under construction)

46 Kinuura Harbour Japan 1973 47 OhgishJm~ Japan 1974 48 Elbe Germ.ny 1975 49 Vlake Netherlands 1975 5O S-mlda Japan 1975 51 Hampton Roads Bridge ~m.~l No. 2 U.S-~ 1976 52 Paris Metro France 1976 53 Tokyo Port Japan 1976 54 Drecht Netherlands 1977 55 Prinses Margriet Netherlands 1978 56 Kil Netherlands 1978 57 WMATA WA~hJnoton (D.C.) ChRnuel U.SJL 1979 58 Kawasaki Japan 1981 59 Hong Kong Mass TrAnRit Hong Kong 1979 6O Hemspoor Netherlands 1980 61 Botlek Netherlands 1980 62 Daiba Japan 1980 63 Tokyo Port DnJnJkcro Japan 1980 64 Pmpol Belgium 1982 65 Metropolitan Rail r~,nn~t (Main) GermAny 1983 66 Bastia Old Harbour France 1983 67 Spijkenisse Metro Netherlands 1984 68 Coo]haven Netherlands 1984 69 Kaohsiung Harbour Republic of China 1984 7O Fort McHenry U.S.A. 1987 71 Second Downtown U.S~_ 1988 72 Guldborgsund DenmA~-k 1988 73 Ems Germany 1989 74 Marne River France 1989 75 Zeeburger Netherlands 1989 76 Hong Kong Eastern Harbour Crossing Hong Kong 1990 77 Conwy U.I~ 1991 78 Liefkenshoek Belgium 1991 79 Interstate 664 U.S~. 1992 8O Third Harbor U.SJ~ 1994" 81 Willemspoor Netherlands * 82 Niigata Port Read T, mnel Japan * 83 T.mA River Japan * 84 Kawasaki Fairway Japan * 85 Sydney Harbour Australia * 86 Osaka South Port Japan * 87 Bilbao Metro Spain * 88 Noord Netherlands * 89 Grouw Netherlands 1993" 9O Medway U.K. 1995" 91 Schipol Railway rI~lnne] Netherlands 1994"

Vob1~ 8, Number 2, 1993 Tum~.T.mo Am) UNmnmaoL~rDSPACE TeC~mOLO~ 179 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 1 Detroit River Tunnel; International tunnel between Detroit, Michigan, U.S.A. end Windsor, Canada; 1910 , ~J // \ /

TUNNEL TYPE AND USE: LANES/TRACKS: Railroad tunnel; steel shell lined with concrete. Two tubes, one track each way. Exterior concrete ballast.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 11 80 m 9.4 m 17m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 800 m 24.4 m

UNUSUAL Method of construction involved sinking elements by flooding them with water and FEATURES: controlling escaping air. Elements were lowered to steel gdllagas on the bottom, where all exterior concrete was then placed. Later, the intedor of the element was dewetered and the concrete lining was then installed under water.

ENVIRONMENTAL River currents. CONDITIONS

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Shipyard Underwater after Unique rubber placement.

WATERPROOFING Continuous steel shell plate. METHOD:

PLACEMENT Pontoons were used to control sinking. METHOD:

FOUNDATION Steel gdllagas were I:daced to exact grade and tubes were lowered to them. Tremie METHOD: concrete, used to make the interface contact with the dredged trench, became the foundation for the tunnel elements.

DREDGING Dipper dredge for first 14 m; remainder was done by clamshell dredge. METHOD:

COVER AND TYPE: Riprap covedng over side backfills to protect them from scouring. Tunnel roof at grade of dver bottom.

ADDITIONAL If this tunnel were to be constructed today, it would be regarded as incorporating many INFORMATION: innovative ideas because it is so different from the way we currently do immersed tube tunnels. Some of the ideas could be very useful someday in e particular situation because they apparently were successful.

OWNER: Michigan Central Railroad. DESIGNER: Detroit River Tunnel Company.

180Tum~.r~o,e~'v UNIzsmwr~v 8P~ T~sxe~ Vol-mA 8, Number 2, 1998 TUNNEL NAME/LOCATION/DATE OF COMPLETION: File No. 2 La Salle St.; Chloago, lllinois, U.S.A.; 1912

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; single steel shell (riveted). Two tubes, each with one track.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 84.8 m 7.3 m 12.5 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 84.8 m 15.5 m

UNUSUAL FEATURES: Was replacement for masonry tunnel on the same alignment. The masonry tunnel was demolished and removed by dredging. Crossing was made with a single element. Intedor lining increased in thickness from top to bottom. Underside of tube had "V" shape to make backfilling easier. Structure had longitudinal central truss encased in concrete.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Constructed in a dry dock in Chicago using a riveted Interior concrete for the Special diaphragms were steel shell (to boiler specifications) lined with concrete. center wall and lower keel provided at the two ends "l'imberend bulkheads were providad. Internal ballast area were placed first in of the single element, to tanks were installed in each tube at each end, dry dock. The element which cofferdams could operated by remotely controlled valves and pumps. was then floated to the be engaged to permit outfitting dock (3,000 land-side construction to tons), where the rest of the proceed. Two manhole interior concrete was shafts were provided at placed, bdnging the total each end of the element to 8,000 tons. Steel shell for access dudng and after roundness was maintained placement. Cofferdam with struts and tierods. detail provided for later bridge pier to straddle the tunnel, if required.

WATERPROOFING Double butt strap caulked longitudinal joints and alternate inside and outside lap METHOD: drcumferential caulked joints. Steel shell provided wstertightness. Coated with red-lead paint.

PLACEMENT Internal water ballast was used for placement. Piledriver barges end/or hoisting engines METHOD: on adjacent piers were used for control of alignment and grecle during placement.

FOUNDATION Two-pUe supported piers were provided for temporary support. Piles were installed by METHOD: statically loading them to a known load, rather than driving, in the expectation that adjustments to grade could be made by overloading by a known amount. As tube was placed on supports and adjusted to grade, sand fill was placed around it.

DREDGING METHOD: A dipper dredge and a clamshell dredge were used. A great deal of difficulty was involved in removing the old tunnel, the roof of which had been demolished by blasting.

VENTILATION TYPE: Piston action of trains.

ADDITIONAL OWNER: Chicago Railways Company. INFORMATION: DESIGNERS: E.C. & R.M. Shenldend and J. W. Pearl. CONTRACTOR: M.H. McGovern/J.A. Green/ChadasGreen and R.H. Green.

Volume 8, Number 2, 1993 ~o AND UN~motmv SPACE T~aSOLOOY 181 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 3 Harlem River Tunnel; New York City, NY, U.S.A.; 1914

TUNNEL TYPE AND USE: LANES/TRACKS: Railroad tunnel; steel shell. Four tubes; one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 5 67 m 7.5 m 23,2 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 329 m 15.2

UNUSUAL Four tubes in a sidle element section. Element ~ent closaly followed Detroit River FEATURES: Tunnel ~ where element was lowered to grade filled with wider and exterior concrete jacket was placed by b'emle. Later intedor was pumped out and lined with concrete.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: At yard I mile from tunnel site. Launched by floating Interior concrete linrogs were Rivetted liner ~ over off shipways on nine canal boats, then sinking the installed after the five steel butt joint; grouted. canal boats out from under the element. elements were placed and tremied and the tunnel had been pumped out between bulkheads placed at the ends. Connections to the land sections were made later through cofferdams. Leakage was minimal.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT 12 in. valves were opened in the bottom 0f the ~ in the two outside~, ~ METHOD: them to fill gradually. The two inner tubes were open. The rate of sinking afar thetubcm were half full was controlled by air valves. Trim was aeco~ by half bulld~mde at two central locations to allow adjustment of filled portions. As the tubN became completely filled, the flotation was carried by four pontoons, which were I~ filled and went down with ~ element. The rest of the walght wm ¢aded by ~ boats moored on either side. Masts were used to measure line and grade. Once In place, the space balow the bottom of the element cau~Jd by overdredging was filled with lean tremie (xxcrete. Then each pocket formed by the diaphragms and wood side legging was filled with sVuctural concrete by the same method.

FOUNDATION Tremie concrete placed after element was in position. METHOD:

VENTILATION Piston action of trains. TYPE:

ADDITIONAL OWNER: New York City Rapid Transit System. IN FORMATION: CONTRACTOR: Arthur McMuilen and Hoff Company.

182 Ttrmamz.n~o A]~JDUm)~ J~PAC~ '/~Cl~O¢OGY Volume 8, N-mhm" 2, 1993 TUNNEL NAME / LOCATION/DATE COMPLETED: Rle No. 4 Freidrichehafen; Berlin, Germany; 1927

TUNNEL TYPE AND USE: LANES/TRACKS: Pedestrian; reinforced concrete. Footway.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 2 52.9 m 6.67 m 7.65 m

TOTAL IMMERSED LENGTH: DEPTH AT BOI-I'OM OF STRUCTURE: 105.8 m 10.8 m

UNUSUAL Constructed as two pneumatic caissons. Element structure was constructed on fill placed FEATURES: halfway to center of river. Excavation under this structure, which was provided with cutting edges, allowed it to be lowered to grade below the river bottom. One side was done at a time. The two elements were sealed at the middle joint after the second element was at grade.

FABRICATION METHOD: JOINT TYPE: In place. Concrete joint formed in cofferdam.

WATERPROOFING Concrete-protected membrane all around. METHOD:

PLACEMENT Caisson method. METHOD:

FOUNDATION Concrete filled caisson under tunnel tube. METHOD:

VENTILATION Natural ventilation. TYPE:

COVER AND TYPE: 1.5 m backfill.

Volume 8, N-tuber 2, 1998 Tum~.v.~To ~ UZ~m~a~0UND SPA(= ~ 188 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 5 Oakland-Alemeda (Posey) Tunnel; between Oakland and Alameda, CA, U.S.A.; 1928

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete cylindrical section. One tube; two lanes; one each way.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 12 61.9 m 11.7 m 11.6 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 742 m 25.5 m

UNUSUAL Circular concrete section (without steel shell) was cast in a dr/dock. Waterproofed with FEATURES: extemel membrane protected with timber legging. Invert waterproofing was laid on timber lagging and ended by metal flashing at end ~. ~ slab and ceiling tierods were used for structural members. Placement and foundation methods were very unusual.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: In drydock with five elements per cycle, chuted At time of fabrication. Tremie concrete joints. concrete, steel forms.

WATERPROOFING As described above. METHOD:

PLACEMENT Ballasting involved piadng dry sand on the floor slab before and after the element was METHOD: positioned over the trench. The lower duct was filled with sea water and an eddi~orm! load of sand was placed. The final load edjustement was made by wetting the sand on the roadway slab. For the first five joints, sand jacks mounted on pile supported piers were used to land the elements. This method was simplified by using Umber gfil~ lowered to bear on Ri.las driven 15 crn high, to allow for settlement. This grillage was intended to crush under settlement. If the element was not to suitable grade, some of the sand bed had to be removod--8 very difficult and time-consuming operation. The elements were supported by a derrick barge at one end and leads from a pile driver at the other. Late~ movements were controlled by lines from winches mounted on ~. Immediate~ after ~ ~t in position, more water ballast was added. The exterior sand bed was ~ by pumping a sand slurry under the element as directed by divers. On compietion of the sand bed, the element was filled with water. The tramle joint was made and completed from inside later. Before dewatering or removing ballast, at least 3.4 m of backfill had to be pieced to overcome buoyancy (the stability of the tunnel depends on this cover being rnaintmined throughout its lifel).

VENTILATION Fully transverse, using lower duct for supply and upper for exhaust. TYPE:

COVER AND TYPE: See above.

ADDITIONAL OWNER: Alameda County bond holders. INFORMATION: DESIGNER: George A. Poeey Chief Engineer; W.H. Burr, , and Charles Dedeth, Jr. CONTRACTOR: Califomia Bddge and Tunnel Co.

184 Tu~s~-v.r~o a~ro U~mmmo~vo 8~acz T~cssov0oy Vob,mA 8, Numi~,- 2, 1998 TUNNEL NAME AND LOCATION/DATE COMPLETED: Rle No. 6 Detroit Windsor Tunnel; International tunnel between Detroit, Michigan, U.S.A. and Windsor, Canada; 1930 ©

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; double steel shell elements. Two lanes, one each way.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 9 76m 10.6 m 10.6 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 670 m 18.5 m

UNUSUAL The tunnel project was a combination of open approach structures, cut-and-cover FEATURES: structures, shield-driven tunnelling, and immersed tunnel construction.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Welded steel construction. Steel fabricator; At dock near tunnel site. Tremie concrete. controlled side launching into dver 6 miles from site. Exterior formwork was erected at oui;;i~;ng pier.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Ballasting was done to bring the element to near neutral buoyancy. Concrete blocks were METHOD: placed at one end to sink it some five feet. A barge was placed transversely to the end and lowering cables were attached. After this was also done at the opposite end, the element could be raised or lowered using these barges.

FOUNDATION Screeded bedding. METHOD:

VENTILATION Fully transverse ventilation system. TYPE:

COVER AND TYPE: No cover.

ADDITIONAL OWNER: Detroit & Canada Trunnel Corporation. INFORMATION: DESIGNER: Parsons Klapp Bdnckerhoff & Douglas. CONTRACTOR: Porter Brothers and Robed Porter of Spokane.

Vol.m,~ 8, Number 2, 1998 Tum~.r.n;o AND Ummmmoum) SPJ~cB T~s~c~,r 185 TUNNEL NAME AND LOCATION/DATE COMPLETED: File No. 7 Benkhead Tunnel; Mobile, Alabama, U.S.A.; 1940

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; double steel shell tunnel. Two lanes; one each way.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 7 90.8 m 10.4 m 10.4 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 610 m 25 m

UNUSUAL Placed from pile-supported frames. Foundation matedal was piacod with element held in FEATURES: position from frames. Elements were piaeed a few inches high to accommodate settlement.

ENVIRONM ENTAL Close to mouth of river at Mobile Bay, with fresh water wedge sometimes extending beyond CONDITIONS the site. The variation from upper salt water into fresh water had to be taken into account in sinking the elements. Hurricane tide gates were provided at the portals.

FABRICATION METHOD: OUTFI'i-rlNG: JOINT TYPE: In shipyard I km away from site. The elements were Concrete was placed from Tremie concrete. side-launched into dver, then placed in shipyard's dry floaSng batch plant. dock for placement of keel concrete (for stability). The element was then towed to the outfitting yard near the site.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Gallows frames supported from H-pile clusters. METHOD:

FOUNDATION Element was held at grade while sand was pieced along the aides with ~emie pipes. METHOD:

VENTILATION Longitudinal; fresh air enters at portals, exhausted by air duct (roadway flues near tunnel TYPE: midpoint).

COVER AND TYPE: A minimum of 3 m of backfill.

ADDITIONAL OWNER: City of Mobile revenue bond issue. INFORMATION: DESIGNER: Messrs. Wilbarding and Palmer, Inc. CONTRACTOR: Arundel Corporation and the Alabama Drydock and Shipbuilding Company.

186Tum~#.mo AND U~CDmmmOUNDSEA(= TzcmzoY.~,z Volume 8, Number 2, 1993 TUNNEL NAME / LOCATION/DATE COMPLETED: Rle No. 8 Maas Tunnel; Rotterdam, The Netherlands, under Nieuwm Maas-Rlver; 1941

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicles, cyclists, pedestrians; concrete-box Four lanes in two tubes for vehicles. One tube for cydists elements. and one tube for pedestrians.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 9 61.35 m 8.39 m 24.77 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOMOF STRUCTURE: 584 m

UNUSUAL Immersed tunnel terminated in ventilation buildings constructed as pneumatic caissons. FEATURES: Construction spanned the occupation of Holland during the Second World War.

FABRICATION Casting basin in Heyse Harbor. Roof slab was left off un'dl the element was in position in METHOD: Waal Harbor. Three cycles of three elements were used.

WATERPROOFING 6-mm steel membrane covered with coating of concrete to inhibit rusting. METHOD:

PLACEMENT Lowedng by means of floating cranes. Pontoons along the sides of the elements were METHOD: used to provide posBve buoyancy.

FOUNDATION Sand-jetted foundation. Very first application of Chris'dani & Nielsen method. METHOD:

VENTILATION Semi-transverse ventJlaUon system. TYPE:

ADDITIONAL OWNER: Municipality of Rotterdam. INFORMATION: DESIGNER AND CONTRACTOR: Christiani & Nielsen, N.V.

Volume 8, Number 2, 1993 Ttml~.T.r~o AND Ul~m~moulqV SP~ ~ 187 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 9 State Street Tunnel; Chicago, Illinois, U.S.A.; 1942

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; double shell steel elements. Two tubes; one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 61 m 7m 12.0 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 61 m 15.8 m

ENVIRONMENTAL Mild currents. CONDITIONS

FABRICATION METHOD: OUTFITTING: JOINT TYPE: In a drydock. Welded construction. Pressurized to At a dock with 6 m of draft Tremie cono-ite. 0.5 psi for soap bubble test. 1,000 cu. m placed in available. drydock.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Element hung from under scows by cables fed through wells. Element had to be sunk METHOD: below scows to attach them.

FOUNDATION Element was landed on Vemie concrete pads formed to exact grade; screw jacks on the METHOD: comers were used to level the element. A screeded bed was placed as well.

DREDGING 2.5-cu.-m damshail ring. METHOD:

VENTILATION Piston action of trains. TYPE:

188 TmOUna~G,aND U~a~O~ S~ Tsc~o~ Vohune 8, N,,mlw¢ 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle N~ 10 AJl River; Osaka, Japan; 1944

TUNNEL TYPE AND USE: LANES/I'RACKS: Vehicular and pedestrian; steel-plate-covered Two lanes with sidewalk. reinforced concrete elements

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 49.2 m 7.2 m 14.0 m

TOTAL IMMERSED LENGTH: DEPTH AT BoI-rOM OF STRUCTURE: 49.2 14.9 m

UNUSUAL Structure acts like a Ixidge in soft muddy soil. Supported at beth ends by abutments FEATURES: constructed by pneumatic caisson method. Single concrete element reinforced with reinforcing steel and rolled steel sections.

ENVIRONMENTAL The depth of water was only 5.5-6.3 m. All navigation had to be stopped for nearly 15 CONDITIONS hours.

FABRICATION METHOD: OUTFI'I-rlNG: JOINT TYPE: The outside 9-mm shell was fabricated at a shipyard. In flotation at dockside 14 Rigid concrete filled joint to The element was then outfitted with reinforcing steel km from tunnel site in abutment structures. and concrete at a dock. Osaka Bay.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT The element was towed supported by two barges and placed using floating manes. Exact METHOD: position between elements was controlled by divers.

FOUNDATION Two L-shaped abutment caissons were sunk in place at the dver shorelines. The river bed METHOD: between the abutments was excavated and the element was supported on the abutments, rather than on a prepared foundation, as might normally be the case.

VENTILATION A semi-transverse ven'dlation system was first adopted; however, the tunnel ventilation was TYPE: later converted to a longitudinal system.

Volume 8, N-tuber 2, 1998 'l'tno~.v.wo AND UNZI~m)UND SPaCZ 'IkcSsc~)oY 189 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 11 Washburn; between Houston and Galveston, Texas, U.S.A.; 1950 ©

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; double shell steel elements. One tube; two lanes, one each way.

NO. OF ELEMENTS: LENGTH: 4 114.3 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 457 m

FABRICATION METHOD: JOINT TYPE: At shipyard in Pucagoula, Miss. end launched and Tremie concrete. towed 640 km to Pasaden¢ Texas. Special launching reinforcing was removed and ballast concrete was placed at an outfitlJng dock before the tow to Texas.

WATERPROOFING Continuous steel shell. METHOD:

190 TUm,~.T.mo ~ U~~ro 8PAc~ Tsc~vo~ Vob~m,~ 8, N,,mher 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: RIo No. 12 Elizabeth River Tunnel; between Norfolk and Portsmouth, Virginia, U.S.A.; 1952 ©

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; double shell steel elements. Singular tube; two lanes, one each way.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 7 91.5 m 11.0 m 10.8 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 638m 29m

UNUSUAL Sequence of construction started with Element A being placed prior to construction of west FEATURES: cut-and-cover section. Elements B, C, etc,. followed, until the final element was placed and connected under water to east cut-and-cover section already in place. Water depth required that the last element be temporarily "parked" some 0.5 m beyond the next to-the-lsst section until that section was connected to the preceding one. The final section was then moved back and connected to both the preceiding element and the cut- and-cover section. This was done within a sheeted trench, using land cranes.

Ventilation building was independently supported on piles off to to one side of the tunnel. Ventilation ducts had flexible connections to the tunnel structure, to allow for differential settlements.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Fabricated on shipways, provided with 1,000 tons of At dock near tunnel site. Tremie concrete joint. concrete for keel, fitted with a launching bow and end-launched.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Two floating derricks; 100-ton negative buoyancy. METHOD:

FOUNDATION Screeded bedding. METHOD:

VENTILATION Semi-transverse system, whereby vitiated air is withdrawn at top and bottom air ducts and TYPE: fresh air enters through portals.

COVER AND TYPE: 1.5 m minimum backfill.

ADDITIONAL OWNER: Elizabeth River Tunnel Commission. INFORMATION: DESIGNER: Parsons Brinckerhoff Quade & Douglas.

Volume 8, Number 2, 1998 Tumm,.,.wo *~o U~moiomm SPacl TeCBNOLOO~191 TUNNEL NAME AND LOCATION/DATE COMPLETED: File No. 13 Baytown Tunnel; Baytown, Texas, U.S.A.; 1953

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; single tuba single steel shell elements. Two lanes; one each way.

NO. OF ELEMENTS: LENGTH: 9 90.3 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 780 m 33.5 m

UNUSUAL Circular element with 12-ram exterior steel shell. ~ concrete dng 91 cm thick. FEATURES: Ternporadly supported on fabricated steel chair until ~. Two alternates were bid; the other was a double shell steel design.

OUTFITTING: JOINT TYPE: At work pier constructed near site. Tremie concrete joint.

WATERPROOFING Continuous steel shell plate. METHOD:

PLACEMENT Supported by two straddling barges attached with the element sitting on bottom. METHOD:

FOUNDATION Screeded bedding. METHOD:

VENTILATION Semi-transverse with fresh air supplied through lower, under-roadway air duct and TYPE: exhausted st portals.

COVER AND TYPE: 1.5 m minimum backfill.

ADDITIONAL OWNER: State of Texas Highway Department. INFORMATION: DESIGNER: Parsons Bdnckerhoff Hall and McDonald. CONTRACTOR: Brown & Root, Inc.

192 TtYm~.T.mo AND U~ SI"ACS~o~ Vob,~ 8, Nm~Der 2, 1998 TUNNEL NAME/LOCATION/DATE COMPLETED: Rla No. 14 Baltimore Harbor Tunnel; Baltimore, Maryland, U.S.A.; 1957

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; two-tube double-steel shell Four lanes; two each way elements

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 21 91.4 m 10.7 m 21.3 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 1920 m 30m

UNUSUAL Shell plate protected with 6.4-cm gunnite coating over extedor 120-degree section of both FEATURES: tubes.

ENVIRONMENTAL Mild currents and tides. CONDITIONS

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Shipyard in Baltimore and end-launched from At dock near site. Tremie concrete joints. shipways.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Two to four floating derricks were used. METHOD:

FOUNDATION Screeded bedding. METHOD:

DREDGING Cutterheed suction dredge spoil used for development of port site. METHOD:

VENTILATION Fully transvenm ventilation system. TYPE:

ADDITIONAL Owner: Maryland State Roads Commission. INFORMATION: Designer: Singsted & BaJllie. Contractor: Merritt-Chapman & Scott, Inc.

Vob~ 8, N-tuber 2, 1998 Tom~.T.nqo XND U~ SP,~.~ T~m~ 193 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 15 Hampton Roads Bridge Tunnel; Hampton Roads, Virginia, U.S.A.; 1957

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; single tube, double steel shell Two lanes; one each way (later became northbound lanes elements when Second HRT was completed in 1976).

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 23 91.5 m 11.3 m 11.3 m

TOTAL IMMERSED LENGTH: DEPTH AT BO'I-I'OM OF STRUCTURE: 2091 m 37 m

UNUSUAL Rrst immersed tunnel to be constructed from two manrnade islands. From the islands, this FEATURES: mossing reached the shores by way of two causeways. Later, four other tunnels using this same arrangement were constructed in the Hampton Roads and Chesapeake Bay aree.

ENVIRONMENTAL Strong currents and wave action made island building difficult until rock dikes were CONDITIONS constructed. Seaward face of islands had to be protected by cydopean-sized dprap to prevent erosion.

FABRICATION METHOD: OUTFITrlNG: JOINT TYPE: Shipyard in Baltimore. At dock near site of tunnel. Tremie concrete joints.

WATERPROOFING Continuous steel shell plate. METHOD:

PLACEMENT Catamaran barges. METHOD:

FOUNDATION Screeded bedding. METHOD:

DREDGING Cutterhead suction dredge for shallower portions of trench. Send was used to build the METHOD: islands. Deeper portions were done with a clamshell bucket dredge.

VENTILATION Full transverse system. TYPE:

COVER AND TYPE: 1.5 m of sand, in some cases protlcted~ ~~ ~, Backfill came from channel dredging being done concurrently by U.S. ~ of E~nsers.

ADDITIONAL OWNER: Virginia Highway Department. INFORMATION: DESIGNER: Parsons Bdnckerhoff Hall.and McDormld. CONTRATOR: Merrltt-Chapment & Scott, Inc.

194 ~.T.mG AND Ul~mmRo~ 8PaCZ T~ssoum~ Volume 8, N,,mher 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 16 Havana Tunnel; Havana, Cuba; 1958

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; prestressed concrete box elements. Two tubas; two lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 5 4 @ 107.5 m and I @ 90 m 7.10m 21.85 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 520 m 23m

UNUSUAL First fully prestressed immersed tunnel. Both longitudinal and transverse prestressing was FEATURES: utilized.

FABRICATION METHOD: JOINT TYPE: All by non-reusable timber formwork in a casting Tremie concrete joints. basin in groups of two.

PLACEMENT Placed from catamaran placing barges. Pontoons were used to assist flotation of element METHOD: prior to sinking.

ADDITIONAL DESIGNER/CONTRACTOR: Soci6t0 des Grands Travaux de Marseille. INFORMATION:

Volume 8, Number 2, 1998 Tulon~.~mo AND UNv]mmw~ro S~Acs Tsc~sNouxn' 195 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 17 Deas Island Tunnel; Vancouver, British Columbia, Canada; 1959

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; reinforced concrete box elements. Two tubes; four lanes (two in each tube).

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 104.9 m 7.16m 23.8 m

TOTAL IMMERSED LENGTH: DEPTH AT~TTOM~STRUCTURE: 629m ~m

UNUSUAL Designed for earthquake Ioadings (Zone 3). FEATURES:

ENVIRONMENTAL Extensive river, tunnel placement, and cover stability laboratory modelling was conducted. CONDITIONS:

FABRICATION OUTFITTING: JOINT TYPE: METHOD: At outfitting jetty next to Inflatable rubber-gasketted joint used for initial seal. Final Casting basin next to tunnel site. seal made in conventional way, by dewatering joint and tunnel site for all six mobilizing hydrostatic pressure. Monolithic permanent elements. joint.

