NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM REPORT
ASSESSMENT OF DEFICIENCIES AND PRESERVATION OF BRIDGE SUBSTRUCTURES BELOW THE WATERLINE
TRANSPORTATION RESEARCH BOARD NATIONAL RESEARCH COUNCIL TRANSPORTATION RESEARCH BOARD NATIONAL RESEARCH COUNCIL
TRANSPORTATION RESEARCH BOARD EXECUTIVE COMMITTEE 1982
Officers
Chairman
DARRELL V MANNING, Director, Idaho Transportation Department
Vice Chairman
LAWRENCE D. DAHMS, Executive Director, Metropolitan Transportation Commission, San Francisco Bay Area
Secretary
THOMAS B. DEEN, Executive Director, Transportation Research Board
Members RAY A. BARNHART, Federal Highway Administrator, U.S. Department of Transportation (ex officio) FRANCIS B. FRANCOIS, Executive Director, American Association of State Highway and Transportation Officials (ex officio) WILLIAM J. HARRIS, JR., Vice President for Research and Test Department, Association of American Railroads (ex officio) J. LYNN HELMS, Federal Aviation Administrator, U.S. Department of Transportation (ex officio) THOMAS D. LARSON, Secretary of Transportation, Pennsylvania Department of Transportation (ex officio, Past Chairman 1981) RAYMOND A. PECK, JR., National Highway Traffic Safety Administrator, U.S. Department of Transportation (ex officio) ARTHUR E. TEELE, JR., Urban Mass Transportation Administrator, U.S. Department of Transportation (ex officio) CHARLEY V. WOOTAN, Dir^cfor, Texas Transportation Institute, Texas A&M University (ex officio. Past Chairman 1980) GEORGE J. BEAN, Director of Aviation, Hillsborough County (Florida) Aviation Authority JOHN R. BORCHERT,/"ro/^iior, Department of Geography. University of Minnesota RICHARD P. BRAUN, Commissioner, Minnesota Department of Transportation ARTHUR J. BRUEN, JR., Vice President, Continental Illinois National Bank and Trust Company of Chicago JOSEPH M. CLAPP, Senior Vice President, Roadway Express, Inc. ALAN G. DUSTIN, President and Chief Executive Officer, Boston and Maine Corporation ROBERT E. FARRIS, Commissioner, Tennessee Department of Transportation ADRIANA GIANTURCO, Director, California Department of Transportation JACK R. GILSTRAP, Executive Vice President, American Public Transit Association MARK G GOODE, Engineer-Director, Texas State Department of Highways and Public Transportation WILLIAM C. HENNESSY, Commissioner of Transportation, New York State Department of Transportation LESTER A. HOEL, Chairman, Department of Civil Engineering, University of Virginia MARVIN L. MANHEIM,/"ro/ejjof, Department of Civil Engineering, Massachusetts Institute of Technology FUJIO MATSUDA, President, University of Hawaii DANIEL T. MURPHY, County Executive, Oakland County Courthouse, Michigan ROLAND A. OUELLETTE, Director of Transportation Affairs, General Motors Corporation RICHARD S. PAGE, General Manager, Washington (D.C.) Metropolitan Area Transit Authority MILTON PIKARSKY, Director of Transportation Research, Illinois Institute of Technology GUERDON S. SINES, Vice President, Information and Control Systems, Missouri Pacific Railroad JOHN E. STEINER, Vice President, Corporate Product Development, The Boeing Company RICHARD A. WARD, Director-Chief Engineer, Oklahoma Department of Transportation NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Transportation Research Board Executive Committee Subcommittee for NCHRP DARRELL V MANNING, Idaho Transp. Dept. (Chairman) RAY A. BARNHART, U.S. Dept. of Transp. LAWRENCE D. DAHMS, Metropolitan Transp. Commission, San Francisco Bay Area THOMAS D. LARSON, Pennsylvania Dept. of Trans. FRANCIS B. FRANCOIS, Amer. Assn. of State Hwy. & Transp. Officials THOMAS B. DEEN, Transportation Research Board
Field of Materials and Construction Area of Specifications, Procedures, and Practices Project Panel DIO-16
CHARLES SEIM, T. Y. Lin International (Chairman) RALPH T. MANCILL, JR., U.S. Coast Guard Headquarters JOHN J. AHLSKOG, Federal Highway Administration RICHARD H. McGINN, Massachusetts Dept. of Public Works D. JAMES KANELLITSAS, Michigan Dept. of Transportation SIDNEY L. POhEYi^ARD, Raymond Technical Facilities. Inc. T. ROBERT KEALEY, Modjeski and Masters JACK W. ROBERTS, Florida Dept. of Transportation GAYLE E. LANE, Illinois Dept. of Transportation CRAIG A. BALLINGER, Federal Highway Administration ADRIAN G. CLARY, Transportation Research Board
Program Staff
KRIEGER W. HENDERSON, JR., Director, Cooperative Research Programs ROBERT J. REILLY, Projects Engineer LOUIS M. MACGREGOR, Administrative Engineer HARRY A. SMITH, Projects Engineer CRAWFORD F. JENCKS, Projects Engineer ROBERT E. SPICHER, Projects Engineer R. IAN KINGHAM, Projects Engineer HELEN MACK, Editor NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM REPORT
ASSESSMENT OF DEFICIENCIES AND PRESERVATION OF BRIDGE SUBSTRUCTURES BELOW THE WATERLINE
M. C. RiSSEL, D. R. GRABER, M. J. SHOEMAKER and T. S. FLOURNOY Byrd, Taliamy, MacDonald and Lewis Falls Church, Virginia
RESEARCH SPONSORED BY THE AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS IN COOPERATION WITH THE FEDERAL HIGHWAY ADMINISTRATION
AREAS OF INTEREST STRUCTURES DESIGN AND PERFORMANCE MAINTENANCE (HIGHWAY TRANSPORTATION) (PUBLIC TRANSIT) (RAIL TRANSPORTATION) FEB 2 51983
TRANSPORTATION RESEARCH BOARD 1 18RAK< NATIONAL RESEARCH COUNCIL WASHINGTON, D.C. OCTOBER 1982 NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM NCHRP REPORT 251
Systematic, well-designed research provides the most effec• Project 10-16 FY '81 tive approach to the solution of many problems facmg high• ISSN 0077-5614 way admmistrators and engineers. Often, highway problems ISBN 0-309-03421-3 are of local interest and can best be studied by highway L C Catalog Card No 82-62041 departments individually or in cooperation with their state Price: $8.40 universities and others. Hpwever, the accelerating growth of highway transportation develops increasingly complex prob• NOTICE lems of wide mterest to highway authorities. These problems The project that is the subject of this report was a part of the National Cooper• are best studied through a coordinated program of coopera• ative Highway Research Program conducted by the TransportaUon Research Board with the approval of the Governing Board of the National Research tive research. Council, acting in behalf of the National Academy of Sciences Such approval In recognition of these needs, the highway adnumstrators of reflects the Governing Board's judgment that the program concerned is of the American Association of State Highway and Transporta• national importance and appropnate with respect to both the purposes and resources of the National Research Council tion Officials imtiated in 1%2 an objective national highway The members of the techmcal committee selected to momtor this project and to research program employing modem scientific techniques. review this report were chosen for recognized scholarly competence and with due consideration for the balance of disciplines appropnate to the project. The This program is supported on a continuing basis by fiinds opimons and conclusions expressed or imphed are those of the research agency from participating member states of the Association and it that performed the research, and, while they have been accepted as appropnate receives the full cooperation and support of the Federal by the technical committee, they are not jiecessanly those of the Transporta• tion Research Board, the National Research Council, the National Academy of Highway Administration, United States Department of Sciences, or the program sponsors Transportation. Each repon is reviewed and processed according to procedures estabbshed and momtored by the Report Review Committee of the National Academy of Sci• The Transportation Research Board of the National Re• ences Distnbution of the report is approved by the President of the Academy search Council was requested by the Association to admin• upon satisfactory completion of the review process ister the research program because of the Board's recognized The National Research Council was estabhshed by the National Academy of Sciences in 1916 to associate the broad commumty of science and technology objectivity and understanding of modem research practices. with the Academy's purposes of furthering knowledge and of advismg the The Board is uniquely suited for this purpose as: it maintains Federal Government The Council operates in accordance with genera] poh- an extensive committee structure from which authorities on cies detenmned by the Academy under the authonty of its congressional charter of 1863, which estabhshes the Academy as a pnvate, nonprofit, self- any highway transportation subject may be drawn; it pos• governing membership corporation The Council has become the pnncipal sesses avenues of communications and cooperation with operaung agency of both the Nabonal Academy of Sciences and the National federal, state, and local governmental agencies, universities, Academy of Engineenng in the conduct of their services to the government, the pubkc, and the scientific and engmeenng commumties It is admmistered and industry: its relationship to its parent organization, the jointly by both Academies and the Institute of Medicine. The National Acad• National Academy of Sciences, a private, nonprofit institu• emy of Engmeenng and the InsUtute of Medicine were estabhshed in 1964 and 1970, respectively, under the charter of the National Academy of Sciences tion, is an insurance of objectivity; it mamtains a fiill-time The Transportation Research Board evolved from the 54-year-old Highway research correlation staff of specialists in highway transpor• Research Board The TRB incorporates all former HRB activiUes and also tation matters to bring the findings of research directly to performs additional functions under a broader scope involving all modes of those who are in a position to use them. transportation and the interactions of transportation with society The program is developed on the basis of research needs Special Notice identified by chief administrators of the highway and trans• The TransportaUon Research Board, the National Academy of Sciences, the portation departments and by conunittees of AASHTO. Federal Highway Admiustration, the Amencan Association of State Highway Each year, specific areas of research needs to be included in and Transportation Officials, and the individual states participating m the the program are proposed to the Academy and the Board by National Cooperabve Highway Research Program do not endorse products or manufacturers Trade or manufacturers' names appear herein solely because the Amencan Association of State Highway and Transporta• they are considered essential to the object of this report tion Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are Published reports of the selected from those that have subnutted proposals. Adminis• tration and surveillance of research contracts are the respon• NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM sibilities of the Academy; and its Transportation Research are available from: Board. Transportation Research Board The needs for highway research are many, and the National National Academy of Sciences Order from Cooperative Highway Research Program can make signifi• 2101 Constitution Avenue, N.W. National Technical cant contributions to the solution of highway transportation Washmgton, D.C. 20418 problems of mutual concern to many responsible groups. The Information Service, program, however, is intended to complement rather than to Springfield, Va. substitute for or duplicate other highway research programs. Pnnted in the United States of Amenca 22161 ^^^^ ,^ Order noMLLW^^ FOREWORD This report contains the findings of a comprehensive evaluation of: (1) meth• ods of assessing the significance of bridge deficiencies below the waterline and By Staff (2) methods of arresting deterioration in bridge elements below the waterline. The Transportation report, including recommendations that are applicable immediately, will be of Research Board interest to engineers, researchers, and others concerned with maintenance, repair, and rehabilitation of bridges below the water or in the splash zone.
