IAEA-TECDOC-819

Earthquakes: Isolation, energy dissipation and control vibrationsof structuresof for nuclear industrialand facilities and buildings

Overview of lectures and papers of a seminar organized jointly withthe Italian Working Group on Seismic Isolation (GLIS) held Capri,and in Italy, 23-25 August 1993

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EARTHQUAKES: ISOLATION, ENERGY DISSIPATION AND CONTROL OF VIBRATIONS OF STRUCTURE NUCLEAR SFO INDUSTRIAD RAN L FACILITIE BUILDINGD SAN S IAEA, VIENNA, 1995 IAEA-TECDOC-819 ISSN 1011-4289 © IAEA, 1995 Printe IAEe th AustriAn i y d b a September 1995 FOREWORD

Seismic isolation is one of the most significant seismic engineering developments in recent years. Researc developmentd han , together with application experienc especialle— y for numerous isolated civil structures alst existinr bu ,o fo g nuclear reactor facilitiesd san d ha , already shown in past years that this technique is extremely promising for a wide range of uses in the industrial field, in particular for advanced nuclear plants. The development and applicatio furthef no r innovative technique suc s— passivs ha e energy dissipation, provisional restraints activd an , e contro f vibrationo l alss begus ha o ha d shownsan — n great potential for reducing seismic or other dynamic loads acting on structures.

The International Seminar on Isolation, Energy Dissipation and Control of Vibrations of Structures provide opportunitn da exchange th r yfo updatef eo detailed dan d information e state-of-the-aronth i thesh t e technologies seminae Th . r addresse developmene dth d an t applicatio f innovativno e techniques that have been develope abatemene th r dfo f seismio t c vibrations of structures. In addition to base isolation techniques which have been accepted for construction in some countries, the topics covered by the seminar were floor isolation, passive energy dissipation and active control of vibrations. The seminar was held following recommendatioe th Internationae th f no l Working Grou Fasn po t Reactor 26ts it t hsa Annual Meeting which was held in Vienna, Austria, from 4 to 7 May 1993.

This report summarize e contributionth s e seminath o t s r together wite maith h n technical issues and conclusions. Particular attention is paid to contributions which provided new or updated information with respect to that given at the IAEA Specialists Meeting on Seismic Isolation Technology, held at San Jose (California, USA), 18-20 March 1992. Attention is also paid to the development and implementation of more recent but very promising innovative technique reductioe th r sfo f seismino othed can r dynamic loads.

e repor bees Th ha tn prepare . MartellA y db i (Working Grou Seismin po c Isolation (GLIS) ENEA, Italy) with the co-operation of M. Forni (GLIS, ENEA, Italy) and A.L. Materazzi and A. Parducci (GLIS and University of Perugia, Italy). A. Rinejski of the IAEA was responsible for the final drafting of the document. EDITORIAL NOTE

In preparing this publication for press, staff of the IAEA have made up the pages from the original manuscript views (s).The expressed necessarilynot do reflect those governments ofthe ofthe nominating Member States or of the nominating organizations. Throughout the text names of Member States are retained as they were when the text was compiled. Theof use particular designations countriesof territoriesor does imply judgementnot any by the publisher, the IAEA, as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of names of specific companies or products (whether or not indicated as registered) does not imply any intention to infringe proprietary rights, nor should it be construed as an endorsement recommendationor partthe IAEA. ofon the CONTENTS

SUMMARY OF THE SEMINAR ...... 7

1. OVERVIEW OF LECTURES AND PAPERS PRESENTED AT THE SEMINAR ...... 10

1.1. Technical sessio isolation o n1 civif no l building bridged san s from seismic and non-seismic vibrations ...... 0 1 . 1.2. Technical session 2 on isolation of civil buildings and bridges from seismic and non-seismic vibrations ...... 13 1.3. Panel sessio shorn o n1 t presentation discussiod san futurn no e prospects for the extension of applications of seismic isolation techniques to civil building bridged an s s ...... 5 1 . 1.4. Technical session 3 on seismic isolation of nuclear facilities ...... 17 1.5. Technical session 4 on seismic isolation of non-nuclear industrial facilities . . 18 1.6. Panel sessio shorn o n2 t presentation discussiod san futurn no e prospects for the extension of applications of seismic isolation to nuclear and non-nuclear industrial facilities ...... 0 2 . 1.7. Technical session 5 on passive energy dissipation and active control of vibrations of structures ...... 23 1.8. Technical sessio passivn o n6 e energy dissipatio activd nan e controf o l vibration structuref so s ...... 5 2 . 1.9. Panel sessio shorn o n3 t presentation discussiod san design no n guidelines and codes & standards on seismic isolation and passive energy dissipation ...... 7 2 .

2. APPLICATIONS OF THE INNOVATIVE ANTISEISMIC TECHNIQUES .... 29 2.1. Bridge viaductd san s ...... 9 2 . 2.2. Civil buildings ...... 1 3 . 2.3. Non-nuclear industrial structures ...... 33 2.4. Nuclear structures ...... :...... 35 2.5. Applicatio passivf no e energy dissipatio oleodynamid nan c systems .....6 3 . 2.5.1. Civil buildings ...... 6 3 . 2.5.2. Industrial structures ...... 37

. REMARK3 DESIGN SO N GUIDELINES, CODE STANDARDD SAN S .....7 3 .

REFERENCES ...... 9 3 .

ABBREVIATIONS ...... 43 SUMMAR SEMINAE TH F YO R

INTRODUCTION

Accordin seminae th o gt r purposes, presente Caprt da i were overview activitiee th n so s progresn i futurd san e programmes state-of-the-are th , applicationf o t designsd san , coded san standards, research and development and observations of behaviours of structures under actual dynamic loads exhibition A . n concerning innovative antiseismic devices developed dan applie Italheln s di parallen yd wa i seminar e th organizes o t lwa t i ; ACEDIy db lasted San d whole th e duratio seminare th f no .

The countries and international organizations which participated in the seminar were Brazil, Bulgaria, Canada, Chile, China, France, Germany, Greece, India, Italy, Japan, Mexico Zealandw Ne , , Portugal, Republi Koreaf co , Russian Federation, South Africa, USA, and the International Atomic Energy Agency and Commission of the European Communities. 138 participants took part in the seminar.

SEMINAR SESSIONS

The seminar consisted of six Technical Sessions (TS), four Panel Sessions (PS) and one Video Presentation Session. Two Technical Sessions (TS 1 and TS 2) and the following Panel Sessio) mainl1 S ny(P dealt with isolatio f industriano l building bridged an s s from seismic and non-seismic vibrations Technicae on ; devotes lwa Sessio) seismi3 o dt S n(T c isolation of nuclear facilities and one (TS 4) to seismic isolation of non-nuclear industrial structures, together wit Panee hon l Sessio regardin) 2 S n(P g both items Technicao tw ; l Session5 S s(T and TS 6) dealt with passive energy dissipation and active/hybrid control; finally, one Panel devotes wa Sessio genera ) o desigt o 3 d t ) S 4 n(P nS l conclusionsguideline(P e on d san .

DISCUSSION CONCLUSIOND SAN S

Seismic isolation of civil structures: The full maturity of seismic isolation for applications to both new and existing civil constructions (bridges, viaducts and buildings) was confirmed. Most experts agreed that the studies performed and large number of ascertained applications existin severan gi l countries (mor bridgeo et tha 0 viaductd n15 san mord san e than 380 to buildings) have already provided all the necessary information on isolators and isolation systems, thus, that it is now necessary to proceed to an extensive application, to bridges, viaducts and important buildings at least.

n particularI o ,mor n ther e ar edoubt s abou e sufficienth t t durabilit f rubbeo y r isolators, which was a major concern until recently. Indeed, both accelerated aging tests performed in various countries and tests on naturally aged bearings confirmed that rubber bearing lifetime of at least 60 to 80 years may be assured, which is not shorter than the usual lifetim f structureeo s (Japanese accelerated aging tests showed that bearings should maintain acceptable characteristics even for more than 100 years). According to this result, replacement feasibilit f bearingo y bees ha s n judge moro dn e necessar Zealandw Ne n i y , wher elona g experienc rubbef o e us r f bearingeo s exists (althoug othee th n rhi countries such a feasibility has still to be ensured).

extensivn A e applicatio f seismio n c isolatio o residentiat n l houses also, mighe b t restraine usually db y higher construction costs, with respec o thost t f conventionallo e y founded structures. However, a complete economic balance (taking into account costs related to possible unhabitableness periods and the necessary repair of the structural and non- structural elements) might be frequently favourable to seismic isolation in this case also; furthermore highee th , r construction costs might easile b y recovered case th f renta eo n i , l buildings, by somewhat higher but still acceptable rents, and advantage could be taken in the future from lower insurance costs. Finally, low-cost seismic isolation systems, similao t r formee th n Chinn i i r d e USSRthosaan us n ei , migh adequate b t r sucefo h applications.

Among others, it was mentioned by Japanese experts during the seminar that seismic isolators, if adequately designed, were proven to be in some cases effective to reduce the effects of non-seismic vibrations also (for instance, those due to traffic).

Most experts agreed that the only problems to take care of in the application of seismic isolation are those related to seismic input, the quality of isolators, the effects on the design of inner equipmen e exacth d t definitioan t f roleso n , especialls maintenanca r fa s a y s ei concerned.

The importance of providing isolated structures (as well as structures using other innovative antiseismic techniques) with adequate seismic monitoring systems was stressed, because increasing information on the actual behaviour of such structures in earthquakes is essential to support development and extension of the new techniques, to high risk plants also.

Finally alignmenn a neee r th , dfo f codeo t r fixed-bassfo isolated ean d structures swa judged feasible and urgent, so as to reduce the unnecessary degree of conservatism that is currently presen desige th n f isolatei tno d structures alloo t economie d wth an ,f thi o se cus technology.

Seismic isolation of nuclear plants and other industrial facilities: Seismic isolation seems now mature enough for a wider use in the industrial field as well, like for high risk facilitie n particular (i t sonly no t , bu nuclea, r structures), electric equipment, other sophisticated strategic or valuable components, and tanks. However, great care must be paid issueo t s mentioned above somd an , e more application needede ar s , witw h fe respec e th o t already existing, in order to fully confirm the aforesaid conclusion: the ascertained numbers of such existing application r non-nuclea fo e onl 4 ar s1 y r facilitie addition (i s somo nt e buildings which may be regarded as industrial structures), and 14 for nuclear structures. Anyway , generaa ther s ewa l consensu f opinio o se semina th t na r tha larga t e numbef o r applications wil sooe b l n available.

With regar nucleao dt r structures, confirme greae th s t interesdwa extenden a n i t e dus f seismio c isolatio t onl nreactorsno n yi t als othen bu oi , r nuclear facilities (like spent fuel element pools, reprocessing plants, etc.); in spite of the only few nuclear applications existin dateo gt , important project r researcheso s have been develope severan di l countries. e reasonaforesaie th Th r fo s d interes bote increasee ar t hth d safet overald an y l reliability achievable economicad an , l reasons, includin possibilite gth keepinf yo g standard designr sfo constructio highln ni y seismic countries also.

additionn I , stresse t Caprda i wer advantagee eth possibla f so e wide applicatiof no seismic isolation to other high risk plants, for instance to allow for a correct antiseismic constructio r retrofio n f somo t e chemical facilities r whicfo , h only very few t verbu , y encouraging, applications already exist. Finally, all agreed on the need for solid international cooperation, especially for the nuclear applications.

Passive energy dissipatio d provisionaan n l restrain f d civiindustriao t an l l structures: Particularl passivr yfo e energy dissipation, recognize neee r t Caprth d a dfo s iwa ane interesdth furthen i t r R&D, before undertakin extensivn ga f thio se techniqueus n ei structures other than bridges and viaducts. Indeed, while in the latter the ascertained number of applications was already significant (more than 90, although mostly in Italy), for buildings only 18 applications were reported, and for industrial plants none.

The aforesaid conclusion was reached according to the very promising features of passive energy dissipation systems, but also taking into account that some doubts still remain, especially on design methodologies.

A similar conclusion applied to oleodynamic systems, for which even lesser applications were reporte seminae th t da r (aboubridger fo viaductsd 0 4 tr building san fo 0 1 ,onld san y largr fo e1 industrial components).

Active/hybrid contro f structureslo : Active/hybrid contro vibrationf o l whicr fo sh— importan9 t applications already existe judges quite Japan di b wa interestinn o ea dt n— g technique, but it was recognized that its purpose must be limited — at the time being, at least — to ensure comfort in moderate earthquakes and especially protection from wind loads, more than seismic safety, for which the technique is still too costly and not reliable enough (also due to the use of complicated equipment and need for quite a large power). 1. OVERVIEW OF LECTURES AND PAPERS PRESENTED AT THE SEMINAR

e topicTh s coveree variouth y db s lecture shord an s t paper e mentionear s d below, following the presentation order. Some remarks are also made with regard to speakers. Special attention is paid to items of interest for industrial structures, including nuclear reactors and other high risk facilities, and to new information and other topics which are particularly innovative or may be important in view of the extension of applications of innovative antiseismic techniques to the above-mentioned structures.

1.1. TECHNICAL SESSION 1 ON ISOLATION OF CIVIL BUILDINGS AND BRIDGES FROM SEISMI NON-SEISMID CAN C VIBRATIONS

Lectures No. 1 and No. 2 (Japan [15, 16]): These lectures were both presented by experts from Japan. The first was given by H. Akiyama (Tokyo University) and concerned state-of-the-arte th , worldwid Japann i d isolation eo ,an n from seismic vibrations t stressei ; d the maturity of seismic isolation and its further potential, which are making it possible to widely use such a technique, especially in Japan, where several building applications already exist (see also Ref. [13]).

Japann I e firsth ,t building applicatio f seismino e Yachiyodac th isolatio o t s nwa i Isolated House in Chiba, in 1982. In 1992, 65 isolated buildings had already been completed in Tokyo and many other sites. They are manly reinforced concrete (r.c.) structures, but there are also examples of composite, steel and wooden structures. They have various sizes (to fourteen floors) and uses; many belong to private owners. Applications have been to residences, apartment buildings, houses, dormitories, museums, laboratories, test rooms, offices, shop apartments, pools, computer centers, machine works, clinics, health resorts, and guard houses. Isolator f mano s y different types have been used: lead plug rubber bearings (LRBs), HDRBs, friction devices, stee l dampinw devicelo d an sg natural rubber bearings (LDRBs) lattee Th . r (which were use severan di l cases) were couple variouo dt s types of dampers: steel hysteresis dampers, viscous dampers, lead dampers or friction dampers.