WATERPROOFING 5-mm steel plate on bottom lapping with membrane up the sides and over the roof slab. METHOD: The waterproofing was protected with a 10-cm layer of reinforced concrete under the bottom and on the top and by 10 cm of wood planking on the walls.

PLACEMENT Four barges, two on each side of the element, were arrayed in a catamaran arrangement. METHOD: Manuevering lines included ve~cal lifting lines, transverse and longitudinal tag lines and dgging from faideads on the element, acting horizontally to main anchors. Control and survey towers were used to access the inside of the elements and control the positioning of the element.

FOUNDATION Send-jetted foundation. METHOD:

DREDGING Cutterheed suction dredging; also used for casting basin. METHOD:

VENTILATION Semi-transverse from two ventilation buildings. Fresh air is drawn into the tunnet through TYPE: the portal. In the second half, air is introduced into the tube and leaves the tunnel at the exit portal.

COVER AND TYPE: Double layers of 1,500-1b. stone on top of the structure with additional protection of the sides consisting of 500-1b. stone extending out 50 ft. on either side of the tunnel box.

ADDITIONAL OWNER: Department of Highways of British Columbia. INFORMATION: DESIGNERS: Foundation of Canada Engineering Corporation, Ltd. and Chdstiani & Nielsen. CONTRACTOR: Peter Kiewit & Sons Co. of Canada Ltd. and B.C. Bridge and Dredging Co., Ltd. Joint Venture; Narod Construction Ltd. and Dawson and Hall.

198 Ttno~a~wo Am) Usmma~tmD Sl,aCz Tmm~OLOm Volume 8, N,~m1~r 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 18 Rendsburg Tunnel; Keil Cans, Rendsburg, West Germany; 1961

TUNNEL TYPE AND USE: LANES/I"RACKS: Vehicular tunnel; reinforced concrete box elements. Two tube; two lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 140m 7.3 m 20.2 rn

TOTAL IMMERSED LENGTH: DEPTH AT BO'I-rOM OF STRUCTURE: 140m 22m

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Cast in approach section. Composed of seven 20-m Gasketted joint. sections tied together with reinforcing steel. Steel shell exterior.

WATERPROOFING Steel shell on sides and bottom; membrane over top. METHOD:

PLACEMENT Hung from pile-supported jacking devices. METHOD:

FOUNDATION Bottom screeded from special screed system attached to rails on side of element, which METHOD: planed the bottom before lowering the element to final position.

Volume 8, N-tuber 2, 1998 ~-,-wo AND U~mmoaov~ SPAcl ~ 197 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 19 Webster Street Tunnel; Between Oakland andAlameda, California, U.S.A.; 1962 ©

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; cylindrical reinforced concrete Single tube, two lanes. elements.

NO. OF ELEMENTS: LENGTH: 12 61 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 732 m

UNUSUAL See below. FEATURES:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Constru(:~d in a gravlng dock excavted 2 miles from the During fabrication in Trernie concrete joints. pro~ s~. Two elemonts were constructed per cyoie. graving dock. A 70-ton stop-log gate, which could be removed by a floating crane, was used to permit the elements to exit the graving dock.

WATERPROOFING Membrane with timber protection. METHOD:

PLACEMENT Bement first brought to !00-ton positive buoyancy with combindon of dry ~ spread METHOD: on roadway and wster bellast in tanks under ~y. The 100 tons were ~ and a50- ton ne~e buoyancy was developed using weder spdnlded on the dry bellast. Derricks on each end supported this modest load and lowered the unit in place. Wood chips were used to extend the dry ballast volume.

FOUNDATION Placed on temporary supports with capacity to take section ballasted to 300 tons. Sand METHOD: placed with tremle pipe bent to direct ballast under element. Additional turbulence at the end of the pipe was produced using a water jet.

Each element was bedded into the original deposit of sand by ballasting to more than 600 tons. Thiswelght was sufficient to guarantee failure of the temporary support after a minimum s~ernant of 10 cm. Actual settlements were only 2.5 cm, aasudng that the load was pldwd up by the bedding. In the channel,13,000 tons of iron ore were used to provide additional ballast because sand ballast alone could not provide the required weight in the available vertical distance.

ADDITIONAL OWNER: California Dlvision of Highways. INFORMATION: CONTRACTOR: Pomeroy-Bates and Rogers-Gerwick.

198 ~o A~w Uh~m~mo;mv SPAc~ ~oux~ Volume 8, N-taker 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 20 Elizabeth Rlver Tunnel No. 2; in Norfolk and Portsmouth, Vl~Inle, U.S.A.; 1962 @

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; double shell steel tunnel. Single tube; two lanes, one each way.

NO. OF ELEMENTS: 12

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 1056 m 30m

UNUSUAL Due to very poor soil conditions, Element No. 1 was supported on timber compaction piles. FEATURES:

ENVIRONMENTAL Mild currents and tides. CONDITIONS

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Side-laurmhed (uncontrolled~ from shipyard in Port At dock near tunnel site. Tremie concrete. Deposit, Maryland, about 30(I km away. Keel concrete placed for towing stability.

WATERPROOFING Continuous steel shell plate. METHOD:

PLACEMENT Placement with floating cranes. METHOD:

FOUNDATION Screeded bedding. METHOD:

DREDGING Clamshell dredging. METHOD:

VENTILATION Semi-transverse ventilation system. TYPE:

ADDITIONAL OWNER: Elizabeth River Tunnel Commission. INFORMATION: DESIGNER: Parsons Bdnckerhoff Hall and McDonald. CONTRACTOR: Merritt-Chapman & Scott Corporation.

Voluz~ 8, N,,mher 2, 1993 ~.~o AND UNm~m~imv SPzcz T~ztNc~zGY 199 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 21 Chesapeake Bay Bridge Tunnel; between Norfolk and Cape Charles, Virginia, U.S.A.; 1964 ©

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; double-shell steel elements. Single tube; two lanes, one each way.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: Thimble Shoal: 19 91.4 m 11.3 m 11.3 m Baltimore Chan.: 18

TOTAL IMMERSED LENGTH: 1750 m

UNUSUAL Part of the 29-kin crossing of Chesapeake Bay. The immersed tunnel consisted of two FEATURES: separate tunnels under the two shipping channels: (1) the Thimble Shoal Channel and (2) the Baltimore Channel. Construction was accomplished in virtually open ocean conditions. Tunnels terminated in manrnade islands, similar to those constnJcted for the first Hampton Roads Tunnel.

ENVIRONMENTAL Severe storm exposure. Hurricane destroyed the "Big D" jaddeg platform. CONDITIONS

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Shipyard in Orange, Texas; end-launched. Trimmed At dock near tunnel site. Tremie concrete joints. with "stem" 4 ft. low for better ocean towing.

VENTILATION Fully transverse ventilation system. TYPE:

COVER AND TYPE: 3 m of selected backfill.

ADDITIONAL OWNER: The Chesapeake Bay Bridge and Tunnel Commission. INFORMATION: DESIGNER: Sverdrup & Parcel and Aseodates. CONTRACTOR: Joint venture of Tidewater Construction Corp., IVlerdtt-Chapman & Scott, Raymond International Inc., and Peter IOewtt Sons Co. TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 22 LIIJeholmsviken; Stockholm, Sweden; 1964

TUNNEL TYPE AND USE: LANES/TRACKS: Railroad tunnel; prestressed concrete box element Two tracks.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 124m 6.03 m 8.82 rn

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 123m 13m

UNUSUAL This tunnel was consVucted in two separate sec'dons, which were post-tensioned together FEATURES: in flotation and placed as a single unit. This unit was designed to act as a continuous structure to span 53 rn between two supports in rock. In effect, this was an underwater bridge between two rock slopes.

A year after completion, a compressive force of 5000 tons was introduced into a temporary joint between a non-prastressed section constructed in a cofferdam and the abutting immersed tunnel. Jacks were used. This arrangement put the whole tunnel into a longitudinal prestressed condition. No leakage has been reported.

ENVIRONMENTAL Crossing between two rock faces underwater. CONDITIONS

FABRICATION METHOD: JOINT TYPE: In a drydock. Constructed in dry cofferdams.

WATERPROOFING Temperature matching between the top and bottom sections of the walls was used to METHOD: prevent cracking. The lower part of the structure was warmed before casting the upper part to avoid tensile cracking in the walls. Waterproof concrete and the full prestressing in all three axes made the section virtually watertight. No membrane was employed.

PLACEMENT Lowered by heavy lift cranes. Ballasting by partial water fill. METHOD:

FOUNDATION Lowered onto fixed supports. METHOD:

DREDGING None required for approaches. METHOD:

VENTILATION Piston action of trains. TYPE:

COVER AND TYPE: Tunnel was not covered.

ADDITIONAL The tunnel has been designed to wittwtand the load of a 1,500 ton ship resting on or INFORMATION: completely filling with water.

Volume 8, Number 2, 1993 Tum~.v.r~o Am) Uxz~iounv SPACZ ~ 201 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 23 Haneda Tunnel (Ebitori River Tunnel); Tokyo, Japan; 1964

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; steel shell rectangular section. Two tubes; two lanes in each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 56.0 m 7.4 m 20.0 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 56.0 m 12m

UNUSUAL Element is supported on caisson founda'dons at both ends (i.e., creating a sort of bridge FEATURES: under water). The design provided for composite action between steel shell and concrete structure. See also "Fabrication Method," described below.

ENVIRONMENTAL Hanede International Airport is located near the site. CONDITIONS

FABRICATION METHOD: JOINT TYPE: Steel shell was constructed in shipyard. Concrete for U-shaped steel plate over rubber joint. bottom slab was placed in flotation. The sidewalls and roof slab were pumped with concrete after the element was placed.

WATERPROOFING Steel skin on sides and bottom. Concrete protectKI membrane on top of element. METHOD:

PLACEMENT Three heavy lift cranes were used to control placement, METHOD:

FOUNDATION Caisson foundations. METHOD:

VENTILATION Longitudinal ventilation. TYPE:

ADDITIONAL OWNER: Metropolitan Expressway Public Corporation. INFORMATION:

202 Ttnm~.r.-+o AND Umnmo~tn

TUNNEL TYPE AND USE: LANES/TRACKS: Monorail system; single-shell steel box section. ~ngletube;twotmcks.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 56 m 7.4 m 10.95m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 56 m 11.7m

UNUSUAL Monorail tunnel. The tunnel is supported at both ends on caisson abutments in common FEATURES: with the Haneda vehicular tunnel adjacent to it to it (see Rle No. 23).

ENVIRONM ENTAL Height of crane booms was limited because the tunnel's proximity to Haneda International CONDITIONS /Urport.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Rectangular steel box section fabricated at the IHI After launching, the Rubber gaskettad joint. dockyard. element was towed to a pier near the tunnel site. The floor slab concrete and protac'dve roof concrete were placed in flotation. The side-wail concrete and ceiling concrete were placed by pumping after the element was immersed.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Heavy lift cranes. METHOD:

FOUNDATION Element spans between abutments. No special foundation preperation. METHOD:

DREDGING Excavation by grab bucket to depth of 11.9 m. METHOD:

VENTILATION Piston action of trains. TYPE:

COVER AND TYPE: Backfill with sand and counterweight of slag on top of tunnel.

ADDITIONAL Cathodic proteotlon was applied to steel shell plate. INFORMATION: OWNER: Hitachi Transport, Tokyo Monorail Corporation.

Volume 8, N-tuber 2, 1998 T~e~.Tmo AND UmzlmRowro SPacn T~oLooY TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 25 Coen Tunnel; , Netherlands; 1966

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box section. Two tubes; two lanes in each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 90m 7.74m 23.33 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 540m

FABRICATION METHOD: OUTFITTING: JOINT TYPE: In a casting basin dredged for the purpose. All six outfit~ was done part~/ Gina-type gasket system. sections were cast in one cycle. at the time of fabrication in the basin and partly at the outfitting jetty in the flooded basin.

WATERPROOFING Asphalt bitumen covered with fiberglass was used to provide a waterproof covedng about 1 METHOD: cm thick. This rnllmdaJ was in tum covered with concrete, which was attached to the main concrete box using ramset studs, each with special waterproof steel collars.

PLACEMENT Four pontoons were used to lower the sections. Towers for survey control and for METHOD: operations control and access were provided (one tower at each end of the elements).

FOUNDATION Raced on four screaded piles of gravel and adjusted to grade, using,jacks. Sand was later METHOD: jetted under the dements.

DREDGING Hydraulic dredge. METHOD:

VENTILATION Semi-transveme system. TYPE:

ADDITIONAL OWNER: Rijkswatemtut, Directle Sluizen & Stuwen. INFORMATION: DESIGNER: By the owner, with Christiani & Nielsen as consultants.

204 ~o asv Ummmlom¢o 8P~ Tsc~oo~ Volume 8, Nm=km- 2, 1998 TUNNEL NAME/LOCATION/DATE COMPLETED: File NO. 26 Wolfburg Pedestrian Tunnels; Wolfburg, Germany--two tunnels under Mlttelland Canal, opposite the VW plant; 1966

TUNNEL TYPE AND USE: LANES/TRACKS: Pedestrian; reinforced concrete box elements. Footways.

NO. OF ELEMENTS: TOTAL LENGTH: HEIGHT: WIDTH: 1 for each tunnel 58.0 m 5.10 m 11.0 m (12.52 m atthe ventilation shafts)

DEPTH AT BO'I-I'OM OF STRUCTURE: 10 m below mean water level.

UNUSUAL Because of the narrow shipping canal and the high groundwater level in the adjacent FEATURES: excavations, the ends of the floating elements had to be provided with an upwards bend to allow for connections to the landside tunnels.

ENVIRONMENTAL Virtually no current. CONDITIONS

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Cast in approach excavation. In casting basin during Construction in the dry. fabrication. Joint made watertight with bitumen seal coat.

WATERPROOFING All around, multiple-layer bitumen seal protected by pearl gravel. Roof slab membrane METHOD: protected with reinforced concrete slab.

PLACEMENT Floating and lowering using block and tackle from transverse steel girders supported on the METHOD: outboard ends of the support of excavation for the approach tunnels.

FOUNDATION Bottom scrseded by a plow (girder) attached to steel girders, which ran on slide rails set to METHOD: grade.

DREDGING Clamshell and hydraulic dredges. METHOD:

VENTILATION Natural ventilation. Fresh air supply at entmncas and exhaust at ventilation shafts also was TYPE: provided for.

COVER AND TYPE: Sandflll.

ADDITIONAL OWNER: Volkswagen AG, Wolfaburg. INFORMATION: OPERATOR: Vol~gerl AG, Wolfaburg. DESIGNER: Philipp Holzmann AG, Frankfurt. CONTRACTOR: Philipp Holzmann AG, Frankfurt.

Volume 8, Number 2, 1998 TUm~.T.-VO AND Ux~mm~-x~ SPAcz T~mNc,.o~ 205 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 27 Benelux; Rotterdam, The Netherlands; 1967

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; reinforced concrete box sections. Two tubes; two lanes of traffic in each tube..

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 8 93 rn 7.84 m 23.9 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOMOFSTRUCTURE: 745 m 24 m

UNUSUAL Tunnel is completely curved, with all tubes cast as identical curved sections. FEATURES:

ENVIRONMENTAL Swift river currents created problems in dredging the soft sediments. CONDITIONS

FABRICATION METHOD: OUTFI'I'rlNG: JOINT TYPE: At casting basin conatmcted for the tunnel. All eight Part of fabrication opera, on Pulled together using a sections were cast at the same time. in casting basin. hook, the Gina-type gasket was engaged; conventional dewatedng followed to make up the joint.

WATERPROOFING Bituminous membrane, protected by reinforced concrete. METHOD:

PLACEMENT Used four pontoons for lowering. A tower for survey was provided at the outboard end of METHOD: the tube; a tower for aocass and control was provided on the inboard end.

FOUNDATION Used foundation plates supported on layer of gravel for tem~ grade adjustment. Sand METHOD: was then jetted using tunnel elements, after acceptable conditions were obtained. Silt skirts were used to protect the area under the elements from being filled with soft silt scour off the bottom of the dver.

VENTILATION Longitudinal, using jet fans. TYPE:

ADDITIONAL OWNER: Amsterdam Public Works Department. INFORMATION: DESIGNER: Locks and Weirs Department of the APWD. CONTRACTOR: N.V. Amsterckamsche Ballast Mij; Chds'dani & Nielsen N.V.; Internationale Gewapendbeton-Bouw N.S.; Nederlendsche Aanneming Mij, v/h flrma H.F. Boarsma and N.V. Nederlendsche Baton Maalm:happij.

208 ~.:~ro Am) U~mmmtousm SP,~_cz Tscss~oo~ Volume 8, Nnmhe~- 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle NO. 28 Lafontaine Tunnel; Montreal, Canada; 1967

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; prestressed concrete box section. Two tubes; three lanes in each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 7 109.7 m 7.84 m 36.75 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 768 m 27.5 m

UNUSUAL Because of difficulty in applying high prestressing forces after the element was placed~ FEATURES: combined with the fact that the same forces could not be applied before placing, temporary vertical midspan prestressing was applied to prevent upward budding of the roof =dab. This permitted the transverse prestressing to be fully applied prior to placement.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: In casting basin constructed in conjunction with As pert of fabrication in Gina-type rubber ~katted approach area. Capacity for four elements at a time. casting basin. joint.

WATERPROOFING Bituminous membrane on walls and roof. Steel membrane on bottom. METHOD:

PLACEMENT Catamaran barges. Lowering using linear winches. Temporarily supported on four piles. METHOD:

FOUNDATION Sand-jetted foundation. METHOD:

COVER AND TYPE: Backfill with minimum thickness of approximately 2 m.

ADDITIONAL OWNER: Department of Highways, Province of Quebec, Canada. INFORMATION: DESIGNERS: Brett & Ouellette, Lalonde & Valois and Per Hall & Associates. Ohristiani & Nielsen designed the sand-jetting operation.

TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 29 Vieux-Port Tunnel; Marmilles, France; 1967

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; two side-by-side concrete box sections. Two single tube =~-'tior~, each with two lanes.

TOTAL LENGTH: 273 m

Volume 8, Number 2, 1993 Tm.,,--,.,,m aND USDm~ROUSD 8PaCl ~ TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 30 Tingstad Tunnel; Gothenburg, Sweden; 1968

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; concrete box tunnel. Two tubes; three lanes each way.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 5 4 elements--93.5 m; 7.3 m 30m 1 element--80 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 455m 16m

ENVIRONMENTAL Siltation of bottom dudng pkmement of elements. CONDmONs:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: In a drydock, one at a time. Partial roof was Completion of roof of jo~s. vera~jou~tsaro constructed to be finished later in flotation. elements was done in ~o~ at interv~ of floating condition at approximately 15 m. dockside.

WATERPROOFING 6-mm steel membrane all around. Roof and slanting parts coated with 10 cm of concrete; METHOD: remainder protected by anti-corrosive paint. Cathodic protection is also provided.

FOUNDATION Elements were placed on large nylon sacks that could be pumped full of grout. These METHOD: sacks formed the adjustment between the element and piled foundations along the element. After the bottom of the trench was levelled with gravel, timber piles q:lCCoxlmately 22-m long were driven into the clay, which is 80-100 m deep. The space under the elements at the pile groups had to be protected against the incursion of mud. After the sacks had been grouted first, to assure good contact, the other areas were also grouted.

VENTILATION Semi-transverse vonffiation, with ventilation building at each end of the tunnel. TYPE:

BUOYANCY SF: 1.1 CONCRETE CUBE STRESS: 35 MN/sq. m

COVER AND TYPE: Protection stone layer 0.5 m thick was placed over the tunnel.

ADDITIONAL INFORMATION: No damage to the concrete has been observed. The lower parts of the walls are covered by tiles because the tunnel was opened. No unexpeoted settlements have occurred. Maximum settlements,most of it occurring eedy, ranged between 40 mm and 50 mm. Minor cracks oocurred in the wall and roof. ~ic protection has been renewed onos. SeUlements directly aftra" immersion were approximately 10 mm. Alter b~, the ~ inoremKI to 20 mm. Backfill surcharge was approximataly 50 kN/sq, m. The differences in ml41lement8 UlWOcalmKi by vadllton in ground conditions and depth of surcharge. Areas of the facilities that were not pile-supported have settled more than 0.5 m.

OWNER: Swedish National Road Administration. DESIGNER: Skaneka. CONTRACTOR: Skanska.

~o Am) Umw~o~-. SP~ T~u~ou~y Volume 8, N.mber 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 31 Rotterdam Metro Tunnels; Rotterdam, The Netherlands; 1968

TUNNEL TYPE AND USE: LANES/TRACKS: Metro rail system; reinforcad concrete sactJons. Two tubes; one track in each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 36 90m 6.0m 10.0 m

TOTAL IMMERSED LENGTH: 1040 m under the Nieuwe Mass and 1,815 m between Central Station and Leuvehaven.

UNUSUAL Because of high ground water and favorable alignment conditions, 24 elements were FEATURES: floated in along the land po~on of the Metro system. This included partial station sectfons as well. Inflatable adjustable pile caps were used to support the tunnel elements.

ENVIRONMENTAL Construction in high ground water table. Construc'don through densely populated urban CONDITIONS: area.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Made of 15-m sactJons temporarily post-tensioned Part of fabrication Gins rubber joints. together into 90-m elements, in a casting basin operation. excavated near the site.

WATERPROOFING Bituminized feit-coverad glass covered with fiberglass fabric. Top and bottom portions METHOD: were protected with concrete attached with dowels.

PLACEMENT Catamaran barges were used for the water crossing. Monorails and hoists were METHOD: suspended from the upper bracing for the elements placed inside the trenches on land. Water ballast tanks were used for both areas to lower the elements.

FOUNDATION Pile foundations were used. Adjustable pile caps inflated with grout were used to support METHOD: the elements.

VENTILATION Piston action of trains. TYPE:

ADDITIONAL OWNER: Municipality of Rotterdam. IN FORMATION: DESIGNER: The client, ChristJani & Nilsen and Hollandsche Baton. CONTRACTORS: ChdstJani & Nielsen N.V. and Hollandsche Baton Maatechappl; sinking was done by the client's organiza'don.

Volume 8, N-tuber 2, 1998 T~'NN~.,Jwa Am) U~~ SP,~,cz T~sm'ou:.~ TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 32 Ij Tunnel; Amsterdam, The Netherlands; 1969

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; reinforced concrete box section. Two tubes; two lanes in each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 9 90m 8.55 m 23.9 m

TOTAL IMMERSED LENGTH: 790 m

UNUSUAL Two sections on Ixecast pilas were made In open~ ~ sheet pile walls; one FEATURES: section was made by rmm~ of four pneumatlc ¢=Jaons. Each of the Immersed sectloP~ was 8ubdMdod by two~por',,d'y jointe and was ~ on four pile caps constructed in the dry at the bottom of the river under a pressurized air chamber.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: In groups of two in a casting basin. Part of fabrication operation Gina-type gasket. in the casting basin.

PLACEMENT Tunnel elements were pulled downward onto the two central pile caps, using muitipart METHOD: lines. Water ballast was added to provide a negative buoyancy of 200 tons. The cables were disconnected and jacking devices were installed by divers topull the element in and make initial gasket contact. The water pressure in the joint spaoe was then released to comprass the gasket. The end sections were dosed using exterior piatas with rubber gaskets, which permitted the joint concrete to be formed in a dry environment.

FOUNDATION Elements were placed on cast..Jn-pla(:o pile cops dascribed above. METHOD:

VENTILATION Fully transverse, with air supply and exhaust ducts under roadway. Fresh air enters on the TYPE: right side and crosses to the left side, exiting through large Iouvres.

210 ~-,.r~o AND U~mz~Bov.mv St,~ TscssowoY Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 33 Scheldt E3 (J.F.K. Tunnel); , Belgium; 1969

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular and railroad; prestressed concrete box Two roadway tubes with three lanes in each tube; one elements. railroad tube with two tracks.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 5 Four elements @ 99 m 10.1 m 47.85 M One element @ 115 m

TOTAL IMMERSED LENGTH: 510 m DEPTH AT BOTTOM OF STRUCTURE: 25 m

UNUSUAL Extremely wide tunnel with combined rail and road usage. The project used the largest FEATURES: tunnel elements ever constructed (47,000 tons) at the time. A quay wall, which was replaced over and supported on the tunnel, was constructed as hollow concrete caissons.

ENVIRONMENTAL River currents of up to 3.0 m/s. Tides with a mean range of 4.8 m and a maximum range of CONDITIONS: 8.86 m.

FABRICATION METHOD: JOINT TYPE: All five elements were cast in one cycle in a casting Gina joint. basin near the tunnel site.

WATERPROOFING 5-mm-thick steal sheet on bottom painted with tar epoxy. Joints between the single sheet METHOD: were sealed with bituminous strips. Wails and roofs were provided with a three-ply membrane. On the wails, membrane was protected by timber sheeting supported on steel beams fixed to the concrete. The 3-cm space between the timber and the membrane was tilled with mortar. Roof protection consisted of a 10-cm-thick reinforced concrete slab. Bulkheads were constructed of 14-mm-thick steel plate supported on horizontal and vertical beams (to save weight). The joints between the sheets were covered with bitumen mastic and the whole bulkhead was covered with a 2-mm butyl membrane.

PLACEMENT Ten tugs (12,000 HP) were required to placa the first element. Barges transverse to the METHOD: element were used with control and survey towers in customary fashion.

FOUNDATION Because of high water velocities, siltation was a serious problem. Skirts around the bottom METHOD: of the elements were tried, but silt penetrated beneath them. A special patented sand jetting system, devised by Christiani & Nielsen, removed the silt and replaced it with sand.

DREDGING River sediments, mainly loamy sand, were removed by cutterhead suction dredges. Stiff METHOD: day was removed by a chain bucket dredge which could dredge to 30 m. Because of current velocities at midstream, the dredge had to excavate the upstream slope and the downstream slope aitemately. In addition, the trench was dredged wide enough to accommodate the elements moored in the direction of the current (floating in the event of an emergency).

VENTILATION: Semi-transverse system with fresh air supply.

COVER AND TYPE: No cover over elements, other than 10 cm concrete.

CONCRETE CUBE STRESS: 450 kg/sq, cm POST-TENSIONING: Partial: 235-ton tendons at 0.5 m.

ADDITIONAL OWNER: Intercommunele E3. INFORMATION: DESIGNER/CONTRACTORS: Enterpdsas Ackermans & van Hearen, Compagnie d'Entreprises C.F.E., Compagnle International des Pleux Armes Frankignol and Soci6t6 Beige des Batons and Chdstiani & Nielsen.

Volume 8, Number 2, 1993 ~.T.wo AND UNDmmm)V~DSPA(= ~OLOO'r 211 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 34 Heinenoord Tunnel; Barendrecht, The Netherlands; 1969

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; reinforced concrete box elements. Two tubes, three lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 5 115m 8.8 m 30.7 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 574 m 28 m

UNUSUAL The third lane in each direction is provided for slow-moving traffic such as cyclists, tractors, FEATURES: and mopeds. Elevators at both ends of the tunnel permit cyclists and pedealda~ to avoid the long, steep gm_das. Placement of elements used a Uvee-point bearing rrmthed, two outboard foundation blocks, and a single point at the tunnel in place.