Federal and state legislation requires periodic inspection and appraisal of all bridge elements. A substantial amount of information is available on repair meth• ods for superstructures and substructures above the waterhne, but procedures for use below the waterline have received little emphasis, and application is compli• cated by inaccessibility. As a result, deficiencies including scour and structural distress, damage, and deterioration sometimes remain undetected or are endured until the potential for a major failure becomes apparent. Information has been needed to guide engineers in assessing the condition of bridge elements below the waterline and in selecting appropriate methods to arrest further deterioration. This report contains the findings of NCHRP Project 10-16, "Assessment of Deficiencies and Preservation of Bridge Substructures Below the Waterline." The objectives of this research were: (1) to develop improved methodology for evaluat• ing the effects of below-the-waterline deficiencies on the structural capacity of the substructure, and (2) to develop solutions to specific deterioration problems that are found in bridge substructures below the water surface and in the splash zone. NCHRP Project 10-16 extended the findings of research completed earlier and published as NCHRP Synthesis of Highway Practice 55, " Underwater Inspection and Repairs of Bridge Substructures." Current practices in structural strength evaluation techniques for bridge substructures below the water surface were evaluated with particular emphasis on quantifying the consequences of the deficiencies on the structural integrity of the bridge. A rating system for identifying the urgency of corrective action is presented. State-of-the-art methods used to arrest deterioration below the water surface and in the splash zone were evaluated and promising techniques identified. Several new or improved methods to arrest deterioration were also conceptualized. 971950 PB83-170159 ^ -Z)^^ |[^ ' —^^^^ "7 . Nj ^ Assessment of Oeffeieneles and Preservation of Bridge Substructures Below the Waterllne — (Finat rept.) i Rissel. M. C. ; Graber. D. R. ,- Shoemaker, M. J. ;.F1ournoy, T. S. Byrd. Tallamy, MacDonald and Lewis. Falls Church, VA. / Corp. Source Codes: 058421000 '' Sponsor: Transportation Research Board, Washington, DC; American Association of State Highway and Transportation Officials. Washington. DC: Federal Highway Administration. Washington, DC. Report No.: NCHRP-251; ISBN-0-309-03421-3 Oct 82 90p Sponsored In part by American Association of State Highway and Transportation Officials. Washington, DC, and Federal Highway Administration, Washington, DC Library of Congress catalog card no. 82-62041. Also pub. In ISSN-0077-5614. , Paper copy also available from Transportation Research Board, 2101 Constitution Ave., NW, Washington, DC 20418. Languages: English Document Type: Journal article NTIS Prices: PC A05/MF A01 Country of Publication: United States Journal Announcement: GRAI8313 Contract No.: NCHRP-10-16 This report examines the state of the art of the assessment I of the effects of underwater deficiencies on bridge substructures. Also reported are methods to arrest the. deterioration of concrete substructure units of all types In and below the splash zone caused by abrasion, corrosion, freeze-thaw and chemical attack. Proposed guidelines for a rating system stressing the urgency of corrective action for assessing various kinds of underwater deficiencies occurring to bridge substructures are developed and presented. Consideration was also given to developing practical methods; to predict reduced structural capacity as a result of underwater deficiencies. This work was accomplished with a literature search, a telephone survey of 26 states and field visits to six of those states. Descriptors: 'Highway bridges: *P11e foundations; *Concrete durability; Water erosion; Deterioration; Protective coatings; Substructures Identifiers: NTISNASTRB; NTISDOTFHA Section Headings: 13B (Mechanical, Industrial, Civil, and. Marine Englneerlng--C1v11 Engineering); 13C (Mechanical,' Industrial, Civil, and Marine Engineerlng--ConstructIon Equipment .Materials and . Supplies); 50A (Civil ; Engineering--Highway Engineering); 50C (Civil Engineerlng--Co- i nstructlon Equipment. Materials, and Supplies)
. i CONTENTS
1 SUMMARY PARTI 3 CHAPTER ONE Introduction Background Objectives Approach
6 CHAPTER TWO Structural Evaluation SI&A Bridge Inventory Assessment of Deflciencies Proposed Guideline Booklet Evaluation of Deficiencies Structural Capacity Analysis
18 CHAPTER THREE Present Methods to Arrest Concrete Detenoration Concrete Detenoration Repair Techniques Summary
28 CHAPTER FOUR Ncw OT Improved Methods to Arrest Concrete Deterioration "Brainstorming" Session Ideas Resulting from the "Brainstorming" Session "Brainstorming" Ideas that Warrant Further Investigation
38 CHAPTER nvE Conclusions, Recommendations and Research Needs Conclusions Recommendations Research Needs
40 REFERENCES PART 11
41 APPENDIX A Bibhography
43 APPENDIX B Research Approach
50 APPENDIX c High Quality Concrete
52 APPENDIX D Concrete Deterioration
53 APPENDIX E Case History Work Sheets
57 APPENDIX F Substructure Analysis
61 APPENDIX G Proposed Guideline Booklet ACKNOWLEDGMENTS The research reported herein was performed under NCHRP tion Engineer, Louisiana Department of Highways and Mr. Larry Project 10-16 by Byrd, Tallainy, MacDonald and Lewis, with Martin Davis, Bndge Mamtenance-PIanning Engineer, Florida Department C. Rissel as the Pnncipal Investigator, and Donald R. Graber as the of Transportation Assistant Principal Investigator. Michel J. Shoemaker and Thomas Time and effort were given by all those who attended the "Bram- S. Floumoy were staff mvestigators. Mr. Shoemaker now is em• storming" session. Outside personnel mcluded: Doctors Alfred Mar- ployed by Tryck, Nyman, and Hayes, Anchorage, Alaska. zocchi and Anil K. Rastogf of Owens-Coming Fiberglas, Messrs Cooperation was received from all state personnel contacted dur• Philhp T. Scola and Wade F. Casey of the Naval FaciliUes Engmeer- ing the field visits that were conducted. Particular effort was given ing Command, and Mr. Schuyler B. Smith of Dow Coming Corpora• by Mr. E. William Ensor, Jr., Chief of Bridge Inspection and Re• tion. medial Engineering, Maryland Department of Transportation; Mr. ^Others who were particularty helpful m special areas were- Mr. John Wood, Structure Maintenance Engineer, Oregon Highway Robert P. Brown, State Corrosion Engmeer, Florida Department of Division; Mr. James N. Welch, Bridge Maintenance Engmeer, Idaho Transportation; Dr. Roger D. Browne of the Taylor Woodrow Re• Transpoitation Department;' Mr. John D. Wood, Assistant to Struc• search Laboratory, United Kingdom, Mr. Kenneth C. Clear of the tures Mamtenance Engineer, Massachusetts Department of Public FHWA's OCSce of Research; and Mr. M. Shanf Aggour of the Um- Woiks; Mr. Mnityuqjaya Piindi, Structure Repairs and Reconstruc• versity of Maryland. Assessment of Deficiencies and Preservation of Bridge Substructures Below the Waterline
SUMMARY The research results presented here are the product of an examination of the state-of-the-art practices in the structural evaluation of underwater deficiencies of bridge substructures and the development of an improved methodology for evaluating the effects of below-the-waterline deficiencies. The research was conducted under NCHRP Project 10-16, and extends previous research developed under NCHRP Project 20-5 (Topic 10-08), which resulted in NCHRP Synthesis of Highway Practice 88. This investigation (Project 10-16) pertains to the techniques used to inspect bridge elements below the waterline and covers both present and new or improved methods and materials used to maintain, repair, and arrest deterioration under water. The findings are summarized in these areas in the following.
A vast amount of information exists on inspection techniques for evaluating concrete, steel, and timber under water. The inspection of concrete under water normally includes visual assessment, measurement of physical dimensions, and soundings. Because of the expense, cores are usually taken under water only when other evidence indicates that further investigation is warranted. Cores are normally used to determine compressive strength and chloride content and penetration, even though they permit a wide variety of other physical and chemical analyses to be performed.
Voltage potential readings of the reinforcing steel are sometimes taken under water. The readings only indicate whether or not corrosion is active and the extent of the concrete surface involved. The most satisfactory results are obtained when the readings are used in conjunction with a chloride penetration analysis of a core sample.
Two additional devices are presently being developed to evaluate concrete: (1) a polarization resistance device that measures the rate of corrosion—several methods are presently being tested for field use in-the-dry; and (2) a cat scanner for testing concrete piles under water—this device is being field tested by the Navy and it will be able to show density, corrosion, and internal structure.
The inspection of steel under water normally includes visual assessment, measurement of physical dimensions, and sounding bolts and rivets. Coupon samples for further testing are taken under water, on occasion, if evidence indicates that this is warranted. ultrasonic testing has also been employed; however. It has several drawbacks when applied under water. The leader in underwater inspection of steel is the maritime industry, which developed this field as an alternative to dry-dock inspection. other methods developed by this industry for detecting cracks include magnetic particle testing, radiographic inspection, and acoustic holography.
The inspection of timber structures under water normally includes visual assessment, measurement of physical dimensions, soundings, pointed probe resistance testing, use of a brace and bit, and use of an increment borer. sonic pulse velocity testing is also available for application under water. Several commercial devices are on the market and a number of contractors offer underwater inspection services using this technique.
The Federal Highway Administration's structural Inventory and Appraisal (si&A) Item 60 is the rating system used to rate substructure condition. However, none of the state personnel interviewed favored using the Item 60 condition statements as a method to assess underwater deficiencies for the purpose of prioritizing maintenance projects. This is understandable because the SI&A condition statements were developed as a means of establishing priorities for rehabilitation projects. Accordingly, in order to prioritize maintenance projects based on the assessment of underwater deficiencies and the urgency of corrective action, the research team developed a maintenance urgency index. The method of arriving at the maintenance urgency index is capsulized in a proposed guideline booklet included in Appendix G.