As to bridges, H. Akyiama mentioned that seismic isolation applications began in Japan much mor t vereno yrecentle numerousar d yan t (indeedye , , Ref. [13] shows thafirse th t t application was to the Onnetoh bridge in Hokkaido in 1992, and that only 15 applications were completed in 1993, which utilize LRBs with the exception of two cases, where HDRBs were adopted).

The second lecture was given by H. Koshida (Kajima Technical Research Institute, Tokyo) t deali ; t with isolatio f Japanesno e buildings from both seismi non-seismid an c c vibration showed san d that seismic isolation system alsy effective osb ma isolatior efo n from micro-vibrations, such as those due to traffic. Examples given were two buildings at Tokyo: the Acoustic Laboratory of Kajima Technical Institute (where the purpose was very accurate acoustic environmental tests, thus vibration isolation was a major requirement), and the Tohshin 24 Ohmori Building (which is only 5 m distant from two JR railroad lines). Both buildings were isolated using laminated rubber bearings (whic mucd hha h thicker rubber layers than ordinary bearing r earthquakfo s e protection only) combined with steed ro l dampers.

Lecture No. 3 (New Zealand [17]): W.H. Robinson of New Zealand Institute for Industrial Researc e "fathersth f Developmentd o f hseismian e o " on s i c o isolatiowh , d nan

10 passive energy dissipation (see Ref. [9]), described applications of these techniques to bridges and buildings in his country; these applications are rather numerous, taking into account the limited populatio Zealandw Ne importand f no an , t worprogresn i developmene s ki th r sfo t systemsw one f .

The first application of innovative antiseismic techniques to bridges and viaducts in New Zealand was to the Motu bridge in 1973; the number of such applications was 49 at the time of the seminar, four being retrofits (see Ref. [13]).

A civio st l buildings Williae th , m Clay ton Buildin Wellington gi firse th ts buildinnwa g which was isolated in New Zealand (1981). Later, isolation was undertaken for the Union House at Aukland (1983) and the Central Police Station at Wellington (1990). Three further applications were in progress: the retrofit to Parliament Building and Parliament Library, and construction of the New Museum of New Zealand, all at Wellington (see Ref. [13]).

(Italy5 . No [18,d Lecturesan 19]):4 . No Thes e lectures concerned applicationn i s Italy. The first was given by A. Parducci (Perugia University), who had designed passive energy dissipation system r somfo s e important bridge viaductd an s Italyn i s t dealI . t with applications of all innovative antiseismic techniques to such structures in this country, where mose th the te numerouyar worle th n dsi (see Ref. [13]).

secone Th d lectur gives ewa P.My nb . Mazzolani (Universit f Napleyo s Federico II): o appliee e firsdifferenth th wh tl s al dwa t e innovativh e antiseismic passive techniques (seismic isolation, passive energy dissipatio oleodynamid nan c provisional restraintso t ) Italian buildings. This lecture dealt with applications of these techniques (mainly seismic isolation and oleodynamic systems) to new and existing buildings in Italy. Special attention was also devoted to the problem of selection of an appropriate design input motion and to evaluation of the force reduction factor for superstructure. Mathematical models for isolation device isolated san d structures recently develope Italiay db n researchers were also illustrated.

P.M. Mazzolani stressed that the number of Italian building applications of seismic isolation and oleodynamic systems was already significant, and among others, included the constructio f ratheno r large structures hig(likm fiv e h5 eth 2 e buildings , each weighting Administratioe th f o , kN 0 n00 Cente0 Nationae 7 th f o r l Telephont a e Compan— P SI y— Ancona), twin isolated and conventionally founded three-storey apartment houses at Squillace Marina (Catanzaro) d retrofian , o historit t c structures completA . e pictur f Italiao e n applications of passive energy dissipation to Italian buildings was outlined later by V. Ciampi.

vere Th y first Italian building applicatio f innovativno e antiseismic techniqueo t s swa the New Fire Station Headquarters at Naples in 1981, which must be regarded as an application of passive energy dissipation, although seismic isolation devices were also used. P.M. Mazzolani mentioned that the purpose of this application was to avoid major modifications of the initially developed design (where seismic loads had not been considered) by matching at the same time the more stringent requirements which were defined a few months after initial design completio a consequenc s a n e 198th 0f o eCampan o Lucano (Irpinia) earthquake (when Naples was declared seismic area).

Afterwards isolate5 1 , d buildings were constructe r werdo e under constructioe th t na seminare timth seconisolatee e f firsb e o th o s t Th t. ddwa Fir e Station buildin t Naplega s (1985), where floor slab supportee sar steey db l towers through neoprene bearings thin i ; s

11 building oleodynamic devices were also located between each floor longitudinal beam and the adjacent steel tower so as to permit free thermal deformation of the structure, but to provide provisional restraint casn i sf earthquakeso e . Further completed applicationf o s seismic isolation concerned: e Montth e d'Ago Civic Cente t Ancona r a (1989), where large diameter neoprene bearings were used; the five SIP buildings at Ancona (1989-1992), where HDRBs were used; e aforesaith d hous t Squillacea e (1992), whic s isolatehwa d using both LDRBd an s HDRBs; Nava y buildin t Anconga a Medica(1992)e th d an ,l Cente foud ran r apartment houses at Augusta Navy base, Sicily (1993), all isolated by means of HDBRs.

In addition, works for retrofitting the S. Pietro Church at Frigento by means of seismic isolation were alread progresn yi s (using again HDRBs seminare time th th f et o a ) , wite hth aim of verifying the applicability of this technique to historic monuments (see Ref. [32]).

s oleodynamia r Afa s c system concernede ar s , afte e aforesaith r d applicatioe th o nt secon Firw edNe Station buildin t Naplesga , this syste uses somr mdwa fo e more structures: mentioned by the author were the retrofit to the Collegiate of S. Giovanni Battista in Carife, Avellino (1990), constructio industrian a f no l buildin FIAf go Melfit Ta , Potenza (1993)d an , f oleadynamio e us e ENEth w c ne device Le th Directiona n i s l Cente t Naplea r s (where, however, the main technique used was passive dissipation). Some more applications are listed in Ref. [13].

Lecture (Greece6 . No [20]): G.C. Manosprofessos i o wh , t Aristotlra e Universitd yan Director of the Institute of Engineering Seismology and Earthquake Engineering (ITEAK) at Thessaloniki, Greece, mentioned that n worprogresi s countrs hi i k n i s y alsr fo o applicatio antiseismiw ne f no c technique bridgeo st s (suc thoss ha e foresee Corinte th n no h Canal [5]), building industriad san l facilitie tankG Revythousat sLN a (suce th s ha , designed by the German D&W [40]). G.C. Manos especially covered the aspects related to the new Greek seismic code, by showing its applicability to seismically isolated structures.

Lecture No. 7 (Portugal [21]): J.J. Azevedo (CMEST - Civil Engineering Department, " Institute Superior Técnico", Lisbon) illustrated studie progresn s i seismi e th r sfo c isolation of irregular buildings in Portugal. He stressed the particular advantages of this technique for such buildings.

Lecture No. 8 (France [22]): This lecture concerned important aspects of work performed in France, which are essential for the reliability and safety of seismic isolation, especiall applicationr yfo higo st h ris r strategiko c structures . Coladan gives C wa y nb t I . t of Electricité de France (EdF), who is a well known expert at seismic isolation, deeply involved in the development of French design guidelines for isolated structures (EdF was the first organization which applied seismic isolatio nucleao nt r reactors).

After summarizing the French applications to civil buildings and nuclear structures, . ColadanC t illustrated test results concernin durabilite gth agind y an elastomef go r bearings, including steel-laminated neopreneR bearingPW e s installeMW 0 foue 90 th r n e duniti th f so at Cruas, which was the first isolated nuclear power plant in the world (3600 bearings). The use of seismic isolation in such a reactor had been decided by EdF to allow for keeping the standardize desig0 90 nR (whicdPW characterizes hi 0.2y db g z.p.a. Cruae th n )si site also, spitn i f largeeo r z.p.a. (0.3g).

12 . ColadanC t showed tha lifetime tth welf eo l positioned existing bearing equas si thao lt t superstructuree ofth stressed an , importance dth accuratn a f eo e monitorin naturaf go l aging effect addition (i s measuremento nt artificialln o s y aged bearings performiny b ) g testt a s appropriate time intervals on bearings kept in actual installation conditions.

Lecture (Germany9 . No [23]): This lectur . giveHeilans D ewa y nb GERf do B (Essen, Germany), which is a well known company for the development and fabrication of isolation and energy dissipation devices, including 3D systems that are efficient for both seismic and non-seismic vibrations (two seismic applications already exist in the USA). The lecture covered this aspect, which may be quite important for some types of structures (e.g. computer centers, etc.), where vertical isolatio alsy e requiredob nma stressed an , e th d advantages of a new GERB system.

1.2. TECHNICAL SESSIO ISOLATION O N2 CIVIF NO L BUILDING BRIDGED SAN S FROM SEISMI NON-SEISMID CAN C VIBRATIONS

Lecture No. 10 (USA [24]): J.M. Kelly of EERC-UBC provided an updated review on numeroue th s application thif so s techniqu buildingo et USAe th n sstressei e ;h w dno thas i t ti generally accepted that a base-isolated building will perform better than a conventional fixed- base building in moderate or strong earthquakes; he also explained the present, rather severe, US building code requirements, and expressed the confidence that about an alignment of codes for fixed-base and isolated structures will be soon possible, so as to reduce the degree of conservatism tha currentls i t y presen desige th n isolatef i tn o d structures alloo t e d wth an , economi f thio se technologycus .

e firsTh t applicatio f seismine Foothilo th buildin S o U t c s lw isolatiogwa ne a o nt Communitie Justicd an w e BernardinCentesLa n Sa t a r 1985n oi r whicfo , h HDRBs were designe cooperation di n wit seismihA MRPRAUS ce th isolatio n firse i , th uses tr nwa dfo tim retrofio et existinn a t g building (the Salt Lake CitCountd yan y Buildin 1988n gi , where LRBs were used).

There wer application8 1 e civiS U l o st building seminae time th th f eo t sa r (see also Refs [7, 10, 13]), including seven in progress (two new constructions and five retrofit). In addition, several new projects were being developed, which included further seismic retrofit and application industriao st l buildings.

Applications in progress concerned:

construction of the LRB-isolated Water Control Center/Water Quality Laboratory at Portland (Oregon), and the new HDRB-isolated Emergency Operations Center at Los Angeles (California); retrofit by means of LRBs to the Channing House Retirement Home at Palo Alto and e Oaklanth d City Hall, bot Californin hi a (the latte beed ha rn damage e 198th n d9i Loma Prieta Earthquake); retrofi Educationae th o t t l Service Kerckhof e Centeth d ran f Hal - lUCLA s , botLo t ha Angeles (California), using Earthquak systemeB BarrieLR d s an r(respectively) ; retrofiMackae th o t t y Schoo f Mineo l t Rena s o (Nevada), using HDRB FPTd an s F sliders.

13 Mos isolateS tU d buildings have been provided with seismic monitoring systems. With regar theio dt r uses applicationS U , s concern:

buildings that are important for civil protection, like the USC Hospital (1989) and Fire Comman Controd dan l Facility (1990Angeles Lo t )a s (which utilize LRB HDRBsd san , respectively), or the above-mentioned new Emergency and Operations Center; other important public buildings, like the aforesaid Foothill Communities Law and Justice CenteBernardinn Sa t ra Sald oan t Lake CitCountd yan y Building, Oakland City Hall, Channing House Retirement Home, and Mackay School of Mines; buildings thae importanar t r strategifo t c reasons, likRockwele eth l Cente t Seaa r l Beach (whic retrofittes hwa 199n di 1 using LRB proteco st t electronic equipment used proceso t s satellit Kaiseee data)th d r an ,Compute r Cente t Corona r a (1992, LRBd san HDRBs); buildings that are important for economical reasons, like the Evan and Sutherland Aircraft Simulator Manufacturing Facility at Salt Lake City (1988, LBRs), and the aforesaid Water Control Center/Water Quality Laborator t Portlandya ; some residential houses, likMarine eth a apartment house whic retrofittes hwa n Sa t da Francisco after the 1989 Loma Prieta earthquake using Friction Pendulum System (FPS), and two residences in West Los Angeles, which were isolated in 1992 by means GERe oth f B Resistant Base system.

Lecture No. 11 (United Kingdom [25]): This lecture was given by K.N.G. Fuller of Malaysian Rubber Producers' Association (MRPRA, Hertford, United Kingdom), which has lona g experienc developmenn eo f naturao t l rubber bearings t dealI . t wit mose hth t recent seismic isolation studies being performed by MRPRA, partly in the framework of a project funde UNIDy db four-stora r Ofo y apartment block mounte HDRBn do Indonesian si .

Some important recent results concern the demonstration that isolation is still effective in moderate earthquakes (in spite of relatively large bearing stiffness), that HDRB hardening at very large displacement is not sufficient as to offer a significant intrinsic restraint to bearing deformation, and that damping larger than 15% may in some instances be a significant disadvantage (thus, dampin f availablgo e HDRB adequate)s si .

Lecture2 (China1 . No [26]): F.L. Zhou (Universit f Guangzhouo y ) outlinee th d research in progress in China on seismic isolation to bridges and buildings and cited the numerous applications that already exist there isolate5 1 : d bridgeisolate0 5 d san d buildings.

As to buildings, the author stressed the existence of 40 very ancient isolated structures: these were palace buildings, monasteries, temple bridged an s s which survived destructive earthquakes. The 10 more recent isolated buildings are:

four 4 to 7 storey brick buildings with sliding layers as isolators and steel elements as energy dissipators, built in West China; risfivw elo e brick buildings with sand sliding isolation, buil Nortn i t h China; 8-storen a y concrete frame house being constructe Shanton di u City (South China), isolated by means of HDRBs.

additionn I , twin isolate conventionalld dan y founded 8-story r.c. buildinge b o t e sar built for test purposes and three further r.c. buildings, to be isolated by means of HDRBs, will be built in South and North China.

14 F.L. Zhou conclude presentatios dhi pointin y believe nb th t geou that applicatiof no seismic isolation will become wide, because "the new system is more safe, effective, economi simple"d can .