FABRICATION METHOD: JOINT TYPE: All five elements were fabricated in one cycle in a Gina joint. casting basin.

WATERPROOFING Bottom covered with S-ram steel plate. Walls and roof ~ with three layers of METHOD: asphalt-impregnated membrane. Roof protected with 15 cm of ralnfomed conc~-~,te.

PLACEMENT Two pontoons were arranged tran~ over the element at each end with ¢x:mtrol and METHOD: survey towers in oonventional fashion. Elements were plaoad on plates; verticldjacl used for verlk~ alignment adjustments.

FOUNDATION Three-point temporary foundation with pivot arrangement to allow good register between METHOD: the tunnel and the element being placed. Jetted sand used for foundation.

VENTILATION Longitudinal, using jet fans, TYPE:

ADDITIONAL OWNER: Rijkswat~-=ba¢l, Direktle Sluizen & Stuwen. INFORMATION: DESIGNER: by the client. CONTRACTORS: Chdstiani & Nielsen N.V. in joint venture with six other Dutch contractors known as the Nastum II Group.

212 Ttno~.v.mo ~ Uv~mmao~o 8~.~cz T~mNo~ Volume 8.1~,m~w 2. 1993 TUNNEL NAMFJLOCATION/DATE COMPLETED: 1:11oNo, 35 LlmfJord Tunnel; Arlborg, Denmark; 1969

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box section. Two tubes, each with three lanes.

NO. OF ELEMENTS: 5 LENGTH: HEIGHT: WIDTH: 102 m 8.54 m 27.4 rn

TOTAL IMMERSED LENGTH: 510 m DEPTH AT BoI-rOM OF STRUCTURE: 20.81 m

UNUSUALFEATURES: Surcharged sendfill was used to support immersed tunnel. Tension piles were used to support and hold down open approach and cut-and-cover sections of tunnel.

FABRICATION METHOD: OUTFn'I"ING: JOINT TYPE: Cast in a casting basin excavated for the Elements were outf'dted at a Gina type. Special gasketted end purpose, about 10 km from the tunnel Site. pier after floating with ciceum plates allowed connection to Elements were cast in 12.8-m- long temporary steeltoundation submerged fane of oast-in-place sections--first the bottom; then the walls; blocks at the free end, tunnel sections. Sequence of and, last, the roof. The sections were two alignment towers and element plac=ement was from one separated by a 1.8-m-gop into which rebar two sets of sinking rigs, shore to the other. Immersed tunnel protruded. These gaps were filled after each consisting of two is monolithic, with a contraction joint concrete shrinkage had taken place. 150-ton pontoons between It and the east4n-place connected by steel girders. tunnel and a combined expanslon- contraction Jolnt between It and the north portal building. The joints are made watertight with rubber gaskets.

WATERPROOFING The elements are waterproofed with a 2-mm butyl membrane, protected on the bottom METHOD: by a gem-thick layer of reinforced concrete and on the top by a 20-el-thick layer of reinforced concrete, and glued to the bottom protection and to the walls and roof of the tunnel by a PVC cement slurry.

PLACEMENT METHOD: Four straddling placement barges were used. Horizontal alignment was accomplished by lines connected at the top of the element.

FOUNDATION METHOD: Sand-jetting.

DREDGING METHOD: Dredging was taken down to -31 m and beddilled to grade with dean sand because of soft mud layers in the riverbed. The sand was surcharged with additional sand to a load equal to the tunnel weight to cause early settlement to take place. The sand was removed shortly before placing the elements.

VENTILATION TYPE: Longitudinally; jet fans.

COVER AND TYPE: No cover provided. 20 cm of reinforced concrete is the only protection to the waterproofing layer.

ADDITIONAL The tunnel is designed to be unmanned, with automatic ventilation and lighting INFORMATION: controls, and automatic and remote control used for traffic conb-ol. Aluminum sunscreans are used at the approaches, An acoustic suepended ceiling is provided.

OWNER: Minis'm/of Public Works. DESIGNER: Chdstiani & Nielsen NS. CONTRACTOR: Various Danish contractors. The tunnel motions by NYBYG and Christiani & Nielsen carded out the installation of the elements, including umd-joffing.

Volume 8, Number 2, 1998 Tum~.TJ~o ~¢v U~~ Sx=+.cs Tmc~ow~ 218 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 36 Perena (Hernendles) Tunnel; between Santa Fe end Perane, Argentine; 1969 ©

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; circular reinforced concrete tube. Single tube; two lanes.

NO. OF ELEMENTS: LENGTH: WIDTH: 36 65.5 m 10.8 m (one 10.75 m element was used on the Parana side, to make 37).

TOTAL IMMERSED LENGTH: 2,367 m DEPTH AT BO'I-I'OM OF STRUCTURE: 32 m

UNUSUAL Ught elements, filled with water to induce final settlomenk were held down with six FEATURES: outrigger pockets esoh. Baddill was vibrocompeoted around the element. A jack-up barge was used for element and locking fill placement. Partial ballasting was accomplished by filling between light end build, ads and intedor bulkheads (the latter capable of taking submerged water pressure), spaced at 13-m intervals. The exterior bulkheads could be det~hed and floated to the dock for reuse.

ENVIRONMENTAL Design current: 1 35 m/s (2.63 knots). CONDITIONS:

FABRICATION METHOD: JOINT TYPE: A casting basin, designed for nine cycles, was excavated. A ramie concrete joint using inflatable gaskets was Four elements were produced on a three-month cycle. used for all elements. A bottom slab was used to form The basin was 156 m long, 46 rn wide, and 13 m high. the tremie. Concrete hoods and cellars were used. The dock was dosed by a 15-m-high, 23-m-die. floating cylindrical caisson acting against two fixed cylindrical tanks with 50 om wall thickness.

WATERPROOFING 4-mm preformed three-layer glmm-fiber-reinfomed polye~er resin waterproofing ell around METHOD: the cylinder. No protection was used.

PLACEMENT Model tests were done. The element was first brought to the site parallel to the current to METHOD: the centerline of the tunnel, using six 465-HP pusher rigs mounted on flexifloat=. Two other similar units were used to guide the element parallel to the current. At the jack-up rig, the element was turned transverse to the current using winches mounted on pontoons. A Volley running under the platform of the jod~-up rig moved the element to its final position. It was then handled by four vertical and horizontal winches of the jack-up rig. Two ballast chambers under the roadway on both sides of the interior bulkheads were filled with water to produce 150 tons of negative buoyancy.

FOUNDATION Sand fill was compacted around each element, using deep compactors. METHOD:

DREDGING A cutterheed suction dredge wee used to dredge the trench and place backfill. METHOD:

VENTILATION Fully transverse. TYPE:

COVER AND TYPE: 4.0 rn of compacted sand fill.

ADDITIONAL OWNER: Argentine govemment. INFORMATION: DESIGN~R/CONTR&CTORS: Consortlum of ~ AG, Vianlni SpA and Sailav SA..

214 Tum~.v.No ~ U~0mmaou~m SeAcz T~m~o~0o,r Volume 8, N.mh~ 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 37 DoJlme River Tunnel (Osaka Subway Tunnel); Osaka, Japan; 1969

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; reinforced concrete box section. Two tubes, one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 2 36/34.5 m 7.78 m 10.43 m-11.04 m

TOTALIMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 70.5 m 14.3 m

UNUSUAL Constructed in very tight quarters. Tunnel crossing is askew the Dojima River. Two FEATURES: elements were immersed between caissons at both banks. Immersed elements were fabricated inside the excavation for cut-and-cover approach tunnels.

ENVIRONMENTAL Tidal river. CONDITIONS:

FABRICATION METHOD: JOINT TYPE: Reinforced concrete elements were fabricated one by Single ¢atilever gasket in combinJon with heavy Omega one in a coffered dock provided near two gasket. Space between gaskets was filled with tremie Nakanoshima caissons, which later became part of concrete. the tunnel. The elements were enclosed in 6-m-thick steel plate. These were prefabricated in six sections and welded together inside the cofferdam.

WATERPROOFING 6-mm steel shell ail-around element. METHOD:

PLACEMENT Catamaran barges. Water ballast was used for each element. METHOD:

FOUNDATION Scrsed rails were installed at grade, attached to steel piles. Spreader box was fed by four METHOD: hopper pipes. Spreader system was supported on floats and guided by minasfrom placement barges. Crushed stone 20 mm to 40 mm in size was placed to form a foundation course, approximately 0.60 m thick, which was grouted after the elements were in place.

DREDGING Grab bucket. METHOD:

VENTILATION Piston effect of trains. TYPE:

COVER AND TYPE: 3.47 m of backfill, including a layer of concrete protec'don 0.50 m thick on the top.

Volume 8, N-tuber 2, 1998 ~.,.wo ~ UNDn~O~ SPAcz TmC~mOLO~215 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 38 Dohtonbori River Tunnel; Osaka, Japan; 1969 i ,

TUNNEL TYPE AND USE: LANES/I'RACKS: Railway; single-shell steel box. Two tubes; one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 24.9 m 6.96 m 9.65 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 25m 10m

FABRICATION METHOD: JOINT TYPE: A temporary working platform was oonstructed at the One end is a ~ joint; the other is an expansion joint. site and the steel shell element was fabricated on this platform.

WATERPROOFING Continuous steel shell treated with a cathodic protection system. METHOD:

PLACEMENT A portal crane was used for placement. METHOD:

FOUNDATION The steel shell element was supported at both ends by caissons in the manner of a METHOD: submerged bridge.

VENTILATION Piston action of trains. TYPE:

216~.T.n~'o ~ Um~mmao~ro SPAcZ ~ Vo~-,,~ 8, N-~ 2, 1998 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle NO. 39 Haneda Tunnel (Under Tams River); Tokyo, Japan; 1970 G)

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; single-shell steel binocular section. Two tubes, one trach each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 80m 7.95 m 13.0 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 480m 17 m below datum.

UNUSUAL Heavy binocular steel-shell section for railway tunnels was largely determined by FEATURES: earthquake forces. Immersed elements tie into pneumatic caissons at both ends. Three pickup points were used for placing. Ventilation tower was constricted by pneumatic caisson method. Last element was specially designed to transition to bored tunnels.

ENVIRONMENTAL Height of crane booms limited by adjacent Haneda International Airport. CONDITIONS:

FABRICATION OUTFITTING: JOINT TYPE: METHOD: At dock in back of trench Rubber gaskets similar to system used in the U.S., ex¢Nq~t Steel shell fabricated excavation. that joint connection sealing area provided outside of main at shipyard. tunnel structural section to permit rigid joint.

WATERPROOFING Continuous steel shell provided with cathodic protection. METHOD:

PLACEMENT Placed from catamaran barges. METHOD:

FOUNDATION 70 cm of 20- to 40-mm crushed stone was placed and soreeded. Bell hole was filled with METHOD: tremie concrete. Screed used mechanical spreading device and soreed box. Fwe vertical riser pipes equipped with hoppers fed matedai to soreed box. Spreader ran on rails installed underwater, supported on plies.

DREDGING Cutterhead suction dredge. METHOD:

VENTILATION Piston effect of trains. TYPE:

COVER AND TYPE: 3 m of protection using riprapped slopes of crushed stone and sand backfill.

ADDITIONAL Special pressure tests were made on the cantilever gasket. INFORMATION:

Volume 8, Number 2, 1998 Ttno~.T.~m zzm U~mmm~ro St,~__cz '/kcs~ 217 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 40 Hsneda Tunnel (Under Keihin Channel); Tokyo, Japan; 1970

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; single-shell steel binocular section. Two tubes, one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 4 82.0 m 7.97 m 12.74 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTrOM OF STRUCTURE: 328 m 17.70 m

UNUSUAL Heavy binocular steel section for railway tunnels. Design of croas-saction largely FEATURES: dstarminedby earthquake forces. Immersed tunrml elements tie into pneumatic caissons at both ends of tunnel.

ENVIRONM ENTAL The height of crane booms was limited by the proximity to Haneda IhternatJonal Airport. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Steel shell fabricated at shipyard. At dock near site. Double rubber gaskets. Joint connection sealing area is provided c~JlskJe of main tunnel structural section, permiffing rigid connection.

WATERPROOFING Continuous steel shell provided with cathodic protection system. METHOD:

PLACEMENT Raced from catamaran barges. METHOD:

FOUNDATION 70 cm of 20 mrn-40 mm crushed stone was placed and scresded using scresd box and METHOD: mechanical scresding device. Five verlicel riser pipes equipped ~ hoppers fed matedai to the scread box. This spreader ran on rails installed under water and supported on piles.

DREDGING Cutterhead suction dredge. METHOD:

VENTILATION Piston action of trains. TYPE:

COVER AND TYPE: 3 m of protection using dprepped slopes of crushed stone and sand backfill.

218"1kncvm.v.~ Am) Um~mmaOtmD SPaCZ TmmNot,o~ Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 41 Bay Area Rapid Transit Tunnel; San Francisco, California, U.S.A.; 1970

TUNNEL TYPE AND USE: Railway; single shell LANES/TRACKS: Two tubes, one track each steel binocular section

NO. OF ELEMENTS: LENGTH: 111 m HEIGHT: 6.5 m WIDTH: 14.6 m 58

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 5,825 m 40.5 m

UNUSUAL Longest immersed tube tunnel. Triaxial earthquake joints, Ventilation building constructed FEATURES: as caisson. Connections to shield-driven soft ground tunnels.

ENVIRONMENTAL Constructed across. CONDITIONS:

FABRICATION METHOD: On shipways and end- OUTFITTING: At dockside JOINT TYPE: launched. near project site. Double rubber-gasketted joints with steel dosure plates. Special triaxial earthquake joints.

WATERPROOFING Continuous steel shell; cathodic protection. METHOD:

PLACEMENT Catamaran barges straddling elements. METHOD:

FOUNDATION Screeded foundation. Sand fed into screed box. METHOD:

DREDGING Cutterhead suction (shallow); 13 CY damshell (deep). METHOD:

VENTILATION Piston action of traJns; exhaust system for smoke during fire emergency using central duct. TYPE:

COVER AND TYPE: 0.6 m fill plus 1.6-m stone blanket.

ADDITIONAL OWNER: Bay Area Rapid Transit System. INFORMATION: DESIGNER: Joint venture: Parsons-Brirmkerhoff-Tudor-Bachtal. CONTRACTOR: Trans-Bsy Constructors and joint venture of Peter Kiewit & Sons Co., Raymond Intemetional Tidewater Construction CO., and Healy Tibbets Construction CO.

Volume 8, Number 2, 1998 Tum~.T.wG AND U~mmmU~D SP,~_c~ T~mOLO~ 219 TUNNEL NAME AND LOCATION/DATE COMPLETED: File No. 42 Charles River Tunnel; Boston, Massachusetts, U.S.A.; 1971 t '

TUNNEL TYPE AND USE: Railway; double-shell LANES/TRACKS: Two tubes; one track each. steel binocular section

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 2 73m 6.86 m 11.4m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 146m 12.3 m below MLW

UNUSUAL Selected as option to cofferdam method of cro~ng dver. Transition sections in 29-m-dis. FEATURES: compression ring cofferdam shafts.

FABRICATION METHOD: Shipyard. Side launched. OUTFITTING: At dockside JOINT TYPE: Tremie joint. near tunnel site.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Lowered from pile-supported structures. METHOD:

FOUNDATION Screeded foundation course. METHOD:

VENTILATION Piston action of trains. TYPE:

ADDITIONAL OWNER: Massaehusstts Bay ~ Transit Authority. INFORMATION: DESIGNER: Praeger ~ and Watod0unj. CONTRACTOR: Steel shells by Wiley Manufaotudng.

220 ~.mo.om U~aoa~o~ro 8~ac~ Tcmmoumx Vnh,,,~, 8, Number 2, 1993 TUNNEL NAME AND LOCATION/DATE COMPLETED: Rle NO. 43 Cross Hart)our Tunnel; Hong Kong Harbour; 1972

TUNNEL TYPE AND USE: Vehicular; single-shell LANES/TRACKS: Two tubes two lanes each way steel binocular sections

NO. OF ELEMENTS: LENGTH: 114 m HEIGHT: 11 m WIDTH: 22.16 m 15

TOTAL IMMERSED LENGTH: 1,600 m DEPTH AT BOTTOM OF STRUCTURE: 28 m

UNUSUAL Ballast concrete in midsection between tubes. No side ballast pockets. Steel shell FEATURES: protected with concrete covering. Fest-tmck design in New York; rolling plate in England and fabrication of elements in Hong Kong. Ventilation building was held down using 100- ton rock archons to develop a 1.25 safety factor against buoyancy.

ENVIRONMENTAL Potential for typhoon conditions dictated heavy cover protection. Possibility of CONDITIONS: out-of-control ships dragging anchor over tunnel or even sinking. Provision made for 1000 PSF allowed for this loading of sunken ship.

FABRICATION METHOD: Shipyard in Hong Kong. OUTFITrlNG: At dock JOINT TYPE: Trernie Rates curved by rolls were fabricated into cans near the tunnel site. concrete joints. rneesudng 10.36-m dia. by 3.5 m long. Five cans were placed on a manipulator to allow them to be welded together automatically. The cans were, in tum, welded together to form each element. Controlled side-launch was used.

WATERPROOFING Continuous steel shell protected with cono-ete coating. METHOD:

PLACEMENT Catamaran straddling barges. METHOD:

FOUNDATION Screeded bedding. METHOD:

VENTILATION Semi-transverse exhaust at portals. TYPE:

COVER AND TYPE: 1.0 m stone cover over 1.3 m crushed stone filter layer.

ADDITIONAL OWNER: Hong Kong ~Harbour Tunnel Co. INFORMATION: DESIGNER: Parsons Brinckerhoff Quede & Douglas, Inc. CONTRACTOR: Consortium headed by Constaln International Ltd.; other members were Raymond International, Inc. and Paul Y. Construction Co. Ltd.

Volume 8, N-,-I~m- 2, 1998 T~ne.~.,.,,m Am) Umozmmo~ 8~acE Tmcmmomoo~2"~1 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 44 63rd Street Tunnel; New York City, New York, U.S.A.; 1973

TUNNEL TYPE AND USE: LANES/TRACKS: Railway and subway; single-shell steel elements. Two NYC transit tracks over two Long Island Railraod tracks. Four tubes; one track in each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 4 114.3 m 11.2 m 11.7 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: Two tunnels, each 229 m long. 30 m

UNUSUAL Only two-over-two tunnel ever constructed. Actually two separate tunnels: one section FEATURES: between New York City and Welfare Island, and the other between Welfare Island and Brooklyn. The ends of each tunnel section were tremied into slots blasted into the rock shores. Once in place, the four ends of the two tunnels were accessed by mining to them. Tunnel was constructed in very strong current conditions.

ENVIRONMENTAL Very swift current of 2.7 m/s (5.2 knots). CONDITIONS:

FABRICATION METHOD: Riverside shipyard OUTFITTING: At dockside JOINT TYPE: Tremle at Port Deposit, Maryland; uncontrolled side-launch. in Norfolk, Virginia, and concrete joints. towed to New York with full draft.

WATERPROOFING Continuous steel shell; cathodic protection. METHOD:

PLACEMENT Placed from straddling catamaran barges. METHOD:

FOUN DATION Screeded foundation consisting of large (15 cm) stone was used due to high current METHOD: velocities in the .

DREDGING Barge-mounted excavators. METHOD:

VENTILATION Train piston action. TYPE:

COVER AND TYPE: 1.3 m riprap over .9 m of crushed stone.

ADDITIONAL OWNER: Metropolitan Transportation Authority and the New York City Transit Au~ortty. IN FORMATION: DESIGNER: Parsons Brtnckerhoff Quade & ~ilB, Inc. CONTRACTOR: Joint Venture: Klewtt-Slattery-~on Knudeen.

222 Tu~.T.~o ~'V U~ao~'v S~Acz T~c~ou~a~ Vohune 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 45 Interstate Route 10 (Mobile) Tunnel; Mobile, Alabama, U.S.A.; 1973

TUNNEL TYPE AND USE: LANES/I'RACKS: Vehicular; double steel shell binocular elements. Two tubes; two lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 7 106 m 12.2 m 24.5 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTI'OM OF STRUCTURE: 747 m 30m

UNUSUAL Portal ventilation buildings equipped with steel joint transition structures to which elements FEATURES: are attached. First project in U.S.A. to use modem sand-jstting method for foundation.

FABRICATION METHOD: Fabrication yard set up on OUTFn-I'ING: At pier near JOINT TYPE: Tremie site. Uncontrolled side launch. site. concrete joints.

WATERPROOFING Continuous steel shell plate. METHOD:

PLACEMENT Four barges straddling the element. Element placed on temporary footings and adjusted to METHOD: line and grade.

FOUNDATION Jetted sand foundation. METHOD:

VENTILATION Semi-transverse ventilation. Air supplied through lower air duct travels longitudinally to TYPE: portal ventilation buildings.

ADDITIONAL OWNER: Massachusetts Bay Rapid Transit Authority. INFORMATION: DESIGNER: Praeger Kavanagh and Waterbury. CONTRACTOR: Steel shells by Wiley Manufacturing Co.

Volume 8, N-,'nher 2, 1998 ~.T.wo ~ UNDnOROUSD S~J~z T~C~OLO~ 228 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 46 Kinuura Herbour Tunnel; Kinuura City near Nagoya, Japan; 1973 !6 Q]

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; single-shell steel box elements. One tube with two lanes.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 80 m 7.10 m 15.6 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 480 m 21.7 m

UNUSUAL Ventilation structures constructed by pneumatic caisson method. Unusually wide box FEATURES: section for steel shell construction. Structural requirements were mainly determined by earthquake design loads.

ENVIRONMENTAL Severe earthquake loading requirements. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Screeded gravel bed, which was later grouted with a Reinforcing steel and Rigid joint with single sand-mortar mix. concrete was placed in the cantilever-type gasket. steel shells. The two alignment towers, and various equipment needed for placing the elernants, were installed at the outfitting pier.

WATERPROOFING Continuous steel shell around reinforced concrete box structure. METHOD:

PLACEMENT Element was supported from ~ontoons and ballasted with water using tanks inside the METHOD: element.

FOUNDATION Screeded gravel bed which was later grouted with a sand-mortar mix. METHOD:

DREDGING Suction dredge was used to remove soft mud; bucket dredge was used for sand. METHOD:

VENTILATION Semi-transverse ventilation system. TYPE:

COVER AND TYPE: 2.0 m of crushed stone was used as protec'don against ships' anchors.

BUOYANCY SF: 1.10 for earthquake; 1.20 for CONCRETE WORKING STRESS: 80 kgf/sq, cm normal conditions.

ADDITIONAL Primary extemal forces due to earthquake. INFORMATION:

224 Tum~.T.r~o ~ UNDmm~ou~ro SPAc~ Tmm~OLOOY Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 47 Ohgishima Tunnel; Kawasaki, Japan; 1974

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular and utility; single shell. Two tubes; two lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 110m 6.9 m 21.6 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 664m 21 m

UNUSUAL Jetted sand foundation treated with cement clinker of various sizes and a special binder to FEATURES: help achieve compaction and preclude liquefaction. Steel shall used to provide flexibility for better earthquake resistance. Closures to cut-and-cover land structures made using gasketted steel panels for joint seal.

ENVIRONMENTAL 0.4 m/s current, 3.2 m high, with waves 6.8-m long. CONDITIONS:

FABRICATION METHOD: OUTFI'I-rlNG: JOINT TYPE: Steel shell assembled in shallow drydock 3.3 km from Outfitted at a wharf 1.6 km Gina-typa joints with steel tunnel site. Fully dosed box section was constructed from the tunnel site; Omega; steel rods coupled including bulkheads and intedor reinforcing steel. concrete placed from across joints; steel panel barges. joints at cut-and-cover structures.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Transverse pontoons and two alignment/control towers with interior access. Joint closure METHOD: and alignment jacks actuated from within the element.

FOUNDATION Jetted sand foundation treated to prevent liquefaction (see above). METHOD:

DREDGING Grab bucket dredger. METHOD:

VENTILATION Longitudinal ventilation. TYPE:

COVER AND TYPE: Sand backfill and rubble stone protection.

ADDITIONAL OWNER: Nippon Kokan Kabushild Kalsha. INFORMATION: DESIGNER: Chdstiani & Nielsen. CONTRACTOR: Talsei Corporation.

Volume 8, N.mher 2, 1993 ~.v.mo AND UNDmm~OUm) SPAcz ~OLOOY 225 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 48 Elbe Tunnel; Hamburg, Germany; 1975

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box section. Three tubes; two lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 8 132 m 8.4 m 41.7 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 1,056 m 29m

UNUSUAL Very wide tunnel, with six lanes providing reverse traffic flow in middle two lanes. FEATURES: Prestressed concrete design was inveslJgated for both transverse and longitudinal loads; conclusion was that it was not economical. Joints were provided at 27-m intervals for both temperature and settlement effects. Initially it was decided that these intermediate joints were unnecessary; however, because of uncertainty in predlotJng settlements, they were eventually included. Special exterior Omega steel plates were used at these joints. Joint was held together by prestress bars until tunnel element was in place on jetted foundation; bars were then cut to allow flexibility. The river channel was switched from one side of the river to the other dudng construction.

ENVIRONMENTAL River currents of 1.3 m/s (flood). CONDITIONS:

FABRICATION METHOD: All eight elements were JOINT TYPE: Gina gasket joint with rubber Omega interior constructed at the same time in a casting basin. gasket. Joint allows for longitudinal expansion and 190,000 cu. m were first removed by dredging. Then, contraction. after closing the end with a 250 x 11 m cofferdam, 380,000 cu. m were excavated in the dry.

WATERPROOFING Steel membrane on bottom and side. Bituminous membrane on top protected with 15 cm of METHOD: concrete. Waterstops and steel Omega (re-entrant) joints at intermediate joints (comers formed, not mitered).

PLACEMENT Transverse pontoons with control and alignment towers. Each tunnel element had 12 METHOD: tanks with a total capacity of about 5,000 cu. m. Buoyancy depended almost entirely on the weight of the concrete. The density, as well as the concrete dimensions, were continuously controlled and the findings treated statistically, in order to maintain the total weight ~in 0.5% of theoretical. Because of the river currents, piled anchorages to pull against were established in the river bottom. Between seven and nine 1,200-Hp tugs were used to tow and position elements.

FOUNDATION Sand-jetting. Element No. 8 ran into a problem with excess mud deposits. The return system METHOD: of the sand-jetting equipment was used to remove this material before placing the sand.

DREDGING The trench was 45 m wide, with side slopes of 1:3. A cutterhead suction dredge was used to METHOD: -15 m; thereafter, a bucket dredge was used, down to -30 m.

VENTILATION Fully transverse. TYPE:

ADDITIONAL OWNER: Freie und Hansestadt Hamburg. INFORMATION: DESIGNER & CONTRACTOR: Joint Venture "E3 Elbtunnel."

226 'Ikne~J.mc~ ~ UNomm~usv SPac~ ~ou~Y Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle NO. 49 Vlake Tunnel; Zeeland, The Netherlands; 1975

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box sections. Two tubes; three lanes each (two active, one breakdown).

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 2 125 m 8m 29.8 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 250 m 17 m

UNUSUAL Used cooling water in wall pours to reduce shrinkage cracking so that exterior waterproofing FEATURES: membrane could be eliminated. Rrst use of the send-flow method, whereby sand/water slurry is pumped under the element from internal ports.