This booklet contains guidelines to describe various types of substructure elements in various states of deterioration. Observed underwater; deficiencies are to be compared to the guidelines to select an initial assessment. The initial assessment, which can range from zero to 9, may then be modified by a factor ranging +2 to -2 to account for the effects of climate and other factors. This final number is the Maintenance Urgency Index. It, in turn, prescribes the type of action to be taken by inspection personnel in the field as well as by maintenance forces in scheduling work that is to be performed. It should be noted that this booklet is not to be construed as a replacement for the rating system now used to rate the substructure condition for Item 60 of FHWA's "Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation's Bridges' (SI&A), but rather it is meant as an adjunct to it. The SI&A rating system is required for consistency of approach for funiaing eligibility from a reconstruction viewpoint. The methods presented herein are only intended to provide a more consistent approach to the process of assessing deficiencies from a imaintenance viewpoint.
Substantial information was also found to exist on concrete deterioration underiwater. A primary active zone is present in the splash zone. A secondary active zone exists at the mud line. The condition of the concrete cover and the availability of oxygen are the ma^or factors in the corrosion of reinforcing steel. Chemical iattack is usually a slow process and significant in itself in that it destroys the concrete cover over the reinforcing steel. Industrial waste was found to be of less concern.
Deterioration was associated with three stages: initiation, propagation, and destruction. The repair techniques discussed in the following are grouped under these three stages according to when they are the most cost effective.
Hydraulic training was found to be of some help in arresting abrasion, although ponding and riprap are the most effective methods. Penetrating sealants are ineffective under water.
surface coatings have several problems including: bond to the concrete surface,' wick action, and encapsulation of the concrete section. ' Vapor-permeable coatings can be helpful against encapsulation. Epoxy resin surface coatings have had only partial success because they must be applied with very strict controls, veneers are used for cases of extreme chemical attack.
Wraps are good >for severe chemical attack. This method is quick and economical. Resin-impregnated-fiberglass cloth is costly and difficult to use. Fabric jackets are quick and econmical, although they deform in water currents. Botn metalic and nonmetalic jackets have had limited success.
Sealing cracks; with pressure injected grout has been successfully used junder water. A nonstructural sacrificial concrete collar can be cast around structural concrete usually at the waterline. ; This method is expensive and used only in extreme conditions.
A variety of grouts are available to restore large areas of deterioration and/or section loss in the splash zone. Use of the proper grout can be an effective measure. A sacrificial zinc anode can be attached directly to exposed reinforcing steel. This method is quick, simple, and arrests corrosion for'up to 2 years.
A 'brainstorming" session was conducted with representatives of industry and government to generate new or improved methods to arrest concrete deterioration under water. Economical methods were sought that could be applied without the need for extensive evaluation of the concrete.
Several ideas were offered at the brainstorming session, including a multiple tape system that could be wrapped around a pile or column. Several coatings -were suggested, such as cycloaliphatic polyurethane silicone elastomeric membrane, silica gel, liquid plastic coatings, silicone latex emulsions, and flaked glass. Other suggestions included a dewatering cofferdam to apply preservation procedures in-the-dry, a floating innertube device to stop ice abrasion, litmus-paper-type indicators to identify chemical attack, a chemical filter, a bubbler curtain to stop ice formation, a vulcanized rubber wrap, greasing the pier to make it hydrophobic, and applying an electric charge to drive out ions.
The multiple tape system was later conceptualized as consisting of four separate tapes—abrasion tape, rubberized asphalt tape to arrest chemical attack, plastic foam tape to arrest freeze-thaw, and conducting tape to arrest corrosion—and two tape applicators. The dewatering cofferdam was considered along with two types of sprayers to be used inside of it for the application of sealants and coatings.
Chapter One
INTRODUCTION
BACKGROOHD The Federal Highway Administration (FHWA) of the U.S. Department of Transpor• Since 1761 when Samuel Sewell con• tation published policies and procedures to structed the , first highway bridge of implement the inspection process, and a importance in York, Maine (1), engineers and Manual for Maintenance Inspection of Bridges contractors in the United States have was published in July 1970, by the American developed a long history of designing and Association of State Highway and Transporta• constructing ever larger, more imposing, and tion Officials (AASHTO). The requirements more efficient bridges. However, when the and procedures have been updated periodical• Silver Bridge over the Ohio River between ly until the inspection program has now west Virginia and Ohio failed, causing loss become a well-defined and orderly system of life in December of 1967, the point was that for the most part serves its intended made with startling clarity that insuffi• purpose with adequate precision. Require• cient attention was being devoted to ex• ments for personnel, procedures, and fequen- isting structures. cy of inspection are sufficiently detailed to ensure that bridge deficiencies will be Older structures had been designed for recognized and repaired in a timely fashion. one set of conditions while technological changes and rapid growth have imposed other Because the failure precipitating the conditions that are considerably different. National Bridge Inspection Program occurred Additionally, time and weather were taking to a superstructure element, and deficien• their toll and many of the bridges that had cies to superstructures are most visible, served so well and for so long could no the greatest initial attention was directed longer be trusted to carry the steadily to that portion of the structure despite the increasing loadings of modern traffic. Con• fact that nothing in FHWA's "Recording and gress took recognition of this fact by in• Coding Guide for Structure Inventory and cluding a requirement for regular bridge in• Appraisal of the Nation's Bridges" (SI&A) spection in the Federal-Aid Highway Act of guideline either encourages or discourages 1968 (Public Law 90-495, SEC. 26, 82 Stat. substructure inspection as compared with 815) . superstructure .inspection. Any emphasis. therefore, was the responsibility of the in• spection agency and not derived from the material provided to them. Several states recognized that equally unsatisfactory con• ditions could exist out-of-sight, under water, and initiated vigorous underwater in• spection and repair programs.
In recent years, many additional states and jurisdictions that are charged with the maintenance of structures have developed and regularly operate underwater inspection programs. Figure 1 shows an underwater in• spector at work.
Interest in both inspection methods and systems to repair and prolong the life of aging substructure units in and below the splash zone is continuing to increase. This has occurred not only because of the evolu• tionary process of improvement in bridge in• spection and repair, but, even more, because of the increasing need to construct off-shore structures in connection with oil and gas exploration and drilling activities.
In the area of underwater inspection of bridges, jurisdictions that are active in this field use a variety of procedures, equipment, and techniques. Due at least in part to this variety as well as a low level of inspection effort, there has been a lack of consistency in both developing and evaluating information obtained from under• water inspections.
Federal and state legislation requires periodic inspection and appraisal of all bridge elements. A substantial amount of Figure 1. Undenoater inspeotor. information is available on repair methods for superstructures and substructures above the waterline, but procedures for use below The procedures, equipment, and tech• the waterline have received little emphasis niques discussed in this report will and application is complicated by inaccessi• overlap, in part, that found in the previous bility. As a result, deficiences including report. This is necessary to provide scour, structural distress, damage, and de• continuity to the subject and to permit this terioration are sometimes undetected or report to stand alone as an independent, endured until the potential for a major self-contained document. failure becomes apparent. Information is urgently needed to guide engineers in The objectives of this project are: assessing the condition of bridge elements below the waterline and in selecting 1. To develop improved methodology for appropriate methods to arrest further dete• evaluating the effects of below-the-wa- rioration. ter-line deficiencies on the structural capacity of the substructure.
2. To develop solutions to specific de• terioration problems that are found in OBJECTIVES bridge substructures below the waterline and in the splash zone. This study is intended to extend previous research developed under NCHRP APPROACH Project 20-5 "Synthesis of Information Related to Highway Problems," Topic 10-08 Literature Search entitled "Below-the-Waterline Inspection and Repair of Bridge Substructures," which The initial effort in fulfillment of resulted in a two-part report on current the project objectives was to conduct a practice (NCHRP Synthesis of Highway literature search and review. The search Practice 88). The first part identifies was conducted in the libraries of the problems found in substructure components Federal Department of Transportation, the and evaluates procedures, equipment, and Transportation Research Board, and the techniques currently used to inspect bridge Library of Congress (see App. B for a elements below the water surface. The complete list) . In addition, a Highway second part covers methods and materials Research Information Service (HRIS) computer used for underwater maintenance and repair search was conducted. Figure 2 graphically of bridge substructures. depicts the research approach. Literature Search LETTERS
State Bridge Companies DOT'S Agencies Institutions Universities
Response Naming Product Contact Brochure Reports Papers T Letter Del-ineatina Ob.ie|tives
Telephone Survey E State Visit Letters Requestina Specific Sites of I Fie^d I I Office Product Use
Second Telephone Survey
Methods to Assessj the Seriousness of Deficiencies
STATE-OF-THE-ART Structural Strength Evaluation Techniques and Methods to Arrest Concrete Deterioration
Figure 2. Reeecapoh approaak.
Correspondence State Visits The second basic method of evaluating state-of-the-art practice was by corres• A personal visit by the principal pondence. Letters were written to state investigator was made to those agencies departments of transportation (or highway selected in order to interview appropriate agencies), universities, institutes, trade personnel and to make field visits to sites associations, councils, laboratories, to review both the deterioration of sub• business concerns, bridge and port structure units and the corrective measures authorities, railroads and appropriate gov• taken. During the interview portion, ernment agencies, both domestic and foreign. information received as a result of the Standard formats were followed with minor telephone survey was reviewed and additional adjustments made to compensate for comments where recorded. differences of interest. Addressees are given In Appendix B. As part of the visit, series of typical sketches were generated which approximated Telephone Survey those that would be developed as a result of an underwater inspection. These were Those agencies indicated in Topic 10-08 combined with a series of descriptions of of NCHRP project 20-5 as having an active various types of deficiencies in the form of underwater Inspection program were selected "suggested guidelines" for various levels of for a telephone survey. The survey severity tied to a numerical rating of the consisted of a series of questions asked substructure condition. In this way, it was following a guide to assure consistency. possible to standardize the level of The answers received from the telephone seriousness of a deficiency and the rating survey were then collected and summarized. number given, utilizing the experience of those individuals with the most "hands on" structions, coding guides, or similar experience. documents was also requested. For this task, the following substruc• Details of repairs that had been made ture types were considered in the develop• in an attempt to arrest deterioration were ment of the descriptions and guideline: discussed during the interview period. Following this, a field visit was made to • Pile bent, concrete, steel, and various sites to view specific types of de• timber. terioration that had occurred and the methods used to repair the damage and to • Column bent or open pier. arrest further deterioration. • Solid shaft pier on spread footings. Brainstorming Session
• Solid shaft pier on piles. For "new or improved methods to arrest concrete deterioration," a "brainstorming" Written information provided by the session was conducted by the research team states in the form of procedural in• with representatives from industry and gov• ernmental! agencies in attendance.