Lecture3 (Chile1 . No [27]): . SarraziM e "Universida death n— f no e Chiled " (Santiago), which has been involved in seismic isolation research for several years — presente lase dth t lecture concerning seismic isolatio buildingsf no detailee H . d such studies and mentioned some first application f seismiso c isolatio othed nan r antiseismic systemo st three buildings and an iron ship-loader at Guadaloca's port.

mose Th t interesting applicatio f seismino c isolatio bee s four-stora nha o nt y building at Santiago, whic supportes hi rubbey db r bearing s adjaceni d twia san o t nt conventional building; both buildings have been provided wit hseismia c monitoring system, which already recorded vibrations from three minor earthquakes, by confirming theoretical predictions. This application is similar to the Sedai buildings in Japan [15, 31] and the Squillace buildings in Italy [19, 39].

1.3. PANEL SESSION 1 ON SHORT PRESENTATIONS AND DISCUSSION ON FUTURE PROSPECTS FOR THE EXTENSION OF APPLICATIONS OF SEISMIC ISOLATION TECHNIQUES TO CIVIL BUILDINGS AND BRIDGES

Paper la (Russian Federation [28]): J.M. Eisenberg presented the work performed hi former USSR, and more recent work in the Russian Federation. He illustrated low-cost isolation systems developed and applied in the aforesaid Republics; he showed that a long experience exists ther applicationn eo buildingo t s shows s(a n below, more thahav0 n20 e been isolate meany db f differeno s t systems) stressed an , interese dth t simpln i no t d ean expensive systems.

e firsTh t application mentione t Ashkabada s wa d , Turkmenistan n 1959i , , whera e pendulum suspensio steed nan l springs syste useds mwa . After that followine th , g numbers of buildings were isolated in the period 1972 to 1990 [13]: Russin i 7 9 a (North Baikal, Siberia Kamchatkad an , ) using flexible ground story columns in conjunction with energy dissipation switching-off elements and rigid inelastic displacement limiters (1972-1990); , agai2 Russin i n a (Tynda, Siberia), using pile-in-tube systems with switching-off inelastic elements (1989); n Kirgizii 8 2 a (Bishkek d Russian ) a (Kamchatka), using low-friction teflon/steel supports with rigid displacement limiters (1984-1990); Ukrainn i 3 e (Sebastopole), using rocking r.c. supports consistin f columngo s with spheric ends with switching-off elements plufrictioy sdr n elements (1972-1974); 61 in Kazakhstan (Alma-Ata) and Russia (Kamchatka), using rocking r.c. supports consisting of upside-down mushroom type supports (1979-1989); Russin i 8 a (Buryatia, Siberia), using rocking r.c. supports consistin columnf go s with plane ends, with displacement limiter frictiod san n (1987-1990); Byelorussin i 1 a (Minsk) using steel-laminated rubber bearings (1985).

Paper (USAb I [29]): A.S. Whittaker, Associate Directo EERC-UBCf ro , presented this pape behalauthore n ro th f o f , R.L. Mayes, Presiden Dynamif o t c Isolation Systems (DIS), Inc., Berkeley (California), who could not attend. The paper focusses on the applications of seismic isolation to bridges and viaducts in the USA, namely a topic which was not included in the US lecture of Ref. [24].

15 . WhittakeMr r provide AASHT w overvien da ne e th Of wo seismic design requirements, force-redistribution concept benefitd an , seismif so c isolatio retrofin i t applications alse h ; o outlined the key features of the almost 50 US bridge applications and stressed that to date, seismiS U e th c f isolatioo abou % 50 tn application retrofie sar t projects [13].

Paper le (India [30]): S.K. Thakkar mentioned that important numerical and experimental studie r seismicallfo s y isolated masonr d r.can y. buildings, equipment, foundatio nuclead nan r reactor buildings have also been performe Indin di fiftee r afo n years, althoug applicatioo hn availabls ni actuao et l structures, yet. Sliding system laminated san d rubber bearings coupled with sliders were considered. One conclusion of the author was that "there is a need to bring awareness and confidence in structural engineers for application of this new technique in seismic areas". Also, he agreed with J.M. Eisenberg that "development of low-cost base isolation syste s mnecessari s wideit r rfo y acceptabilit n developini y g countries". Paper Id (Japan [31]): M. Izumi illustrated earthquake recordings on isolated buildings in Japan, namely a very important topic which needed to be particularly stressed. He mentioned that abou building0 2 t equippee sar d with seismic monitoring system Japann si , and showed that available recording demonstrated that seismic isolatio s effectivi n n i e decreasin e shearinth g g force produce n buildingi d y earthquakesb s . Furthermoree h , proposed "passive intelligent systems s systema " s which "are expecte o wort d k more efficiently with much less expenses and more reliability than active control systems".

Papers le and If (Italy [32, 33]): These contributions provided information on work in progress in Italy for seismic retrofitting of existing buildings by means of isolation systems, namely on a topic which may be particularly important in seismic countries like Italy, where so many historic buildings have already been damaged or risk to be damaged by earthquakes, and where a large number of residential buildings is not seismic-resistant.

The first paper was presented by R. Giacchetti; it mentioned cases where the application of seismic isolation to retrofit existing buildings, although demonstrated both technically and economically advantageous, was made impossible for "bureaucratic and cultural" reasons (e.g. the landmark building "Villa Fiorita" near Ancona).

The second paper concerned the already mentioned first application of seismic isolation to an existing building of historical interest: the S. Pietro Church at Frigento. This paper (coauthore . SparaciR Universite y db th f oo Naplef yo s Federic . CavuotF , oII f S.A.Soo . Progetti, . NapoliZampinoG d an , , Superintenden r Environmentalfo t , Architecturad an l Historical Goods at Avellino) could not be presented at the seminar, but the text has been included in the proceedings. It reports on the rehabilitation works which were beginning on projece churce th th d f insertino than g HDRB bases it t sa .

Paper g (ItalyI [34]): This pape agais wa r ncontributioa f Italyno , which concerned a further issue tha rathes i t r importan correca r fo t t desig f seismicallno y isolated structures, namel problee yth f reductiomo response th f no e spectr arathee ordinaleth o t r large sdu e damping which characterizes isolated structures i Pasqualepresentes D wa . t G o I . y dwh b , confirmed that damping doe t affec responssno e th tver d an y t ver ea higw ylo h frequencies, and showed that the indications of some codes (EC8) are slightly optimistic, while those of others (SEAOC, AASHTO) are adequate. Paper h (CECI [35]): . GutierreE z stresse potentiae dth Reactioe th f o l ne Walth f o l ELSA Laborator seismir JRC-Ispre fo th C t ya c CE isolatio f ao n studies pointee H . t thadou t

16 pseudodynamie th c method applie t ELSda Aapplicables i correce th r fo t, accoun f rato t e dependency of rubber compounds also.

1.4. TECHNICAL SESSIO SEISMIN O N3 C ISOLATIO NUCLEAF NO R FACILITIES

Lecture No. 14 (USA [36]): This lecture was given by E.L. Gluekler (GE Nuclear Energy, San Jose, California, USA), who summarized the topics discussed at the IAEA Specialists Meeting held at San Jose in 1992 [6], and — as far as the most recent developments in the USA are concerned — reported on the progress of seismic isolation studies in view of the application of this technique for the ALMRs.

As regards the IAEA Specialists Meeting, Mr. Gluekler recalled, among others, the existing isolated nuclear facilitie d isolatean s d reactor projects being developede Th . applications which have already been completed are mainly due to French (with the only exception of a fuel reprocessing plant in the UK). These applications, concerning plants which traditionally make use of proven and safe technologies, stress the maturity level which, even several year salread d agoha , y been attribute seismio dt c isolation systems.

More precisely, in 1963 the French began isolating, by means of neoprene bearings, e vesselth f GCRo s t Saina s t Lauren Buged an t Francen t i yVandelloa d an , Spainn i s ; although the purpose of these applications was to control thermal deformations, rather than seismic isolation, interesting results to this aim also were obtained (bearings had not shown any detrimental aging effects, yet).

f Crua o 1970s)e Late th R France n isolatesF i n (i rPW Ed , e ,dth using again neoprene bearings: as also stressed in Ref. [22], such a solution was selected to avoid modifying the PWR standard desig Francen ni r similaFo . r reasons Framatome isolate Koebere dth R gPW Soutn i h Africa, using sliding systems forme neopreny db e bearings coupled with friction plates (see als contributioe oth n presente D.Ey b . 2 d LeeS lateP n i r, ESKOMd ha [44 d ]an begun isolatin meansamy e g(b th ef s o slidin g system Karue )th n River reacto Islamie th n ri c Republic of Iran (construction was interrupted in 1978 due to well-known events).

Furthermore s explainea , d later mor . n J detaiDalberi e y b l a [38] e Frenc,th h COGEMA isolated thre edecae poolth f spenr yo fo s e reprocessint th fue n i l g a planL t a t f neopreno Haguee us y eb , bearings simila thost Cruaso t a r F e use.Ed (Mry db . Coladant had also mentione a furthed r application two-stora o t , y building containing radioactive wastes, which was isolated by the French Navy at Tolon in 1981, using the G APEC neoprene bearing system.)

e nucleath Ao t s r plant desige th s whicn i n e phasehar , applications cited were eth French PWR at Le Carnet (1300 M We), for which the nuclear island should be supported by neoprene bearings, the European Fast Breeder Reactor (1500 M We), some US advanced reactor projects r whic(sucfo , PRISs ha HDRBGE f Mo s have been foreseen)e th d an , seismic isolation projects concerning future Japanese nuclear reactors of different kinds (PWRs, BWRs, FBRs) e latte experience basee Th th . ar r n do e attaine r conventionadfo l structures alloo t r constructios wa fo o s , siten ni s thamore ar t e seismic tha e (alreadnth y scarce) moderate seismicity areas used to date: as shown by M. Izumi [31] several isolated buildings have been provided with seismic monitoring systems, which already gave very precise information on the behaviour of isolated structures in real earthquakes. For the work in progres r Japanesfo s e FBRs more details were provide e subsequenth y db t lectury eb M. Kato [37].

17 With regare developmentth o dt e isolateth f o sd ALMR projece USAth . n Mr i ,t Gluekler outlined the considerable design and experimental and analytical work in progress, focussin seismin go c bearin isolatiod gan n system performances evaluatiod an , f seismino c bearing environmental effects (aging, temperature, irradiation).

As a conclusion, Mr. Gluekler stressed the full maturity achieved by seismic isolation nuclear fo e us r fos reactorit r s also, whic demonstrates hwa PRISe th r Mdfo projece th y b t fac e performanctth thal al t e requirement f isolatioo s n bearing d beeha sn exceeded considerably and all technical problems concerning isolators and isolation system had been solved. Finally, he also pointed out the importance of international collaborations.

Lecture No. 15 (Japan [37]: As mentioned above, M. Kato (Japan Atomic Power Company) illustrated the progress of studies for base-isolated FBR in Japan. He confirmed that fundamenta sucr applicatiofo n ha D R& l beed nha n completed, together with conceptual desig horizontar nfo l isolation stressee h ; d that demonstratio f seismino c safety, economical merit and construction feasibility in highly seismic sites had been achieved, although some safet reliabilitd yan y problem systee resolvee th stilb d f mso o ha t l relation d i desig e th o nt n systee oth f m itself.

Lecture(France6 1 . No [38]): This lectur contributioa s ewa f Franceno , presentey db M. J. Dalbera (COGEMA) and co-authored by experts of SGN, which dealt with the applicatio f seismino c isolatio threo nt e spent fuel storage reprocessine poolth f so g plant a t a HagueL . After describing suc application ha detailn ni . DalberMr , a stressed thae th t available nine years experienc f serviceo f suceo planha t demonstrated thaelastomee th t r bearing pads used in this system "are a good choice for all unusual supporting problems which occu spenn i r t fuel storage pools".

Lecture No. 17 (Italy [39]): M. Forni (ENEA, Bologna) — who is the GLIS secretary responsibls i d an r seismiefo c isolatiot ENEa D gavA— nR& e this lecture, coauthorey db representative f severaso l organization whic collaboratine har framewore Italn gth i n yi f ko GLIS.

Mr. Forni outlined the considerable progress made in Italy on numerical and experimental studies for HDRB compounds, HDRBs, isolated structure mock-ups and isolated buildings (on-site testdetailed an s buildinP d SI analysi e t Ancongon a f o sbotd aan h twin houses at Squillace). He also cited design guidelines development being performed in Italy on seismic isolation of nuclear and non-nuclear structures, and recent installation of seismic monitoring systems on both SIP buildings at Ancona and the twin houses at Squillace.

showee H d thaabove-mentionee th t d studies confirme adequace d th HDRBe th f yo s considered, for wide-ranging applications. Finally, he mentioned collaborations existing with futurd an e A CECe workth US ,e , Japath suc d thas ha nan t beginnin cooperation gi n with Germany (D&W and SHW) and the UK (MRPRA) in the framework of a CEC-funded Brite- Euram II project.

1.5. TECHNICAL SESSIO SEISMIN O N4 C ISOLATIO NON-NUCLEAF NO R INDUSTRIAL FACILITIES

Lecture No. 18 (Germany [40]): L. Stempniewski of D&W (Muenchen, Germany) focusse applicatioe th n do seismif no c isolatio liquefieo nt d natura (LNGs ga l ) storage tanks. d designeha W d D& seismically isolate tankG r highlLN fo ds y seismic areas, sucs a h

18 Revithousa (Greece Incod )an n Korea)f (Repo . , using HDRBs notes i t I .firsde th that tr fo , application, the installation of HDRBs manufactured in Italy (ALGA) is foreseen.

. StempniewskL i stressed thaaforesaie th t d application f seismio s c isolation wile b l amon firse gth t one higo st h risk non-nuclear facilities suc thoss ha f chemicaeo l industry. The lecture demonstrated the great potential of this technique for these facilities also, where it permits larg eved ean n extremely large safele tankb o t sy erected withou neey r an tdfo embedment to quite high ground acceleration (0.5g).

Lecture (Italy9 1 . [41]):No . responsibls Bonacini G o seismie wh th ar — efo c isolation project at ISMES SpA (Bergamo, Italy), where most Italian seismic isolation experiments have been performed — illustrated the research program which was undertaken by ENEL, cooperation i n with ISMES witd suppore an ,hth ALGAf o t , ENE Napled Aan s University, on seismic isolation of two different typical types of electric gas-insulated substations (outdoor plan substatiod an t n house smala n di l building). e hanon d e e electrireasone studth s thath Th n o r wa yt cfo s substation e quitar s e strategic for civil protection (i.e. they must remain functional in strong earthquakes) and are quite otheth e n rcostly o hand d an ,, experience shows thae conventionallth t y founded substations may be severely damaged even in not too severe earthquakes.