FABRICATION METHOD: Casting basin next to WATERPROOFING METHOD: Shrinkage control and tunnel site, later to become part of projected canal division of elements into shorter lengths of 21 m, widening. post-tensioned together.

PLACEMENT Transverse pontoons with two control and alignment towers. Three-point beadng method METHOD: used for alignment adjustement.

FOUNDATION Sand-flow method (used for the first time on this project). METHOD:

DREDGING Cutterhead suction dredge. METHOD:

VENTILATION Longitudinal. TYPE:

ADDITIONAL OWNER: Rijkswaterstaad. INFORMATION: DESIGNER: Rijkswaterstaed. CONTRACTOR: Kombinatie Vlake joint venture of Hoilandsche Beton Meatschappij B.V., de Amsterdamse Ballast-Beton en Waterbouw N.V.

TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 50 Sumida River Tunnel; Tokyo, Japan, 1975 ~-~

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; single shell steel. Two tubes; one track each.

NO. OF ELEMENTS: 3 LENGTH: 67 m HEIGHT: 7.8 m WIDTH: 10.30 m

TOTAL IMMERSED LENGTH: 201.5 m WATERPROOFING METHOD:Continuous steel shell

VENTILATION TYPE: Piston action of trains.

Volume 8, Number 2, 1993 Tuz~'z~z.~o AND UZ~Uzzo~wU~ Sz'*cz T~SHOLO~ TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 51 2nd Hampton Roads Bridge Tunnel; Hampton Roads, Virginia, U.S.A.; 1976 ©

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; double steel shell elements. One tube ; two lanes.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 21 105 m 12.3 m 12.0 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 2229 m 37 m

UNUSUAL This tunnel was constructed adjacent to the existing tunnel about 75 m away without FEATURES: damaging it. Ground near the south half length of the tunnels was very poor. Sand drains and surcharge were used to stabilize the expanded South Island before the elements could be placed and before the ventilation building and open approach structures could be constructed.

ENVIRONMENTAL Faldy severe winds, waves and currents during storm conditions. Currents about 1 nYs (2 CONDITIONS: knots).

FABRICATION METHOD: OUTFITTING: JOINT TYPE: At a shipyard at Port Deposit, Maryland about 300 km At a pier about 5 km from Double rubber gasket by water from the site. Elements were side-launched tunnel site. Up to six system with interior liner (uncontrolled). Draft slightly more than 2 m. elements were outfitted plate to join steel shells. with concrete at one time along one side of a pier (elements were moored in twos).

WATERPROOFING Continuous steel shell joined at joints, with welded and liner plates tested for METHOD: watertightnass.

PLACEMENT Straddling laybarge, consisting of two railroad car barges with support beams between METHOD: them in catamaran form.

FOUNDATION Screeded foundation. Screed rig was designed to be unaffected by tidal variations by METHOD: being taut moored with flotation tanks held underwater. Three dements had to be removed from trench and reset after rescreeding due to siltation of screeded foundation.

DREDGING Cutterheed suction dredge used for depths up to 15 m; then a 12-ms clamshell bucket dredge METHOD: was used for deeper work. Sumharge sand on South Island was pumped to construct North Island using a booster pump to mix sand and water under a truck grizzly.

VENTILATION Fully transverse ventilation, divided between two ventilation buildings. TYPE:

COVER AND TYPE: 1.5 m sand cover, with some areas of riprap protection against scour.

ADDITIONAL OWNER: Virginia Department of Highways and Transportation. INFORMATION: DESIGNER: Parsons Bdnckerhoff Quade & Douglas, Inc. CONTRACTOR: "Rdewater Construction Corp., Raymond Intemational and Peter Kiewit and Sons, Inc.

228 ~J.~ z~ Uszmmm)UZ~D Sr+.~ 'Ik(msoI~oY Volume 8, H~ 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 52 Paris Metro Tunnel; Paris, France; 1976

TUNNEL TYPE AND USE: LANES/TRACKS: TOTAL IMMERSED Railway; reinforced concrete box. One tube, two tracks. LENGTH: 128 m

TUNNEL NAME/LOCATION/DATE COMPLETED: File No, 53 Tokyo Port Tunnel; Tokyo, Japan; 1976

TUNNEL TYPE AND USE: LANES/rPACKS: Vehicular; reinforced concrete box section. Two tubes, three lanes each.

NO. OF ELEMENTS: 9 LENGTH: 115 m HEIGHT: 8.80 m WIDTH: 37.4 m

TOTAL IMMERSED LENGTH: 1,035 m DEPTH AT BO'I-I'OM OF STRUCTURE: 23 m

UNUSUAL 1. Flexible seismic joints were provided. FEATURES: 2. Steel pipe pile foundation was adopted for elements near ventilation shafts to limit force due to consolidation. 3. New foundation method was developed whereby bentonite mortar was pumped from inside the elements. Very wide, heavy elements.

ENVIRONMENTAL Site is located in fairway. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Casting basin close to site for all nine elements. In casting basin, using Flexible joint using Gina travelling forms. type joint. A steel Omega- type gasket was also used.

WATERPROOFING 6-mm steel skin on sides and bottom. Concrete protested rubber membrane on top of METHOD: element.

PLACEMENT Placed from catamaran barges. METHOD:

FOUNDATION A bentonite mortar layer 0.5 m thick was pumped under the elements over a 0.7-m-thick METHOD: crushed sandstone layer. Edges of elements were sealed with sand/gravel filter to prevent mortar from escaping. Steel pile foundation was used for terminal elements.

DREDGING METHOD: Cutterhead suction dredging.

VENTILATION TYPE: Semi-transverse, using side and center ducts.

COVER AND TYPE: 1.5 m sandstone riprep for protective cover. Sandstone rock spoil used for locking fill.

BUOYANCY SF: 1.10 CONCRETE WORKING STRESS: Approx. 90 kgf/sq, cm

Volume 8, Numlz~ 2, 1998 TUNs~.,.,~o ~u) Uxz)m~ous9 SEA(= T~HNOLO~ 229 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 54 Drecht Tunnel; Dordrecht, The Netherlands; 1977

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box elements. Four tubes; two lanes in each tube.

NO. OF ELEMENTS: 3 LENGTH: 115 m HEIGHT: 8.7 m WIDTH: 48.6 m

TOTAL IMMERSED LENGTH: 347 m DEPTH AT BOTTOM OF STRUCTURE: 15 m

UNUSUAL FEATURES: Widest elements ever constructed. Displacement 45,000 MT. Approach structures are of a very unusual construction, utilizing drained slabs and top-down construction, with slurry walls carded to clay. Tunnel elements were attached to end structures already in place on one end of tunnel, using a Gina joint; and on the other, using a gaskettsd plate joint system. Two-lane spans were used to reduce depth of elements. Sand-flow method was used for second time.

ENVIRONM ENTAL River currents. CONDITIONS:

FABRICATION METHOD: JOINT TYPE: At casting yard at Barendrecht (used previously for Gina-type joints. the Heinenoord and some pipeline tunnels), 12 km from site.

WATERPROOFING Membrane waterproofing was used because of the great width of the tunnel. The METHOD: elements were divided into six subsections with temporary prestress, which was cut after backfilling.

PLACEMENT Model tests were used to determine the number of tugs required to handle the segment. METHOD: The tests indicated 5,000 to 6,000 HP; however, 11,000 HP eventually were provided for safety. Clearances for towing were very restricted, and an elaborate electronic horizontal control method was implemented to keep elements from running aground. Element blocked 40% of river at times during towing.

Transverse pontoons with two control/alignment towers were used for placement. Four-point support was used at plasement because of the width of the section. Vertical and horizontal jacks were used for adjustment of alignment.

FOUNDATION The send-flow method used on the Vlake tunnel was repeated for this tunnel. METHOD:

DREDGING METHOD: Because of the tunnel width, rough dredging was done and the variations were compensated for with the placement of the sand foundation.

VENTILATION TYPE: Longitudinal; jet fans.

230 TL~lq~.T.r~GAND UNDERGROUNDSPACE TECHNOLOGY Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 55 Prinses Margriet Tunnel; Sneek, The Netherlands; 1978

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box element. Two tubes; three lanes each.

NO. OF ELEMENTS: 1 LENGTH:77 m HEIGHT: 8,0 m WIDTH: 28.5 m

TOTAL IMMERSED LENGTH: 77 m

UNUSUAL FEATURES: Single element designed to engage the walls ot; both open-approach structures. Element was constructed in one of the approaches with transverse wingwalls attached. The element was floated into position and sealed using inflatable gaskets.

FABRICATION METHOD: JOINT TYPE: Faloricated in open approach section. Element was Inflatable gaskets at both ends of element in wingwalis and cast in four articulated sections to limit shrinkage along bottom. This arrangement was used as a temporary cracking. seal so that permanent closure could be cast.

WATERPROOFING 6-mm steel membrane on bottom. Two-ply bituminous membrane of sides and top. Top METHOD: protected with layer of concrete.

PLACEMENT METHOD: Floated into position and lowered by winching. Clearance of wingwalis only 4.5 cm. Ballast tanks were used.

VENTILATION TYPE: None required; natural ventilation.

TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 56 Kil Tunnel; Dordrecht, The Netherlands; 1978

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box elements. Two tubes; three lanes each. Two lanes for fast-moving traffic and one truck lane.

NO. OF ELEMENTS: 3 LENGTH: 111.5 m HEIGHT: 8.75 m WIDTH: 31.0 m

TOTAL IMMERSED LENGTH: 330 m

FABRICATION METHOD: JOINT TYPE: At the Barendrecht basin alongside the elements for Gina gasketted joints on the elements. Gasketted plates at plates at the end joint. the end joint.

PLACEMENT METHOD: Transverse pontoons with two control/survey towers.

FOUNDATION METHOD: Sand-flow method, similar to Vlake and Drecht Tunnels.

VENTILATION TYPE: Longitudinal.

Volume 8, Number 2, 1993 Ttms,~.v.wa aND Uk"Dmm~omm SPscz TIc~mot~oY 231 TUNNEL NAMF.JLOCATION/DATE COMPLETED: File No. 57 WMATA Washington ; Washington, D.C., U.S.A.; 1979

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; double-shell steel elements. Two tubes; one track each.

NO. OF ELEMENTS: 3 LENGTH: 103.6 HEIGHT: 6.7 m WIDTH: 11.3 m

TOTAL IMMERSED LENGTH: UNUSUAL FEATURES: 311 m Use of double steel shell is somewhat unusual for a tTansit tunnel.

FABRICATION METHOD: OUTFI'I-I'ING: At shipyard at Port Deposit, Maryland, about 120 km At dockside at f~on yard in Port Deposit. from the site. Uncontrolled side launching was used,

WATERPROOFING Continuous sheel shell. METHOD:

PLACEMENT METHOD: Winches from pile-supported guide beams.

FOUNDATION METHOD: Screeded bedding.

VENTILATION TYPE: Piston action of trains.

ADDITIONAL OWNER: Washington Metropolitan Transit Authority (WMATA). IN FORMATION: DESIGNER: Parsons Brinckerhoff Quade & Douglas, Inc. CONTRACTOR: Joint venture of Perrini, Horn and Morrison-Knudsen.

232 TusNm.v.~o AND UNomm~wu~ SF,~ T~HSOLO~ Volume 8, N~mh~. 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 58 Kawaaakl Tunnel; Kawasaki City, near Tokyo, Japan; 1981

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; single-shell steel box elements. Two tubes; two lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 8 100-110 m 8.8 m 31.0 m

TOTAL IMMERSED LENGTH: 840 m DEPTH AT BOTTOM OF STRUCTURE: 22 m

UNUSUAL Wide box section for steel shell construction. Land tunnel support on steel pipe piles. FEATURES: Sectional dimensions mainly based on earthquake Ioadings. Earthquake observations have been carried out since 1980 on this tunnel.

ENVIRONMENTAL Severe earthquake loading requirements. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Steel shells were fabricated at shipyard next to Reinforcing steel and Rigid joint with rubber outfitting pier. concrete were placed at gaskets. Rexible joint was outfitting pier with element in used between terminal flotation. Alignment towers element and ventilation and placement equipment also were installed at the tower. outfitting pier.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT Element supported by pontoons. Ballasting with water into tanks in element. METHOD:

FOUNDATION Mortar bed pumped in place from inside elements. METHOD:

DREDGING A bucket dredge was used to dredge the main trench. A suction dredge was used to METHOD: eliminate soft mud and sand that drifted into the trench.

VENTILATION Semi-transverse ventilation system. TYPE:

COVER AND TYPE: 1.5 m of gravel was used over the tubes as a protective layer.

BUOYANCY SF: CONCRETE WORKING STRESS: 1.1 for earthquake and 1.2 for normal conditions. 100 kgf/sq, cm

ADDITIONAL Deformed bars of 51-mm dia. were used for longitudinal reinforcement to resist axial INFORMATION: earthquake forces.

Volume 8, Number 2, 1993 TUSNEa~O ~ UNDnUlWU~ SP,~ TEC~SNOU~ 288 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 59 Hong Kong Mass Transit Tunnel; Hong Kong Harbour, between Kowloon and Victoria Island; 1979

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; reinforced concrete double binocular Two tubes; one track each. elements, longitudinally prestressed.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 14 100m 6.6 m 13.1 m

TOTAL IMMERSED LENGTH: 1,400 m

UNUSUAL Screeding and placing of elements using same jack-up rig. Caisson ventilation buildings FEATURES: set on end elements.

ENVIRONMENTAL Currents of 1.5 m/s (2.9 knots). Several typhoons had to be contended with during CONDITIONS: construction. Tunnel was designed for 5-m tides.

FABRICATION METHOD: JOINT TYPE: Casting basin. Gina gasketted joints.

WATERPROOFING From the bottom to the first construction joint, 6-mm steel plate treated with corrosion METHOD: protection. The remainder was waterproofed with two-ply bit and two-ply protective membrane.

PLACEMENT Used jack-leg special marine platform. METHOD:

FOUNDATION Screeded bedding, using jack-up rig. METHOD:

DREDGING To -19 m, with bucket dredge; finished with clamshell dredge using 2.5-cu.-m to 14-cu.-m METHOD: buckets.

VENTILATION TYPE: BUOYANCYSF: Piston action of trains. 1.20

ADDITIONAL OWNER: Mass Transit Railway Corporation. INFORMATION: DESIGNER: Freeman Fox and Partners (Far East) Per Hall Consultants Ltd. CONTRACTOR: Kumagai Gumi Co. Ltd.

~.T.r~O AND U~Dm~ROUND SPAc~ TZC~SSOLO~ Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 60 Hemspoor Tunnel; Amsterdam, The Netherlands; 1980

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; reinforced concrete box elements. Three tubes; one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 7 See =Unusual Features" 8.7 m 21.5 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 1,475 m 26 m

UNUSUAL Three-track tunnel; middle track is used for wide goods trains. Four straight elements were FEATURES: const~Jcted twice as long (268 m) as the remaining three curved elements (134 m). These long elements displaced a record 50,000 tonnas. This was possible because there is no current in the North Sea Canal and there was sufficient room to manuever. The sections of each element were temporarily tied together with plain reinforcing steel instead of prestressing rods. As in other tunnels, these ties were cut after the element was in its final condition.

ENVIRONMENTAL Virtually no current in canal. CONDITIONS:

FABRICATION METHOD: JOINT TYPE: In the combined casting basin of the Coen and Ij Gina joints. ! A-~tjoint was made using gasketted plates to Tunnels. permit joint dewatedng.

WATERPROOFING Intermediate joints at 22.35-m intervals were provided to reduce shrinkage cracking and METHOD: accommodate settlements. The roof was protected with a concrete slab placed just prior to sinking the tube. This reduced the freeboard to only 5 cm.

PLACEMENT Transverse placement barges on top of element. Survey towers were not used, but an METHOD: access shaft was provided on each element. The center between immersion load lines was used for positioning. Proper register between elements was obtained with a sensor operated between the bulkheads. Levelling was done internally.

FOUNDATION The sand-flow method was different, in that sand slurry was pumped into the individual METHOD: elements through hoses attached by divers.

DREDGING Cutterhead suction dredges, placing spoil in adjacent land areas. METHOD:

VENTILATION Piston action of trains. TYPE:

ADDITIONAL OWNER: Dutch MinisW of Public Works. INFORMATION: DESIGNER: Locks and Weirs Division of the National Public Works. CONTRACTOR: Hemspoor joint venture (Royal Bos Kalis Westminster Group N.V. Stevin Groep N.V.)

Volume 8, Number 2, 1993 TUNN~.TmO AND U~mmo~trm~ SPA~ T~mSOLOOY 235 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 61 Botlek Tunnel; Rotterdam, The Netherlands; 1980

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; prestressed concrete box elements. Two tubes; three lanes each (two traffic lanes plus a breakdown lane).

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 5 105 m 8.8 m 30.9 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 508 m (4 elements @ 105 m; 1 element @ 87.5 m) 23.3 m

UNUSUAL Heavy floating shear leg cranes were used for placement. FEATURES:

FABRICATION METHOD: JOINT TYPE: In a casting basin, for all five elements. The sections Gina joints were used, except at the end tube, where were left submerged for about three months. They gaskatted plates were employed. were refloated without problems by pumping out ballast water.

WATERPROOFING The elements were constructed of six 17.5-m sections post-tensioned together. The METHOD: post-tensioning was bonded. The wall pours were cooled using water pipes to eliminate cracking due to heat of hydration.

PLACEMENT Elements were placed using shear leg manes. Survey and control towers were used for METHOD: alignment control and access.

FOUNDATION Sand-flow method. As for the Hemspoor Tunnel, sand slurry was pumped into each METHOD: individual element directly.

DREDGING Cuttersu~on dredger. METHOD:

VENTILATION Longitudinal, using jet fans. TYPE:

ADDITIONAL OWNER: Municipality of Rotterdam. INFORMATION: DESIGNER: Gemeentewerkan Rotterdam (GWR). CONTRACTOR: Joint venture of Voormolan and Wayys & Fretag.

286 T~'N~.TmO ~ U~ro~scmou~ SPacB Tmc~ou~y Volume 8, Number 2, 1998 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 62 Dalba Tunnel; around Tokyo Port (Japan); 1980

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; single-shell steel binocular. Two tubes; one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 7 96.6 m 8.05 12.68 m to 17.53 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 672 m 23.9 m

UNUSUAL Tunnel was designed to be sufficiently flexible to accommodate up to 1.2 m of settlement FEATURES: and survive a severe earthquake. Joints are tied together with cables, but allow some flexibility. These flexible joints are provided between all of the elements and at the terminal joints. Immersed elements tie into pneumatic caissons at both ends of tunnel. Element Nos. 5-7 transition 5 m in width to meet bored tubes.

ENVIRONMENTAL Site is situated in fairway of an active port area. CONDITIONS:

FABRICATION OUTFITTING: JOINT TYPE: METHOD: Concrete reinforcement, Joints between elements have a rubber gasket on the Steel shells were and concrete was placed in outside and a small gap on the inside for flexibility. Cables fabricated at flotation at outfitting dock through the joints tie the elements together. H-shaped shipyard. Bulkheads near tunnel site. Alignment steel members form a shear key embedded in the ends of and rubber gaskets towers and placement the elements at each joint to prevent excessive vertical and were installed and barges were installed. horizontai displacement under settlement and earthquake the elements were Ioedings. Caissons were used for the end structures to towed to pier at protect existing port structures. outfitting yard.

WATERPROOFING Continuous steel shell. Each element was protected with 200 aluminum anodes, giving an METHOD: estimated life of 60 years.

PLACEMENT Racemant from semi-submemible jack-leg platform because of space restrictions in Port METHOD: area precluded use of anchor lines. Crushed stone was used for placement ballast.

FOUNDATION A 70-cm-thick, 12.4-m-wide layer of 30-mm to 40-mm crushed stone foundation course, METHOD: screeded from jack-leg platform.

DREDGING Bucket dredge was used for sand; a cutterheed suction dredge was used for the soft mud. METHOD:

VENTILATION TYPE: BUOYANCY SF: Piston action of trains. 1.1

COVER AND TYPE: 1.1 m of crushed stone.

ADDITIONAL OWNER AND DESIGNER: Japan Railway Construction Public Corp. INFORMATION: CONTRACTOR: Joint venture of Kajima Corp., Sato Kokyo Co. and Tekken ConsVuction Co.

Volume 8, Number 2, 1998 ~z.n,T(~ Am) LT~meRm~OUNDSPACZ TexnmOLOm,287 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 63 Tokyo Port Dainikoro Tunnel; Tokyo, Japan; 1980

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box elements. Two tubes; two lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 124 m 8.8 m 28.4 m

TOTAL IMMERSED LENGTH: 744 m DEPTH AT BO'I-I'OM OF STRUCTURE: 23 m

UNUSUAL 1. Usa of bentonite mortar mixture, pumped in the manner of a sand-flow system for the FEATURES: foundation of the tunnel elements. 2. Flexible joints for earthquake displacements. 3. Moderate longitudinal prestress used to control cracking and resist earthquake stress.

FABRICATION METHOD: JOINT TYPE: At a casting basin near the tunnel site. One cycle for Gina/Omega gasket batwean elements; gasketted plates to all six elements. Approximately two years was cut-and-cover sections. required to establish the basin and produce the elements.

WATERPROOFING 8-mm steel plate on bottom and sides; 2.5-mm membrane on top of element, protected with METHOD: 15 cm of reinforced concrete.

PLACEMENT Catamaran barges. METHOD:

FOUNDATION Modification of sand flow method. Instead of plain sand slurry, bentonite mortar was METHOD: injected into a cobble-stone bedding.

DREDGING Grab bucket dredger for rough dredging; a cutterheed suction dredge for fine dredging and METHOD: clean-up.

VENTILATION Semi-tmnsvarse ventilation, using side ducts with a ventilation building at each end of the TYPE: tunnel.

COVER AND TYPE: Fine crushed stone on both sides, with crusher run on top.

ADDITIONAL OWNER AND DESIGNER: Japan Railway Construction Public Corp. INFORMATION: CONTRACTOR: Joint Venture of Kajima Corp., Seto Kokyo Co. and Tekken Construction Co.

288 TUN~T~.~G AND UND~m~OUND SPAC~ T~CaNOLOGY Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 64 Rupel Tunnel; Boom, Belgium; 1982

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box elements. Two tubes; three lanes each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 3 138 m 9.35 m 53.10 m

TOTAL IMMERSED LENGTH: 336 m FABRICATION METHOD: Elements were cast in the open approaches to the tunnel.

WATERPROOFING Steel plate on bottom of elements and bituminous membrane on the sides and top. METHOD:

PLACEMENT Conventional for concrete elements. METHOD:

FOUNDATION Jetted-sand method. METHOD:

VENTILATION Longitudinal, using booster fans. TYPE:

Volume 8, Number 2, 1993 Tum~.,.r~o AND UNDmm~OU~ SPAC~ T~mSOL0OV239 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 65 Metropolitan Railway Tunnel under the Main; Frankfort/Main, Germany; 1983

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; reinforced concrete box elements. Two tubes; one track each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 2 1 element @ 61.5 m 8.55 m 12.10 m-13.10 m 1 element @ 62 m 8.55 m to 10.28 m 12.10 rn-12.70 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 123.5 m 17 m below water level.

UNUSUAL Varying cross-sections. FEATURES:

ENVIRONMENTAL Mild currents; flow of bottom sediments during periods of high water. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Casting basin in the approaches on each side. In casting basin as part of Gina/Omega joints. Intermediate joints provided at 13.70-m spacing to fabrication operation. reduce temperature and shrinkage cracking.

WATERPROOFING Impermeable reinforced concrete. METHOD:

PLACEMENT Lowering from bridging frame over the excavation and from a pontoon bridge in the river. METHOD:

FOUNDATION Sand-flow methodl using openings in bottom slab. METHOD:

DREDGING Upper portion of sloped trench above 7 m was dredged using regular dredge; lower portion METHOD: was cut between sheetpile walls using a large floating backhoe dredge capable of 19 m depth.

VENTILATION Piston action of trains. TYPE:

COVER AND TYPE: Fill plus stone blanket.

ADDITIONAL OWNER: Deutsche Bundesbahn (German Railway). INFORMATION: OPERATOR: Deutsche Bundasbahn, Frankfurter Verkenreverbund (FVV). DESIGNER: Deutsche Bundesloahn. CONTRACTOR: Joint Venture: Dyckarhoff + Widmann AG, Frankfurt; Bilfinger + Berger, Frankfurt; Josef Riepl AG, Strabag AG.

240 ~.z.n~a AND UNDm~W.OUNDSPa T~C~NOLOGY Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Flle No. 66 Beetle Old Harbour Tunnel; under Old Harbour In Beetle, Corsica, France; 1983

TUNNEL TYPE AND USE: LANES/TRACKS: TOTAL IMMERSED LENGTH: Vehicular; concrete box elements. One tube; two lanes, plus shoulders. 249.72 m

NO. OF LENGTH: HEIGHT: WIDTH: ELEMENTS: 4 62.33 m 7.58 + .5 m 14.10 m

ADDITIONAL CONTRACTORS: G.T.M. France. INFORMATION:

TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 67 Spijkenieee Metro Tunnel; Rotterdam, The Netherlands; 1984

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; reinforced concrete box elements. Two tubes; one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 82m 6.55 m 10.3 mm

TOTAL IMMERSED LENGTH: 530 m ENVIRONMENTAL CONDITIONS: River currents.

FABRICATION METHOD: JOINT TYPE: Elements were cast in casting basin used previously Gina/Omega rubber joints between element. Final joint for the elements for the Rotterdam Metro. Three between last two elements was made using gasketted steel elements were cast at a time, in two cycles. plates installed by divers. Provision was made in joint to the land section for settlement.

PLACEMENT METHOD: Lowered by cranes. Survey tower on outboard end.

FOUNDATION Jetted-sand method was used. Silt was first removed by air-jetting for agitation and the METHOD: action of the river current. At one end, unsuitable material was removed by over- excavation and replaced with sand, which was then vibro-compacted.

DREDGING METHOD: Cutterhead suction dredge.

VENTILATION TYPE: Piston action of trains.

ADDITIONAL OWNER: Municipality of Rotterdam. INFORMATION: DESIGNER: Gemeentewen Rotterdam (G.W.R.). CONTRACTOR: Van Hattum & Blankevoort, Netherlands.

Volume 8, Number 2, 1998 ~o AND Um~m~ao~m~ 81,~c~ Tm~,ooY 241 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 68 Coolhaven Tunnel; Rotterdam, The Netherlands; 1984

TUNNEL TYPE AND USE: LANES/TRACKS: Metro railway; reinforced concrete box elements. Single tube; two tracks.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 7 3 elements @ 45.59 m 6.35 m 9.64 m 3 elements @ 74.98 m 1element @ 49.00 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 411 m Shallow metro tunnels.

UNUSUAL Elements were floated into place between cross-braced sheetpile walls. They were then FEATURES: hooked up at both ends to carriers, which ran on rails supported on the sheet piling. The elements were then ballasted intemally and drawn together with jacks on the top slab. The water pressure was then released in the joint area in the conventional way. The foundation was also unique, as it utilized special piles provided with tops that could be adjusted to the underside of the tunnel element by inflation with grout. This was acco~ with a precast upper section connected to the lower section with a guiding dowel. The expandable section was enclosed within a folded nylon beg.