Chapter Two
STRUCTURAL EVALUATION
SI&A BRIDGE INVENTORY Overall Structure Adequacy Appraisal
The purpose of the Federal Highway Item 67 is the "Overall Structure Administration's "Recording and Coding Condition Appraisal." It is a composite Guide for the structure inventory and rating representing the average of several Appraisal of the Nation's Bridges" (SISA) factors. The load carrying capacity of is to develop a bridge inventory data base the deck, the superstructure, and the in order to report to the Congress the substructure as well as the condition number and condition of the nation's rating of the deck, the superstructure, bridges for their use in preparing future and the substructure are evaluated in legislation. The information is also used relation to the highway system and how to inventory Defense Bridges and Critical they affect the bridge as a unit. The Highway Facilities for military purposes. structure is then compared to a new bridge built to the state's current standards for The data are collected as coded items that particular type of highway. The on the SI&A sheet, which is shown in overall structural condition is appraised Figure 3. Of the 88 items listed on the from zero to 9, taking into account the sheet, items pertinent to this report are major structural deficiencies. discussed in the following. Of the total items considered in Sufficiency Rating Formula establishing this appraisal, deficiencies below the waterline constitute a The sufficiency rating is a method of relatively small part. Yet underwater evaluating many factors that are deficiencies are clearly of a critical indicative of the sufficiency of a bridge nature and affect the load carrying to remain in service. This rating is used capacity. In this case, they can be the as input into the Highway Bridge determining factor for the overall Replacement and Rehabilitation Program for structure condition appraisal. prioritizing bridge replacement and rehabilitation projects for federal Inventory Rating funding. Item 66 is the capacity rating of the The sufficiency rating is generated structure to a load level that can safely through use of a complicated formula using utilize the structure for an indefinite the input of many factors. Among them are period of time. The capacity to be Item 67, Overall Structure Adequacy recorded is the lesser of the deck, Appraisal; Item 66, inventory Rating; Item superstructure, or substructure ratings. 64, Operating Rating; and Item 60, The code used represents the truck type Substructure Condition Rating. The final used in the analysis and the total tonnage output is a number from zero to 100. of the truck. STRUCTURE INVENTORY 8 APPRAISAL aCET
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Oafanaa Bridga DaacrtpUon Appr Rdwy WIdlh coNorrioN retructoe Sul)atructura Chorawl a Channel Protection Culvert a Retaining Walla Roadimr CendHon Openting Ralbig hveMory Rattng •APPRAISAL Oeftelandea Retina im Undarcteeroncea-VMIeal a Lateral- W Sofa Lood Capacity H Wotararay Adaquocy Approach Roadway Allvgnenl. PROPOSED MPROVEtlENTS M Year Needed. Completed- Deacribe atom 791- S Type of Service ^ Type of Work ^ Improvement Length. M Daaign Loading SI Roodvoy Width S Number of Lonea Prop. Rdwy linprovement-Y»ar_ @ AOT C08T OF IMPROVEMENTS Preliminary Engineering Coat. Damolltlon Coat Subatruchira Coal Superetruetuie Coat Figure 3. SISA eheet. Operating Rating Substructure Condition Rating Item 64 is the capacity rating of the Item 60, Substructure Condition structure to the absolute maximum Rating, is a code, from zero to 9, permissible load level to which the representing the condition of the piers, structure may be subjected. The capacity abutments, piles, fenders, and footing to be recorded is the lesser of the deck, scour. The code is selected by referring superstructure, or substructure ratings. to condition statements given in the The code used represents the truck type Coding Guide. used in the analysis and the total tonnage of the truck. ASSESSMENT OF DEFICIENCIES deterioration has been noted; however, there are still no immediate plans for urgency of Corrective Action repair. At this level, an increase in inspection frequency may be deemed SI&A Condition Rating necessary. At level 6, repairs become necessary and should be scheduled by the None of the state personnel end of the following season. interviewed favored using Item 60 condition statements as a method to assess when the structure deteriorates to deficiencies and prioritize maintenance level 5, the urgency of corrective action projects. This is not surprising because increases to the point where the repairs the SI&A condition statements were must be placed in the current schedule. developed to establish priorities for The structure should be repaired at the rehabilitation or replacement projects. first reasonable opportunity. At level 4, Major maintenance, minor rehabilitation, the repairs become a priority item. In and similarly worded definitions have this case, the maintenance engineer should little significance to maintenance review the work plan to determine its engineers. These statements reflect relative priority and adjust the schedule increasing expenditure levels for needed if possible. In any case, the repairs repairs. must be carried out during the current season. Findings show that although maintenance engineers are far more At level 3, the repair is given high concerned with the urgency of corrective priority and the work should be scheduled actions, current guidelines are of little as soon as possible. If deterioration help in setting ' priorities. Major reaches level 2, the repairs should be maintenance can usually be performed given highest priority. If required, within a year, while even minor other work should be discontinued. Other rehabilitation may have to be scheduled actions such as traffic restrictions may several years in advance in order to be considered. acquire or even program the necessary funds. The structure should be closed when the level of urgency reaches level 1. The amount of money required may also Emergency actions are required and traffic be unrelated to the degree of urgency. An must be rerouted. If the facility is example of this point is the repair of closed for repairs, the structure should scour or replacement of a defective pile. be rated as a zero. These are considered maintenance items of the utmost importance under some PROPOSED GUIDELINE BOOKLET conditions, but neither of these examples would be considered "rehabilitation." Appendix G contains the Proposed Guideline Booklet which summarizes the The example also exists where one pile method of arriving at the Maintenance of one pier in a mile-long structure has Urgency Index. The booklet is intended to underwater deterioration and may cause the be an independent document that may be bridge to collapse. In this case, the carried into the field and used by Overall Structure Adequacy Appraisal would inspection personnel. It contains a be high while the inventory and operating number of guidelines describing several ratings would be low. The low ratings types of substructure elements in various would, in turn, lower the sufficiency stages of deterioration. These guidelines rating but not to the point where the can be used to select an initial structure would qualify for federal assessment of a deficiency which, in turn, rehabilitation-replacement funds. This may be modified to determine the condition would be viewed as a maintenance Maintenance urgency Index. The booklet project. includes instruction for its use in assessing underwater deficiencies. Maintenance Urgency Index Proposed Guidelines In order to prioritize maintenance projects based on the assessment of Of the states surveyed, only a few deficiencies and the urgency of corrective have developed their own guidelines to actions, the research team proposed the help their inspection personnel in Maintenance Urgency Index. Figure 4 assessing deficiencies for SI&A Item 60. compares the SI&A condition statements to Most states simply use the FHWA bridge the Maintenance Urgency Index. A inspection training course to standardize condition level of 9 under the FHWA's SI&A their engineering judgment. As a result rating guidelines is "new condition"; of the low level of information found, the however, because the description is not research team developed its own guidelines indicative of its condition, this was for assessing deficiencies. Appendix G changed to "No Repairs Needed." contains the guidelines that were developed. These guidelines were reviewed The next level^ of urgency, 8, is with state personnel during the field essentially the same, except that a list of visits. specific items should be made for closer inspection on the next regular In general, certain common views inspection. For urgency level 7, become apparent. Scour of piles, either SI&A Item 60 Ratings Maintenance Urgency Definitions Maintenance Based on Maintenance Based on Perceived Immediacy of Urgency Index Rehabilitation Level * Action 9 New Condition No repairs needed. 8 Good Condition No repairs needed. List specific items for special inspection during next regular inspection. 7 Minor Maintenance No immediate plans for repair. Examine possibility of increased level of inspection. 6 Major Maintenance By end of next season - add to scheduled work. 5 Minor Rehabilitation Place in current schedule - current season - first reasonable opportunity. 4 Major Rehabilitation Priority - current season - review work plan for relative priority - adjust schedule if possible. 3 Immediate Rehabilitation High priority - current season as soon as can be scheduled. 2 Urgent Rehabilitation Highest priority - discontinue other work if required - emergency basis or emergency sub• sidiary actions if needed (post, one lane traffic, no trucks, reduced speed, etc.) 1 Facility Should be Closed Emergency actions required - reroute traffic and close. 0 Facility is Closed Facility is closed for repairs. •Paraphrased from FHWA SI&A (1978) page 27. Figure 4. Urgency of aorreotive action—.alternate definitions. in a bent or under an exposed footing, is Scour Around Piles of little concern to states with respect to structures in salt water. The When evaluating scour around piles, exception is untreated timber piling under the major concerns are scour resistance of footings that are then vulnerable to borer the streambed and pile penetration. In attack. States consider scour of pile all but a few states visited, light scour footings in fresh water to be critical is of no concern, requiring no riprap, because of the abrasive action of some because of the minimum length of pile fast flowing streambed materials. needed to meet specifications. In ' those states where the greatest lengths are All states interviewed regarded the required, the bridge maintenance engineers exposure of a footing not on piles to be a believe that a substantial amount of scour critical condition requiring immediate will not endanger the structure. In attention. The loss of lateral support on states with particularly scourable a pier shaft, however, was not considered streambeds, any scour problem is critical by any state unless the spread considered serious because of possible footing was exposed as well. abrasion damage. Section loss of a concrete pile Undermining of Footing becomes critical when a reinforcing bar is completely exposed. Section loss on the Two parameters that should be inside of a timber pile is critical and considered for a pile footing are type of requires immediate replacement in warm water (salt or fresh) and type of pile salt water because of the action of marine (timber, steel, or concrete). Borers and borers. corrosion are the two main concerns in salt water. In fresh water, however, Specific comments from the states abrasion of piles due to granular soils is concerning the proposed guidelines are a factor. Actually, when scour of a given below. The reader should refer to footing exposes a pile, the pile should be Appendix G before continuing. rated separately. 