For isolators, reference was already made in the study to HDRBs; the use of other isolators type s alswa os planned. Finite-element analysi d beeha s n performe r botfo d h substation types, and experiments had begun to qualify isolation devices. The first results obtained indicated an excellent performance of the isolated design; the study should also provide important information to evaluate the applicability of seismic isolation to other industrial plant types.

Lecture0 (USA2 . No [42]): This lectur s presenteewa F.Fy db . Tajiria f Bechteo n l Corporation (San Francisco, California), who is a well-known expert at the innovative antiseismic technique USAt outlinee I th . n si state-of-the-are dth applicationn o t f seismiso c isolation to US industrial plants; these are already relatively numerous and include the use of this techniqu componentsr efo , tank buildingd san sclassifiee whicb y h ma industrias da l facilities.

Most of the latter have already been considered among isolated buildings, although they may be also regarded as industrial applications (this is especially the case of the Evans and Sutherland Aircraft Simulator Manufacturing Facilit t Salya t Lake City).

Ao isolatiot s f componentso n , F.F. Tajirian mentioned that applications were completed for: CircuiV k 0 t23 Breaker Californif so a Departmen Watef to r Resources (HDRBs, 1979; ) Liquie th d Argon Calorimete Mard ran DetectoI kI Stanfore th t ra d Linear Acceleration Center (LRBs, 1987); art objects at the J. Paul Jetty Museum in Malibu, California (which were isolated by off-the-shell ball transfer units which rol steen o l l plates placefloor)e th n do ; e Tita th soliV nI d rocket motor upgrade segment t Vandenbera s r ForcgAi e Base, California (HDRs, 1992).

HDRBs were also fabricated and placed in storage at Diablo Canyon nuclear power plant, to be used for isolating two 32 tons mobile exciters (consisting of transformers and

19 switch gear mounted on a truck trailer) which would replace the main turbine generator excitee turbinth n i re buildin e cas th f majo o en i g r malfunctionin f suco gexcitern ha . Furthermore, some more component isolation cases were extensively studied (although no application existed, yet), like tha f computeo t r floors (whic s mentionedha commoa s i , n practic Japan)n ei wasta d ean , storage facility weather enclosure structur t Idahea o National Engineering Laboratory (fo considered)s r whicwa S hFP .

Finally, with regar tano dt k isolation . TajiriaMr , n mentioned tha certaia t n numbef ro applications were studied, and in a few cases already undertaken. More precisely, the existing toweemergencn a f ro yChemica wateW DO re tanlth Compant ka Pittsburgn yi s hwa seismically upgrade d1988n i usin HDRBd S an ,gFP s were more recently use upgrado dt e large (3.78 million liter capacity) tank Seattlet sa , Washington ton0 20 s a ammoni; a tans kwa isolate dn Calveri usinS FP gt City, Kentucky n 1993i , ; finally a detaile, d studs wa y performed for large concrete and steel LNG tanks, which demonstrated large benefits of seismic isolation.

. TajiriaMr n stresse benefite dth seismif o s c isolatio componentf no s which e havb o et requalified for higher seismic loads, and those concerning the design of large tanks, where f thio se techniquus e th resuly eeliminatioma n i t r simplificationo holf no d down anchors. However emphasizee h , neee mordr th dfo e comprehensive quality assurance test tighted san r acceptance tolerances than normally required for isolated buildings, especially where only four isolators are used.

In any case, he judged that seismic isolation has a great potential for non-nuclear industrial plants r whicfo , conventionae hth l desig adequatene b approac t no alse y h ; ohma mentioned that the development of new isolation techniques including soft elastomers and low friction rollers wil lisolatioe alloth r w fo f lighte no r component extendinr fo e d us san e gth of isolatio sofo nt t sites.

Lecture (Japan1 2 . No [43]): . HazumotY Chubf oo u Electric Power Company, Japan, stressed that, although no applications of seismic isolation to actual industrial plants existed in Japan, yet, this technique had been adopted there for some buildings which may be classified as industrial facilities (computer centers, buildings of thermal power companies, etc.Refe se , . [15].

Thus, this lecture e mosdealth f tt o interestin wite hon g among such applications, namel twie th no yt building s formin ease westhermad w gth an t ne t e winglth powef so r administration centeauthor'e th f o r s compan t Nogoyaya beine on , g isolate meany db f so improved LRBs and the other by means of HDRBs. Both buildings have been provided with seismic monitoring system werd san e subjecte detaileo dt d analysi forced san d vibration tests (performe dachievo t usins wa eg experiencm vibrator ai e roof) e th widea Th n .r o s efo r applicatio o industriant l structures, including nuclear reactors. Good agreement between calculation measurementd san founds swa .

1.6. PANEL SESSIO SHORN O N2 T PRESENTATION DISCUSSIOD AN S N NO FUTURE PROSPECTS FOR THE EXTENSION OF APPLICATIONS OF SEISMIC ISOLATION TO NUCLEAR AND NON-NUCLEAR INDUSTRIAL FACILITIES

Paper (Southa 2 Africa [14]): D.E describee .Le base dth e isolation systeme useth n di two 900 MWe units of the PWR Koeberg Nuclear Power Station, owned and operated by ESKOM Soutn i , h Africa wels a ,tests a l s complete 199n di 2 (som year4 e1 s after isolators'

20 installation evaluato t ) e lonth e g term characteristic f suco s e relateha system th d dan , analysis.

The Koeberg nuclear reactor was the second (after that at Cruas in France) which was isolated in the world: indeed, it was constructed by Framatome in 1977 to 1978; it makes use of 1829 steel-laminated neoprene bearings provided with bronze friction plates containing fine led droplets at the top (the so-called "EdF system", which was characterized by a design friction coefficien f 0.1o t 0.25)5o t .

Tests showed that friction coefficients increase abouy db t 70%; however noticeablo n , e corrosion was evident on friction plates, and the neoprene shear modulus remained within the design range. Furthermore, it was found that both neoprene bearings and the superstructure are capable of withstanding the larger stresses caused by increased friction coefficients (i.e. by the beginning of sliding at higher seismic loads). Finally, analysis showed that progressive sliding will occur during strong motions, due to the fact that bearings sustain different vertical loads: this will lead to a decrease of the response, but will further increase stresses acting on the neoprene bearings.

Paper (Russiab 2 [45]): J.M. Eisenber co-authors hi d gan f Atomenergoprojectso . St , Petersburg, suggested the use of a seismic isolation system for industrial structures in Russia, particulan i r nucleafo r r reactors suc s VVER-500ha r thiFo s. reactor projeca , s beini t g developed in the framework of space industry technology transfer and consists of pneumo- shock absorbers combined with viscous dampers.

Both numerical analyses (carrie 0.4-0.o t t dou 6inpug t acceleration experimentd )an s (performe o magnitudt d e 9-1 meany 0b f explosivo s e technique r differenfo d an s t soil conditions on a 1/7 scale reactor building model) showed that the above-mentioned system is capable of considerably reducing the seismic loads acting on reactor building and inner equipment, by limiting at the same time displacement (to about 0.1 m). It was also mentioned that further tests have been planned on a full-scale part of isolated reactor building to complete the project, so as to enable construction of seismically isolated high risk plants in highly seismic area Russian si .

Paper c (India2 [46]): R.S. Soni illustrated studiee applicabilitth n o s f seismio y c isolation to PHWRs in India. He mentioned that further work is necessary in India before adopting this techniqu meany (b e f laminateo s d elastomer bearings r primarfo ) y systems, while great advantage had already been derived from the use of energy absorbing devices in secondary systems.

Paper 2d (China [47]): D. Li (also on behalf of his co-author L. Lin of China Institute of Atomic Energ CIAEy— ) commente technologiee th n do approached san s which have been adopted or developed in China for seismic isolation of industrial facilities, focussing on the use of rubber bearings and friction devices. D. Li stressed that industry constructions including nuclear power plants, hydropower stations on the three gorges of Yantze River and many other industry projects and facilities all face the problem of seismic and non-seismic vibrations. He mentioned that several vibration research centers have been constructed thad an ,t mor mord ean e engineer attractee topisar e th f vibratio co y db n isolatio Chinan ni , which opens importan f thio se t techniquprospectus e th r botn i efo s h nuclea non-nuclead an r r industrial facilitie than si t country, although many still worry there abou qualite tth higd yan h market cost f isolatioso n materials particularn I . i mentioneL . D , d that seismic isolation will

21 wil experimentaconsideree w lb ne e th whicr R dfo FB lbeins h i g designe CIAEy db , because withstano t s iha t magnitudda earthquakee8 .

Paper e (Korea,2 f Kore o Rep. o , a[48]): Yo of Atomi . B c Energy Research Institute (KAERI) and his co-authors of the same institute and Korea Advanced Institute of Science & Technology summarized the current status and prospects of the applications of seismic isolation technology in the Republic of Korea.

Anucleao t s r structures mentioneo Yo . B , d that seismic isolatio s beinni g seriously considered for both an advanced demonstration LMR and an away-from-reactor interim spent fuel storage facility; analysis of the isolated LMR was in progress and a prototype laminated rubber bearing had been designed and would have been ordered shortly to evaluate the manufacturing process and to evaluate bearing properties by test. Numerical models were also develope spene th r t dfo fue l storage facility whicr fo , h HDR mose judges th Be twa b o dt effective isolation device.

As to non-nuclear structures, B. Yoo mentioned that seismic isolation had been already applie Koreao dt n highwa tanksyG bridgeLN , d usinsan g laminated rubber bearingss i d an , being considere furthesucr n i dfo he structuresus r ; wit htanks G regar pointee LN h , o dt t dou that constructio e firsth t f no isolate d tanks dated several years thad an t, tests were later performed usin pseudodynamiga c method incorporatin gsubstructurina g technique, which demonstrated adequacy of such an application.

Finally, B. Yoo's conclusions were that there are good prospects that seismic isolation application will expand in the Rep. of Korea in the future (in association with vibration control), also to tall buildings, critical public buildings, computer fabrication facilities, and rehabilitation of historical buildings, and that to this aim, solid international co-operation is essential. Paper 2f (Canada [49]): A. Alizadeh reported that the design of CANDU 6 plant was currently being reviewed by AECL CANDU, Canada, for locating in areas of high seismicity, and that the use of isolation bearings was being considered in such an analysis. He summarized an analytical study undertaken to predict the seismic behaviour of isolated CANDU 6.

Steel laminated rubber bearings were considere studye conclusionth e n di Th . s were that isolation will lea largo dt e reduction f seismiso c load t Safe-Shutdowsa n Earthquake (SSE), that such a design earthquake will envelop the conditions for lesser earthquakes, and that only minor adjustments wil requiree b l layoun di interfaced an t f interconnecteo s d systems: these results will make the standard plant design adequate for a wide range of seismic conditions.

Paper 2g (New Zealand [17]): The text of the contribution of W.H. Robinson concerning applications of seismic isolation to industrial non-nuclear structures in New Zealand (no nuclear plants exist in this country) was included in his Lecture No. 3, presented inT. S1

W.H. Robinson mentioned that three important applications to very different structures already existes countryhi n i d , namel a brittl o t y e cast-iron printing pres Petonen i s a , chimney in Christchurch, and AC capacitor banks at Haywards Substation. In the first case LRBs were used, seconwhile th n ei d rocking with steel damper lase adopteds th t n swa i d an , case steel LDRBs coupled with steel dampers were inserte base th seismicall o et t d a y retrofit the capacitor stack and its insulators.

22 The latter was a first example of a process undertaken by electricity suppliers in New Zealan f selectivo d e retrofittin f seismio g c isolatio y item ke f highl o so t n y vulnerable substation equipment.

1.7. TECHNICAL SESSION 5 ON PASSIVE ENERGY DISSIPATION AND ACTIVE CONTROL OF VIBRATIONS OF STRUCTURES

Lecture(Italy2 2 . No [50]): . Ciamp V Universite th f o i f Romyo Sapienzaa aL o wh , wela s i l known exper t passiva t e energy dissipatio Italyn ni , opene presentatione dth n so passive energy dissipation, according to the considerable Italian experience achieved at this technique. Because applications of passive energy dissipation to Italian bridges had already been describe presentatioe [18]1 th ,S detain di T . Ciampn V i l f s devoteno n wa ia o dt overvie e systemth f wo s whic beed hha n investigate Italn i d y with specific referenco t e buildings.

He illustrated theoretical and experimental studies concerning dissipative bracing system dissipativd san e couplin f adjacengo t buildings, together wit e fouhth r applications reported in Italy. These applications concerned:

the New Fire Station Headquarters at Naples (1981), where yielding steel devices were inserted between steel roof and top of cores, in addition isolators introduced between top steel grid and towers (see also Ref. [19]); a hospita t Siena l a (1988), where dissipatio provides nwa frictioy db slotten ni d bolted connections at the end of braces; a CNR laboratory building at Frascati (1990), where rectangular yielding steel devices, crosn i s bracing, with tension only struts were used; e twi th ENEnw buildingNe L e Directionath f o s l Cente t Naplea r s (1991), where yielding steel devices have been inserted between r.c. cores and steel suspended floor slabs.

e lasth t n structureI , oleodynamic systems were also used: thee locatee ar yth t da bottom of the suspended part (furthermore, elastic devices were also used at upper trusses).

V. Ciampi mentioned tha developmene tth energf to y dissipation technique buildinr sfo g protection against earthquakes, although less advanced with respect to that of seismic isolation growina s i , g field worldwid thad ean t ther mucs ei h interes subjece th n Italyn to i t : spitn i f verapplicationeo w yfe s already existing, important experimenta theoreticad an l l research activity is in progress (for instance, detailed shake table tests were performed at ISME detailea n So d scale modetwie th nf buildinglo Naplest sa , which included foundations and soil).