ENVIRONMENTAL CONDITIONS: Construction JOINT TYPE: Gina-type joint. through residential urban area and existing canal.

PLACEMENT Lowered from carriers on roils (see above). METHOD:

FOUNDATION Installed on adjustable piling (see above). METHOD:

DREDGING Clamshell bucket excavation. METHOD:

VENTILATION Piston action of trains. TYPE:

ADDITIONAL OWNER: Gerneentabestuur Rotterdam. INFORMATION: CONTRACTOR: Hoofdeannerner BBM, Bredase Beton-en Aanneming Maat~j B.V.

242 ~.T.n~o ~ UNDE~mO~'~WSPACZ T~C~TO~ Vohune 8, Number 2, 1998 TUNNEL NAME/LOCATION/DATE COMPLETED: IRk) No. 69 Kaohsiung Cross Herbour Tunnel; Keohslung, Tslwsn, Republic of China; 1984

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box section. Two tubes; two lanes each. Each tube is also provided with 2.6-m-wide motorcycle way.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 120 m 9.35 m 24.4 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 720 m 23m

UNUSUAL Used to interconnect the harbour facilities. Longitudinal post-tensioning was used for the FEATURES: immersed elements.

ENVIRONMENTAL Designed to take loads of a sunken ship or earthquake, including consideration of CONDITIONS: liquefaction of the silty sands beneath the tunnel, differential settlements, and frictional restraint of movement caused by temperature, shrinkage, and creep.

FABRICATION METHOD: JOINT TYPE: Casting basin constructed near the site. All elements Gins/Omega system was utilized. Tension ties were cast in a single cycle. provided across the joints for earthquake loads.

WATERPROOFING Two-ply bituminous membrane system was specified for the sides at top. Steel plate was METHOD: used for bottom and cellars. Waterproofing was protected with concrete. Tube was cast in six sections of 20 m each.

PLACEMENT Transverse barges with survey and control towers were used. METHOD:

FOUNDATION Sand-flow method, using pipes previously cast in the bottom of the tunnel elements; METHOD: accessible from the outside.

VENTILATION Longitudinal system. TYPE:

ADDITIONAL OWNER: Kaohsiung Harbor Bureau. INFORMATION: DESIGNER/CONTRACTOR (Tumkay): Retired Serviceman Engineering Agency (RSEA).

Volume 8, N,,mher 2, 1993 ~.,.n~o Am) U~ro~ro ~ACZ TZCS~OLO~Z 243 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 70 Fort McHenry Tunnel; Baltimore, Maryland, U.S.A.; 1987

TUNNEL TYPE AND USE: Vehicular; two LANES/TRACKS: Two parallel tunnels, each with two tubes and double-shell steel binocular tunnels. two lanes in each tube, for a total of eight traffic lanes.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 25.1 m 32 (16 elements for 104. 8 m 12.7 m each tunnel)

TOTAL IMMERSED LENGTH: 1,646 m DEPTH AT BOTTOM OF STRUCTURE: 31.7 m

UNUSUAL Two parallel immersed tunnels, only 3 m apart, mostly on a curve. Overall largest vehicular FEATURES: immersed tunnel project in the world. Elements were placed altemately from the northbound tunnel to the southbound tunnel. An 11-m-deep ship wharf was removed during construction and later replaced as a float-in caisson on top of the twin tunnel. Scheduling of element placement depended on the relocation of a 122-cm critical city watermain, which crossed the alignment. This relocation involved a deep cofferdam in the middle of the river, to make the changeover. Rrst use of remotely controlled wedges for horizontal alignment adjustment.

ENVIRONMENTAL Very mild currents and tidal conditions, except for storm effects. Flow of bottom sediment CONDITIONS: was a problem affecting several elements. Three elements required rascreeding.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Shipyard at Port Deposit, Maryland about 65 At dockside in Baltimore, a short Double rubber gasket. km from tunnel site. Uncontrolled side launch. distance from the site. Up to six Welded, grouted liner plate. elements were being outf'~ed at one time.

WATERPROOFING METHOD: Continuous steel shell.

PLACEMENT METHOD: Catamaran barge system.

FOUNDATION METHOD: Option was provided for either jetted-sand or screeded bedding. The contractor opted for the screeded method. A special taut moored rig was used, with the flotation tanks fully submerged to prevent tidal effects.

DREDGING METHOD: Virtually all dredging was done by a large cutterheed suction dredge (69-cm-dia. pipe) pumping via a submerged pipeline to a disposal site 4 krn away. A booster pump was mounted on a barge.

VENTILATION TYPE: Fully transverse ventilation, shared by a ventilation building located at each end of the pair of immersed tunnels.

COVER AND TYPE: 1.5 m of ordinary backfill.

ADDITIONAL Disposal site for dredged matedal was segregated into two areas. One area contained the INFORMATION: highly contaminated near-bottom materials behind a sealed cofferdam and clay-lined dikes. The other area was used to contain the better, more granular materials; it has since been developed into a major container port facility.

OWNER: Interstate Division Baltimore City (IDBC). DESIGNER: Joint Venture: Sverdrup Corporation and Parsons Bdnckarhoff Quade and Douglas, Inc. CONTRACTOR: Joint Venture: Peter Kiewit & Sons, Inc., Raymond Intemational, Inco and Tidewater Construction Corp.

244 Tum~.Tmo AND UNVmm~ousv SPAc~ T~SNOLOOY Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 71 Second Downtown Tunnel; Norfolk to Portsmouth, Virginia, U.S.A.; 1988 D

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; double-steel-shell horseshoe element. Single tuba; two lanes.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 8 101.5 m 10.5 m 12.2 m

TOTAL IMMERSED LENGTH: 765 m DEPTH AT BOTTOM OF STRUCTURE: 13.7 m

UNUSUAL Horseshoe shape was used for economy because of the ventilation method adopted. FEATURES: Elements were fabricated in Texas and shipped in pairs on a semi-submers~le ocean- going barge.

ENVIRONMENTAL Current 1.0 m/s (2 knots) max. Tide 1.2 m. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: In shipyard in Corpus Christi, Texas, 3,500 krn from At dockside near site. Double gasket system. tunnel site.

WATERPROOFING Continuous steel shell. METHOD:

PLACEMENT From catamaran barge system. Tube was brought out almost fully ballasted to reduce the METHOD: time in the dver channel. Remotely controlled wedges used for horizontonal alignment.

FOUNDATION Screeded gravel bedding. METHOD:

VENTILATION Semi-transverse, using ceiling exhaust air duct. One ventilation building. TYPE:

COVER AND TYPE: 1.5 m of ordinary backfill.

ADDITIONAL OWNER: Virginia Department of Highways and Transportation. INFORMATION: DESIGNER: Parsons Brinckerhoff Quade & Douglas, Inc. CONTRACTOR: J.A. Jones Construction Co. and Schiavone Construction Co.

Volume 8, Number 2, 1993 ~.T.~a AND Um)EZ~nOUND SPAC~ TEC~OLOaY 245 TUNNEL NAME AND LOCATION/DATE COMPLETED: File No. 72 Guldborgsund Tunnel; crossing the sound between the Islands of Lollsnd and Falster, Denmark; 1988

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box sections. Two tubes, each with two lanes.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 2 230 m 7.6 m 20.6 m

TOTAL IMMERSED LENGTH: DEPTH AT BO'I-rOM OF STRUCTURE: 460 m 13.8 m

UNUSUAL 230-m-long-, vertically curved elements are some of the longest ever produced. FEATURES: Computer-controlled dynamic ballasting was used. Elements were floated out under water.

FABRICATION METHOD: JOINT TYPE: The two tunnel elements were cast one at a time in a Between tunnel elements: Gins gasket supplemented with dry dock located in the future tunnel ramp at Lolland. fiat rubber interior gasket. At shore ends of tunnel: The elements were cast in 15-m to 15.3-m segments Temporary tightening by rubber lip gaskets, allowing ramps to prevent cracks. When cracks occurred in the first to be emptied of water, whereupon the permanent rubber segment, cooling was used in the second element, Omega gaskets were installed between the tunnel and the and no cracks were found. portal structures. The tunnel was made monolithic by casting reinforced concrete in the temporary gap between the two tunnel elements.

WATERPROOFING The elements are waterproofed with a 6-mm steel membrane on the bottom and sides. On METHOD: the top, a bituminous membrane was installed and protected with 15 cm of reinforced concrete.

PLACEMENT Each of the tunnel elements was provided with bulkheads at the ends and equipped with METHOD: six ballast tanks with a total capacity of 4,000 cu. m of water. After flotation, the elements were moved to their final position and sunk onto temporary supports approximately 1 m above the bottom of the excavated trench.

FOUNDATION Sand-jetting. METHOD:

DREDGING A cutterhead suction dredge was used. METHOD:

VENTILATION Longitudinal ventilation by means of jet fans. TYPE:

COVER AND TYPE: The eastern part, where the tunnel is located above the seabed, is protected with 1 m of gravel. No cover is provided for the remaining part of the tunnel.

ADDITIONAL The tunnel ramps are located in low water areas in the sound, and surrounded by dikes. INFORMATION: W'dhin the dikes, dswi~tlo is mRrformed by ralisf~w~: ~ ~ water is Du~ out into the sound at the tum~l portats. The tunnel is ~ to be unmanned, wtth automatic and remote co(,;~ois.

OWNER: Road Directorate. DESIGNER: Christiani & Nielsen A/S. CONTRACTOR: Guldborg Sound Consortium: Armton A/S/, and E. Phil & Son/VS.

246 Tu~u~.r~G ~'D U~E~aou~m SP,~ TEaSNOU~Y Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 73 Emstunnel; Leer, Germany; 1989

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; concrete box elements. Two tubes; two lanes plus one emergency lane/tube.

NO. OF ELEMENTS: 5 LENGTH: 127.5 m HEIGHT: 8.40 m WIDTH: 27.50 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 639.5 m 19 m below mean water level

UNUSUAL An unexpectedly high rate of sedimentation (approx. 15 cm per tide change) filled the FEATURES: trench immediately after each element was placed. Special equipment was developed to remove the siltation under the element a few meters in front of the sand jetting operation.

ENVIRONMENTAL Mean tide 2.61 m. Mean current 1 m/s. Siltation was a problem. CONDITIONS:

FABRICATION METHOD: The elements were OUTFI'I'rlNG: JOINT TYPE: built together in a graving dock adjacent to the After all of the elements were Gine/Omega system. tunnel trench. Each element was cast in five finished, the dock was flooded and Elements divided into 25.5-m-long segments. To prevent cracks, a the dike was removed using a 25 segments. cooling system was installed. The segments dredge. Before floating each were post-temsioned for placing, after which the element, two pontoons equipped with post-tensioning bars were cut. lowering and mooring winches were floated over the elements and connected to them. After deballasting, the element floated with the pontoons on top.

WATERPROOFING Impermeable reinforced concrete with a bituminous layer over the roof, prtected with 0.2 METHOD: m of protection concrete.

PLACEMENT After winching the element to its location, it was placed by ballasting and lowering. It was METHOD: temporarily supported by primary and secondary supports.

FOUNDATION Jetted-sand foundation. Special equipment was developed to clean the area under the METHOD: tunnel just in front of the sand-jetting operation.

DREDGING METHOD: Cutterhead suction dredge and dustpan dredger.

VENTILATION TYPE: Longitudinal.

COVER AND TYPE: Approximately 1 m of stone cover on reinforced concrete slab on toof the elements.

BUOYANCY SF: 0.02 for placement. CONCRETE WORKING STRESS: DIN B35

ADDITIONAL OWNER: Autobahn-Beubaumt Oldenburg, Ministry of Transport, Federal Republic of INFORMATION: Germany. OPERATOR: Motorway-Authority Oldenburg. DESIGNER: IMS Ingenieurgesellschaft mbH, Hamburg. CONTRACTOR: HBW, the Netherlands: BREWABA; Bauunternehmen Hein; Beton und Tiefoau Mast; Martin Oetk.en.

Volume 8, Number 2, 1993 Tum~.T.wo +.m) Um)~totmv SPAcz Tzc]m~z)~r 247 TUNNEL NAME/LOCATOIN/DATE COMPLETED: File No. 74 Marne Tunnel; under the River Marne, Paris, France; 1989

I

TUNNELTYPE AND USE: LANES/TRACKS: Two separate tunnels, with three lanes Vehicular prestressed concrete box sections. of traffic in each tunnel.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 7 45-55 M 9m 17.5 m

TOTAL LENGTH: West Tunnel: 210 m. East Tunnel: 140 m.

ENVIRONMENTAL Restricted channel area. CONDITIONS:

FABRICATION METHOD: JOINT TYPE: In a casting basin at northem ramp site. Phoenix pdmary gasket and Omega secondary gasket.

PLACEMENT METHOD: Using moodng lines and balla~ng. Level control maintained by four comer tanks. Two access shafts, one at each end of element.

FOUNDATION METHOD: Jacks and jetted or sand-flow foundation.

DREDGING METHOD: Backhoe-typedredge.

VENTILATION TYPE: Transverse, using side ventilation ducts.

248 TUNS~:T.mO+,NO Um~me~OUNV SPACZ TS~SNOX~r Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 75 Zeeburger Tunnel; Amsterdam, The Netherlands; 1989

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box section Two tubes, three lanes each

NO. OF ELEMENTS: 3 LENGTH: 112 m HEIGHT: 8.125 m WIDTH: 29.8 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 336 m 14.60 m

UNUSUAL Used telescoping pile to element closures. Constructed inside cofferdam for FEATURES: cut-and-cover tunnel. End of last element protrudes into dock, and has a collar around it to permit dewatering and construction in the dry.

FABRICATION METHOD: JOINT TYPE: Gina and Omega gaskets. Each of the three elements was constructed in sequence in the open construction dock at one end of the tunnel, which was equipped with a specially designed gate. Each element was cast in five 22.4-m-long sections, using a cooling system to prevent cracking.

WATERPROOFING To prevent cracking, the elements were constructed of 22.4-m-long sections, METHOD: post-tensioned together. No exterior waterproofing system was used.

PLACEMENT A conventional system was used. The element was temporarily supported at the METHOD: outboard end on two piles while the permanent pile connections were made.

FOUNDATION Supported on piles driven to a depth of 46 m. Eight piles were used along the outer walls METHOD: of the tunnel for each 22-m section. The piles are equipped with telescoping inflatable forms, which can be post-grouted to complete the closure between the top of the pile and the underside of the tunnel. 120 steel tubular injection piles 0.5 m in diameter were used to support the elements.

DREDGING METHOD: Barge-mounted Crane and bucket.

COVER AND TYPE: Gravel was placed on top of the CONCRETE QUALITY: B25 tunnel. The trench was filled to -10 m, with the rest to be filled by natural siltation.

ADDITIONAL Bad soil conditions to -28 m. INFORMATION:

Volume 8, N-tuber 2, 1998 TUSl~.T.-qO AND U]~suaOUl~ SPAcz TBc~sI~C~ 249 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 76 Hong Kong Eastern Harbour Crossing; Hong Kong Harbour; 1990

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular and railway; reinforced concrete box. Two rail tubes; two two-lane highway tubes; one tube for ventilation.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 15 10 @122 m; 4 @128 m; 9.5 m 35m 1 @126.5 m

TOTAL IMMERSED LENGTH: DEPTH AT BO'I-I'OM OF STRUCTURE: 1,859 m 27 m

UNUSUAL Very large elements with 40,000- to 42,000-ton displacement. Use of waterfilled inflatable FEATURES: rubber bag "jacks" to hold element at grade until sand could be jetted in place under it. The Cha Kwo Ung Ventilation Building was built as a floating structure with the last five elements.

ENVIRONM ENTAL Very busy harbour. Typhoon weather. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Elements were constructed in a rock quarry on the Installation of control and Gina and Omega gaskets. alignment. Gates were constructed in place before survey towers and first flooding. Five elements were constructed at a pontoons equipped with time. Cycle times were 27 weeks, 25 weeks and 22 winches. Special weeks, respectively. telescoping towers were used for the last three shallower elements.

WATERPROOFING Concrete was poured in three stages--base, walls and roof---in successive bays up to 18 METHOD: m long. Reinforcement was designed to limit crack width to prevent seepage. Heat of hydration was limited by replacement of 20% of cement with flyash. This also limited sulphate attack. The sides and roof were externally coated with sprayed-on epoxy rubber membrane. Visible cracks were grouted with epoxy resin prior to float-out.

PLACEMENT Pontoons, mounted transversely over the element and controlled from the tower, lowered METHOD: the element in place. Wsterfilled inflatable I~gs were used as temporary (6 mos.) support element. Sand was jetted under element using slurry nozzles on each side of the element, fed from a barge.

FOUNDATION Jetted sand. METHOD:

VENTILATION Fully transverse. TYPE:

COVER AND TYPE: 1.5 m of backfill. BUOYANCY SF: 1.02 with no backfill; 1.15 with backfill

ADDITIONAL OWNER: New Hong Kong Tunnel Company. INFORMATION: DESIGNER: Freeman Fox. CONTRACTOR: Kumagai Gumi Co. Ltd.

9.50 ~.r.mG AND UmDn,Z~OtmD SPACe TJmCmNOLOOY Volume 8, N-taKer 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 77 Conwy Tunnel; North Wales, United Kingdom; 1991

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; concrete box elements. Two tubes; two lanes each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 6 118m 10.4 m 24.1 m

UNUSUAL The first immersed tunnel in the U.K. Due to the traffic requirements in the U.K., the tunnel FEATURES: is approximately 2 m higher than usual. The tunnel is skewed to the river, with an angle of less than 45 degrees.

TOTAL IMMERSED LENGTH: DISPLACEMENT: DEPTH AT BOTTOM OF 710 m 30,000 MT STRUCTURE: +17m

ENVIRONMENTAL Sensitive scenic area. River crossing. Required relocation of small boat anchorages. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: GineJOmega Elements were constructed together in a After all of the elements were joint with six separate graving dock located next to the trench. completed, the dock was flooded and shear keys. Continuous Before casting, exterior waterproofing the dike was removed by dredging. shear keys of concrete not plates were placed on the bed. Each Before float-up, two pontoons with provided at joint. Joint element was cast in segments, although lowering and mooring winches were covered with stainless steel continuous reinforcing was used. No floated over each element to be joint covers on inside of cooling system was installed for the wall placed and hooked up to it. After tunnel. pours. deballlasting, the element floated with the pontoons on top.

WATERPROOFING The underside and walls are waterproofed with steel plate with a passive cathodic METHOD: protection system and a concrete protected bituminous waterproofing membrane is provided on the roof.

PLACEMENT After winching the element to its location, it was placed by ballasting and lowering onto METHOD: temporary footings.

FOUNDATION Jetted-sand foundation. Restrictions on ability to start sand-jetting caused sedimentation to METHOD: occur under the tube. This was removed by airlifting.

DREDGING Cutterhead suction dredge. Spoil used for project embankment construction. METHOD:

VENTILATION Longitudinal jet fans. TYPE:

ADDITIONAL OWNER: Government of North Wales. INFORMATION: DESIGNER: Travers Morgan & Partners in association with Chdstiani & Nielsen/VS. CONTRACTOR: Joint venture with Constain-Tarmac.

Volume 8, Number 2, 1993 Tr.rm~.T.mo AND UND~tCatOVm) SPACZ Tr~mNo~ 251 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 78 Liefkenshoek Tunnel; under River Schelde, Antwerp, Belgium; 1991

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced concrete box elements. Two tubas; two lanes, each with shoulders.

NO. OF ELEMENTS: 8 LENGTH: 142 m HEIGHT: 9.6 m WIDTH: 31.25 m

TOTAL IMMERSED LENGTH: 1136 m DEPTH AT BOTTOM OF STRUCTURE:

UNUSUAL FEATURES: Specifically designed to carry vehicles with hazardous cargoes. Designed to be fire- and explosion-resistant. Funded under a concession contract. Separate escape passageways provided for each tube. A simulation was done of an anchor dropping on the immersed elements, by impact tests on the in-situ tunnel. Dynamic responses were measured.

ENVIRONMENTAL Strong currents. CONDITIONS:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: All eights units were built at the same time in a After all elements were finished, the Gina and Omega casting basin located in the harbour area. Each dock was flooded and the dike was gaskets. element was cast in six 23.65-m-long segments. A removed by a dredge. Transverse cooling system was used to prevent cracks. floats were used. A temporary post-tensioning system was used. The elements had to pass through a lock before entering the river.

WATERPROOFING The elements were divided into six 23.7-m-long segments. Longitudinal prestressing was METHOD: provided in the floor and roof. Carefully designed concrete was used: 1140 kg 4/28 gravel; 730 kg sand 0/5; 270 kg blast-fumaca cement HL30; 80 kg flyash; 130 1water; and 3 kg superplasticiser.

PLACEMENT A complate fiver and placement modelling study was carried out. The study showed that METHOD: placement should be restricted to periods of neap to ~ tides to limit holding forces. A layer of trimming concrete was placed to reduce the freeboard without water ballast to 50 ram. Alignment towers 30 m high and other placement equipment was installed. The units were towed using four 3,000-HP tugs. Other tugs ware on standby. The element was supported on two support points on the tunnel in place, and on two jacks at the outboard end. Support pads 6 x 6 x 1.2-m ware used.

FOUNDATION Sand-water mixture was pumped through sandfill valves. To avoid siltation, this METHOD: operation was started within one hour after the sinking operation was completed.

DREDGING METHOD: A cutterhead suction dredger.

VENTILATION TYPE: Full transverse was used because of the hazardous cargo criteria.

COVER AND TYPE: Special asphalt mattresses were incorporated in the tunnel cover design to I>,-otectthe tunnel.

ADDITIONAL The interior of the tunnel was protected by 50 mm of insulation as a result of testing for a INFORMATION: four-hour fire exposure. The tunnel design required some 50-60 Kg of additional reinforcing to cope with a 5-bar explosion overpressure. OWNER: Ministry of Public Works and Transport. DESIGNER: Haecon NV. CONTRACTOR: Joint venture of De Meyer-Van Laere-Batonac.

252 TUN~.TmO ~ U~-DZRm~Um) SPACB~OLOGY Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 79 Interstate 664 Tunnel; Hampton Roads, between Newport News and Chesapeake, Va., U.S.A.; 1992

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; double-steel-shell binocular section Two tubas; two lanes in each tuba.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 15 95 m 12m 24 m

TOTAL IMMERSED LENGTH: 1425 m DEPTH AT BOTTOM OF STRUCTURE: 36 m

UNUSUAL Extends between man-made peninsula and a man-made island, where it joins a trestle. At 6 FEATURES: miles long, it is one of the longest subsea crossings. This is one of the few immersed tunnel projects in the U.S. for which a drydock was used. The navigation channel was so narrow • at it had to be closed dudng placement of the elements.

ENVIRONMENTAL Very strong tidal currents around the point where the James River meets the open water of CONDITIONS: Hampton Roads required heavy anchor lines and special precuations during maneuvering and placement of the elements. Very active ship channel, with much pleasure-boating.

FABRICATION METHOD: OUTFI'I-I'ING: JOINT TYPE: Elements were fabricated in Baltimore at the Interior concrete was Standard double gasket Sparrows Point Shipyard of Bethlehem Steel Co. placed at a shipyard. Final and closure plate detail The elements were assembled in a drydock, and all concrete was placed at used in the U.S. for many interior concrete (except walk'ways) was installed jetty in Newport News, Va. years. before closing the ends with bulkheads. The elements were then floated out with approximately 7.5 m draft. An additional 2,700 cu. m was added at a pier pdor to towing the element to Newport News (draft was about 10 m).

WATERPROOFING Steel shell and liner plate. METHOD:

PLACEMENT Remotely controlled wages used for horizontal alignment. Conventional catamaran barge METHOD: system was used, with a laybarge consisting of two railroad car barges with support beams between them.

FOUNDATION Screeded foundation. Screed rig designed to be unaffected by tidal vadations. METHOD:

DREDGING Cutterhead suction dredging and pumping behind dikes to form manmade island and METHOD: peninsula. Cleanup dredging was done with a clamshell dredge.

VENTILATION Fully transverse ventilation system split between two ventilation buildings. TYPE:

COVER AND TYPE: A 0.90-m wall was constructed BUOYANCY SF: 1.03 CONCRETE WORKING on each element to contain rock ballast. In addition, After dewatedng, joints, STRESS: rock and armor stone were placed on top of the 1.07 without backfill. 4,000 psi element as protection.

ADDITIONAL OWNER: Virginia Department of Transportation. INFORMATION: DESIGNER: Sverdrup Corporation. CONTRACTOR: Morrison Knudsen, Inc., and Interbeton Inc. joint venture.

Volume 8, N-m~m" 2, 1993 ~.T.USPACm Tmcn~oLom, 255 TUNNEL NAME/LOCATION/DATE COMPLETED: FileNo. 80 Third Harbour Tunnel*; Boston Harbor, Boston, Massachusetts, U,S.A.; U/C (1994)

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; double steel shell binocular section. Two tubes; two lanes each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 12 98.30 m 12.29 m 24.43 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 1,172.9 m 30m

UNUSUAL Much of tunnel trench excavated through hard argellite rock. Immersed tunnel ends FEATURES: incorporeted into very deep cofferdams. Depth at cofferdams at bottom of end elements more than 20 m below sea level. First use of Omega gasket in a U.S. tunnel.

ENVIRONMENTAL Many environmental constraints regarding filling in harbor, Sl~wning of fish, blasting, CONDITIONS: siltation, work around and airside at Logan International Airport, and impacts from harbor celebrations and activities such as "Sail Boston '92."

FABRICATION METI-K)D: OUTFITTING: JOINT TYPE: At shipyard, elements assembled in drydock two at a At pier near tunnel site. Double gasket system time and floated out. Each tube floated onto large commonly used in U.S., but ocean-going submersible barge (106 x 30 m) for tow with Omega secondary to Boston. Tow made using a single 9,000-HP ocean gasket. Joint detail tug direct route between Norfolk, Va., and Cape Cod, provides for thermal Mass. expansion at joint.

WATERPROOFING Steel shell and Omega gasket closures. Closure plate detail not used on this project. METHOD:

PLACEMENT From catamaran barges. Remotely controlled wedges used for horizontal alignment. METHOD:

FOUNDATION Screeded foundation. METHOD:

DREDGING Drill and blast. Used the =Super Scoop', owned by Dutre Corp., with up to 17.5-ms buckets METHOD: for removal of silts, sands, till and rock.

VENTILATION Fully transverse ventilation system. Centrifugal fans. TYPE:

COVER AND TYPE: 0.6 m of protective rock over .9 m of gravel.

ADDITIONAL OWNER: Massachusetts Highway Department. INFORMATION: DESIGNER: Preliminary Design: Bechtel/Parsons Brinckerhoff. Final Design: Sverdrup Corporation. CONTRACTOR: Morrison Knuedsen/Interbeton/J. F. White joint venture.