10 Several states felt that the suggested guidelines could; be slightly refined by guideline was too liberal, thereby giving adding percent areas of deterioration. the condition as described therein a lower rating. One state considers load capacity General Deterioration of Timber to be a more important criterion than the percentage and depth of piles exposed. Half the states interviewed agree with the suggested guidelines, although several All states visited regarded any scour would like a distinction made between of a spread footing, critical and subject cracking, which is age induced, and to repair as soon as possible. Scour splitting, which is stress induced. resistance of the streambed material is a Several are more concerned with borers factor that should' be considered, with entering through checks, and if those more attention given to material that can checks go to the heartwood. These states erode rapidly. A majority of the states would simply replace that member. One visited felt that a rating system was state is more interested in the function almost superfluous and would give any of the member as opposed to its general amount of undermining a rating that would condition. indicate that repairs were needed Immediately. Settlement A distinction needs to be made between There was relatively little agreement scour near a bridge site and scour around with the proposed guidelines concerning and affecting the substructure. scour of settlement because there was more concern the stream channel should be considered as with the ability of the bridge to function part of the stream channel condition and carry traffic. Ridability and the rating. ability of the bearings to contract or expand are important. One state Section Loss of Concrete Pile considered a 3/8 in. settlement of a simple span pier to be serious and cause All states visited agree with the for a complete study of the situation, guidelines with only minor alterations. while another thought that most dimensions Most states believed that if the main that were given in the guidelines should reinforcing bars are completely exposed, be halved. the rating should be a 3, but one felt that a rating of 4 would apply. Several states had difficulty distinguishing between minor and moderate Section Loss of Steel Pile tilt in a member. Two other states would require an analysis at a rating of 4 or 5. With some minor differences in boundaries between ratings (less than +10 percent), all states agreed with those values listed. One state, however, would Guideline Booklet Use qualify its ratings by the amount of stress induced in the pile due to the Initial Assessment given amount of section loss. Each deficiency of a structure must be assessed independently. Inspection Section Loss of Timber Pile personnel must observe a particular deficiency, compare it to the guideline An important factor here is whether provided in Appendix G, and select the the decay is internal or external. description that most closely depicts the Internal decay, rather than external severest example of deterioration found. decay, would more than likely be due to The number appearing adjacent to the borer activity in salt water. Two states chosen description is the initial said they would replace internally decayed assessment. piles immediately, while one would closely monitor the situation. Assessment Modification System A majority of the states visited It was found that there were generally agree with the percent loss of inconsistencies between states as to how areas suggested in: the guidelines, with various deficiencies should be assessed. only minor differences. one does not At the beginning of the study, the consider section loss because all of their inconsistencies were thought to be timber structures are being replaced, and arbitrary, but after additional research another bases its rating on the capacity and closer observation, it was discovered of the member to carry traffic. that true differences do exist between and within states. These differences led to General Deterioration of Concrete the development of an assessment modification system. The purpose of the All states visited generally agree modification system is to account for with the guidelines. Although, two variations in the primary factors believed the guidelines to be slightly influencing deterioration. conservative, a majority agreed that for a 3 to be given, a! main rebar should be The modification system consists of a exposed, free standing, and probably have set of numerical values assigned to section loss. One suggestion was that the various conditions. The values range from 11 Modification Description +2 No threat for imnimum of 5 years and one or more of the following: 1. Deficiency condition is stable; 2. External causes of deterioration substantially reduced or eliminated; 3. Deficiency has history in similar circumstances of being self correcting; 4. Deficiency is entirely "cosmetic" in nature and has little or no structural effect.* (Note: May be used for original rating of 2 to 6 inclusive.) +1 No threat for minimum of 3 years and one or more of the following: 1. Deficiency condition is worsening slowly; 2. External causes of deterioration have lessened somewhat; 3. Deficiency has history in similar circumstances of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect.* (Note: May be used for original rating of 2 to 7 inclusive.) No threat for minimum of one year and one or more of the following: 1. Deficiency condition worsening at expected or "normal" rate; 2. External causes of deterioration have remained constant; 3. Deficiency has history in similar circumstances of growina worse at consistent rate; 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: May be used for any original rating.) -1 Threat anticipated within one year and one or more of the followina: 1. Deficiency condition worsening at increasing rate; 2. External causes of deterioration are gradually increasing; 3. Deficiency has history in similar circumstances of growing worse at gradually increasing rate; 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 inclusive.) -2 Threat is imminent and one or more of the following: 1. Deficiency condition is worsening rapidly; 2. External causes of deterioration are rapidly increasing; 3. Deficiency has history in similar circumstances of growing more severe at rapidly increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 inclusive.) * Structural effect includes redundancy of load path and other factors. Figure 5. Modification chart haeed on threat to integrity of etruature. +2 to -2. The modifications are shown in and chemical attack. The temperature Figure 5 . The appropriate modification fluctuation will indicate whether is chosen on the basis of how long it will freeze-thaw is a factor. be before the deficiency is a threat to the structure. The modification is Bridge orientation or surroundings may selected after a review of the history of create a condition where timber piles in the site, the environment, and future land the splash zone are never exposed to the use for the region. sun, remaining constantly moist and causing accelerated decay. The administrative level at which the assessment modification is approved is not Future land use for the area is addressed here. It is conceivable that a significant. Clearing of land would modification may be suggested by the affect runoff, a dam would affect stream inspector and then approved by others. flow characteristics, and an industrial plant upstream from the structure could The history of the site is significant affect the chemical environment in the because it helps the inspector determine water increasing deterioration. whether conditions have remained the same or if they are changing. It helps him One example that highlights the determine what deficiencies require closer inconsistency which can arise when observation. Defects resulting from assessing a deficiency is the case of settlement, such as cracking, may be exposed piles under a footing. These exacerbated if the structure is located in piles might be subjected to totally an active seismic area. different environments depending on geographical location. Photographs from The environment must be considered to different locales showing identical determine various parameters. Rainfall degrees of deterioration will look the and streambed materials are significant in same. However, to an engineer in a assessing abrasion and scour. Knowledge coastal region, exposed timber piles could of the chemical environment is needed to be subjected to marine borers; whereas estimate the expected rates of corrosion this would be of no~ concern to an engineer 12 in a freshwater area. On the other hand, destructiveness, underwater usefulness, the same piles in fresh water would be provision of quantitative strength more subject to abrasion and scour because measurements, and cost effectiveness. of fast moving water, while in coastal regions scour pockets may simply fill back in during the next season. Inspection Techniques For Concrete An actual example of how the Various methods are presently in use environment can have an effect on the or currently under development for the seriousness of a particular problem is the evaluation of concrete under water. A Wareham Narrows Bridge on U.S. Route 6 in summary of these test methods is presented Massachusetts. The bridge is of in the following. particular interest because recently an electrical crossing signal was installed Visual Assessment on a railroad bridge close by. Shortly after installation, the Wareham Narrows Bridge began experiencing abnormally high Visual assessment is invariably the corrosion rates believed to be caused by first test that is applied. It is quick, stray currents coming from the crossing easy, and nondestructive; however, it has signal. In this case, corrosion would had only limited success under water present a much more serious problem to the because water turbidity, i.e. poor inspector because of its high rate than it visibility, affects the result. would if the signal was removed and Additionally, it is only qualitative in corrosion would stabilize. nature and does not provide a direct measure of strength. one final example of the effect of Physical Dimensions Measurements geographic location is that of the effect of terrain, which is most dramatic in The measurement of physical dimensions mountainous regions. A bridge on the provides direct information about section windward side of a large mountain would loss of concrete and reinforcing steel. more likely receive more rain and, This method is quick and easy, results are consequently, more runoff, than a bridge quantitative, and it is economical even only a few miles away on the lee side. under water because of the minimal amount of time and equipment involved. The Maintenance Urgency Index method is nondestructive, is applicable to underwater use, and provides a partial Once all the parameters have been measure of the member's strength. Its considered, the inspector must then select primary drawback is that it does not the appropriate modification. By algebra• provide information on the strength of the ically adding the initial assessment and remaining concrete which is generally in the modification together, the inspector question at this well-advanced stage of can arrive at the maintenance urgency deterioration. index. It is intended that this index will more accurately depict the urgency of Soundings corrective action, relating to how local conditions affect the rate of Soundings are taken by striking the deterioration. The index does not imply concrete surface to locate areas of that if two structures are numerically the delamination of the concrete cover caused same, that the structures are in the same by the effects of freezing and thawing and specific condition. It means that the corrosion of the reinforcement. The urgency of repair is the same for both method is economical but not particularly structures. effective because it is only qualitative in nature and the inspector's ability to Once the maintenance index has been hear sound in water is reduced by waves, established, three modes of action are currents, and background noise. indicated. For levels 6 through 9, the inspector need only note the deficiency in Cores the inspection report. For levels 3 through 5, a structural capacity analysis Cores are taken under water to provide is necessary. For levels 1 and 2, the a cross section of the concrete. Cores inspector should notify the appropriate permit petrographic analysis and other personnel immediately, either by telephone laboratory procedures that measure or in person. ' If required, traffic compressive strength, diffusion constant, restrictions should be imposed and repairs permeability, electrical resistivity, undertaken immediately. Traffic density, x-ray diffraction, moisture restrictions include: posting a weight content, chloride penetration, extent of limit on the structure, reducing the carbonation, and air entrainment. number of traffic lanes, or reducing the The technique requires a coring drill speed limit. The flow chart in Figure 6 equipped for underwater use and a outlines this process. materials laboratory. The method is destructive in that it causes microcracks EVALUATION OP DEFICIENCIES and leaves holes. Coring gives a direct measure of strength, but because it is The following techniques for moderately expensive, cores are typically evaluating deficiencies were assessed for taken only when other evidence indicates ease and speed of application. that further investigation is warranted. 13 INSPECT SUBSTRUCTURE OBSERVE DEFICIENCY MEASURE DEFICIENCY COMPARE TO GUIDLINES SELECT INITIAL ASSESSMENT I REVIEW: HISTORY, ENVIRONMENT, CLIMATE. AND FUTURE LAND USE I SELECT MODIFICATION INDEX 0-2 URGENCY INDEX 6-9 INDEX INDEX 3-5 CALCUUTE LOAD CAPACITY DETERMINE CONSEQUENCES TO SERVICEABILITY PRESENT & FUTURE ARE NOTIFY AUTHORITIES REPAIRS NOTE IN IMMEDIATELY WARRANTED INSPECTION REPORT DEVELOP ALTERNATE REPAIR AND/OR PRESERVATION PROCEDURES SELECT REPAIR AND/OR PRESERVATION PROCEDURE REPAIR ESTABLISH INSPECTION TYPE AND FREQUENCY Figure 6, Flew chart outlining the aeeeeement, evaluation, analyeie and maintenance proaeee. strength. The test evaluates homogeneity Ultrasonic Pulse Velocity and determines crack location. Ultrasonic pulse velocity measurements The results can be affected by many are taken under water of the time of factors including aggregate and transmission of an ultrasonic pulse of reinforcing steel location. The results energy through a known distance of obtained are quantitative, but they are concrete. The velocity of the pulse is only relative in nature. Results need to proportional to the dynamic modulus of be correlated with other tests such as elasticity, sometimes referred to as corings, in order to obtain absolute hardness, which, in turn, infers concrete values (2). 