Lecture(USA3 2 . [51]):No I.D. Aike f EERC-UBno C provide dsummara f threyo e viable types of passive energy dissipation devices (ADAS device, 3M viscoelastic shear dampe Taylod ran r Devices' fluid viscous damper) that have been studied experimentalln yo shak beeed tableha n d implementedan s procese r werth o , n ei f bein o s g implementedn i , structure describe d USAe an th ,n si d provision analysise th r sfo , design implementatiod an , n which had been developed. Steel yielding ADAS (Added Damping and Stiffness) elements were used to retrofit a two-story r.c. structur downtown ei Franciscn nSa o afte buildine th r g suffered structurad an l non-structural damage in the 1989 Loma Prieta earthquake; this was the only completed application of passive energy dissipation systems to US buildings at the time of the seminar.

23 However retrofia , t project using viscoelastic shear damper alss oswa underwa- 13 a r yfo story building, located in San Jose, for which significant non-structural damage had occurred in a number of small and moderate earthquakes.

Furthermore f viscouo e us s e damperth , beins swa g considere seismicallo dt y retrofit seven-store th y Travelers Hote Sacramentn i l o (whic constructes hwa 1920s)e th n di , because detailin criticae th f go l component connectiond san beed sha n found inadequat spitn ei f eo seismia c upgradin 1984n gi . Preliminary analysi showd sha n that this typ devicef eo s should be the most adequate among various solutions considered (the use of seismic isolation was preclude non-structuray db l issues).

I.D. Aiken stressed that although building code provisions being developed for the implementation of passive energy dissipation devices require the use of detailed non-linear analysis, experience will allow for a simplification of analysis and design procedures; at any rate, the publication and adoption of such provisions will immediately result in increased interest and application for buildings, bridges and industrial structures.

Lecture No. 24 (Japan [52]): K. Tamura (Shimizu Corporation, Tokyo, Japan) first presented a brief review of the common mechanisms and algorithms of active control systems for buildings. Then describee h , response dth e propertie activelf so y controlled mass damper systems using optimal control theory and showed that Hybrid Mass Damper (HMD) system, which utilizes the effects of passive and active control forces simultaneously, has very effective performance through comparative studie somn so e typical mass damper systems. He mentioned that passive forces in HMD may be provided by rubber bearings, a spring plus rail device, pendulum, or arch shaped roller.

K. Tamura also introduced a fifty-story building (more than 200 m high) as an example of adoptin systemD stressed gHM an , d that suc hsystea proves mwa havo nt e excellent characteristic suppreso st vibratioe sth n response buildinge th f so , through in-situ testd san results observed during strong winds.

Lecture No. 25 (Japan [53]): This lecture was presented by T. Fujita (Institute of Industrial Science, University of Tokyo), who is one the most renowned expert at all innovative antiseismic technique a coorganize s e wa seminarn Japai sth d f an no e r H . complete presentatioe dth . TamurK f n o summarizin y ab maie gth n feature e manth f yo s types of active/hybrid mass damper systems which have been developed in Japan for active response contro talf o l l building improvo st e habitabilit humar yo n comfort during windd san weak but frequent earthquakes.

He mentioned that systems were hybrid type, utilizing various passive device types, namely the XY-Motion Mechanism type, Multistage Rubber Bearing type, Multistage Pendulum type, and Rigid Body Pendulum type. Control systems with both hydraulic actuators and servomotors were described, together with experimental results obtained on large scale structure models.

Finally, T. Fujita outlined active/hybrid mass damper systems applied to five of the nine existing Japanese application: these are high-rise, all well taller than 100 m. Two of Hankye thesth e— u Chayamachi Building (1992 Lone , th highOsaka m gd 1 Teran ) 16 , m Credit Bank of Japan Building (1993, Tokyo, 130 m) — utilize the multistage rubber bearing syste d hydrauliman c actuators, whil ee Yokoham threth — e a Landmark Tower (1993, Symbo0 20 C l ToweOR e Yokohamath Shinjuke r, th (1992 m) d 6 an u ,29 , Osakam) 0 20 ,

24 Park Tower (1994, Tokyo, utiliz226.— ) e5m servomotor contro thred an l e different types of systems (multistage pendulum, multistage rubber bearing, and rigid body pendulum, respectively). The lecturer also mentioned that 7 or 8 further buildings are under construction r desigo Japan ni n with active mass dampers.

worthwhils Ii t e noting thatallese th t t amon aforesaie gth d building higsm (thh6 e29 Yokohama Landmark Tower) has a first natural period of 5.4 s, which makes it evident why control of vibrations is essential, and also, why a very large power is necessary to operate the control system: such a power (720 kW) is of the same order than the overall power consumptio l activitieal r nfo s insid buildinge eth .

In his conclusions T. Fujita stressed that:

the main purpose of active vibration control is to effectively control the first-mode vibration of the buildings due to wind; active/hybrid mass damper systems are mainly applied to tall buildings with upper floors used for hotel rooms; tall buildings with flat plans have a strong requirement for active/hybrid mass damper systems to control the first-mode lateral vibration in transverse direction coupled with the torsional one caused by strong winds; hybrid mass dampers become general, and can work as passive mass dampers anyway against strong earthquakes and winds beyond capacities of actuators, although technology levels are various for the active/passive mode switching; it would be necessary to make hybrid mass damper systems more intelligent in various senses, in order to make full use of such expensive systems.

1.8. TECHNICAL SESSION 6 ON PASSIVE ENERGY DISSIPATION AND ACTIVE CONTRO VIBRATIONF LO STRUCTUREF SO S

Lecture No. 26 (Japan [54]): H. Kitamura of Nikken Sekkei Ltd (Tokyo) addressed the topic of development and application of passive energy dissipation techniques in Japan, where experience in the use of such techniques is certainly the largest in the world (similar to seismic isolation and active/hybrid control of vibrations). Indeed, starting in 1984, ten building alreadd sha y been constructe Japan di n utilizing Hysteresis Damping Mechanisms (HDM) or Viscous Damping Mechanisms (VDM) as energy absorption systems to control seismic vibrations. VDM systems make use of round steel bar dampers (HD), lead dampers (LD) or friction dampers (FD), while VDM systems may utilize oil dampers (YD), viscous dampers (VD) r viscouo , s elastic dampers (VED).

aforementionee Th d application listee sar d below indicatiny b , g location, construction year, system adopte used d:an Hitachi Head Office (Tokyo, 1984, HD, office); Sonic-City Office Building (Saitama, 1988 , office)FD , ; Kajima Kl Building (Tokyo, 1989, HD, office); Asahi Bear Tower (Tokyo, 1989, FD, office); Fujita Corporation Head Office (Tokyo, 1990, LD, office); TV Shizuoka Media City (Shizuoka, 1991, VD, complex building); Shibaur Vana aSe s S-Building (Tokyo, 1991, VED, office); Sato Building (Tokyo, 1992 , comple,VD x building); Shimura 3-chome Dormitory (Tokyo, 1993 , dormitory),YD ; Cyba City Gymnasium (Chiba, 1993, VED, office).

25 H. Kitamura showed that adoption of the aforesaid systems made it possible to considerably reduce seismic loads. However stressee h , d tha tenerg e mosth f o ty absorption systems were still under development in Japan, and that it is not clear, yet, which system will predominate. He also pointed out that the purpose of installing damping systems had still to clarifiede b thad an t, their effect confirmede b stild o ha t sl .

Lecture No. 27 (Italy [55]): This lecture was presented by R. Medeot of FIP Industriale (Padova), whic s veri h y e developmenactivth n o e d installatioan t f passivo n e energy dissipation devices and provisional restraints bridges and buildings in Italy. The contribution . MedeooM f t focusse recenterinn do f elasto-plastigo c devices afte earthquaken a r , which n obvioua s i s important feature. More precisely, this lecture aime t clarifyina d y wh g recentering of such devices can take place spontaneously in a matter of a few weeks, as observed experimentally.

e authoTh r showed thae sunth t o ,thit whic e soffey t behavioudu h(a ma r e b y ma r least, partly) the necessary energy, and that such a phenomenon could intervene for other device types also, provided thaforce-deformatioe th t n characteristic curv dissymetris ei o ct compression and traction.

Lecture (Mexico8 2 . No [56]): . Martinez-RomerE o (EMRS UniversitA& f Mexicyo o City) gave a detailed description of the retrofit to three r.c. buildings in Mexico using ADAS devices. These buildings (Izazaga n. 38-40, Cardiology Hospital and Reforina n. 476) are all locate Mexicn di o City.

The twelve-storey Izazaga n. 38-40 building, constructed in the late 1970s suffered moderate structural damage in the 1985 earthquakes (magnitudes 8.1 and 7.3); it was repaired in a conventional way, but it was damaged again in the 1986 earthquakes (magnitude 7.0); thus the possibility of retrofit by means of ADAS devices was examined. The five-story Cardiology Hospital buildin constructes gwa d 1970'agaie th suffered n i san d structurad an l non-structural damage in the 1985 earthquakes. Retrofit by means of ADAS was selected. complea s i Reforin 6 f threxo 47 . en a nine-story buildings which were constructee th n di 1940's and are the headquarters of the Mexican Institute of Social Security. They survived at leas earthquakes1 1 t f magnitudo r moreo 0 e,7. with some damag 195n ei 7 only, which was repaired. However, according to both the architectural and strategic importance of the buildings, retrofit by means of ADAS elements was decided.

E. Martinez-Romero showed that the use of ADAS devices allowed for a very substantial improvement of building seismic responses at reasonable costs. He mentioned that retrofi mads wa t e whil e buildingth e s wer operationn i e , whic possibls leso t hwa se edu construction activity required with respec o conventionat t l strengthening. Howevere h , stressed that retrofittin meany b g f passivo s e energy dissipatio neasn a system yt no s i s technical problem t demandbu , s good engineering judgmen d prompan t t engineering response broaa o t , d variet f constructioyo n issues difficul forese o t retrofie t th n ei t project.

Lecture9 (USA2 . No [57]): S.C. Liu, responsibl e activth r efo e vibration control programm t Nationaea l Science Foundation (Washington, D.C. USAe th )n i , describee dth concept, scope, and research activities which characterize such a program. He emphasized programme th e focu broar fo s d practical applications through system integratio f existinno g knowledg d technologicaan e l innovation e alsH .o discussed technical implicationf o s intelligent control systems, smart materials, and hazard mitigation research as applied to civil structure systems.

26 S.Cnoteu Li . d that considerable progres bees sha n mad improvo et e structural safety through research in structural, earthquake, and wind engineering. He stressed that the possibility of applying control systems to mitigate the structural damage against earthquakes and wind open e dooa wid th so t re rang f researco e h challenge r multi-disciplinarfo s y investigators in the field, to be met through team efforts involving academic, industrial, and governmental participation, and through international cooperation.

1.9. PANEL SESSION 3 ON SHORT PRESENTATIONS AND DISCUSSION ON DESIGN GUIDELINE CODED SAN STANDARDS& SEISMIN SO C ISOLATION AND PASSIVE ENERGY DISSIPATION

Paper 3a (New Zealand [17]): W.H. Robinson summarized the design approach to seismic isolation Zealand w tha uses Ne i t mentionee n di H . d tha t consisti tmaio tw nf o s rules: (i) the natural period of the seismically isolated structure is increased to more than (iid contro)an o t ; s 5 l1. displacement, hysteretic dampin addes gi d wit hyiela d forcf eo approximately 10% of the structure weight.

Paper (Japanb 3 [58]): . IshidK a summarize configuratioe dth maid nan n contentf so the document "Design and Technical Guidelines for Seismic Isolation", which was being drafte Japan i d CRIEPIy nb . This document completee b o t , 1994n di , concerns nuclear facilitie particulan (i s FBRe th r ) with buildings' horizontal seismic isolatio laminated nan d rubber bearin seismis ga c isolation elements; however authoe th , r stressed thate mosth f o t basic matters described in the guidelines draft will be applicable to general structures other than reactor facilities and to other seismic isolation systems as well.

Among others, Japanese guidelines require the reactor to be constructed on bedrock, the superstructure to be designed in a more rigid domain than the natural frequency of seismic isolation systems, and all structures, systems and components (including isolators) e designehavo b t e sam s o th et a eo ds degre f reliabiliteo conventionalln i s ya y founded reactors. For the definition of design basis earthquake ground motions, the need for a correct evaluation of short period earthquake components is stressed. The need for accounting uncertaintie d seculaan s r isolators chang s alsi e o stressed when establishing permissible design limit isolaton i s r design, together wit e requiremenhth t that isolators shall resist deterioratio o environmentat e du n l effects n designinI . g building d structuresan s n a , appropriate integrity assessment shall be performed, and a relevant structural plan shall be formulated with respect to the lay-out of buildings and isolators and each part around the seismic isolation layers. Finally, Japanese guidelines provide specific requirement ensuro st e that equipment and piping systems shall have a construction that cannot induces any major accident unde l possiblal r e earthquake conditions.

Paper Be (USA [59]): H.H. Chung presented an ASME perspective on the development of codes, standard desige guided th maintenancan s d r nan sfo f seismieo c isolation system for nuclear power plants in the USA. He noted that acceptance of seismic isolation to such plant mucs si h dependent upo availabilite nth supportinf yo g code standardsd san addition i , n s technicait o t l maturity, realizable economic benefits, favourable regulatory positione H . stressed that codes and standards should cover not only design and fabrication, but also all other phases including installation, inspection, certification, repairs, replacement, and .maintenance of seismic isolation systems.

To this aim, based on his ASME experiences, H.H. Chung discussed utilization of the ASME Boiler Pressurd san e Vessel Codes Operatioe th , Maintenancd nan e e Codesth d an ,

27 Qualification of Mechanical Equipment Standards, together with other US industry standards. He stressed the need for a joint effort by mechanical and civil engineers through their respective professional organizations: indeed, if on the one hand seismic isolation system is considere a civi e b l structuro t d e froe functionalitmth y standpoin f supportino t a g superstructure othee th n r o ,han sophisticates dit d dynamic characteristics signifyn thaca t i t also be considered as a mechanical system akin to snubbers.

Paper (Franced 3 [60]): . ColadanC t presente maie dth n feature desige rulef th so r nsfo of base isolated structure isolatord an s s which have been recommende Francn e di th y eb French Associatio r Earthquakfo n e Engineering (AFPS) e summarizeH . e generath d l requirements, and those on response analysis, behaviour coefficient, safety checks for elastomer bearings, validation and tests.

mentionee H d that, accordin AFPo gt S recommendations basl al , e isolated buildingr so structures shall remai elastie th n ni c range, althoug absorption ha n capabilit allowes yi f di strongly limited and justified. In response analyses, a simplified method can be used for regular rigid structures only in the case of rock or stiff soil, but torsional effects shall always be considered.