254 Tum~.v.~a AND UNDmm~OUNV SPACE TZCSNOLOOY Volume 8, N~m~r 2, 1993 TUNNEL NAME / LOCATION/DATE COMPLETED: Rle No. 81 Willemspoortunnel*; Rotterdam, The Netherlands; U/C

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; concrete box elements. Two tubes; two tracks each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 8 115-138 m 8.62 m 28.82 m

TOTAL IMMERSED LENGTH: UNUSUAL FEATURES: Unusually difficult, restrictive 1,012 m urban and madne site. Elements placed between cofferdam wails in some areas.

ENVIRONM ENTAL Very difficult urban and madne constraints on construction. Heavily trafficked waterway. CONDITIONS: Close to many sensitive existing structures and rail facilities.

FABRICATION METHOD: OUTFI'I-I'ING: JOINT TYPE: Elements were fabricated in five or six 23-m Outfitting for placement was done in Gins/Omega. segments post-tensioned together. A cooling system the casting basin. Elements were was used. Segments have large triangular shear ballasted to keep them on the keys shaped in the vertical wails. Casting was done bottom prior to placement. Each in an existing basin at Barendrecht, where several was then floated individually and other immersed tunnels have been built. towed to the site with 20 cm of freeboard. The tdp took one day. A catamaran barge system was used for placing.

WATERPROOFING No waterproofing layers were used. Concrete segments were sized and designed to METHOD: prevent cracking, and careful concrete mix and temperature control were used for each segment.

PLACEMENT On the left (northwest) side of the Maas, the elements were lowered from girders. On the METHOD: right side, across the Nieuwe Maas, floating pontoons were used. The closure joint was made between the last two elements.

FOUNDATION Sand-flow foundation. METHOD:

DREDING METHOD: Backhoe dredging and a COVER AND TYPE: 1.0 m protec~on. cutterhead su~on dredge.

VENTILATION TYPE: Piston action of trains. CONCRETE QUALITY: B30.

ADDITIONAL OWNER: Dutch Railway. INFORMATION: DESIGNER: Rijkswaterstaat Bouwdienst. CONTRACTOR: KWT Joint Venture: Dirk Verstoep Rotterdam; Ballest Nedam; Van Hattum in Blankevoort; Strukton Baton bouw.

Volume 8, Number 2, 1993 TUNN~.T.r~O AND UNDm~OaOUNDSPAC~ TS~OLOOY 255 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 82 Niigata Port Road Tunnel*; Niigata, Japan; U/C

TUNNEL TYPE AND LANES/TRACKS: Two tubes; TOTAL IMMERSED LENGTH: 850 m USE: Vehicular two lanes each tube.

NO. OF ELEMENTS: 8 LENGTH: 107.5/110.5 m HEIGHT: 8.75 m WIDTH: 28.6 m

TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 83 Tams River Tunnel*; Tokyo, Japan; U/C

TUNNEL TYPE AND USE: Vehicular; reinforced LANES/TRACKS: Two tubes; three lanes each. Escape concrete box prestressed Iongitudially for passageways and utility space for gas, electric and drainage watertightness. lines in the side ducts.

NO. OF ELEMENTS: 12 LENGTH:128.6 m HEIGHT: 10.0 m WIDTH: 39.7 m

TOTAL IMMERSED LENGTH: 1,549.5 m DEPTH AT BOTTOM OF STRUCTURE: 30 m

UNUSUAL FEATURES: All of the tunnel was constructed on a curve. Flexible earthquake joints ware provided between all the tunnel elements. Piles were driven in casting basin bottom after it was stabilized with soil cement. Liquid nitrogen was used to cool sand during summer concreting. Blast fumace cement was used to reduce thermal cracking.

ENVIRONMENTAL CONDITIONS: At the mouth of the Tama River.

FABRICATION METHOD: JOINT TYPE: Fabricated in a graving basin used jointly for the Gina/Omaga-type joint. Flexibility is provided by the rubber Tama River and Kawasaki Fairway Tunnels. The joint, in combination with the use of post-tensioned rods basin accommodated 11 elements at a time and tightened across the joint. Three verticet shear keys had a floor area of 107,000 sq. m (592 m x 190 m). provided in the walls and one horizontal key in the floor provide stability against displacements due to earthquakes and/or settlements.

WATERPROOFING 8-mm steel plate on sides and bottom of elements; concrete protected by 2.5-mm-thick METHOD: rubberized membrane on top slab. Steel plates are cathodically protected.

PLACEMENT METHOD: Catamaran barges. 10-cm freeboard. 500 MT during lowering (1%) and 1500 MT in place (3%) prior to placing final ballast (1.1 SF against flotation, not counting backfill).

FOUNDATION METHOD: Mortar pumped over gravel foundation bed.

VENTILATION TYPE: Longitudinal ventilation. COVER AND TYPE: 1.5 m of stone cover.

ADDITIONAL Mix proportions for tunnel element concrete: wlc .515; water 155 kg/cu, m; cement 301 INFORMATION: kg/cu, m; sand 834 kg/cu, m and gravel 1034 kg/cu, m.

OWNER: Metropolitan Expressway Public Corporation. CONTRACTORS: Tamagawa Tunnel Joint Venture: Kajima Corporation; Kumagai Gumi Co. Ltd.; Ohbayashi Corporation; Shimizu Corporation; Nishimatsu Construction Co., Ltd.; Okumura Corporation; Fujita Corporation; Toa Corporation.

256 T~a~.v.~a ~ UNDmmROUNDSPACE "I~mNOLO~Y Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No, 84 Kawasaki Fairway Tunnel*; Tokyo, Japan; U/C

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; reinforced box concrete elements Two tubes; three lanes each. Escape passageways and utility prestressed longitudinally for watertightness. space for gas, electric and drainage lines in the side ducts.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 9 131.2 m 10.0 m 39.7 m

TOTAL IMMERSED ELEMENT DISPLACEMENT WEIGHT: 52,000 MT DEPTH AT BOTTOM OF LENGTH: 1180.9 m STRUCTURE: 26 m

UNUSUAL Rexible earthquake joints were provided between the tunnel elements. Piles were driven in FEATURES: casting basin bottom after it was stabilied with soil cement. Uquid nitrogen was used to cool sand during summer concreting. Blast fumace cement was used to reduce thermal cracking. Part of same roadway as Tama River Tunnel.

ENVIRONMENTAL At mouth of Dalshi Canal and entrance to Kawasaki Port. CONDITIONS:

FABRICATION METHOD: JOINT TYPE: Fabricated in a graving basin used jointly for the Gins/Omega-type joint. Flexibility was provided by the rubber Tama River and Kawesaki Fairway Tunnels. joint, in combination with the use of post-tensioned rods Basin accommodated 11 elements at a time and tightened across the joint. Three vertical shear keys in the had a floor area of 107,000 sq. m (592 m x 190 walls and one horizontal key in the floor provide stability m). Basin was used jointly for Tama River Tunnel. against displacement.

WATERPROOFING 8-mm steel plate on sides and bottom of elements; concrete-protacted rubberized METHOD: membrane on top slab. Steel plates are cathodically protected.

PLACEMENT Catamaran barges. 500 MT during lowering (1%) and 1500 MT in place (3'/o) prior to METHOD: placing final ballast (1.1 SF against flotation, not counting backfill).

FOUNDATION Mortar pumped over gravel foundation bed. METHOD:

VENTILATION Longitudinal ventilation. TYPE:

COVER AND TYPE: 1.5 m of stone cover.

ADDITIONAL Mix proportions for tunnel element concrete: w/c, .515; water, 155 kg/cu, m; cement, 301 INFORMATION: kg/cu, m; sand, 834 kg/cu, m and gravel, 1034 kg/cu, m.

OWNER: Metropolitan Expressway Public Corporation. DESIGNER:: Oriental Consultants Co., Ltd.; Pacific Consultants Co., Ltd. CONTRACTORS: Meeda Construction Co., Ltd.; Hazarna Gumi, Ltd.; Tobishima Corporation; Penta-Ocean Construction Co., Ltd.; Sato Koyo Co., Ltd.

Volume 8, Number 2, 1993 T~m~.vmo AND UND~m~OUND SPA(= T~m~owoY 257 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 85 Sydney Harbour Tunnel*; Sydney Australia; U/C

TUNNEL TYPE AND USE: Vehicular; concrete box LANES/TRACKS: Two tubes; two lanes each tube. elements.

NO, OF ELEMENTS: 8 I LENGTH: 120 m HEIGHT: 7.43 m I WIDTH: 26.1 m

I I TOTAL IMMERSED LENGTH: 960 m DEPTH AT BOTTOM OF STRUCTURE: 2,5 m

UNUSUAL Element No. 1 was laid against the ventilation building at the north end of the tunnel. A FEATURES: short stub section of tunnel built into the ventilation building was provided with a sill beam to receive the first element. Element No. 2 was placed next. Element No. 8 was then placed; the connection to the land tunnel was made in a unique cofferdam in order to protect the Sydney Opera House forecourt. A cofferdam was built over and around the end of the element; a tremle seal to the sandstone rock was made at the front. To allow for differential settlement between elements No. 7 and No. 8, a special flexible joint was attached to the end of element No. 7. Temporary bars were cut after the elements were in place. Unique protective stone armour for dragging or falling anchors was used.

ENVIRONMENTAL Very environmentally sensitive area at scenic Sydney Harbour, with the Sydney Opera CONDITIONS: House almost in the alignment. These conditions led to the unique use of a bridge pier for vent stack.

FABRICATION TOWING/OUTFITTING: JOINT TYPE: METHOD: Elements were cast in Port Kembla, 100 km Gina/Omega type of joint. A special The elements were away. Exter,~ive model studies were undertaken prefabricated settlement joint was built in two groups of to assure feasibility of tow. A freeboard of 0.5 m provided on element No. 7, which four in a graving dock. was used during tow. At the outfitting pier in was founded on sand. Element No. The elements have Sydney, further ballast and placing equipment 8 was connected into a sandstone continuous was installed, bringing elements to almost neutral wall and a tunnel was mined to it. reinforcement, but buoyancy. were cast in sections.

WATERPROOFING A PVC membrane was used on the bottom. The sides and top were covered with an METHOD: epoxy resin coating. Low heat of hydration with good impermeability to chlodde ion penetration was achieved using a high replacement blend of Type A cement and ground granulated blast furnace slag. Sulphate resistance was also good. Blast furnace slag was not chosen for coarse aggregate because of a 3% lower density than natural basalt aggregate mix.

PLACEMENT Transverse pontoons. METHOD:

FOUNDATION Sand-flow method utilizing pipes installed in the walls from the roof slab to the base slab. METHOD: Element No. 8 was supported on a foundation of cement-based grout. The other elements were founded on sand.

DREDGING METHOD: Alluvial deposits were dredged using a grab dredge. Sandstone deposits were dredged using a cutterhead suction dredge. Provisions made for blasting were not required.

VENTILATION TYPE: Semi-transverse, using side ducts. Pier shafts of ceble-stay bddge were used as exhaust stacks at one end of tunnel.

COVER AND TYPE: A 2-m cover of rock fill with rock armour flanks was provided. The rock fill was designed to absorb the impact of a falling anchor; the rock armour was designed to deflect an anchor dragged across the tunnel.

258 Tum~.T.mo ~ U~-OF~mOt~'V SPACE TRaSNOU~Y Volume 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 86 Osaka South Port Tunnel*; Osaka, Japan; U/C

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular and railway; rectangular Four-lane vehicular; two-track railway.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 10 102.5 m 8.80 m 34.8 m

TOTAL IMMERSED LENGTH: UNUSUAL FEATURES: Mixed highway and railroad 1025 m service.

TUNNEL NAME/LOCATION/DATE COMPLETED: Rle No. 87 Bilbao Metro*; rail tunnel under Bilbao Estuary for Deueto-Olavega section of Bilbao Metro Line 1, Bilbao, Spain; U/C

TUNNEL TYPE AND USE: LANES/TRACKS: Metro railway; reinforced concrete box elements. Two tubes; single rail each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 2 85.35 m 7.2 m 11.4

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 172.2 m 17m

FABRICATION METHOD: OUTFITTING: JOINT TYPE: In casting basin within excavation for cut-and-cover Gina/Omega. tunnel on Deueto side of river.

WATERPROOFING Steel membrane on bottom and sides. Bituminous membrane on roof. METHOD:

FOUNDATION Jetted sand found~don. METHOD:

VENTILATION Piston action. TYPE:

ADDITIONAL OWNER: Basque Govemment, Department of Trarmport and Public Works. INFORMATION: DESIGNER: Chdsitiani & Nielsen. CONTRACTOR: AGROMAN Empresa Constructuora, S.A.

Volume 8, Humber 2, 1993 T~o~.~o z~o U~aoRoum) SP~ Ts~,z 289 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 88 Noord Tunnel*; Alblasserdam, The Netherlands (crossing De Noord River); U/C

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular tunnel; concrete box elements. Two tubes; three lanes each tube.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 4 3 @130 m; 1 @ 100m 8.30 m 29.95 m

TOTAL IMMERSED LENGTH: 492 m DEPTH AT BOTTOM OF STRUCTURE: 16 m

UNUSUAL To avoid dredging of the river to allow transport of the elements, the roofs of the elements FEATURES: were only partially cast. This reduced the draft of the elements enough to tow them to the site. The roofs were then completed.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: Th elements were constructed together in a graving The elements were Gina/Ornsga. dock, at the same time that the elements for the deballasted, floated, and Willemspoor Tunnel were under construction. Three prepared for a two-day tow elements were cast in five 26.15-m segements; one over tidal water and rivers. element was cast in four 24.85-m segments. A After the elements ardved at cooling system was installed. the site, the remaining portions of the roof were cast, as well as a portion of the ballast concrete on the bottom slab. This was used as added weight for placing.

WATERPROOFING No exterior waterproofing was used. Concrete segments were sized and ~ to avoid METHOD: cracking. Concrete was designed to reduce thermal cracking and produce high-dansity impermeable segments.

PLACEMENT Four small pontoons with hoisting and mooring winches were hoisted on top of the tunnel. METHOD: Conventional piecing methods were used. The closure joint was made in the river the last two elements.

FOUNDATION Sand-flow method. METHOD:

DREDGING Cutterhead suction dredge. METHOD:

VENTILATION Longitudinal. TYPE:

COVER AND TYPE: 1.0 m of gravel protection.

ADDITIONAL OWNER: Rijkawetemte~, The Department of Public Works. INFORMATION: ENGINEER: Consortium - DHV, Haskoning and W'~lenveen & BOS forming Tunnel Engineering Consultants (TEC) to work in kind of Joint Venture with Engineers from Rij~t. CONTRACTORS: Komblnatie Tunnelbouw (KTB), a conlmtium of four firms: Baltut Nedam, Van Hattum & Blankevoort, Hollen~mhe Beton & Watedoouw, and Dirk Verstoep.

260 ~.,mo AND U~um) SPAcz 'Ikcz~ou)eY Voblm~ 8, Number 2, 1993 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 89 Grouw Tunnel*; Grouw, The Netherlands; U/C (1993)

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; concrete box tunnel Two tubes, two lanes each (two highway, two local mac[s)

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 1 88m 7m 32m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 88m 11.5 m

UNUSUAL Supported on the abutments. FEATURES:

FABRICATION METHOD: OUTFITTING: JOINT TYPE: The element was constructed in the approach. It was After the approach An inflatable rubber gasket cast in four sec'dons wit ~out flexible joints, structure was flooded, the and an Omega gasket. Reinforcement was continuous and the tunnel was element was pulled through permanently prestTessed. it across the channel. Water ballast tanks were in river retaining structures on top of the element.

WATERPROOFING There was no separate exterior waterproofing membrane. METHOD:

PLACEMENT The dver retaining stnJcturas were designed to eliminate the need for additional equipment. METHOD: Water ballasting was sufficient.

FOUNDATION The element was supported on both abutments like a bridge. METHOD:

DREDGING Cutterhead suction dredger. METHOD:

VENTILATION No ventilation system. TYPE:

COVER AND TYPE: CONCRETE QUALITY: 10 cm of concrete. B35

Volume 8, N,,m1~r 2, 1993 Ttm2~.,.~TO ~ UNVJmalW~TD SPACZ TJZC~mOIZ)OY261 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 90 Medway Tunnel*; Rochester, U.K.; U/C (1995)

TUNNEL TYPE AND USE: LANES/TRACKS: Vehicular; concrete box sections Two tubes; two lanes, with shoulder in each tube

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 3 126/118 9.15 m 25m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 370 m 18.65 rn

UNUSUAL First dasign/construct tunnel in the U.K. The tunnel is designed to withstand po~ib~ uptift FEATURES: from water pressures in a chalk layer.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: A graving dock for the elements was provided at the The elements will be Gina/Ome gaskat eastern portal. On completion of the elan, the debellasted, floated and system. graving dock will be opened, and the elements will be towed out of the dock into removed and placed. The approach structure will the trench and placed. A then be constructed in the closed dock. The small catamaran barge elements were cast in six 21-m segments. system was developed.

WATERPROOFING A separate waterproofing membrane was used. METHOD:

PLACEMENT The elements ~11 be lowered by two small caternm while the elements are positioned METHOD: with winches. "rhe closure joint wiU be made ~the last alement and the ~ structure.

FOUNDATION Sand-flow method. METHOD:

VENTILATION Longitudinal. Fans are located in receases in the cut.and-cover section. This arrangement TYPE: reduced the height of the elements considerably.

COVER AND TYPE: 2 m of stone protection and a seal in the river on top of the dredged area, to prevent river water from entering the chalk.

262 Tumna.T.mo aso U~mmmmo~rv SPas Tsc~ou~ Volume 8, Number 2, 1998 TUNNEL NAME/LOCATION/DATE COMPLETED: File No. 91 Schlphol Re.way Tunnel*; Amsterdam, The Netherlands; U/C (1994)

TUNNEL TYPE AND USE: LANES/TRACKS: Railway; concrete box tunnel Two tubes, one track each.

NO. OF ELEMENTS: LENGTH: HEIGHT: WIDTH: 4 125 m 8.05 m 13.60 m

TOTAL IMMERSED LENGTH: DEPTH AT BOTTOM OF STRUCTURE: 500 m 9m

UNUSUAL The railway backs under the airport are being doubled (from two to four). The new tunnel FEATURES: will be constructed directly adjacent to the existing tunnel. Most of the 5.7 km of the railroad tunnels are being constructed by cut-and-cover methods; however, 500 m under a runway will be constructed by immersed tunnel methods to save time.

FABRICATION METHOD: OUTFITTING: JOINT TYPE: The construction dock was made in the adjacent The constructed dock Gina and Omega gaskets cut-and-cover area. Each element consists of six consisted of a sheetpile were used. segments with flexible joints. cofferdam with bracing across the to The elements were fully outfitted in the dock.

WATERPROOFING No extedor waterproofing membrane was used. METHOD:

PLACEMENT After the dock filled with groundwater, the elements were floated to a ~eeboard of 15 cm METHOD: and pulled by winches under the bracing to their posis'don. The elements were lowered from hoists on beams across the top of the cofferdam while they were ballasted with water.

FOUNDATION Sand-flow method. METHOD:

DREDGING Land excavalJon. METHOD:

VENTILATION No ventil~on system. TYPE:

COVER AND TYPE: CONCRETE WORKING STRESS: 1 m of compacted layers under the runway B35 pavement.

Volume 8, Number 2, 1993 ~.T.~o AND U~mmm~ousD Swat= Tm~moLo~ 263 Chapter 6:

SUBMERGED FLOATING TUNNELS

by

CH. J. A. HAKKAART (chairman) Hollandsche Beton en Waterbouw/DMC The Netherlands

A. LANCELOVrl Parsons Brinckerhoff U.S.A.

H. OSTLID Statens Vegwesen, Vegdirektoratet Norway

R. MARAZZA Tecnomare Italy

K. A. NYHUS Norwegian Contractors Norway

D. R. CULVERWELL (editor) U.K. Consulting Engineer

Contributions and comments by: W. Grantz U.S.A. A. Gursoy U.S.A. P. C. van Milligen The Netherlands

Tunnellmgand Underground Space Technology, Vol. 8, No. 2, pp. 265-285, 1993. 0886-7798/93 $6.00 + .00 Printed in Great Britain. Pergamon Press Ltd Chapter 6: Submerged Floating Tunnels

I. INTRODUCTION 1.1 ITA and Submerged Floating Tunnels 1.2 Submerged Floating Tunnel 1.2.1 Description 1.2.2Name

2. FEASIBILITY of SUBMEH~ED FLOATING TUNNELS 2.1 Opportunities for Submerged Flostln E Tunnels 2.2 Safety 2.3 Costs 2.4 Environment 2.5 Possible Locations 2.5.1 Coastal regions 2.5.2 Inland regions 2.6 Study and Research up to the Present 2.6.1 Hcgsi~ord in Norway 2.6.2 Strait of Mesaina in Italy

3. STRUCTURAL PRINCIPI,ES 3.1 Comparison with Other Fixed Crossings 3.2 Design Methods 3.3 Dimensions 3.4 Buoyancy 3.5 Supports 3.6 Static and Dynamic Analysis 3.7 Risk ~n~lysis 3.8 Inst~lmentation 3.9 Durability and M A;n~n~ce

4. CONSTRUCTION METHODS 4.1 Construction in Elements 4.2 Incremental Construction and Launching 4.3 Element Construction and Incremental Launching 4.4 Abutments 4.5 Anchor Points 4.6 Construction Time

5. MARKET EXPECTATION

6. REFERENCES

266 Tum~.r.~o AND UNDEm~OVNVSPACE TE~OLOOY Volume 8, Number 2, 1993 1. Introduction The differenes between tiffs type of • Combinations of the above 1.1 The ITA and Submerged Floating bmnel and a cenve~tionallmme~ed or methods. bored bmnel iS that the floating bmnal • Anchoring at the abutments only. Tunnels structure is surrotmdsd by water. That The tlmnA1 iS positioned below the In 1989, the International Tunnel- iS, the bmnel iS neither placed within water surface in such a way that ships ling Asseeiation (1TA) established a ner bored threugh the groun& Instead, can pass above it without undue Working Group on Immersed and the tannel ~cture is kept in pesiticn interference. Floating~lnnels in order to give more by virtue of its own structural capshil- Different types of submerged worldwide attention to this type of ity, though it may be augmented by a floating tunnels are presented in tunnelling. support systen~ The support system Figures 6-1; 6-2, 6-3, 6-4, and 6-5. The task of the Working Group is to may take several forms, such as: The submerged floating t~mnel ex- present the state of the art for two • Pontoons on the surface. Amined herein uses existing technol- types of tunnels: • Tension anchoring to the bed. ogy. The matorlela, the design meth- 1. Immersed or 8ubmet~d Tun- • Compression anchoring to the ods, and the construction methods are ns/S, which Can be used in rivers or bed. known and conventional, but they are waterways when it is possible to • Horizontal anchoring. combinedin anew and specific way. It place the t~nnel in the riverbed or seabed. These types of tnn-els have been built for many years. 2. Submerged Floating Tunnels ! (SFTs), which represent a new concept i for crossing deep waterways. In thiR case, the bln~el iS not an embedded structttre, but instead iS suspended. I~scatlse both types of bmnelg in- volve many different aspects, a num- ber of subworkin~ groups were estab- lished. Each sub-group was composed of specialists in the particnlm" field. The development in recent years of proposals for "floating~ sub-aque- ous t~mnels resulted in the forma- tion of the subworking group on Sub- merged Floating ~mnels. Figure 6-1. Pontoons on the surface. In a nnmher of countries, especially Norway, Italy and The Netherlands, extensive research has been done on specific tunnel schemes for crossing ~ . /\\ deep and relativelynarrow waterways. The solution--a suspended t.nnel structure--has passed the prellmln aTy and conceptual design stage, supported by detailed research and hydraulic model tests. It has now reached the stage where an actual project employingthis new type oft~m nel could be re~li~.ed in the near future. The state of the art for this type of l~mneliSpresentedinthischapter. Part Chapter 6 explRin~ the concept of the Submerged Floating Tunnel (SFT) and the opportunities it represent& The second half of the chapter presents relevant ~hnlcal information about Pigure 6.2. Tension anchoring to the bed. the SFT concept.

1.2 Submerged Floating Tunnel (SFT) 1.2.1 Description The tunnel structure discussed in this chapter would serve all types of traffic between two shores separated by deep water. The unique feature of this type of t~mnel iS that it bridges both shores and iS not buried in or placed on top ofthe bed ofthe waterway. From the ns¢~' point of view, the s~ucture has all the urn.m1 chm'acteris- tics of a tunnel. Because it iS closed, it iS considered a tttnnntll~ rather than a "bridge ~. J Figure 6-3. Compression anchoring to the bed.