14 Voltage Potential Readings voltage and current give an indication of the rate of corrosion. Voltage potential readings are taken to assess the state of corrosion of the Various methods to analyze the reinforcement by making an electrical resulting data include: slope of the connection to the reinforcing steel. Once polarization curve near zero current the connection has been made, the test is method, three-point method, graphic easy to perform and is nondestructive. A analysis, and "break in the curve" porous tip electrode connected to a high method. The test is nondestructive except impedance voltmeter is placed directly on for an electrical connection to the the concrete surface over the reinforcing reinforcing steel. This technique has not steel and a comparison is then made of the been developed for underwater testing thus potential between the steel and a standard far and is still under research for field reference electrode, usually silver-silver testing in-the-dry (4). nitrate under water and copper-copper sulfate in the splash zone. Other Methods The most satisfactory results are Other methods were revealed in the obtained when the readings are used in literature search that have not been conjunction with a chloride penetration developed for underwater use but analysis of a core test. The readings conceivably may be in the future. These indicate whether or not corrosion is tests are the: active and the extent of the concrete surface area involved. However, it gives • Pull-out test (5, 6). neither the rate nor the amount of corrosion. No indication of strength is • Penetration test (2) • provided. • Indentation test. Computer-Assisted Tomography • Resonance test. Computer-assisted tomography (CAT) scanning uses a nuclear source to develop At present, the states surveyed use a cross sectional view of a member. It only cores, sounding, physical dimensions, yields information on the size and visual assessments, and engineering location of aggregate, cracks, and voids; judgment to arrive at values for reduced density; and extent of corrosion {3). allowable stresses and cross sectional This method is nondestructive and can scan area. These tests are likely to reveal members up to 3 ft thick. The method is trouble only after the deterioration very expensive, gives no direct measure of process is well under way and substantial strength, and poses a potential health damage has already occurred. The best risk to the user. Its underwater results are most likely to be obtained application is presently experimental and from a combination of several different is under development in the united Kingdom tests with a large number of samples (2) and at the University of Texas. because of the wide variation in results that can be expected due to the Polarization Resistance Measurements nonhomogeneous nature of concrete. Polarization resistance measurements As a rule, destructive testing should can actually measure the rate of be avoided. Any test that induces cracks corrosion. Several techniques are or reduces concrete cover can only possible to apply this technology. The encourage deterioration. However, if best candidates are the AC impedance, after testing, all holes are filled and two-electrode, and three-electrode all cracks are sealed, the deleterious methods. The AC impedance method has not effects of testing can be minimized. This been pursued in research because of care should be applied to all materials. potential equipment problems in field use. The two-electrode method applies a Inspection Techniques for Steel 20 mv potential between the electrodes, one being the rebar that is being Various methods are in use or are measured. The current necessary to currently under development for evaluating produce the change is noted and the steel under water. The leader in this polarity is then reversed to allow the field is the maritime industry. Because average current to be determined. This putting very large, crude-carrying (VLCC) method suffers from several problems, ships in dry dock is prohibitively however. expensive, the underwater inspection of VLCC ships has become a necessity. The three-electrode method shows the Although the test procedures may be best reliability. One electrode is the expensive because of the size of their rebar whose corrosion rate is being operations the procedures can become cost measured. The second electrode serves as effective. a source of current during polarization, and the third electrode is a standard Special consideration should be given reference to which measurements are made. to the cleaning of steel surfaces to bare The normal potential of the steel is metal which is required for some of these modified by an external current similar to tests. Visual Inspection should be made the two-electrode method. The resulting before cleaning because a change in color 16 of marine growth can indicate a crack. permanent record of the crack. It is Additionally, cleaning should be avoided expensive, hard to use, and poses a health in the case of dense marine growth or risk to the diver unless extreme caution greenish-black rust both of which provide is exercised. a dense covering inhibiting further corrosion. Acoustic Holography Most of the tests (Q) presented below Acoustic holography locates cracks are to detect cracks in welds. Some of under water using an array of ultrasonic these procedures could find limited use in transducers to produce a multidimensional bridge engineering. picture and a permanent record, but the test is expensive. Visual Assessment Visual assessment is only qualitative in nature and does not provide a direct Inspection Techniques For Timber measure of strength. One of the oldest building materials Physical Dimension Measurements is wood. Experience in the deterioration of timber dates from antiquity. Even so, The measurement of physical dimensions various methods are under development to provides necessary information required in evaluate timber under water, while others analyzing the structure. are in current use. These are the following, soundings visual Assessment Sounding bolts and rivets method can only be effectively used under water in Visual assessment, as before, is only low noise areas. qualitative in nature. Coupon Samples Physical Dimension Measurements Coupon samples are taken under water The measurement of physical dimensions for laboratory analysis, but this is only applicable in areas of low noise. procedure is destructive and is generally only done if other evidence indicates that Soundings this is warranted. Sounding with a hammer will detect Ultrasonic Testing voids and can be used to subjectively estimate the quality of existing timber. Ultrasonic testing will locate This method can only be effectively used cracks. This nondestructive test uses a under water in low noise areas. hand-held transducer below the water surface combined with a meter above the Pointed Probe surface. Water acts as the coupler so grease is not necessary to ensure Resistance to a pointed probe is contact. The procedure is slow and another method to subjectively estimate difficult to use because the diver cannot the quality of existing timber. see the read-out unless he has a display in his helmet. Reflection at the Surface Probe steel-water interface is not as efficient as at a steel-air interface. Probing of the surface, drilling several inches into the timber and probing This device has been used to measure again, is a procedure that aids in the member thickness even though pitting of separate assessment of surface and the surface will scatter the signal. A interior conditions. transducer on a long cord also tends to reduce its efficiency. Brace and Bit Magnetic particle Testing Brace and bit will yield qualitative results by noting the resistance to Magnetic particle testing will locate advancement of the bit and residue on the surface cracks in steel with an induced bit upon withdrawal. Resistance may magnetic field. The particles are change, however, because of the internal fluorescent and suspended in slurry in a structure of the wood and not decay. squeeze bottle for underwater use. The Also, residue may shift along the bit, method is quick and economical although also distorting the results. The method limited because only surface defects are does not provide a measure of strength. located. Radiographic Inspection Bores Radiographic inspection locates cracks Increment bores produce undisturbed under water by using a film cassette with continuous samples, but the results are an x-ray or gamma ray source placed on qualitative. This method is slightly opposite sides of a weld. It produces a destructive and does not measure, strength. 16 Sonic Pulse Velocity Testing Sonic pulse velocity testing indicates relative timber strength and/or section loss as a single value based on a transmitted pulse velocity that is proportional to density and the modulus of elasticity. Correlation of results with samples of known strength is required in order to arrive at an absolute value. Research has been under way for about 20 years. Several commercial diver-operated devices are on the market, and a number of contractors also offer underwater inspection services using this technique. M. Sharif Aggour of the University of Maryland leads a research team that is developing a hand-held device that will be operational from a boat to a depth of 1 m below the waterline. They have built up a data base of 50 points. Figures 7 and 8 show this device. Other Methods Other methods were identified in the literature search that have not been developed for underwater use, although they may hold promise for such use in the future. These tests are: • CAT scan (£). • Electrical resistance test (10). • Sonic pulse frequency test (_11) . • pH test (10, pp 22-23). Figure 7. Inteimal decay of timber pile. At present, states surveyed are using borings, brace and bit, pointed probe, sonic testing, soundings, and engineering judgment to arrive at a value for reduced stress. STRUCTURAL CAPACITY ANALYSIS A great body of work exists on the deterioration of materials used for substructure construction and its causes, but relatively little information is available concerning the consequences of such deterioration to the structural i integrity of substructure units. Because of the necessity of rating structures under the federally mandated bridge inspection program, state highway agencies have evaluated the consequences of deterioration, but it is largely '4 "engineering judgment" in nature. Current Practice Only a few states always analyze substructure units. Most states analyze substructure units when it appears warranted by a deficiency, but other states simply repair the deficiency and do not perform an analysis. None of the states surveyed have developed novel Figure 8. Sonio testing device. methods for the structural analysis of bridge substructures above or below the waterline. Reduced stress and cross-section area are incorporated into 17 commonly accepted stress analysis State highway agencies usually analyze computations. in arriving at these a bridge substructure only when a values, no state surveyed has developed deficiency exists. These agencies believe methods that are considered unique to that there is no need for an analysis when measure the adequacy of concrete, steel, repairs can be promptly accomplished. or timber. What is needed for inspection Settlement personnel is to have a quick indication of the severity of a deficiency. Much could None of the states surveyed analyze a be gained if inspection personnel had the substructure unit for settlement when it ability to determine the severity of occurs. Shimming is the corrective action deterioration on the load capacity of a selected because it is an inexpensive and structure. Three methods are suggested to relatively easy process. Uniform answer the need. settlement of all the substructure units of a bridge will not usually induce Method one overstress. Modest differential settlement of a simple span structure will In the first method, specific likewise create no distress. If instances of borderline deterioration settlement is deemed significant, steps would be exemplified. Cases would be are usually taken to determine the cause. delineated such as scour of spread Computations can be performed on a footings and internal decay in salt continuous span superstructure to water. These qualitative discussions determine stresses induced due to might provide inspection personnel with differential settlement. Here again, the ability to quickly assess the severity analysis of the substructure is not of a deficiency. This assessment should performed. All states interviewed agree be verified later with a more exact office that it is not the settlement itself that analysis by an engineer knowledegable in is the crucial factor, but rather it is structural and foundation analysis. the distress that settlement causes to the structure as a whole. Method Two Scour A second method would be to derive equations for the structural capacity Scour of foundation material from before the inspection is performed. These beneath spread footings is evaluated for equations would account for material stability by few states. The action most strength reduction and section loss, and often taken is not to analyze the could be used, for example, to analyze deficiency but rather to repair it. In deterioration in any pile at any Maryland, once scour of a spread footing location. The equations would be included is discovered, it takes highest priority. as a permanent part of the bridge If necessary, all other activities by the inspection folder. This method would maintenance crew are suspended and