For safety checks of bearings, earthquake conditions are considered as an accidental situation; the partial safety coefficient, when checking for buckling, shall be equal to 3; horizontal shear strains shall be limited to a value depending on the slenderness and vertical bucklino t g loads ratio verticae th ; l pressure actin eacn go h bearing, includin effecte gth f o s overturning moment, shall always be compression.

Isolation systems shall be validated to ensure their reliability and to give the appropriate characteristics. Qualification tests are required for new systems, new materials or in case of interpolation impossibility. The dynamic characteristics shall be obtained from dynamic tests on representative test bearings or scaled bearings.

Paper (Italye 3 [6 1. Dolc J)M : e summarize maie dth n feature f desigo s n guideliner sfo isolated buildings which had been drafted in Italy in 1992-1993 by the National Seismic Survey with the co-operation of ENEA, ENEL and ISMES (an English translation of the entire document has been published in the seminar proceedings). M. Dolce explained that the reasons for writing such guidelines were that the current Italian seismic code, as well as many other similar codes, is specifically addressed to conventional buildings: thus, it is somn i difficuld e an respect — t , dangerou desigo t s— n isolated structures using this code.

e ItaliaTh n guidelines cover both elasti non-elastid an c c devices (including energy dissipators); they provide design criteria, rules for structural modelling and analysis, prerequisites for acceptance and directions for testing the isolation devices, which are in general rather simila thoso t r e presente previoun di s papers documene Th . t should forma clear referenc desigr efo f isolateno d buildings, consistent wit currene hth t seismic codd ean usefu o designerst l , manufacturer e authoritieth d an s s responsibl r desigfo e n checd kan approval.

28 . APPLICATION2 INNOVATIVE TH F SO E ANTISEISMIC TECHNIQUES

2.1. BRIDGE VIADUCTD SAN S

Several application innovative th f so e passive antiseismic techniques (seismic isolation, passive energy dissipatio oleodynamid nan c systems providing provisional restraints) already exis moderateln i t highlo yt y seismic areas considerablA . e numbe f thes o rs bee eha o nt bridges and viaducts: according to the available data they were at least 285 in 1993. This type of design approach for bridges and viaducts — which aims at limiting the force transmitted by the superstructure to substructures by inserting antiseismic devices at the top somn oi f s pilei e respec— s t complementar baso t y e isolatio f buildingno s (where eth purpose is to reduce accelerations transmitted by the foundations to the superstructure).

The largest number of bridges and viaducts which is provided with innovative antiseismic systems (mor n 1993ei e locatetha0 ar )15 n Italyn i d , where elastic-plastic dissipator mose th te commonlsar y used system preferree Th . d solutiof o e us n e therth s ei devices which slightly harden after yielding, as to control transmitted force and limit device deformatio e samth t ea n time r bridgeFo . s with continuous superstructure elastic-plastic l pileal bot n f i sdeviceo hp longitudinato e inserte ar se th t da transversd an l e directions; shock transmitters ensure operatio l structureal f nearthquakeo n a n si t permibu , t free slow deformations (such as thermal deformations, etc.)

Several applications also already exist in New Zealand and the USA, and some in China, France, Japan e Republith , f Koreo c s wel a an Japa (i le numbe nth f bridgo r e applications is still limited, compared to the case of buildings, although an important implementation programme recently began, see Ref. [13]). Important applications have also been planned in Chile, Greece and Turkey (some of them — e.g. in Turkey, at least — should f energmako e eus y dissipation devices fabricate Italyn d i below)e se , .

Chile. There are no applications of innovative antiseismic techniques passive to Chilean bridges, yet, but the use of passive energy dissipation devices (for instance based on the principl frictiof eo slotten ni d bolted connections bees )ha n planne botr dfo h constructiof no som bridgew e ne retrofi d san somo t t e existing bridges consequenca s a , investigation a f eo n seismie th n o c safet existinf yo g conventionally founded bridge based san researc n do h which is beginning [13].

China. 21 modern bridges have been isolated in south and north China [26]. Fifteen of them were isolate y meanb d f elastomerio s c bearings, whil utilizex si e a drolle s isolatoa r r combined with steel element energs sa y dissipator.

France. Seismic isolation of bridges began in France in the mid-1970s [22]. However the number of these applications was not given at the seminar; thus, it has been denoted by ? in Table I.

Greece. The use of seismic isolation or passive energy dissipation had been planned for 3 bridges over the Corinth Canal, although the system to be used had not been decided, yet (the initially considered system was FPS, see Ref. [5], but instead of this, elastic-plastic devices might be selected).

29 TABLE I

BRIDGES & CIVIL NON-NUCLEAR INDUSTRY NUCLEAR COUNTRY VIADUCTS BUILDINGS CH EL OTHER ALL STRUCT.

SI ED OS tot. SI bU OS tot. SI SI SI OS SI- SI OS Canada | P Chile 1 P 3 3 1 1 France ? 20 20 10p Greece ? ? W 2[3j 2 (1) Germany s s s India s P Indonesia 1 1 Italy 39 75 42 156 15+ 4 10+2 29 P 1 1 s 1 Japan 15 15 65 10 75 P Korea, ? 9 HD 1 P Rep. of Mexico 3 3 New 40 9 49 6 6 IP 2 3 Zealand P.R. China 15 6 21 50 50 P (5) South 2 Africa Spain 1 Turkey 1(1) 1 UK s 1s USA 43 43 18 Hl) 19 2 2 6 10 P Former 201 201 P USSR Former 1 1 Yugoslavia TOTAL || 152 91 42 285 381 18 10 409 3 2 9 1 16 14

Numbe f reporteo r d application f seismio s c isolation (SI), passive energy dissipation (ED oleodynamid )an c systems (OS bridgeo t ) viaductsd an s , civil buildings, non-nuclear facilitie nuclead an s r structure= H (C s chemical facilities; EL = electric equipment; OTHER= other non-nuclear industrial facilities; ALL=all non- nuclear facilities; (i) = number i of structures to be certainly constructed; [i] = number i of designed structures for which construction was not approved, yet; ? = applications exist, but the number was not reported; p = projects are being developed; s = only studies are in progress; + i = additional number i of structures which have already been included in lists related to other device types). Total numbers refer to ascertained constructed structures only.

30 Italy. The applications to bridges and viaducts began in Italy in 1974; their ascertained f 199o 2 d en [13 e , th t 18])a . numbe6 Som15 s quittheso f t rewa o e eear long structures (like the 9.6 km long Mortaiolo bridge). For 75 Italian bridges or viaducts use was made of steel passive energy dissipation devices, for 42 of oleodynamic systems, and for 39 of elastomeric devices (these includ applicationx esi f LRBs)so .

Japan. Isolation of bridges began in Japan in 1992 only. According to Refs [13, 17], there applications5 1 e ar , which LRBf mako e seus wit exceptioe hth caseso tw f ,no where HDRBs have been utilized. No applications of other innovative antiseismic devices were reported.

Korea, Rep. of. Laminated rubber bearings have already been used in Korean highway bridges as decks supports, but the number of such applications was not given at Capri [48]); thus, this numbe denotes i r Tabldn i agai ? . eFurtheI y nb r application foreseee b y sma n ni the future.

New Zealand. Applicatio innovativf no e antiseismic technique bridgeo st viaductd san s began Zealanw Ne n 1973n i di ; seminare time theith th f eo t r a numbe,9 4 fou s r rwa bein g retrofit [13, mosn I 17] mad.t s case caseLRBswa f o eo e stw sus (39n i ;LED) s were used, whili eh one case a combination of LRB and LED, and in three cases steel energy dissipation devices were adopted.

Turkey. Large elastic-plastic passive energy dissipation devices (±20 mm design deformation) were designed and tested in Italy by ALGA for two two-ways viaducts of the Istanbu Ankaro t l lonam gfreewa0 Gumusova-Geret15 x y 2 (the x 2 e e viaducth d an t 1500 m long Bolu Mountains Viaduct); 1 viaduct (the first mentioned above) is already under constructio dissipatord nan s fabricatio progresn i s ni s [13].

numbee Th USA reportef . ro d application swhicf o (whic 7 1 h , beinh 43 bega s g wa 1985n i ) retrofit [13, 29]. LRBs were use mosn di t cases.

2.2. CIVIL BUILDINGS

addition I bridgeo nt viaductsd san , several public, commercial, industria privatd an l e buildings have been provided with seismic isolation system numeroun i s s countrieso Tw . different typical design approaches have been utilized e firsth t n i approac: h (that more commonly used to date) horizontal flexibility and energy dissipation were obtained using special isolation devices e seconth n i d; approach e contraryth n o , , horizontally flexible foundation systems were used, together with elastic-plasti rigid-plastir co c device provido st e horizontal restraint and the necessary (hysteretic) energy dissipation.

Example secone th f so d approac buildingo Zealandw tw e Ne har Unioe n si th : n House at Auckland and the Central Police Station at Wellington [17]. The first is a twelve-stiffened- story building, constructed in 1983, where the foundation system consists of piles inserted hi co-axial steel tubes wit hsuitabl a permi o t s a eto s fregap, e bending deformation pilesf o s , and steel elastic-plastic bending dissipators are located around the outer building perimeter at pillevelp e seconeto Th . d building, constructe s characterize i 1991n di , similaa y db r foundation system, but energy dissipators are located inside the building and consist of LEDs. Some application f thiso s kind were reporte Russin i also dt e ob a [28].

The overall ascertained number of applications of seismic isolation to civil buildings was 381 in 1993. At present, the most numerous are in the former USSR and Japan; however,

31 several isolated buildings also exis Chinan i t , France, ItalyZealanUSAd e w th an Ne ,,d dan some also exist or have been designed in Chile, Indonesia, and Greece.

Chile. Ther alreade ear applicationy3 seismif so c isolatio Chileao nt n buildings, namelo yt the CEPAL building at Santiago (which has some parts hanging through cables from the main structure), the computers and control building of the Disputada Copper Mine near Santiago (which were recently mounte n LRBs)a four-storo d d an , y buildin e Andalucith f o g a Community (which is adjacent to a twin conventionally founded building, both being provided with seismic monitoring systems [27].

China. The number of recent applications of seismic isolation to Chinese buildings which was cited at the Capri Seminar is 10, in addition to the 40 ancient applications (see (Ref. [26]). Completed modern applications were to nine brick buildings (with sliding layers as isolators steed an l element energs sa y dissipator sanr so d sliding isolation) concreta d an , e frame house whic beins hwa g isolate meany db HDRBsf so additionn I . , twin isolate conventionalld dan y founded r.c. buildings are to be built for test purposes, together with three further buildings, isolatee b o t meany db f HDRBsso .

France. In France, the ascertained number of existing isolated civil buildings is 20 [22]); the first application was to the three-storey high school at Lambesc in 1977, which was isolated b APEyG meane Cth f systeso m (neoprene bearings) furthe9 1 . r civil building three-stora s( y building close to Nice and 18 one- or two-storey houses) were isolated in 1988 to 1990.

Germany. Although there is no application of seismic isolation in Germany, development work concerning isolation systems is being performed by GERB [23] and SHW.

Greece Greecen I . building2 , s (one being rather high) were isolated using LDRBs [13]. Furthermore, a hospital center at Mesoligi, consisting of four buildings on the same basemat, should be seismically isolated (the initially considered isolators were LRBs, see Ref. [5], but actuae th l beet systeno ns mselectedha , yet); finally, isolatio beed nw ha n ne planne e th r dfo Acropolis Museum at Athens and to retrofit a Byzantine church [13].

India. There are no applications of seismic isolation to Indian buildings, yet, in spite of non- negligible research mentioned in Ref. [30].

Indonesia. The construction of 1 building isolated by means of HDRBs has been sponsored by UNID IndonesiOn i a [22].

Italy firse Th .t applicatio seismif no c isolatio Italian a o nt n building dates 19851993n 5 I 1 . , isolated buildings had already been completed or were under construction (16 if the first New Fire Station Building is also considered [19]. The New Fire Station Headquarters at Naples, e Navth y buildin t e NavAncona gth yd an Medicaa l Cente t Augustaa r e structurear , s important for civil defence, while the five isolated buildings of the SIP Center at Ancona may be regarded as industrial structures. One retrofit was in progress to the S. Pietro Church at Frigento. With the exception the New Fire Station Headquarters at Naples and the Civic Cente Montt ra e d'Ago, Ancona (where neoprene bearings have been used), HDRB beed sha n adopte isolato dt l otheeal r Italian building conjunction (i s LDRisolatee o nt th r Bfo d house at Squillace). Both twin houses at Squillace and SIP buildings at Ancona were provided with seismic monitoring systems, after being subjecte on-sito dt e dynamic tests [39].

32 Japan. In Japan, isolation of buildings began in 1982; in 1992, 65 isolated buildings had already been completed [7, 13]. They have various sizes (some being quite tall) and uses, many belongin privato gt e owners. Isolators used have been LRBs, HDRBs, friction devices, steel devices and LDRBs. The latter (which have been used in several cases) have been couple varioudo t s type dampersf so . Abou Japanes0 t2 e buildings were provided with seismic monitoring systems, which already recorded seismic vibrations [31]. No retrofit using seismic isolation have been reported to exist in Japan, yet.

Korea, Rep . Applicatioof . f seismino c isolatio foreseee b Republie y th nma n n i Koref co a in the future in association with vibration controls to high rise buildings, critical public buildings, industrial structures and rehabilitation of historical buildings [48].

New Zealand. The first civil building was isolated in New Zealand in 1981 (Ref. [17]). Applications concern now 6 buildings, which are important for civil protection, or for historical reasons. aforesaie Threth f eo d applications (includin retrofio gtw f historicao t l buildings) wer i progresseminare h time th th f eo t a s . Isolation systems use mainle dar y LRB conjunction s(i n with LDRB botn si h above-mentioned retrofit); different systems were used — as mentioned above — only in the Union House at Auckland (flexible piles and steel dampers), and the Wellington Central Police Station (flexible piles and LEDs).

United Kingdom. Although there is no application of seismic isolation to UK buildings, considerable work is being performed by MRPRA for the development of HDRBs for building application [25].