Volume 8, N,Im1~r 2, 1998 Tvm~J.~o AND U~WZm~OU~ Se~ T~mOLOOY 267 Figure 6-4. Horizontal anchoring. Figure 6-5. Abutment anchoring.

is important to stress that these struc- toon bridge, a floating bridge, a bored ally acceptable, the httman ~ta- tures do not include any totally new t~mnel or an Jmm~ed tunnel. I.nvew tion ofsuch movemant~can be ofmajor features that have not been encoun- tigations have shown that the Sl~f importa~. Itistherd~~that tered in tunnelling. may be highly competitive with these the movements ofthe ~ be kept solutions in some situations. below the l;m;ts ofh;,r.A- observation. 1.2.2 Name of b-'tru~um Type Another advantage of the SFT is Research has -hewn that fh;- is the that the crossing is invisible, mAk- case for the two SFT ~ currently This type of~ hes been called beh~ prepared (see Seee~ 2.6). T. by various names, such as: ing it attractive from an environ- mental standpoint. In addition, the ~meral, it oan be said thatthe p~ycho- • Submerged Tube. gradients are very SmAll and sur- los~linterpreta~"~tofthemove- • Submerged Tube Bridge. face waterway traffic is, in prin- ments is more critical than the tsohno- • Submerged Floating Tube. ciple, not obstructed. logical I;m;ts. • Floating ~,--el. Until now, considerations for S~'Ps Because the SFr concept is new, • Underwater Bridge. have most oi~en focused on their use extra attanti~ must giv~to tl~ safety • Submerged Floating ~mnel for road traffic (e.g., as with the aspects. This meens that the first The last of these terms seems to be H~gsfjord and Strait of Messina cress- Submerged Floati-~ ~1...1 will be the most accurate for describing the ing, desoribed in sections 2.6.1 and based on rather conservative criteria following main features of such 2.6.2.), However, the SI~ concept can and dmign amumpt~,.. ~on structures: be applied for other p~, such as: tha~and~Straitu'oes- * Pedestrian tunnels: connecting ings has ahown that all safety regula- Submerged: the b~nnel is located tions can be met. under water. the mainland and a recreation islendin a deepiske, fer e~unple. Measurements canbe takento ,-i-i- Tunnel: it is a closed structure. m;,e the risks of ship eollim'on and to F/oaring: the structure has a large * Service tunne/s: to guide pipe- lines and cables. bring these risks into a range that is floating capacity and is surrounded lower fhA,, that for comparable risks by water. (seealsothe discussionin seetion 8,2.4). Therefore, this report will refer to 2.2 Safety this type of structure as a "Submerged Research has shown SFTs to be 2.3 Costs Floating Tunnel, ~ abbreviated as technically and economically feasible. ?-3.1 Construction Costs ~SFT~. But are they also safe? The answer is yes, because the level of safety required At present, the cost of building an for an SFT will be the same as that SFT can only be an order of mag- 2 Feasibility of Submerged nitude estimate. Obviously, the con- Floating Tunnels required for comparable structures, e.g., bridges. Comparisons ofthe prob- struction cests will vary from project to 2.1 Opportunities for Submerged ability of failure of an STT with the project bemuse they are hi~y depen- Floating Tunnels probability of failure of other forms of dent on the local site conditions. Based on cost experienes on projects An SFT can span different types crossings show that the chance of fail ure is of the same order. This is not of sJmilA~ magnitude and on the pre- of waterways ~stuaries, rivers, lJmJnwey COld;~ ~projects fjords, sounds, lakes, etc.--without in- surprising, considering that the tech- studied in recent years, a terfering with shipping. nologies used for the SFT, notably those concerning materials and de- with the cost of relevant alternatives, In some cases, an SFT may be the such as a suspension bridge, can be ordy possible, affordable and accep- sign methode, are based on already existing technologies. made (see Fig. 6-6). The construction table form of fixed crossing because of costs of an SFT, per meter length, do constraints such as deep water, dis- There are two particular aspe~ related to safety of SFTs: not increase sisnifieantly with the tance between the shores, or envi- ~dt~~~withtt~ 1. Techno/ogica/safety. This will ronmental considerations (see discus- of the waterway, ~ an Sl~ com- sions below). be assured dur~ the design of the pet~ve with ~ bn~ hav- The SPT tech-ique offers the oppor- total structure and its components, ing sl:-n- greater than 800 t~ 900 m. tunitytoplan crossingswhoretheyhave by adapt~ design ruJes and knowl- Evenincaem wherethe ~~ never before been thought possible. edge derived from experie~e (see sec- be considered the only feasible altor- In other cases, an SFT may be an tion 3). native, the costs are not un- alternative to another type of fixed 2. Pr/cholos~al safety. Although reasonably high. crossing, such as a bridge, a pon- the expected ~ts are structur-

268 TUNNI~.t.mIG AND UNDERGROUNDSPAn TFA~NOIf~Y VohIIne 8, N-tuber 2, 1993 3. A Submerged Floating ~i--el. If the lake is very deep, a t~,--el underneath the bed might be very long 'EN$ I ON BE I DGE and, consequently, expensive to con- fig struct, maintain and use. W If the water depth is moderate, b- ~- -z~; an immersed tunnel may be con- tiJ templated; however, if the depth is considerable, this solution must be IX ruled out. ttJ ft. For such a situation, an SFT could be the only answer. It could be located I'-- invisibly at a level fairly near the sur- q') ..~X~.~;~.~' 0 face ofthe water, because the sea state of the lakes is much more thA~ moder- 0 1000 2000 3000 ate, and the t, mnel cotdd take the short- est route across the lake (see Fig. 6-7). LENGT H Purthermore, an SFT would require only a limited constrtxction area at the Figure 6-6. Cost comparison for SFT solution vs. suspension bridge. side of the lake, thereby m;.;m;~i.g interference with the existing traffic. Additieva]ly,the $1~ solution would For an SFT with more than two continue throughout the life ofthe tun- have the meritoftlm;ted enviro~m~utal lanes, the large upli~ forces may in- nel. This maintenance may require impact. creaee the costs. replacing components, although the to- Case #2: A city or an area of envi- tal cost of such inspection and mA~-te- ronmental interest alongside a fjord or 2.3.2 Operational Costs nance is not expected to be high. lake has busy traffic passing through it, and no options to reroute the traffic In general terms, the expected op- on land available because of geosra- 2.4 Environment erational cost of an SZI' wR1 comprise: phical and/or environmental reasons. * The usual operating and ~,~i-te- SFTs have a number of special fea- The solution could be to re-route the -n-~e costarelated to t~,,m-lm in ttlres, many of which offer good solu- fragile through an underwater t-nnel general, such as lighting, venti- tions to environmental constraints. As parallel with the shore (see Fig. 6-8). latien, interior ele~-i-ff, drain- noted above, the use of an SFT may An SFT would be invisible and, in com- age, tral~e control, etc.; and mnim a cress~ possible where p]an- parison with an immersed tunnel, • Costs particular to an SFT nets in the past thought it was impes- would mnkA fewer demands on the structure. The first SI~ con- sible. Some examples of the SFT solu- underwater bathymetry. structed witl carry additional tion are given below. Case #3: A strait of considerable costs, at least during the early Case #1: An inland lake having w/dth to be crossed. Using an SFT years, for instrumentation, severe traffic problems around the pe- anchored to the sea bottom would avoid monitoring, inspection, repor- rimeter, especially during tourist sea- creating a visible impact on the envi- ting and, subsequently, verifi- sons. The ear and heavy truck trat~ ronmeat. There are no construction cation of the design. has becomo such a problem that the l*-~tatic~s to the length ofsuch a struc- area is becoml-g less attractive every ture. In contrast, a bridge has llmlt~t- Maintenance costs for the external year. However,because of the natural tions in its span length; and the piers surface are expected to be very low. beautyofthe lake, a susI~nRionbridge and anchorages that might be required Because marine growth is one of the or floating bridge is not desirable. for a multi-span lridge would pose design criteria, no costs for removal of In such a case, only three "inw_eib~" obvimm di~culties in deep water (see such growth will arise. alternatives are possible: Fig. 6-9). For t~mneis that involve separate Case #4: A deep fjord or wa- meAnA of support or tie-down for the I. A b,nnel underneath the bed of terway with high mountains directly structure, external inspection and the lake. main tenanco will be necessary and will 2. An immersed t~lnnal. adjacent to it, and the need for a

CITY

__

: LA~

~ ~ CITY ~ ~ROAIcITY D

F~gure 6-7. SFT used for crossing a lake. Figure 6-8. SFT used for by-passing a city.

Volume 8, N-tuber 2, 1993 Tvm~.~.~o Am) Um)zm~sou~m SPA(Z T]~motcoY 269 The technicalities related to each of these locations are discussed below.

2.5.1 Coastal Regions Coastal regions, which include 0ords, sounds, and connections between islands, often pose the greatest diffi- culties for fixed crossings. Although there are possible loca- tions for SFTs on all continents, some areas present partic-la~ly worthwhile opportunities. Some ofthese are listed in Table 6-1. Figure 6-9. An SFT used for a very long crossing. 2.5.2 Inland Regions Large lakes exist in virtually every country. In the past, many of these lakes have been considered impossible to cross, for a number of reasons. In many cases, the lakes have been con- sidered too wide for conventional bridges, and environmental concerns have prohibited a visible structure. The obvious choice would be to con- struct a t-nnel underneath the bed of the lake. However, these t~mnels often become very long and expensive, orthe depths are excessive. The SFT offers the poesi~ty of crossing at very gentle gradients and without visible environmental impact. In addition, some of the increasing road traffic around a v-tuber of lakes could be eliminated by reducing the Figure 6-10. An 8FT used to cross deep water with mountains adjacent. travel distance, as well as removing the traffic from visible view. Table 6-2 shows a n-m~ of lakes fixed crossing as part of the national competitive alternative if it is to be throughout the world that are of par- transportation system. In the past, adopted. ticular interest for application of the pl a--~ would have censidered such a In contrast,at sonm locatiens an SFT SFT concept. This list, although in- crossing ;m~sible. However, an SFT may be the only feasible alternative. complete, reflects current opportuni- could be built to connect directly with Po~ible locations for SFTs can be ties perceived by the authors. There lamnels at both sides through the moun- divided into two main groups: are undoubtedly further opportunities talns, as shown in Figure 6-10. The in other parts ofthe world. It will be for 1. Coastal regions. local authorities and developers to de- SFT would make it possible to create a 2. Inland regions. crossing in which no part of the strnc- ture is visible a char~c that could yield great environmental ad- Table 6-1. Possible locations for SFTs worldwide. vantages. These four examples illustrate pos- Po~lble Locations for Submerged Floating sible ways that an SFT may offer a Country Tunnels unique solution to important and diffi- cult environmental problems. In many parts of the world, it is Norway Many fjords necessary that certain crossings be made invisible in order to avoid inter- Ita~ Strait of Messina fering with the natural beauty of the Greece Mainland to islands surroundings. Structures such as sus- In-between continents; between mainlar¢l and Islands pension bridges, cable-stayed bridges or floating bridges, no matter how el- Spain/Morocco Strait of Gibraltar egant and qligh-tech% c~nnot avoid France Gironde interfering in some way with the sur- face environment. U.S.A. F'jords on west coast Alaska Bedng Strait 2.5 Possible Locations Canada Fjords on west coast As discussed above, a Submerged South China Sea Between Islands Floating Tunnel may be applicable in a D--tuber of locations where alterna- Coast of Southeast Asia Mainland to islands tive structures are also feasible. In Japan Mainland to islands; between islands such cases, the SI~ will need to be a

270 Ttrm~.1.mo Am) U~mmmmotn~DSPACE TZOHNOLOOY Volume 8, Number 2, 1993 Table 6-2. Possible sites for submerged floating tunnels. term~-e whether there are lakes in their area that might be suitable for Country Location of Lake this form of crowing.

EUROPE: 2.6 Study and Research to the Italy Como/Lecco Present Italy Maggiore The development of the principle of Italy Lugano an SFT to a feasible concept has ex- Italy [seo tended over appro~m-tely a decade. Italy In the context of the development of Garda comparable complex structures in his- Sw~zedand Neuchatel tory, this is a short period. However, Switzedand Vierwaldstettersee the brevity of the development period Sw~zefland Zi~richsee is offset by the fact that those involved France, Switzerland Geneve/Leman have gained experience in comparable Germany, Austria, Switzerland Bodensee technologiss in the civil, ~-~ine and Sweden V~ttem offshore industries. Portugal Rio Tejo Conventional design methods and existing technologies have been used and found s-CRcientto enable feasible $1~ schemes to be developed. THE AMERICAS: Extensive studi~ have been car- Canada, U.S.A. Superior tied out resard;-~ the feasibillty of an Canada, U.S.A. Huron SFT under the Hcg~ord in Norway and at the Strait of Messina in Italy. Canada, U.S.A. Ede Conceptual work has been done for Canada, U.S.A. Ontado other ]ocationsin1~orway and for Lakes U.S.A. Michigan Como and Lecco in Italy, and general Nicaragua Managua desk studies have been done in other Peru, Bolivia Titicaca parts of the world. Tha~~thn~hthese •tudi~ h.. provided in=em~ confi- ASIA: denosin the feasibility of a Submerged Floating Israel, Jordan Dead Sea ~,..~I, Japan BNva Ko Ukraine Azov 2.6,1 Hmgsflor¢lin Norway The Norwegian Road Directorate has choeen the ~ en the west OCEANIA: coast ofNorway as a pilot peqject for an New Zealand Taupo S1~. Tha propesed tumad win be in a New Zealand Wakatipu remote 15ord area, where a fixed cross- ins between the ~ of Lauvvik and Oanes is needed. The SFT will be part of the Norwegian coastal road system (see Fig. 6-11). Some relevant site conditions are listed belew: Width of waterway: 1400 m Water depth: 150 m Average currents: 0.6 ntis Water depth above b~nnel: 20 m SigniRcant wave height: 1.5 m Amt. of shipping tral~c: low The research and studies on the ~,.~ %~Oanesj~ relevant aspects ofth;, project began in 1987 and were completed at the end of 1991. This work involved both the Norwegian Govor-mAnt and interna- tional consultants and contractors. Bergen~ The work has followed conventional of which were: ,tavanger 1. Feasibility study. 2. co~ept~ 3. Hydraulic models tests. 4. ~t ofdedgn criteria. Figure 6.11. Location of Norway's Hcgsl~ord, for which a submerged 5. Tender design. floating tunnel solution has been proposed. 6. Final desig~

Volume 8, Number 2, 1993 Tu~u~T.v.mGAND Umml~mouNv SP~cz 'I~:c~Noz.oa~271 The first four stages have been com- tions in the various design disciplines in the near future. pleted. During the first two stages, are anticipated. Some of the most important areas of four classified contractor groups devel- The necessary documents for the research for the Hcgsi~ord project have oped the design and construction meth- tender for the Hcgsi]ord crossing are been: ods for a Submerged Floating 'I~lnnel n~.qhed, and the owner's requirements * Site-specific measurement of en- at the specific Hcgsi~ord location. and specifications have been worked vironmental loads. As promoter of the project, the Nor- out. Pre]~mlnary approval has been * The development of pro- wegian Government has initiated fur- given to four different concepts grammes for calculating dy- ther hydraulic modelinvestigations and (shown in Figs. 6-12-, 6-13, 6-14, and IlRmlc forces and the behaviour has prepared and adjusted the final 6.15), which will be entered in a final of the structure. design criteria. The feasibility design design and construction competition. * Hydraulic model testing of the has reached the status of technical The resttlts of the competition will be dynRmlc behaviour of several approval, which means that no obstruc- decided by the Norwegian Parliament concepts.

Figure 6-12. Design of Norwegian contractors and partners for the Hcgsfjord subsea crossing.

272 Tu~.~.~o AND UNVEP.m~OUNVSPACE T~C~mOLOGY Volume 8, Number 2, 1993 Figure 6.13. Design of HoUandsche Beton en Waterbouw, Veidekke and partners for the HCgs~ord subsea crossing.

Figure 6-14. Design of Kvaerner Rosenberg and partners for the Hcgsfjord subsea crossing.

Volume 8, Number 2, 1993 'I'vm~.,.mo AND Ul~mmcmot~rv SPAC$ Tzc~molz~ 273 Figure 6-15. Design of Selmer Furuholmen and partners for the Hcgsfjord subsea crossing.

* Development of special instru- Width of waterway: 3000 m Th6 all- mentation for monitoring dy- Water depth: 350 m adic behaviour. ~n-rents: 1 to 2 m/s, de- • Mater~ ~z~aScns ~r tethers. pevdlngonload station is ~ ofa ho~u~ con- • Preparation of specifications. case. ~ with the tmm~, a ~ anther The estimated cost of a two-lane Water depth above block and a cable in~, v,n,~;-g SFT, apprm~m~taly 1400 m long, in t~lnnel: 35 m 4~ de~r~ to the ~ U to pre- the ~ win be about US$60 to vide horizontal and ~ ~ess. Significant wave 9 to 16 m, de- The use of~ steel ~kevlar as $100 m;ll~n (1991 level). This cost is height: pendlngonload compemble with that of alternatives, cable matted is being inve~pted. case. Th~ ~ will ~m~b~lan~ the such as a bridge or ferry, at the Amount of same location. This cost e~dmate, al~ppin~ traffic: high together with previoualy mentioned S~mic losdi-~ is expected. ~n~~~tun- aspects of the project, makes an nel ~ extreme environ- SFT the preferred alternative. Soveral alternativeshave been stud- ied, such as differenttypes and layouts or ~ events. Each of the three proposed 2.6.2 Strait of Messina ofbridges. Because the preference is to use e~d;ing naval docks for the con- schemes (one bi~l_iroe~oaal rail- In Italy, extensive studies to ex- struction, the SFT concept was devel- way plore the possibility of an $I~ connect- opod around these facilities. ~)~i~ to cost ing the ~elAnd of Sicily with the m~n- After numerous alternative studies about U~,5 bilJion (~1 level). land, passing under the Strait of had been completed, a conceptual de- The crossing would be a major Messina, have been undertaken by the s~n based on concrete elements with a project. ~Stretto diMessina S.p.,~ ~, the conces- steel casing was selected over a double sionaire company (see Fig. 6-16). An steel element structure (see Fig. 6-17). s arrangement of three separate t~nn~]L Con~derat~ns in the dec~don in- alignmente (ons for rail) 500mapartis 3.1 ~ ~ otto. ~ cluded the structural behaviour of c~ contemplate~L The studies have shown the tube wA11a both during installa- that an SFTwould he a viable solution, tion and during their dem__gn life; the To ~ the s~uztural prin- notwithstanding the harsh environ- amount of steel required; the avail- cipl~ ~ ~, w, may ~ them mental and seismic conditions existing able construction methods; and, fi- with other fixed ~. Sl~s may in the area. nally, the durability and reliability have a variety of h'ms, ~4.~ on Some relevant site conditions for of the structure. parAm,~rs such am distance between the project are given below: the shores, water depth and ~asa state"

274 T~-~ Tmo AND UZ~aOUSD SPACE T~n~ov~Y Volume 8, Humber 2, 1998 Shaft Ventilation Station in Cavern Ventilation Station Submerged Floating on the Coast Road

0.00 Y

Road Crossing: Calabria ~ Sicily 22.648 m ] Basin Sicily -~ Calabria 23.848 m Rail Crossing: 16.968 m

F~gure 6-16. Location of the Strait of Messina.

Figure 6-1Z Design of Stretto di Messina S.p.4. for the Strait of Messina subsea crossing.

Volume 8, Number 2, 1993 TUNN~.V.ma AND UNDERGROUNDSPACE ~C~[NOLOGY27~ (i.e., waves affecting the structure). this design event. The accepted risk will be permanently present during Table 6-3 shows whether or not the level differsamong countries. the lifetime of the structure. The struc- different structures are affected by PLS (Progressive Collapse Limit ture will first be exposed to those loads these parameters. State): The PLS conditions are desig- during the construction period. The The comparison shows that one of ned to preserve humnn lives in the event most common permanent loads are: the most critical advantages of the SFT of certain loads or load combinations at • Structural dead weight. is that it opens up possibilities where a very low probabilityof occurrence. In • Hydrostatic pressure. formerly no fixed connection was con- this case, even if the structure may be sidered possible. severely damaged, loss of lives is still • Buoyancy. not acceptable. These conditions are 2. FL (Functional Loads): Func- 3.2 Design Methods often defined at a probability level of tional loads are those loads that will be approximately 10"(-4)per an~l~m caused by the usage of the structure. Like every other structure, an SFT FLS (-Fatigue T.imlt State): The FLS For an SFT, these loads are: must be designed on the basis of ex- is required to account for the fact that • Loads due to traffic. pected and possible combinations of some materials lose strength due to loading cases. • Loads due to changes in ballast repeated loading. By computing the conditions. The allowable design methods and accumulated damage in the material general criteria are mainly deter- • Variable loads during construc- and consequently checking the com- tion. mined by the national codes. Other- puted life of the structure against the wise, the client/owner, together operational life, the sensitivity of cer- 3. DL (Deformation Loads): Defor- with the designer/contractor, must tain components of the structure can be mation loads are caused by geometric establish them. established. A safety factor of 3 to 10 cb~ges in the structure itself. These Today's design methods are often between computed life and required loads are oRen associatedwith the prop- related to those used in the o~l~oce operational life is often adopted, de- erties of the materials involved. Typi- industry, and are cemm-nly based on pending on the consequences of failure calloads within this category are caused the semi-probabilistic l/m/t state ap- and the opportunities for repair of the by: proach, lmlng partial safety ~ts components. • Shrinkage. on both loads and strength ofmater/a/s. Materials: The safety factors to be • Creep and relaxation. used for each type of material are often 3.2.1 Limit States determined in the national design • Post~ or pre-tensioning. Differential settlements. The semi-probabilistic approach di- codes, or they may be specifiedexplic- • vides the design into the following de- itly by the client. • Temperature variations. sign limit states: • RemAinlng interual loads result- SL8 (ServiceabilityT,imlt State): The 3.2.2 Loads ing from the constructionmethod. SLS conditions are set to ensure that The individual loads are combined EL (Environmental Loads): Envi- the structure meets practical criteria to give the design loads by using par- ronmental loads are caused by the (lo- with regard to deflections, crack widths, tial load factors. These load factors are cal) site conditions. Special investiga- factors of safety, accelerations, etc. generally established in the national tion and study are often required to ULS CU-ltimate TAmlt State): The design codes, or they may be specified det~,,,ine the mA,~itude ofthese loads. ULS conditions are set to confirm that explicitly by the client. To assess the effects of such loads on the structure has the necessary Five different types of loads usually the structure, mathematical and hy- strength to survive loads and load com- must be considered: draulic models may be needed. For an binations at an accepted risk offailure. 1. PL (Permn~ent Loads): Perma- SFT, the most important environmen- The structure must be capable of con- tal loads are: tin-ing to operate satisfactorily ai~r nent loads are classified as loads that • Loads due to wave action. • Static loads caused by current. • Dynamic loads caused by vortex Table 6-3. How different structures are affected by the parameters of distance, of current. water depth, and sea state. • Loads resulting from tidal varia- tion~ Type Distance Water Depth Sea State • Loads caused by floating ice on the water surface. • LOads resulting from changes in Bridge Yes Yes No water density. • Response due to earthquake. Pontoon Bridge No No Yes AL (Accidental Loads):Accidental loads are, by their nature, not sup- posed to happen. However, the fact Floating Bridge No NO Yes that they do happen from ~me to time necessitates their specifmation and a rationalway ofdeMingwith theee loads. Bored Tunnel No Yes No Effects to be considered in this load category are: • Loads due to trafficaccidents. Immersed Tunnel NO Yes No • Loads resulting from ship colli- sions or an anchor dragging. • FRlling ship anchors and other debris. Submerged No No Limited Roating Tunnel • SinHng ships.

276 TUNN~.T.U~IGAND UNDERGROUNDSPACE TECHNOLOGY Volume 8, Number 2, 1993 • Rffiploeions inside or outside the In cases where thereis heavy mrface fore, nmst be defined bythe user. Space tube. traffic, the probabih'ty ofa ~inir;n~ ship also is required for supporting facih'- • Fire from burning cars or fiuids. at that particular location, and the tisa such asvantilatlon, llghtlng, signs, • Less of buoyancy. subsequent consequences, must be ballast, emergency equipment, etc. • Failure within the support considered. The energy amociated with systen~ the impact of a ~nk;n~ ship (or other 3.3.2 External dimensions object) agRinAt the structure must be The external r]imenJdons are mainly (partially) absorbed by local and/or determ;-ed by: 3.2.3 Other design methods global deformation. The mnmnitude of The design method used may differ absorption will depend on the type of • Thereq~internaldlmensions. between cotmtries. A more conserva- ship. • The overall structural concept. tive method used in the past employs For ~r~mple, for the S~ proposed • The local structural require- the elastic and plastic theory. In this for the Strait of Messina, the impact of ments. case, several levels of acceptable struc- a 5000-dwt ~in]rln~ ship must be Wjthln • Thelnfluence ofexternal leadings. tural behaviour are defined for load level 1, while the impact of a 250,000- • The construction methods. conditions based on certain return pe- dwt mn~ing ship must be within level riods. As an example, for the Strait of 3. The type and size of ship and the It has been found that the m;nl- Messina cro~'n~, which has a design appropriate levels will be different for mum internal dlm~msions, which are life of 200 years, the following levels each SFT. required to accommodate the re- wore adopted: Another form of accidental loading, quired n-tuber of tral~c lanes and 1. Return period equal to 50 which is probably more frequent but the necessary equipment, result in years: Elastic behaviour of both the less sensitive, is the impact of fish- almost the optimum design. The main structure and the secondary ing equipment. This type of impact consequent external r]JmAn~c)ns have components, without any d~m~e or can largely be avoided by adherence a significant influence on the need for inspection atter the event. to marine regulations. behavienr of the t-nnel because the most important design loads are 2. Returnper/od equa/to 400years: A traffic regulation system has to be provided for submarine traf- related to its volume. Effi~mples of Elastic behaviour of the m~Jn struc- such loads are the circ~,mCerential tures and local plastic behaviour for fic. If necessary, measures must be taken to ensure that beth the t~,nnel compression load, the buoyancy and the secondary components. Limited the added ,~Aas, and the forces of if any, must be repairable and its supports system ~-pocially d~m~ge, inertia associated with wave mo- without any interruption in the use of cables--can be monitored by the sub- tion and seismic excitation. the b~nnel. turbine navigational equipment. A warning system may be used to Recently developed concepts have 3. Returnperiodequalto2OOOyears: ensure the safety of the traffic in featured eircular~h ~ped or hexagonal- Plastic behaviour with the complete the SFT itself. shaped~mnels. To reduce these loads, exploitation of the ductility resources in the case ofthe SFT proposed for the of all the structural components. 3.3 Dimensions Strait of Messina Crossing, three D~m~ge, but not collapse, of the main parallel and independent t11nnelA are structure is accepted. D~m~ge and Site conditions have an impact on planned. collapse are accepted in the secondary the dim~esion ofthe structure, in terms components. ofboth criteria for the design of a cross- ing and criteria for the construction 3.4 Buoyancy The load cases are slmJl~ to those methods. The vertical stability of an $1~ is a described above. However, there is one Conditions to be taken into account very important conAidoratio~ The con- special load case associated with the include: cept can best be explained by cemparing Strait of Messina project that must be • Water depth. the SFT with other types of bmnels. taken inte account. This lead occure by In the case of a bored tunnel, the means of: • Length. vertical stal~tyis sumdently ens._,~ 1. A slow tectonic slip between Sic- • Marine environment: currents, by the weight of the soil above the ily and Italy, occurring in the longitu- water densities. t~m-eL This weight is always greater dinal direction of the t--nel, the value • Sea state: long and short waves. than the buoyancy (in ground water), of which could reach apprnrlm~tely • Geology at the entrances. beth during construction and in the 0.20 m during the expected life span of • Geology atthe foundations ofthe final situation. the structure. support system, if applicable. In the case of an immersed tunnel, 2. A slow relative movement of the • Environment. the vertical stability is ensured by ad- several faults present in the area, which • Seismic activity in the area. ditiomd ballast concrete, whichis added could cause a difi~ential settlement of • Access for bringing marine alter the sleene~t is placedin thetrench. the foundation blocks. equipment to the site. There will always be a remdtant down- ward vertical force, equal to the differ- • Surface and subsurface water ence between the final structural 3.2.4 Ship collision traffic. weight and the buoyancy of the ele- All of the feasibility studies for SFTs The dim~n~ines of the body of ment. The weight of the backfill in the must focus attention on the accidental main an SlUr are deter.:,ined by the internal, trench will increase the vertical loading caused by the collision of a ship stability. Only during the transport or st~marine. extemal and structural requirements. The di~slonc of the secondary and, in some cases, during placing of The safety of an SFT is based on components of an SFT are rnalnly the element, when no ballast con- avoiding colli~ion with vessels large crete is present, will the buoyancy enough to ~lamAo~ the structure seri- determined by structural require- merits and installation methods. ex~esd the weight of the element. ously, as has happened many times to In the ease of a submerged floating various bridges. Collision of surface 3.3.1 Internal dimensions tunnd, the relationship betweEm buoy- vessels can be easily avoided, as the ancy and self-weight is very important. SFT can be positioned at virt-~lly any The internal dimensions depend on In general, the weight ofthe SFT and its depth beneath the water surface. the purpose of the t~mnel and, there- buoyalLey are Alrnnst in eq1111ihriunl,