USA e firsTh .t constructio isolateS U a A seismi f dno US buildin e n 1986i cth s n i ;gwa isolation was used for the first time in the world to retrofit an existing building (1988). The numbe seminare f application timo re th th f eo t a buildingS ,8 U 1 includin o t s wa s g seven in progress (two new constructions and five retrofit), in addition to several new projects [7, 10, 13, 66]. Applications concern buildings that are critical for civil defence, other important public buildings, structures important for strategic or economical reasons, and some residential houses also. The relatively large number of retrofit (8) must be noted. Most US isolated buildings have been provided with seismic monitoring systems. Isolators used in the USe mainlar A y HDRB r LRBo s s (the latter frequentl n conjunctioi y n with LDRBs), although FPS and GERB systems were used for houses at Marina, San Francisco, and West Angeless Lo , respectively.

Former USSR totae Th .l numbe f applicationo r f seismio s c isolatio formee th n ni r USSR whic reportes hwa t Caprd a quits wa ie large [28]1 notes i 20 :t I .d that several among these applications utilize low-cost systems, which are rather different from those adopted in other countries. The first isolated building was in Turkmenistan in 1959; the others followed in Russia, Kirgizia, Ukraine, Kazakhstan Byelorussid an , perioe th n ai d 197 1990o 2t .

Former Yugoslavia schooA . constructes wa l f higo e h 196n dus dampini y 9b g (but non- laminated) rubber bearing.

2.3. NON-NUCLEAR INDUSTRIAL STRUCTURES

The applications of seismic isolation to non-nuclear industrial plants were not very numerous seminare tim,e th yetth f et o a , , although some civil building regardee b y sma s da industrial structures (namely those containing industrial equipment or computers). Some remarks on these applications are useful here also, although — as far as the numbers in

33 Table concernear eI thed— y have been kept among those concerning civil buildingsn I . addition, ther furthee ear r applications somn i , e countries componentso t , , tank othed san r facilities, which shall be mentioned: the overall ascertained number of these further industrial applications was 14 at the time of the seminar.

Chile. Isolation and energy absorption devices were used to support 1 non-nuclear industrial facility, namely an iron ship loader at Guadaloca's port, in the middle 1970s [27].

China. Although no existing applications of seismic isolation to Chinese non-nuclear industrial structure Chinn si a were mentione Seminare th stresses t da wa t i , d that there ear good prospects for such applications to thermal power plants, hydropower stations on the three gorge f Yantzso e Rive mand an r y other facilities [47].

Germany. Although there is no application of seismic isolation in Germany, design work concerning isolation of LNG tanks in Greece and the Republic of Korea was performed by D&W [40].

Greece. The LNG tanks of the Revithousa Terminal have been designed as to be isolated using HDRBs.

Italy five eTh . isolate buildingP dSI t Anconisolatee sa th d Firw daan ebuildinNe e th f go Station Headquarter t Naplesa regardee s b [19] y industria,ma s da l structures, together with other buildings provided with passive energy dissipation devices or oleodynamic provisional restraints. Studies are in progress to verify the applicability of seismic isolation to Gas Insulated Substation ENEr sfo L electric plants. Finally, seismic isolatio e tanks th ga t f sa n o Montalto di Castro plant have been proposed [13].

Japan. Abou Japanes0 t2 e isolated buildings among those mentioned regarde e beforb y ema d as industrial structures (they are computer centers, laboratories, test rooms, pools, etc.). With regar applicationo dt computeo st r centers worthwhils i t i , e stressing thos floof eo r isolation, whic importans hi sucr fo t h equipment permittiny b , isolationD 3 s notegs it i t I .d that some Japanese industrial companies r instancfo , e electric power companies, applied isolation system theio st r civil building orden si achievo t r e desig behavioud nan r experienc vien ei w of an extension of this technique to industrial facilities, including nuclear reactors.

Korea, Rep. of. There is already 1 application of seismic isolation to LNG tanks, using laminated rubber bearings; further applications to LNG tanks have been planned, and isolation of computer fabrication facilities may be undertaken [40, 48].

New Zealand importan3 . t application vero t s y different structures alreadyw exisNe n i t Zealand, namelconstructioe th o yt brittla f no e cast-iron printing pres Petonn i a s d ean chimne Christchurchn yi retrofio t d capacitoC an ,A t r ward y bankHa st sa Substation . Retrofit furtheo t r electric equipmen planneds wa t . Systems use thesn di e applications were LRBs, rocking devices with steel dampers and LDRBs coupled with steel dampers, respectively [17].

USA. There are already 9 applications of seismic isolation to industrial structures, components and tanks in the USA [7, 42], in addition to some buildings which may be also regarde s industriaa d l applications, like Evan th ed Sutherlan an s d Aircraft Simulator Manufacturing Facilit t Salya t Lake City. Components isolation bega 1979n ni t alread;i y concerns electric equipment (e.g. back-up 32-tons mobile excitere maith nr fo sturbin e generator at Diablo Canyon nuclear power plant), other sophisticated equipment (e.g. Titan

34 IV solid rocket motor upgrade segment Vandenbert sa Forcr gAi e objectt Base)ar d san , also (at J. Paul Jetty Museum in Malibu); extensive studies were also performed for computer a wastfloor d ean s storage facility weather enclosure structure o wateTw . r tanks were upgraded by means of seismic isolation, and a new ammonia tank was constructed using this technique; isolation of large concrete and steel LNG tanks was also studied in detail. Isolators used were HDRB, LRB, FPS, and special devices for art objects.

2.4. NUCLEAR STRUCTURES

The only existing applications of seismic isolation (14) are in France, South Africa, Spain and the United Kingdom. Construction of a further isolated reactor had begun in the Islamic Republic of Iran, but it was interrupted. However, several projects exist in other countries also, like Canada, China, Japan, India, the Republic of Korea, Russia and the USA, and studies are in progress also in Italy.

Canada applicationo N . seismif so c isolatio nucleao nt r structures exis Canadan i t ; however AEC developins Li gprojeca r isolatinfo t g CANDU- keepiny 6(b standars git d design)n i , countries whic requiry hma e suc hdesiga n approac severo t e hedu seismic conditions [49].

China. Seismic isolation will be adopted for a new experimental FBR which is being designed in China [47].

France. There are already 10 applications of seismic isolation to nuclear structures hi France (all using neoprene bearings) vessele OCRe th :th f t Sainsa o t Lauren Buged an t y (1963); the four 900 MWe units of Cruas PWR; three spent fuel storage pools at La Hague; and a two-story building containing radioactive wastes owneFrence th y db h Nav Tolont e ya th n (I . first applications — those to GCR vessels — isolation aimed at limiting thermal deformation). French projects concern seismic isolation of the 1300 MWe PWR at Le Carnet and the 1500 MWe European Fast Reactor, in which France is participating [13, 22, 36, 38].

India. Design studie progresn i e sar s concerning possible isolatio primarf no y structured san secondary system Indiaf so n PHWRs [46].

Iran, Islamic Rep. of. The construction of the seismically isolated Karun River reactor was interrupte well-knowo t i 197 dh e 8du n events. This should have been isolate neopreny db e bearings coupled with friction plates, similar to the Koeberg reactor in South Africa [13].

Italy. No more nuclear reactors are in operation or being constructed in Italy; however, considerable R&D work is in progress on the development of seismic isolation for nuclear facilities, also in the framework of international cooperation with the CEC, Japan and the USA [17]).

Japan . o applicationn Ther e ar e f seismio s c isolatio o Japanest n e nuclear reactorr o s facilities, yet t project,bu r isolatinfo s l reactoal g r type i d FBRsh an (BWRe ar )R PW , progress (based on the experience achieved for isolated civil buildings), in order to permit reactor sitin n highli g y seismic areas [36] e projec.Th t concerning Japaness i R FB e particularly advanced [37]. Different types of isolators have been considered (HDRBs, LRBs and LDRBs coupled with energy dissipators); the feasibility and advantages of 3D isolation is also being studied.

35 Korea, Rep . Project. of progresn i Republie e th ar s n i s isolatioe f Koreco th n r a a fo f no ALMaway-from-reacton a d Ran r interim fuel storage facility meany b , f laminateso d rubber bearings [48].

Russian Federation. A project is being developed in Russia for seismic isolation of the WER-500 reactor by means of pneumo-shock absorbers combined with viscous dampers [45]. unitR Koebergt sa PW e MW ,Sout Sout0 90 h h o Africa Africatw e Th ., were isolated using sliding systems formed by neoprene bearings coupled with friction plates [44].

t Vandellosa R SpainGC vessee e , th Th .Spain f o lisolates wa , Frency db h using neoprene bearings, similar to those of the same type reactors at Saint Laurent and Bugey, France [13].

United Kingdom onle Th y. reported applicatio fue a f seismi no o lt s i cK isolatioU e th n ni reprocessing plant [36]. However, studie supporn s i isolatio e th ALMR S o t U f no s have been also performe MRPRy db A [25].

USA. Therisolateo n s ei d nuclear reacto USAe th n i r, yet t considerabl,bu e researcd han design activit alreads yha y been performe supporo dt ALMe tth R projects (PRIS SAFRd Man ) and others (NPR) which include seismic isolatio meany nb f HDRBso s [36].

2.5. APPLICATION OF PASSIVE ENERGY DISSIPATION AND OLEODYNAMIC SYSTEMS

2.5.1. Civil buildings Passive energy dissipation systems for buildings are typically formed by special brace systems wit e insertiohth f elementno s capabl f dissipatino e g energy whe e horizontanth l seismic loads cause interventio stiffenine th f no g system. Application f thesso e systemo st structures other than bridges and viaducts are not numerous, yet, compared to those of seismic isolation. In fact, an overall number of 18 applications to Italian, Japanese, Mexican anciviS dU l building reportes wa s t Caprida , ascertaine8 agains37 e th t d applicationf o s seismic isolation,

Germany. Although there is no application of passive energy dissipation in Germany, development work concerning passive energy systems is being performed by GERB [23]).

Italy. Passive energy dissipation devices had been used for constructing 4 new Italian buildings: the New Fire Station Headquarters at Naples (which was the first application in 1981), a hospital at Siena, a CNR laboratory building at Frascati, and the recent twin buildings of the New ENEL Directional Center at Naples (these twin buildings also use oleodynamic and elastic devices [50].

Japan. Passive energy dissipation systems which utilize Hysteresis or Viscous Damping Mechanism alreadd sha y been applie Japanes0 1 do t e office, comple dormitord xan y buildings in Tokyo and other towns, in period 1984 to 1993 [54].

Mexico. Application passivf so e energy dissipatio Mexicn ni o consiste f retrofido r.c3 f .o t buildings using the ADAS system: the Izazaga n. 38-40 Building, the Cardiology Hospital and the Reforina n. 476 Building, which are all located in Mexico City.

36 USA. There was only 1 application of passive energy dissipation to US buildings at the time of the seminar [51], namely to a two-story r.c. structure in downtown San Francisco. However, a second retrofit project of this kind was also underway for a 13-story building hi San thir Josea beins d dwa an ,g considere seven-store th r dfo y Travelers Hote Sacramenton li .

Examples of applications of oleodynamic systems (which provide provisional restraints durin f strongo g earthquake motions structureo t ) s other than bridge viaductd an s s were reporte Capre th t da i Seminar onl Italr yfo y [13 1985, n seconi 19]e firss e th th ,o ,wa t d Fire Station Building at Naples (which, in Table I, has been included among seismically isolated building, because it is also supported by neoprene bearings), and three further applications were the retrofit to the Collegiate of S. Giovanni Battista in Carife, construction of an industrial building of FIAT at Melfi, and use in the new ENEL Directional Center at Naples (wher maie eth n syste mformes i energy db y dissipation devices).

However, the actual number of buildings provided with oleodynamic systems in Italy — even excludin firslase d gth tan t cited abov somewhas i e— t larger (10) than that reportet da Capri: in fact, such systems were also used in a second FIAT Industrial building at Prato La Serra (Molise) Spore th , t Hal t Riminia l Faculte th , f Engineerinyo t Bresciaga , hangart sa Bologna and Torino Caselle airports, and the Turbine and Thermal Cycle Buildings of Montalto di Castro Power Station [13].

2.5.2. Industrial structures

Similar to seismic isolation, among the civil buildings provided with energy dissipation or oleodynamic systems which were mentioned in the previous sections, some may also be regarde applications da non-nucleao st r industrial structures addition I . theseo nt , however, onl mory1 e application, relate oleodynamio dt c systems knows i , n [13] larga :o t thie s i s water supply pipe at S. Giacomo (Abruzzo) in Italy.

Active contro f vibrationo l s aim t suitabla s y modifyin e dynamith g c response th f eo structur meany eb controllef so d inpu f artificiallo t y generated energy. Practical applications are hybrid, because there is a simultaneous combination of tuned mass dampers and actuators which provide external forces. The only structures using active/hybrid control systems which were reporte seminae th t da locatee rar Japann di . There, startin 1992n gi , active/hybrid mass damper systems had already been applied to 9 buildings, which include 5 high-rise buildings (mor highem thaOsaka0 n )i n10 , Toky Yokohamad oan ; buildingfurthe8 r o 7 r s were under construction or design [52, 53]. Because the main purpose of the aforesaid applications was contro f wind-induceo l d vibrations, their numbet beeno ns includerha Tabln di . eI

. REMARK3 DESIGN SO N GUIDELINES, CODE STANDARDD SAN S

As clarified in PS 3 and by previous contributions, the first recommendations for design and constructio f isolateno d structures were publishe Zealanw Ne n 1979dn i di .

Afterwards, considerable design guidelines development activities were performed in the USA. In 1989 SEAOC published specific codes for buildings as an appendix of Recommended Lateral Design Requirements and Commentary (Blue Book), which were later implemented in the 1991 version of Uniform Building Code (UBC). With regard to bridges, in 1990 AASHTO adopte standards da 198s sit 3 Guide Specifications r nucleaFo . r reactors, design guidelines coverin case ghorizontath f eo l isolation systems using HDRBs were jointly develope NucleaE G y db r Energ ENEd yan A (Italy werd an ) e publishe tentativa n di e form

37 in 1990; work is continuing in the framework of both cooperation with Italy and activities of the American Society of Civil Engineers (ASCE).

In Japan — where applications of seismic isolation to buildings began relatively late — design guide sucr sfo h structures were only recently published; however, guidelines have also already been drafted for isolated nuclear reactors. All seismic isolation applications are still regarde s "innovativda e methods", thus they still requir speciaea l procedur approvar efo y b l the Ministry of Constructions.

Francen I recommendatioa , r guidelinenfo r isolatefo s d structure s publishewa s y db AFP 1990n Si .

Italyn I , existing code bridger sfo buildingd covet san no o rs d seismi c isolatio other nno r innovative systems, yet. As to bridges, however, "Società Autostrade" published specific recommendations in 1991. For buildings, two guidelines documents have been tentatively propose alloo broaa dt r wfo d review from experts e firstth : , prepare e Nationath y db l Seismic Survey in 1992 to 1993 with the co-operation of ENEA, ENEL and ISMES, concerns isolated building e secondth ; , prepare a specifi y b d c Working e GrouNationath f o p l Standards Authority (UNI) focusses on the design, use and control of innovative antiseismic devices. Finally, the ENEA/GE proposal for isolated nuclear reactors was updated and is being extended to isolators other that the HDRBs in the framework of a CEC funded project.

Most above-mentioned guidelines, recommendation standardd san o tw f so require us e eth seismic design levels. A lower level characterized by relatively short return period (OBE for nuclear reactors) r whicfo , h structural elements shall remain elastica highe d an ,r level characterize lony db g return period (SS nuclear Efo r reactors) whicr fo , h non-linear response is permitted. Requirements are given as to the evaluation of low frequency energy content of design earthquakes, which is an essential topic for an adequate design of isolated structures.

For buildings having a limited height and for which specific rather stringent requirements e satisfiedar tendence f simplifieo th , e permio t us s yi e dth t calculation proceduree th n i s design. f dynamiAnywayo e l guideal us ce n i ,sth analysi s base floor-responsn do e spectra or step-by-step direct integration methods is encouraged. For modal analysis, approximated methods, based on modification of design spectral values, are proposed to evaluate the effects of larger dissipative effects cause isolatioy db energd nan y dissipation devices.

e timAth t e being, recommendation d guide an r sstructure fo s s using innovative antiseismic devices are frequently much more severe (e.g. in the USA ) than design rules applicable to conventionally founded constructions. This feature is certainly understandable when technology is still in an early development stage; however, according to the already achieved demonstration of reliability of seismic isolation, the confidence was expressed by most expert t Caprsa i that abou alignmenn a t f codeo t fixed-basr sfo isolated ean d structures will be soon possible, so as to reduce the unnecessary degree of conservatism that is currently present in the design of isolated structures, and to allow the economic use of this technology.

38 REFERENCES

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39 [17] W.H. Robinson, Applications in New Zealand of Seismic Isolation to New Construction d Retrofittinan s g Existing Buildings, Bridge d Industriaan s l Plant, Lecture No. 3, New Zealand (TS 1) ibidem. . Parducci[18A ] , Applicatio f Seismino c Isolatio Passivd nan e Energy Dissipatioo nt Italian Bridges ,ibidem) Lectur1 , Ital4 S . y(T . eNo [19] F. M. Mazzolani and G. Serino, Most Recent Developments and Applications of Seismic Isolatio f Civino l Building Italyn si ,ibidem) 1 Lectur , Ital5 S . y(T . eNo [20] G.C. Manos, A Discussion of Earthquake Load Issues of the New 1992 Greek Seismic Cod Possibld ean e Implication Desige th o st f Bas no e Isolated Structuren si Greece, Lectur , Greecibidem) 6 1 . S eNo e(T . . AzevedJ [21 . Guerreiro]L d oan , Studie Progresn si Portugan si Evaluato t l Speciae eth l Benefits of Seismic Base Isolation for Irregular Buildings, Lecture No. 7, Portugal ibidem) 1 S (T . [22] Ch. Coladant, Durability and Ageing of Elastomeric Bearings in France, Lecture No. , Franc) ibidem8 1 S e(T . [23] D. Heiland and P.M. Weber, Development and Application of 3D Isolation Systems Capable of Accommodating Seismic and Non-Seismic Vibrations of Buildings, Lecture No. 9, Germany (TS 1) ibidem. [24] J.M. Kelly, Recent Developments on Isolation of Civil Buildings in the United States, ) ibidem2 S (T . A US , Lectur10 . eNo [25] H.R. Ahmadi, K.N.G. Fulle A.Hd ran . Muhr, Current Researc MRPRt ha A Related Seismio t c Isolatio ) ibidem 2 Buildingsf n o S (T . K U , , Lectur11 . eNo [26] F.L. Zhou, Most Recent Development Seismin so c Isolatio f Civino l Buildingd san Bridges in P.R. China, Lecture No. 12, China (TS 2) ibidem. [27] M. Sarrazin, M.O. Moroni, R. Boroschek and E. Herbach, Experiences on Base Isolation in Chile, Lecture No. 13, Chile (TS 2) ibidem. [28] J.M. Eisenberg, Low-Cost Seismoisolation in View of Recent Strong Earthquakes, Paper No. la, Russia (PS 1) ibidem. [29] R.L. Mayes (presente A.Sy db . Whittaker), Seismic Isolatio Bridgef n o USAe th n si , ibidem) 1 S (P . A US , PapeIb . No r [30] S.K. Thakkar, Seismic Base Isolatio f Structureno Indian i s , ,Indi le Pape . a No r (PS 1) ibidem. [31] S. Kurita and M. Izumi, Observed Response of Base-Isolated Buildings to Earthquakes in Japan, Paper No. Id, Japan (PS 1) ibidem. . SparacioR [32] . Cavuot F . ,Zampino G d oan , Retrofittin . PietrS e oth f Churcgo t ha Frigento by Use of Seismic Isolation, as a First Experience in View of Applications Artistio t Historicad can l Building Italyn i s ibidem) 1 , ItalPapele S . y(P . rNo . AgostinelliS [33] . AntonuccR , . GiacchettiR d an i , Remark Potentiae th n so Seismif lo c Isolatio r Retrofittinnfo g Existing Buildings ) ibidem1 , Ital If PapeS . y(P . No r [34] G. Di Pasquale, Verification of Damping Reduction Coefficients for Response Spectra, Paper No. Ig, Italy (PS 1) ibidem. [35] E. Gutierrez and G. Verzelletti, Possibilities of Vibration Isolation Testing at the ELSA Laborator Joine th f t yo Researc h Center , ,Commissio Ih Pape . No re th f no European Communitie ) ibidem1 S s(P . [36] E.L. Gluekler, Status of Reactor Seismic Isolation Technology Development in the USA and Summary of IAEA Specialists Meeting, Lecture No. 14, USA (TS 3) ibidem.

40 [37] M. Kato, Seismic Base Isolation System Studies for FBR Plant in Japan, Lecture No. 15, Japan (TS 3) ibidem. [38] J. Dalbera, M. Bouchon and M. libelle, Elastomer Pad Application to the Seismic Isolation of Spent Fuel Storage Pool, Lecture No. 16, France (TS 3) ibidem. . Forni[39M . Martelli]A , . SpadoniB , . BettinaliF , . BellingeriL , . CesariF , . GrassiL , , . SobreroE . BergamoG , . BonacinaG , . MazzieriC , . OlivieriM , . MarioniA , . G , . VestroniSerinF d an o , Most Recent Development e Studieth r f Seismio sfo s c Isolation of Nuclear and Non-Nuclear Structures in Italy, Lecture No. 17, Italy (TS 3) ibidem. [40] H. Bombard and L. Stempniewski, LNG Storage Tanks for Seismically Affected Sites, , GermanLectur 18 ibidem) 4 . S eNo y(T . [41] G. Bonacina, M. Venturuzzo, F. Bettinali, M. Forni, A. Marioni and G. Serino, Seismic Isolation of Non-Nuclear Power Plants in Italy, Lecture No. 19, Italy (TS 4) ibidem. [42] F.F. Tajirian, Seismic Isolatio f Non-Nucleano r Industrial Facilitie USAe th n i s, ) ibidem4 S (T . A US , Lectur20 . eNo [43] Y. Hazumoto, A. Yasaka and T. Komura, Forced Vibration Test of Twin Base Isolated Building Thermar sfo l Power Administration Center, , LecturJapa21 . n eNo (TS 4) ibidem. [44] D.E. Lee, The Base Isolation of Koeberg Nuclear Power Station 14 Years after Installation, Pape , Soutr2a h ) ibidemAfric2 S (P a . [45] V.S. Beliayev, V.V. Vinogradov, J.V. Kuchtevich, M.V. Rubinstein and J.M. Eisenberg, Pneumatic Seismic Isolatio Nucleaf no Non-Nuclead ran r Structures, Paper 2b, ) ibidemRussi2 S a(P . [46] R.S. Soni, H.S. Kushwaha, S.C. Mahaja . KakodkarA d nan , Present State-of-the-Art in the Seismic Isolation of Nuclear Structures and Components - An Overview with Regards to Indian Pressurized Heavy Water Reactors, Paper 2c, India (PS 2) ibidem. . Luanf SeismiL o d e ,an Us Prospeci c L e Isolatio . th [47D r fo t] Nuclean ni Nond an r - Nuclear Industrial Facilities in the Peoples's Republic of China, Paper 2d, China (PS 2) ibidem. [48] B. Yoo, J.I. Kirn, Y.S. Choun and D.G. Lee, Prospects for the Use of Seismic Isolatio Nuclean no Non-Nuclead ran r Industrial Facilitie Korean si , Pape , Korer2e a ) ibidem2 S (P . . Biswa. Alizadeh[49K A d ] san , Seismic Isolation Stud CANDUr yfo , Pape , Canadr2f a ) ibidem2 S (P . [50] V. Ciampi, Development of Passive Energy Dissipation Techniques for Buildings, Lecture No. 22, Italy (TS 5) ibidem. [51] I.D. Aike A.Sd nan . Whittaker, Developmen Applicatiod an t f Passivno e Energy Dissipation Techniques in the USA , Lecture No. 23, USA (TS 5), ibidem. [52] K. Tamura, Technology of Active Control Systems for Structural Vibration, Lecture No. 24, Japan (TS 5), ibidem. [53] T. Fujita, Applications of Active Mass Damper Systems for Response Control of Tall Buildings in Japan, Lecture No. 25, Japan (TS 5), ibidem. . KitamuraH [54] . TeramotT , . FujitaT d oan , Developmen Applicationd an t Passivf so e Energy Dissipation Technique Japann si , ,ibidem , LecturJapa6) 26 S . n(T . eNo [55] R. Medeot, Self-Centering Mechanism in Elasto-Plastic Bridge Bearings, Lecture No. 27, Italy (TS 6), ibidem.

41 . Martinez-Romero[56E ] ,Supplementarf o Experience e Us e th n so y Energy Dissipators on Building Structures, Lecture No. 28, Mexico (TS 6), ibidem. [57] S.C. Liu, Development of Active Vibration Control Techniques in the USA, Lecture No. 30, USA (TS 6), ibidem. . IshidaK [58 . Shibat] . FujitaH , T d aan , Introductio Design no Technicad nan l Guidelines for FBR, Paper 3b, Japan (PS 3), ibidem. [59] H.H. ChungDevelopmene th n O , Codesf o t , Standards GuideDesigd e th an , r snfo and Maintenance of Seismic Isolation System for Nuclear Power Plants: an ASME Perspective, Paper 3c, USA (PS 3), ibidem. . Coladant[60Ch ] , Recommended Rule Desigr sfo Seismif no c Bearing Francen si , Paper 3d, France (PS 3), ibidem. [61] Servizio Sismico Nazionale della Presidenza del Consiglio dei Ministri (presented by M. Dolce), Design Guidelines for Buildings with Seismic Isolation, Paper 3e, Italy (P , ibidemS3) . [62] S. Dimova, W.B. Kraetzig and K. Meskouris, On Some Numerical Problems in the Analysi f Structureo s s with Friction Devices (additional paper, presentee th t a d conclusion of TS 6), ibidem. . Faella G Luce d D . aan , A Respons[63] f Fixeeo d Bas Basd ean e Isolated R.C. Frames (additional paper, written contribution only), ibidem. . Vulcano[64A ] , Design Criteri f Dampeo a d Steel Bracing System r Earthquakfo s e Protection of Framed Structures (additional paper, written contribution only), ibidem.

42 ABBREVIATIONS

Organizations

ACEDIS Italian Association of Manufacturers of Structural Restraint Devices AFPS French Association for Earthquake Engineering ANL Argonne National Laboratory ASCE American Societ f Civiyo l Engineers ASME American Society of Mechanical Engineers BARC Indian Bhabha Atomic Research Centre CEA-DMT French Nuclear Agency, Department of Mechanics and Technology C CE Commissio Europeae th f no n Community CIAE China Institute for Atomic Energy CMEST Cente f Mechanicaro Structurad an l l Engineering, Lisbon, Portugal CNR Italian National Research Council CREA Italian Center for Building and Environmental Rehabilitation, srl CRIEPI Central Research Institut f Electrieo c Power Industry, Japan DIS Dynamic Isolation Systems, Inc., USA D&W Dyckerhof Widmann& f , GermanAG , y F Ed Electricit France éd e (French National Utility) EERC Earthquake Engineering Research Institute, BerkeleyA US , ENEA Italian Agency for New Technology, Energy and Environment ENEL Italian National Utility, SpA GLIS Italian Working Grou Seismin po c Isolation IWGFR International Working Grou Fasn po t Reactors C JR Joint Research Cente f CECo r , Ispra, Italy N LI Nuclear Engineering Laboratory, Universit f Bolognayo , Italy MRPRA Malaysian Rubber Producers' Research Association, UK KAERI Korea Atomic Energy Research Institute SHW Schwaebische Huettenwerk GmbH, Germany P SI Italian National Telephone Company TsNIISK Central Research Institute of Building Structures, Russian Federation UBC University of California at Berkeley, USA I UN Italian Standard Authority UNIDO United Nations Industrial Development Organization

Reactor types

ALMR advanced liquid metal reactor BWR boiling water reactor FBR fast breeder reactor GCR gas cooled reactor LMR liquid metal reactor NPR productiow ne n reactor PHWR pressurized heavy water reactor PWR pressurized water reactor

43 Antiseismic device types

ADAS added damping and stiffness device S FP friction pendulum system dampinw lo LDRg Bsteel-laminate d rubber bearing HDRB high damping steel-laminated rubber bearing D HM hybrid mass damper LRB lead plug steel laminated rubber bearing LED lead extrusion damper

Others

FPTF polytetrafluorinethylene LNG liquefied natural gas OBE operational basis earthquake S P panel session r.c. reinforced concrete R&D research and development SMiRT structural mechanics in reactor technology SSE safe-shutdown earthquake TS technical session z.p.a. zero-period-acceleration 3D three-directional; three-dimensional

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