Volume 8, Number 2, 1993 Tu~w~.T.-~a ~ U~v~osou~ SPACE Tzc~¢o~ 277 even with the large mA~aitude of each can easily be measured. Nevertheless, Some proposed schemes span the of these loads. Because an SFT will the acceptable range has to be estab- total waterway, using the principle of never be covered by soil, the vertical lished beforehand, during the design an arch to carry the horizontal loads stability has to be ensured by the struc- stage. After construction, this para- (see Fig. 6-19). tare and its support system, meter is known exactly; by using bal- At a certain span width, the arch There are two possib'flities for ac- last concrete, the final weight of the shape will not be sufficient to cope with complishing this: structure can be adjusted. the horizontal loading. A horizontal 1. A tether system, in which the The "weight" of the structure may mooring system is then required. structure delivers a resulting upward alter slightly over ~me, due to the force (more buoy~cy than weight), water absorption ofthe concrete. How- 3.5.2 Vertical Bottom Supports which is taken by the downward force ever, this alteration is minimal in com- parison to the capacity of the support The reqtd~ment of safe vertical sta- in the support systen~ biSty under all loading cases results in system, 2. A pontoon system, in which an upward force that is generally larger The specific gravity of water. the structure delivers a resulting down- in magnitude than the forces in the ward force (more weight than buoy- The range in the specific gravity of the water will be partic~dAr to the site, and horizontal direction. A support system ancy), which is taken by the upward is therefore required at shorter inter- force in the support system. should be obtained at an early stage in the design process. The variation in vals. The structural principle in the vertical direction involves a continu- Because the resulting load in the buoyancy resulting from the change in tether or pontoon system is the ditfer- ous beam with intermediate supports. the specific gravity of water is a The principle ofthe bottom mooring ence between two large forces, accu- permanent variable, and may have racy in determining these forces is of is that the SFT should have sufficient special importance in coastal areas, positive (upward) buoyancy to keep the utmost importance. The following where the amount of rivor run-off or the tethers to the bottom under tension uncertainties in regard to these forces melting ice or snow can change the at all times, even during seismic events. may arise: value rapidly. The design has to A tethered solution is attractive Tolerances in geometry and cope with these variations. because it can be used in very great dimensions. The acceptable toler- The amount and stability of water depths. ances in the geometry and dlmen- marine growth. Marine growth is must be established during the The tethers or tether groups spac- sions known to concentrate at the sea floor ing depends on the weight/buoyancy design stage, depending the choice of and at the surface (see Fig. 6-18). If the on ratio and the cross-sectional strength constructionmethod. Dtud.ng construc- SFTis not located in the critical surface an experienced contractor with an of the tube (see Figs. 6-20 and 6-21). tion, layer, the effects of marine growth will The intervals between the tethers appropriate ql~Mity assur~ce system be mlnor. However, where such growth will vary. For example, the intervals in is the client's best insurance in keeping does occur, it will increase the weight the studies for the Strait of Meesina the tolerances under control. Atter con- and the current resistance. Therefore, crossing varied between 50 m and 70 struction, this parameter is no longer a accurate ofthe and predictions amount m, compared to 400-mintervals for the variable but, rather, is exactly known. weight of marine growth are required. Given su~cient fl~ihilityin the amount The amount of marine growth may HcgetSord cros~-g. of ballast concrete, it is possible to ad- The tethers can be fabricated ofsteel differ among projects, dependl-g on wire or steel tubes, s;mJlA~ to those just the weight afterwards. the seawater temperature and the The specific weight of concrete. used in the offshore industry for the depth that the tlmnel lies below the mooring oft~n~on leg platforms (TLPs). Although the specific weight of con- water surface. crete will vary during construction, it Because the tethers of an SFT are The range in weight/buoyancy ratio subject to smA|ier motioDs and loads of the t-nnel and the support compo- than those of a TLP, the tethers and nents has to be investigated carefully connections for S1~rs can be less com- THICKNESS CM in order to avoid a net reverse in the S 10 IS plex than those used in the offshore resultant forces. industry. Experience has been gained During installation,other conditions with this type of tether mooring in may occur, depending on the design water as deep as 560 m. and the construction method. The use of ArAm/d cables has also been studied. These cables have ad- -20 3.5 Supports vantages related to corrosion resis- The SFT is supported by the abut- tance, stit~ess/resistance ratio and low merits at the shores and, if necessary, by weight in the water, which facilitates further supports along the tlmn~l. installation and avoids catenary ef- When the SFT reaches a certain focts. A disadvantage is the lack of length, which will depend on factors catenary effect during large motions of such as diameter, shape, material the t~m-el. choice, etc., it will be necessary to sup- The tethers transfer the upward port the bin-el in both the horizontal tension force to the bottom anchor and vertical directions. points. The type of anchor point used will depend on the soil conditions and 3.5.1 Horizontal Supports installation methods. Both piled an- *20 chors and gravity anchor bloelm have Usually the static horizontal loads been proposed for projects. When rock are relatively small in relation to the .10 existsin the bottom, dr;li~-g and grout- allowable span length. Currents are ing of the anchors may be a solution. I the main cause of these horizontal t~SPONGES An alternative is the use of fixed loads. This means that large spans S 10 1S bottom supports. The height, which CM may be used with a minimum of hori- depends on the water depth, can range zontal support. from some tens of meters to about a Figure 6-18. Marine growth profile.

278 Tum~.~.~o AND UNDEm~OUSD SPACE TECHNOLOOY Vob,mA 8, Number 2, 1993 Figure 6.19. Arch shape horizontal support. Figure 6-20. Anchor cables in groups.

Figure 6-21. Anchor cables along the tunnel. Figure 6.22. Fixed supports.

Figure 6-23. Pontoon support. Figure 6.24. Combined horizontal and vertical support.

Figures 6-19 through 6-24. Different types of support systems for Submerged Floating Tunnels. hundred meters. The base of the sup- the surface. This is a more elastic the cables may be chosen so as to yield port generally will be a gravity struc- system than the bottom support aye- an appropriate ratio between the hori- ture, which will require goed soil concli- tom (see Fig. 6-23). zontal and vertical forces and stiffness tions. The structural system (see Fig. Although this solution has the ad- for the particular solution. 6-22) formed by the bl..a! and its vantage of being independent of water supports will correspond to a continu- depth, it has to cope with the interac- 3.5.5 Abutments ous beam with fixed supports. Nor- tion with ships, waves and ice. At each shore a special form of shut- really the analysis will be fairly ments is needed that will contain an straightforward. 3.5.4 Combined Horizontal and axial expeneion/~al h;~e de- The response under lead of such an Vertical Supports vice. This device will limit the arrangement may be quite different If the SFT is long and suttciant longitudinal and transversal forces from the response when a cable ar- horizontal Support c~nnot be obtained induced, for example, by the seis- rangement is used. from the shore, a combined horizontal mic effects. and vertical bottom Support can be It is preferable t~t the abutments 3.5.3 Vertical Pontoon Supports achieved by using an anchor cable con- be below water level; otherwise, the In thecaso of a pontoon support, the figuration, such as that shown in Fig- may be subject to wave losd;n~. SFT will be carried by the pontoons at ure 6-24. The angle of inclination of Where such an arrangement is not

Volume 8, Number 2, 1993 ~.T.mo AND Uzmm~atovtm SpAcz Tr~mou3oY 279 possible, a protective barrier such as These areas must be studied in detail. Fatigue in the different components an earth-filledstructure is desirable. Some typical areas requiring study are: (e.g., the tunnel, cables and connec- The approach structures on each • The joint between the SFT and tions), caused by sea states of different shore may be composed oframps, bored the abutment. magnitudes, is expected to be very low. or cut-and-cover t~nnels, or a combi- • The tether connections. Even though the SFT is a slender nation of these. Depending on the • The pontoon connections. structure,the possibilityofvortex shed- construction method, one of the ramp clingby current needs to be considered. structures may be used as a construc- 3.6.3 Dynamic Analysis However, the studiesmentioned herein tion site. have not indicated that thiswould pose A characteristic feature of an SFTis difficulties.For example, at Hcgsfjord, 3.6 Static and DynamicAnalysis its dynamic behaviour. This behaviour where currents are below 1 m/s, no can be analyzed using the same or movements are expected. As part of the design process, sev- more specialized finite element soft- eral static and dynamic analyses must ware programs that are used for static be the structure as 3.6.3.2 Dynamic Response Due to performed, both for analysis, and by executing hydraulic Seismic Loading a whole and for certain components. model tests in a laboratory. The SFT must be considered as a In the dynamic analysis, consider- Under seismic disturbance, the re- long continuous beam that is unsup- able care must be taken in selectingthe sponse can occur in three directions: ported or is on fixed or flexible sup- data used and the interpretation of the transverse, vertical and longitudlnM ports. At the ends, however, the read results. It takes experience to ensure A seismic disturbance results in has to be continuous; and, therefore, no analyses of acceptable quality. Items of motions with frequencies in the higher significant rotations can be accepted importance for these analyses are: and lower r~nges. The low frequencies there. are typical of ground displacements. • The mass and expected added The SFT has a large number of eigen- mass of the structure and its in- 3.6.1 Global Static Analysis frequencies in the high and low ranges. dividual components in relation Analysis indicates that the system Global static analyses are neces- to each other. filters the high frequencies, but is sen- sary to investigate the interactions • The stiffness ofthe structure and sitive to the low frequencies. This may between the components of the its individual components in re- differ from project to project and from structure, and to reach a balanced lation to each other. design to design. design following an optimi~.ation pro- • The damping ofthe structure and The vertical excitation will cause cess. its individual components in re- the maximum accelerations of the The global model can begin with a lation to each other. SFT. This type of excitation is straightforward beam-column model. mainly caused by the seismic pres- However, a (three-dimensional) finite Because of the length of the SFT, the highest resonance periods of the tube sure waves in the water, generated element model, which takes the elastic by the earthquake. foundations into account, will be needed will be well above the wave period range. However, continuous beams such as an The transversal excitation will cause soon after, in order to achieve a suffi- the ma~qmum displacement and, thus, ciently accurate a~Mysis. SFT have a large D,lmher of eigen- periods, some of which inevitably will the mA~dmum bending moment in the Displacements of the structure de- tunnel section. The mAxdmum axial pend on the structural system used. be in the wave range. The dynAmlc amplification of a resonant system is forces will occurin the anchoring cables, They must be correctly taken into ac- if they are used. Here, again, the count in order to investigatethe conse- very sensitive and requires careful investigation. excitation is mainly caused by the seis- quent geometric changes. mic pressure waves in the water, gen- Special so[tware may be required to Ai~r an SFT has passed the concep- tual stage, further analysis can be done orated by the earthquake. handle the large number of load cases The/ong/tudina/excitation requires and the considerable quantity of data. with a hydraulic model, mmulating certain loading cases. Furthermore, expansion devices at the connections to The load cases and the limit states are the shore in order to llmlt the effects of discussed above, in Section 3.2. The the hydraulic model can be used to calibrate the results from the math- the earthquake. Otherwise, as~zmi,S critical load cases will be combined perfect linear elastic behaviour, very with the results from the dynamic re- ematical models. However, it must be kept in ml, d that both are only models. high axial forces will occur. This sponse analyses before the dimensions behaviour could be critical for the con- and stresses are checked. nection of the tunnel to the shore. The At this point in the design, the pre- 3.6.3.1 Dynamic Response due to Marine Loading longitudinal excitation may be caused ferred pre-tension in the support sys- by the seismic input at each end of the tem has to be establiAhed. This pre- The reeo-~-nce frequencies in the t~mnel. tension will act together with the Ioad- system cause the structure to be sensi- ings, in both the tether system and the tive both to wave freql,an~es and to pontoon system. 3.6.3.3 Dynamic Response Due to structural damping. Therefore, an de- Passing Trains Experience gained in conceptual sign wave analyses approach is not suf- studies for proposed crossings has ficient; rather, the analyses should be The effects of a passing train on the shown that the weight/buoyancy ratio based on a stochas~ appreach. Shert- global SFT are negligible, compared is the determini-~ factor in the d~mAn. term analyses may be acceptable if un- with the effects of environmental and sioning of the structure. All other load certainty in the wave spectrum period seismic loads, in the case of the Strait conditions are of minor importance. is properly accounted for. The prefer- of Measina. able approach for the wave dynamle Analyses fromthe ssme project have 3.6.2 Local Static Analysis analyses involves king-term analyses. shown that for the case in which a train separates in the t, mnel and the indi- Local static .n.lysee are norm.lly Analysis has shown that for beth of the SFT projects that have been stud- vidual parts hit behind each other, the performed as detailed Rnlte element dynamic lateral forces caused by thi~ models, both two-dimensional and ied (i.e., the HCgst~ord and Strait of Messina crossings), the response on event can be taken by an 8FT, assure_ three-dlmensional, for areas where ing the rail support system has been high stress concentrations are expected. sea states is well under the acceptabie design values. designed for it.

280 Tum~.T.~o AND UNDEm~tOtUVD SPACE TEC~NOLOGY Volume 8, Number 2, 1993 3.7 Risk Anaiysis 3.8 Instrumentation It is hoped that the instrumanta- During the design, a probabflistic To monitor the SFT for safety and to tion results in savings on the design of risk analysis needs to be performed. validate the design, the first 81~ will future SFTs. The possibility of failure of an SFT be outfitted with extensive instrumen- will be deter~-ed by studying the tation. The instrumentation will be 3.9 Durability and Maintenance probability of failure of the individual specially designed to monitor both the In a m-Hne environment, the dura- structural components. environmental forces and the response bility of the mater~Ale used requires The distribution of the possibility of of the overatl structure and the indi- special attention. The t,,'n'net itself failure of the components can be indi- vidualelements. Materialbehavior, as should have a design life of perhaps cated by fault trees (see Fig. 6-25). If well as displacements, will be moni- 100 years, although elements such as necessary, action can be taken to re- tored. The instrumentation will be pontoons, cables, connections and elec- duce the local risk. used during construction and will be trical and mechanical plant may have operational after completion. a shorter design life.

SFT FALLS

I J J VERTICAL TUBE SHORE JOINT PONTOON CABLE CABLE STABILITY CONNECTION SUPPORT ANCHORAGE L I I I I i I TUBE EXCEEDING CALAMITY SINKING CONNECTION ANCHOR SINKS OF NEAR OF CABLE FALLS LOADS ENTRANCE PONTOON I TUNNEL ANCHOR I FAILS FALLS

I I CABLE MATERIAL I OFALL GROUP FALLS IDISPLACBF..NT FAILS

I 1 ] CALAMITY CABLE CABLE IN TUNNEL FAILS CONNECTION FAILS

Fibre 6-25. Fault tree showing the failure possibilities for SFT components.

Volume 8, Number 2, 1993 Tum~.,mo AND U~mot~D SPACZ Tr~mOLO~ 281 avoid surprises later on in the project. length of the elements for an SFTis not Additional loading cases must be kept limited to the 100 to 150 m typical of to a m'irr~mt.H~to reduce extra costs. immersed tllnnels. Particularly when The successful construction of a permanent prestressing is used, the project of this degree of complexity length ofthe elements can be increased. L relies largely on the experience of and Aiter reaching the site, the installa- equipment available to the contractor. tion barge supports the element dur- It is therefore advisable to obtain ad- ing assembly and lowering to the in- vice from experienced contractors dur- tended depth. ing the feasibility study phase. At each joint location, a set oftethers Two basic construction methods is pre-installed and coupled in a horse- have been developed: shoe-shaped support. The element is 1. Construction in elements. The lowered under the support while tem- tllnnel is fabricated in elements in a perarily plllllng the support aside. Figure 6-26. Type of installation construction dock and coupled to the After the element has been fitted at site. previous installed elements. The into the predetermined tether support supports can be cables, pontoons or system, it is de-bMlasted, cau~ng the fixed piers. load to transfer from the installation 2. IncrernentaI launching. The tun. barge to the tether system. During this A comprehensive maintenance nel is fabricated in sections and pushed process, the length of the tethers is progrsmme should be established to out in successive steps. Launching is adjusted at the support shoe to prevent include periodic inspections and the repeated until the opposite side of the unacceptable deflections ofboth tethers, scheduled replacement, as neces- i~ord is reached. During launching, a the position of new element and of pre- sary, of individual components. cable-stay system supports the t~mnel. vious elements. The adjustments can be made by remote control or by diver or Special provisions and loading Each of these methods is described cases arising from replacement op- ROV (Remotely Operated Vehicle) as- in detail below. It should be noted that erations can be taken into account sistance. Both forces as displacements the suggested methods are generic and during the design stage. are monitored during this process. must be modified to suit the given site It also may be useful to develop Hydraulic couplers located on the requirements. special equipment to inspect and main- previously installed element then pull tain the structure and its parts. the new element into place. Of particular importance is the 4. I Construction in Elements An initial watertight seal is resistance of the concrete in a chlo- The SFT elements are constructed provided by a rubber gasket. After ride enviro-ment and the anti-cor- in a dock. After all or a n,lmher of de-watering the area between the rosion provisions required for a steel the elements have been completed, bulkheads, the permanent joint shell, if used. the dock is flooded and the elements between the two elements is made In the case of a cable support are towed to the site. B-lkheads, and post-tensioned to obtain full system, the durability of the cables used to seal the ends and to maintain structural strength. The rubber needs to be investigated with re- positive buoyancy during construc- gasket has only a temporary function gard to both corrosion and fatigue. tion, are joined at the site. The during construction. Sufficient experience with the length of each element is deter- This operation is mmilar in m,ny maintenance of structures in sea wa- mined partly by the structural ca- respects to the placing of immersed ter and in rough enviro-mental condi- pabilities of the SFT (the designed bmnel elements. A notable differ- tions has been gained from offshore distance between the supports) and ence, however, is that the support from projects. This experienco includes both partly by the available length of the cable system is much weaker than the structural repair and maintenance existing ship docks, slipways or that founded by the ground in the case procedures and the worldng methods construction docks. The construction of an immersed blnnel. This must be to fillfill the operations. Special pro- of the elements is slml]ar to construc- taken into account in piAnnlngthejoin- cedures and working methods for both tion for immersed t~mnels. iug operations. repair and m-l-tenance of the vari- Because SFTs and immersed tun- Several solutions may be used for ous parts of the tunnel must be pre- nels are designed for differentperma- the final connection between the tun- pared as contingency measures. nent and temporary loading cases, the nel and the tethers. These connections

4 Construction Methods Experience with similar complex projects, such as those offshore, has proven that design and construction cannot be isolated from one other. Therefore, feasibility studies for SFT projects must consider both design and constructlon--includlnz, with regard to the latter, the possible methods of construction and the availability ofsuit- able construction sites. Site-specific conditions, such as mA'rjne environment and soil condi- tions, may affect both the design of the preferred structure and the construc- tion method. It is important that struc- tural analyses of the construction stages be performed early, in order to Figure 6-2Z Incremental construction and launching of SFT elements.

282 TUNN~-T-'VG AND UND~.m~aOUND SPACE TECHNOLOGY Volume 8, Number 2, 1993 low the tube to move, a special guid- ance and support system is needed at the top end of the tethers. Such an arrangement calls for ingenuity. It may be possible to install rollers, guid- ('3] ° I~ ' " ance plates or hydro-jet bearings in a saddle, which may be temporary or which may become a part of the final construction. As the tube is pushed forward, it meets the guidance struc- ture. The tether tension is then pro- vided by the buoyancy of the tube.

4.3 Element Construction and Incremental Launching Another construction method in- volves fabricating t,,nnel dements in a basin, and then towing them to a specially constructed push-out dock at one of the abutments (see Fig. 6- 28). The element is floated into the dock and lowered on a temporary foun- dation. After the dock is de-watered, the dement is pushed forward, coupled to the previous dement, and pushed through a launchln~ gate into the wa- ter. Support of the t~mnelis Rimilar to the arrangement described above.

4.4 Ab~men~ The constrttction of the abutments depends on the chosen SFT concept, i.e., prefabricated elements or in- cremental launching. In the case of rock abutments, either of two classic methods--the ~collection chamber" method or the ~concrete plug~ method--can be used to connect the t~mnel with the abut. ment. These methods are described Figure 6-28. Incremental launching. below. Collection r hAmber method. In thismethod, tha~,m~! entmncoism~le depend on the location of the connec- the abutment. For thin purpose, the in advance and the joint is prepared to tion, i.e., whether they are external or segment is constructed on saddles end receive the tunneL In front of the abut- within special cbamhers added to the pushed forward by hydraulic jacks, ment, a collection ¢h~ml~r is made in tamneL It also depends on whether the almJlar to those used in *~o-Di~ tech- the rock. After the preparatkms have preference is to connect the tethers nology. Before it is p, ahed through the been completed and the abutment has first to the anchor points on the bed or gate, the tube is coupled to the previ- been temporarily sealed with a bulk- to the elements before it is lowered. An ons segments with pretension cables. head, the rock between the abutment eTRmple showing a possible method The part of the tube p,,shed out into and the sea is blasted andis allowed to iS given in Figure 6-26. the water must be kept under control. fall into the collection ehAmlw~r(~ l~g. Remotely operated vehicles A temporary cable system and/or a 6-29). The area in frcmt ofthe abutment (ROV's) will be used for inspection pontoon support system is a likely is now clear and the bmnel can be and for installation assistance. method for this purpose. placed andjoined to the abutment. This If pontoons are used for the vertical joint is Rnlah~] in a mann~, aimilA~ to 4.2 Incremental Construction and support during push-out, a shore- joints between elmnents. All special Launching based cable system may be needed to facilities can be instene& keep the SFT under control in the Concrete plug method. This In this method, the construction horizontal direction. The stiffness of method also calls for the bmnel en- takes place at one of the abutments, the cable system in relation to the trance to be made in advance. At the which are modified and increased in stiffness at the push-out gate will re- seaside, enough rock is removed ~uder size to accommodate the construction quire careful consideration. water to allow the t~mnel to be placed site and the associated plant, equip- New pontoons are connected to the in the invert. After a tremis concrete ment and materials. tube as it moves forward. The pon- plug has been placed over the front end The tube is constructed in consecu- toons, which may be temporary or per- of the t~,~n,1, the rAmR~n~,,~ rock be- tive sections on an inclined skidway in manent, follow the structure across tween abutment and t, mn.I can be the abutment. After each section is the waterway. removed from the in, de. completed, the tube is moved forward An alternative would be to use Rnal If special facilities are required, into the water, over the length of one tethers, installed in advance and sup- another separate joint has to be made section (see Fig. 6.27) through a gate in ported by temporary pontoons. To al- at some distance from the abutment.

Volume 8, Number 2, 1993 Tm~.T.~G AND UND~OUND SPAc~ Ts~mou3oY 283 I

ROCK I ~--7-~./Z~L ~ o,~_ TOBE "'~..~ ':~ =~_ BIBLASTED

COLLECTION ARI-_=A

Figure 6-29. Abutment in rock. Figure 6-30. Pile driving at great water depth.

For other soft conditions, the tether may be anchored by a single pile * Suitable space at the abutments, ramps may be constructed as a cencrete orby a group of piles; mm~lA=ly,a group with good access, to allow in- situ struchn~ in a cefferdanL Alter the ofpilce may serve a n-tuber oftothers. fabrication. ramp is finished, the cofferdam is The latter situation would require a • Anadequate supplyofraw mate- broached and the first element is joined pre-fabricatod pile cap, which can also rials during production. to the cenorote ramp. Finishing can be serve as a template for the piles. • The avAilAbility ofsuitable plant, done similarly to the Oini~hJn~ of the Given the technology and experi- equipment and manpower dur- joints between the elements. ence available in the offshore industry, ing both construction and in- For incremental launchln~, one no specific problems are foreseen dur- stallation. of the ramps is used as a temporary ing the installation of the templates * Adequate periods of workable cen~mction site. After the full length and piles. weather, especially during the of the t, mnel has been pushed out, the The template can be fabricated in inst~l]Ation stages. ramp structure can be completed. steel or conorete, ami incerporatce pile " The client's requirements sleeves and connection points for the regarding the final outfitting. 4.5 Anchor Points tendons. Additional conne~ points should be provided to facilitate tendon Obviously the censtructiou time will Several possibleanchorage systems replacement. The idles are driven from vary from project to project. The con- may be used to secure an SFTto the a surface vessel using an underwater structiou times for the H~ord end bed of the waterway. These include pileh~rnrnor (seeFig. 6-,30).This tech- the Strait of Mcesina submerged float- gravity anchors, driven piles and drWed nique has been uaod in beth the North ing t-,~,,els are given below. piles. Selection of the appropriate sys- Sea and GulfofMexico, in water depths H~gsfjord crossing: It is tom will depend on the site geology. of up to several hundred meters. estimated that the H~gs~rd SFT In the case of a cable suppm-t system, Attention must be paid to the toler- could be constructed in about three anther ixdnts are required at the bod, ances that may be adopted in installa- years. This period is comparable to which may be at considerable depth. tion of the template. These tolerances that for suspension bridges of simi- As noted above, two concepts are dopond on the adjustment ~ ~r length. avAilAble from the offshore industry: of the tethers and the allowable toler- Strait of Messina crossing: 1. Gravity foundations. ances in the t,m-,~i alignment. Two studies of mdsting resources, 2. Piled templates. in naval and in offabere yards, have shown that it would be possible to These two types of foundations 4.5.3 Fixed supports find md~cient materials, equipment are described in more detail below. When fixed supports are used for and manpower in Italy to carry out the foundation, the construction the prefabrication of all of the re- 4.5.1 Gravity Anchors method for the piers may be ~,~I-~ to quired components. Foundations based on gravity an- that used for ~ ldatf~s. If It is estimated that constnaction chors may be used if the soil conditions the height of the supports is in the of the 120 elements would require are favorable. This type of founda- range of 50 m to 250 m, the sup- approximately 1800 man-years tion may take the form of caissons ports could be fabricated afloat in a over a period of about seven years. (in concrete or steel), prefabri- deep ~ord. The corresponding estimate for cated in a dock on land or on a Alter completion, the piers must the construction of the templates, floating barge, transported to the be outfitted with a temporary piles, collars and cables is 1,600 per- site and lowered on the sea bed .mn~ extension to reach the water son-years, also over a period of seven a floating crane. Ballastis then placed surface, in order to facih'tate placing years. into the caisson to obtain the necessary them in position accurately. weight. 6 Market Expoetation 4.6 C,on~n Time Although there is undoubtedly a 4.5.2 Piled Foundations The construction time will depend m--ket for ~ ~ Tun- Different arrangements may be mainly on the following factors: nels, it willbe !era7 to deagm~rate adopted for piled foundations and the • The avaflaldlityof suitable eodst- tha str-_cture iupraetice. Afar this has associated tethers. For A~nmple, a ing facnitles for fabricating the been done, and when the public end units. politicians have become ~,,~1;,~ with

284 Tuspw.~.mo AND U~rDEaO~OUNDSPACE ~I~nmoLo~ Volume 8, Number 2, 1993 this typo ofs~mre, mauy sites around The results of the conceptual stud- 6 References the world could benefit from it. ies for the H¢gst~ord sFr have been Strait Crossings: Proeeedinss of the First At present, the market for SFTs is sufficiently promi~;n~ to give a green International Symposium, 1986, llmlted to areas where roads have to light to the technical considerations. A Stavanger, Norway. Trendheim:Tapir cross deep watsrwaya However, SFTs positive political declm'on is expected p~hliAhm.8. can assmt the en~ro-m~t in other soon, thereby opo~in~ the way for the Stralt Crowing: Proe~din~s of the ~eond locations by enabling traffic to be actual project to proce~L International Symposium, 1990, handled ~nvisibl~'~i.e., out of s~ht of , Norway. Rotterdam:A. A. the surface. Balkma~

Volume 8, Number 2, 1993 Tt~.Tmo AND UNDEI~G~OUNDSPACE ~CHNOLOGY 285