repairs require an extra effort beforehand, but undertaken immediately. Because many would save time at the bridge site. bridge failures are caused by scour, their concern is justified. Other states vary An application of this method would be in their response, depending on the for the Inspection team to carry a history of the region and the scourability programable calculator with analysis of the soil. This point will be discussed programs for several types of common further in the next section. substructure units with them into the field. Programable calculators may prove Friction to be an expensive addition to the bridge inspection paraphernalia. Durability of Reduced friction capacity of a pile the calculator in the field may also be a due to scour is calculated in few states. problem. Reduced lateral support of a pile due to scour is calculated rarely. Again, these An alternative to this would be to deficiencies are normally just repaired. perform a complete analysis in the office and determine the limits of deterioration for each member. An illustration of the substructure showing the allowable deterioration could then be included in Proposed Practice the bridge folder to aid inspection personnel in determining how critical a Inspection and analysis of bridge deficiency is to the serviceability of a substructures is important, even though structure. A method for displaying this many states do not analyze this portion of information is shown in Appendix F. a structure. The structural members in substructures are just as critical and often less redundant than their Method Three superstructure counterparts. An example would be that of a timber bent that may A third method also available is to support up to 10 lines of beams, while the use generalized charts and graphs for the bent itself may consist of only three determination of live loads and dead piles. The failure of one pile could be loads. By applying the laws of statics, much more critical than the failure of a and following the example in Appendix F, single beam. inspection personnel could then determine 18 the structural capacity of the supporting long spans are also designed substructure at the bridge site. This for larger superstructure forces, i.e. method is essentially the same as an longitudinal forces due to the live load, office analysis; however, it should again and larger substructure forces, i.e. be verified later with a more exact office stream force and wind. These forces which analysis by an engineer knowledgeable in are included in the original design are structural and foundation analysis. ignored in the live load capacity analysis. This gives the substructures of The deterioration of a substructure long-span structures a larger capacity unit supporting short spans can under than necessary to support dead and live certain circumstances be more critical loads. It is for this reason that than that of a substructure unit Appendix F includes an example of an supporting long spans. This is because analysis of a timber pile bent supporting the ratio of live load to dead load is short spans that has suffered 1 in. of small in the latter, while it is much external decay to one of its piles. larger in the former. Substructures Chapter Three PRESENT MEtHODS TO ARREST CONCRETE DETERIORATION CONCRETE DETERIORATION lowest water the concentration of oxygen decreases rapidly with depth. Water also The vast amount of information found has the effect of sealing the concrete on concrete deterioration and its causes from the ingress of oxygen when compared is testimony to the widespread problem to the atmospheric zone. Above the splash that exists. Research into methods to zone there is a lack of water that is repair concrete below the waterline is necessary to lower the electrical less impressive. This situation can be resistivity of the concrete and to provide attributed to financial limitations and to additional aggressive agents. The zone the fact that concrete deterioration of between these two limits, which includes bridge substructures is not in full view the tidal zone and the splash zone, is of the traveling public. One disturbing referred to by the research team as the observation is that most states defer "Primary Active zone," maintenance until replacing deteriorated concrete becomes the only practical method Secondary Active Zone remaining for an attempt to arrest deterioration. Deterioration at the mud line, whether due to abrasion, reactive soils, or a A majority of the bridge maintenance macrocorrosion cell, also occurs. This engineers contacted during the field area may tentatively be considered as a interviews estimated that 75 to 90 percent secondary active zone. If deterioration of the concrete that is deteriorating is confined to the primary active zone, under water in their states can be traced repairs are greatly simplified. to a lack of quality control during construction or to other construction and Types of Deterioration preconstruction faults. This is because nigh quality concrete is virtually inert Corrosion in most natural environments. Appendix C contains detailed information about The primary factors influencing the concrete and concreting practices that can corrosion of reinforcing steel are: be used for either repairs or new construction. • The presence of chloride ions at the reinforcing steel, Zones of Deterioration • The decrease in electrical Primary Active Zone resistivity, or conversely, the increase in electrical conductivity of the concrete One reason for the lack of information cover. on underwater repair techniques is that most deterioration does not occur under • The availability of oxygen. water. It has been observed that deterioration occurs most frequently above The first two of these factors are the level of low tide and below the top of properties of the concrete cover and the the splash zone. Below the level of last is a property of its environment. 18 Interaction of these factors determines Initiation stage the time at which corrosion becomes active, the rate of corrosion, the time at The initiation stage is where chemical which damage becomes visible and the and mechanical forces affect the concrete nature of the damage. surface only. All coastline states surveyed are most Propagation stage concerned with the deleterious effects of salt water. This concern seems to In the propagation stage, chemical and overshadow any difficulties these states mechanical forces affect the concrete are having with their structures in fresh cover. In unreinforced concrete this water. action will simply weaken the outer surface layers. Pre-existing porosity, Chemical Attack cracking, and scaling allow aggressive agents to reach the reinforcing steel and Chemical attack is usually a slow begin the corrosion process. process and significant In itself in that It destroys the concrete cover over the Destruction stage reinforcing steel. At this point, corrosion takes over as the dominant force The destruction stage is where in concrete deterioration. Carbonation, chemical and mechanical forces have the most prevalent form of chemical negated the protective qualities of the attack, was found to progress no further concrete cover. Corrosion of the than 1 in. into the concrete surface. reinforcing steel then becomes an This would be of no consequence to accelerating process. In unreinforced nonreinforced concrete. concrete this stage is noted by the loss of the outer surface layers of concrete. Interviews revealed somewhat less Appendix D contains detailed information concern with deterioration caused by on each stage of deterioration. industrial waste than was anticipated. Of the states surveyed, two report a problem Grouping of Repair Techniques with paper-mill outfall. Other states report problems with the outfall from a Permitting \ deterioration to progress phosphate plant, a sewage treatment plant, to the last stage before repairs are made a steel mill, and an insecticide plant. is not necessary. Many steps can be taken Tannic acid, fluoride, logging debris, and before that point to arrest concrete mining in basic soils were also reported deterioration. Cores, drillings, voltage to be a problem. No state surveyed potential readings, and/or chemical reported a problem with acid runoff from analyses will be necessary to determine mining activities. It was explained by the depth and concentration of chlorides, the Kentucky Department of Transportation extent of carbonation (see App. D, that acid concentrations become diluted carbonic acid, for details), and whether before they have a chance to react with or not corrosion is occurring. These bridge substructures. tests are necessary to ascertain the stage of deterioration of the concrete. Once the stage of deterioration is established, Abrasion a suitable repair method can be selected. Abrasion occurs in two zones. Ice fluctuating with the tides can cause The methods described as follows have section loss at the waterline. At the mud been grouped under different stages of line, sand movement in the surf zone can deterioration; the groupings represent the cause a similar problem. It is suspended most cost-effective technique available to solids in fast moving streams, however, arrest deterioration of concrete at that that causes the greatest concern. particular stage: Preeze-Thaw 1. Initation stage. • Hydraulic training. Freeze-thaw is a mechanism that is • Penetrating sealants. most active at the waterline. The process occurs when the tide drops, exposing wet 2. Beginning of the propagation concrete. The water in the concrete pores stage: then freezes, expands, and creates large • Surface coatings. internal stresses. When the tide • Veneers. eventually rises, the internal ice melts and the cycle repeats. 3. End of the propagation stage. • Wraps. • Jackets. Stages of Deterioration 4. Beginning of the destruction In order to select a method to arrest stage: deterioration, some understanding of the • Crack sealing. deterioration process that is occurring is • Sacrificial concrete collar. necessary. This process has been broken • Grout repair down into three stages: (1) initiation • Passive cathodic protection. stage, (2) propagation stage, and (3) • Active cathodic protection. destruction stage. 20 REPAIR TECHNIQUES fair to chemicals in general but poor against strong acids: Hydraulic Training • Hydrofluoric acid or its salt. Abrasion attacks the concrete surface • Hydrosilicofluoric acid or its and is a major force in the initiation salt. stage. Abrasion also aggravates other • Magnesium fluosilicate. forms of deterioration throughout the life • Zinc fluosilicate. of a structure. Hydraulic training structures are of some help in arresting 2. Vapor permeable coatings: abrasion. The methods include the • Acrylic latex paints. following: • Cement base paints. • Cement mortar coats. Deflectors • Polymer-modified cement mortar. • Water-base epoxy paints. Fenders and dolphins arrest abrasion • Silicone resin solutions. at the waterline. They can be efficient, • Mineral oils in solvents. and are able to absorb a large amount of energy. This method can be expensive, however, requiring heavy machinery to Surface Coatings drive piles and a moderate amount of construction time. The main purpose of a coating is to prevent physical and chemical contact Riprap between the concrete and its environment. By sealing the surface, the ingress of Probably Is the least expensive method chemicals, especially oxygen, can be where abrasion concern is only at the stopped thereby helping to arrest mudline. However, cost is dependent on deterioration. Resistance to abrasion, location since suitable stone is not chemical attack, and the effects of always readily available. freezing and thawing are desirable characteristics. Ponding The coating should have an adhesion Ponding of the water beneath a bridge strength greater than the tensile strength is quite effective in arresting abrasion of concrete, a coefficient of expansion by reducing the water velocity. This is that is compatible with concrete, and a accomplished by means of a downstream dam, long service life; it should also be by mangement pond, or by widening the economical. Its viscosity should be stream. This method is expensive, selected so that it will provide maximum requiring labor, heavy machinery, sealing of the surface, considering the rights-of-way, and construction time. It porosity and texture of the concrete. It has limited application because of should be elastic and should not creep. topography, because of permit If aesthetics are important, the color and requirements, and because the procedure is texture of the sealant should have a self-defeating in some cases. As water matching appearance with the concrete velocity decreases, the stream will surface. deposit its suspended solids, silting the pond back in, and alter the hydraulic flow beneath the structure. Figure 9 shows an island that was created by deposition when a river was widened. Other Training Structures Spurs, dikes, jetties, and channelization can be used to direct flood waters away from piers. This method is moderately expensive and will require environmental and 404 permits. Penetrating Sealants Much experience has been gained in the field of concrete pipe linings and bridge deck membranes; however, no in situ underwater application was found for any of the penetrating sealants listed below. The sealants listed are not elaborated upon because they cannot currently be placed under water. Inorganic surface sealants include the following synthetic compounds (12): 1. Coatings which react with calcium in the concrete to form practically Figure 9. Island created by ponding. insoluable compounds; their resistance is 21 Surface preparation is very important Epoxies were thought to have almost to the success of sealants and coatings. unlimited application when they were first Most sealants and coatings do not perform introduced. Use under field conditions well when applied to concrete under over the years, however, has not provided water. However, if water could be pumped satisfactory results in many instances. from within a dewatering form, these Figure lo shows a typical epoxy failure. materials could be applied "in-the-dry." Mixing requirements are exacting and Several portable cofferdams were components are hazardous to the users. discovered during the literature search The mix has a short pot life and is heat (14, 15^). One of these is large enough to sensitive during mixing and application. aTTow a man to work inside of it. Strain incompatibility results from rapid hardening and a thermal coefficient of Three problems exist when trying to expansion that differs from that of seal the surface of damp concrete. First, concrete. good bond is hard to attain. Second, no matter how thoroughly the concrete is Epoxies creep, relax, and are impact dried, if it is permeable, it will become sensitive. Physical and chemical saturated again due to the wick action of properties are very selective, varying partially submerged concrete (Wick action between manufacturers and between is the process in which water and environments. Field tests should be chemicals are drawn in at the bottom of a conducted to determine the performance of surface coating or treatment and water an epoxy brand and mix. Because epoxy is vapor is expelled from the top leaving a impermeable, moisture trapped beneath the high concentration of chemicals under the coating may cause it to spall off in concrete surface.) Third, encapsulating direct sunlight or under the effects of concrete that is, or that will become, freezing and thawing, Epoxy should not be damp is a poor practice because the used unless the concrete can resist frost sealant is more likely to pop off in action by itself. It is expensive and as direct sunlight due to increased a result tends to be economical for small jobs only. vapor pressure. Vapor-permeable coatings that claim to keep water out while permitting vapors to escape can solve this problem (_15 ) . These coatings include (17 ): • Acrylic latex paints • Cement base paints • Cement mortar coats • Polymer modified cement mortar • Water-base epoxy paints • Silicone resin water repellant solutions • Mineral oils in solvents Surface coatings suitable for underwater use include those listed below. There are multitudes of others, however, whose underwater application is doubtful. Asphalt and Tar Asphalt and tar were widely used at one time. Asphalt has a high resistance to acids and oxidants. It can be applied cold with the use of a solvent. Tar is the sealant most often used against seawater attack. It is an excellent water repellant, but it is mediocre against acids and bases and poor against abrasion. For both of these bituminous products, the second coat may contain a filler such as silica for stiffness. Strict quality control is necessary to ensure a continuous coat. Epoxies Epoxies have many advantages. They have good adhesion, low shrinkage, a wide range of physical and chemical properties, and a very high compressive strength. They attain a high early strength, are inert to most chemicals, and are moisture Figure 10. Typical epoxy failuve. resistant. They are impervious and both abrasion and chemical resistant. They may be applied with a roller or brush. 22 Tar Epoxy polyethylene. These wraps sometimes have vertical wooden ribs that are interlocked Tar epoxy is a low ratio mixture of and drawn tight around the pile or column polymerized tar and epoxy. It was with a ratchet wrench. A metal clamp can developed as a lower cost alternative to provide a seal at the top and bottom of epoxy (13). the pile to insulate it from its environment. Epoxy Polysulfide The rationale for this process is that Epoxy polysulfide is resistant to residual oxygen trapped within the wrap solvents and has improved impact will be consumed and deterioration will be resistance (1_3) . arrested. This system is very quick and inexpensive; however, it offers little Other Surface Coatings resistance to impact and can only be used on relatively smooth surfaces (1£). An Other surface coatings that are used example is shown in Figure 11. for concrete pipe linings but have not been applied to underwater deterioration Resin-Impregnated Fiberglass Cloth of bridge substructures (l^) are: Resin impregnated fiberglass cloth Polyvinyl chloride wrap is placed around a pile or column and Polyethylene soaked with brushed-on epoxy. This method Styrene copolymers is quick and lightweight but costly and Chlorinated rubber difficult to use. Neoprene Coumarone - indene Jackets Phenoplastic - furnace resin Polyurethane There are several types of jackets Polyester that have been used. Chromated rubber paint Bituminous mastic Fabric Asphalt mastic Proprietary rubber compounds. Fabric jackets offer low labor and materials cost with a minimal Installation Dried oil time. An example is shown in Figure 12. • Tung oil The jacket is assembled above the • Linseed oil waterline and then clamped around the pile Sodium silicate or column at the bottom and filled with Resins concrete. Bleeding of mix water through • Spar the fabric results in a denser mix. • China wood • Bakelite Veneers In case of extreme chemical attack, facings can be applied to the concrete surface. Bricks and tiles of clay, glass, or carbon are usually 230 x 115 x 75 (or 50) mm in size. Kilned at high temperatures, these semivitrified facings are very dense with low water absorption. The bricks and tiles are joined to the concrete with a chemically inert mortar. Three types of mortar are available. (1) synthetic thermo-setting cements consist of resins of phenol, furnace blast, epoxy, cashew, polyester, and polyurethane. (2) potassium silicone cement suitable for acid conditions performs poorly in alkaline and fresh waters; and (3) for less corrosive environments, modified hydraulic cements, such as natural rubber latex and synthetic resin emulsion, may be used (18). Wraps Plastic and Rubber Sheets Plastic and rubber sheets are good for Figure 11. PVC pile wrap (note metal bands). severe chemical attack and most can be vulcanized. Types include: neoprene, butyl, nitrile, polyisobutalene, polysulfide, and chlorosulfonated 23 uI Figure 12. Fabric pile jacket, concrete filled. Ropes used to suspend jacket during construction were left in place. This method is quick and easy; however, the jacket can deform in currents and waves, reducing the cover over the reinforcing steel cage that is placed around the pile inside the jacket. Aesthetics are also compromised when the bag deforms. A concrete sample is hard to Figicre 13. Fiberglass jacket filled with obtain because of in situ bleeding. epoxy. Nonmetallic Nonmetallic Jackets, usually fiberglass, consist of a one-piece or a two-piece semirigid unit that may bolt or interlock at the seam(s). These forms can be removed or left in place for added protection. They can be filled from the top or with a valve from the bottom with either epoxy, epoxy mortar, or concrete, and if the forms are left in place, they can be sealed at the top and/or the bottom with a layer of epoxy. Nonmetallic jackets are lightweight and easily handled in the water by a diver. Their rigidity makes them more desirable than fabric pile jackets for some applications. Fiberglass jackets have been observed, in some cases, to have a tendency to separate from the grout filler material and even to become dislodged. Figures 13 through 17 show these jackets in service. Steel Jackets Steel jackets and metal collars are sometimes used. They come in many sizes, Figure 14. Fiberglass jacket filled with up to several feet in diameter. They can epoxy grout. be filled from the top or the bottom with either epoxy mortar or cement mortar with epoxy bottom and top seals. These jackets 24 Figure 16. Fiberglass jacket filled with epoxy grout (note failure in background). Figure 17. Round fiberglass jaaket; surface has been scraped. can then be removed or left in place to provide protection. Their high initial cost can be offset by reusing these durable forms. Removal of the forms also allows for monitoring of the performance of the repair. These jackets have been observed to have a tendency to become dislodged. Figures 18 and 19 show this repair technique in operation. Sheet Piling Sheet piling with backfill is a type of jacketing that is very effective in isolating the concrete from its environment. It can be filled with either concrete grout or earth with a concrete cap. The latter can also be designed to resist severe impact damage. Crack Sealing Epoxy Injection Epoxy injection is a method by which low viscosity epoxy is pressure injected into a crack to restore full structural capacity and to stop corrosion. It has been used successfully under water and can seal cracks as narrow as 0.002 in. Its aesthetic value is questionable, however. Other Resin Grouts Other resin grouts for crack injection are currently being developed. These resins have the advantage of reacting with the water that is inside the crack and not simply displacing It. This results in there being no residual film of water left between the inside concrete surface and Figure 16. Round fiberglass jacket, the injection material. concrete filled. Sacrificial Concrete Collar In this method, a nonstructural concrete collar is cast around structural 25 Figure 18. Corrugated metal jacket. Figure 20. Sacrificial concrete armament. Figure 19. Steel collar jacket. Figure 21. Sacrificial concrete armament. concrete usually at the waterline only. Grout Repair When the sacrificial concrete deteriorates it is replaced. This method is expensive A variety of epoxies and concretes and increases the dead load to such a with modifiers or admixtures are available degree that the decision to use this for the underwater resurfacing of large procedure may depend on a structural areas of deterioration and/or section analysis. Examples are shown in Figures loss. These may be used in conjunction 20 and 21. with pile jackets or formwork and may or 26 may not include sandblasting of the subject to three potentials for reinforcing steel. With the proper grout, corrosion. Steel piles have successfully they can be an effective repair measure, been cathodically protected because they some commonly used grouts are: have the advantage of being in direct contact with ^ an electrolytic solution, concrete with seawater, whereas the reinforcing steel in Portland cement concrete is initially insulated from it. modifiers and mixtures. See As the cover deteriorates and the Appendix C fori further details. electrical conductivity of the cover increases, that portion becomes highly Latex-modified concrete slurry (IZrP active, accelerating corrosion. 532). I High alumina cement (21r 22)• Sulfur impregnated concrete (22)• Epoxy mortar grout. Gun-applied mortar (Ifi, p 532 21, PP 509-526). See Figures 22 and 23 for examples of typical failure. SOMMARY • Preplaced aggregate concrete. Repair of Concrete Arresting of Deterioration i' The question hais been raised as to A few of the methods that have been whether permanent ,, formwork helps to discussed are best suited for only new protect a repaired ' area or whether it construction. The others are considered simply hides additional deterioration. It either methods to repair concrete is known that water 'absorbent forms, such deterioration or methods to arrest as wood, will dewater the concrete mix concrete deterioration. The distinction adjacent to it, making the surface is that methods to repair deterioration harder. if these forms are left in place typically are simply those which put back for an extended period of time until a something that may have been Inferior in repair is fully cured, they can then be the first place and which do not address removed so that assessment of the repair the cause of deterioration. On the other can be undertaken. Permanent forms, hand, methods to arrest deterioration are however, promote wick action. those which attempt to intervene in the natural chain of events known as When patching chloride contaminated deterioration and to slow or even to concrete with a patch of fresh concrete, arrest its continuation. if the patch comes in contact with the reinforcing steel, a corrosion cell can be Case Histories established. in this instance, there is an increased potential for corrosion that Case histories of specific repairs are simply shifts to . surrounding cathodic included in Appendix E. They are areas of the same bars forming an anodic presented in work-sheet format so that the area and corrosion :then continues. This judgments provided by the owner and the situation may be remedied by coating the researcher will not be construed as the inside of the concrete cavity and all final word on any particular repair exposed reinforcing steel with epoxy method. Any assessment of a particular bonding compound to electrically insulate repair installation must be qualified with the fresh patch. such factors as: conditions at the site on the day repairs were made, quality Passive Cathodic Protection control, and field conditions since installation. A sacrificial zinc anode, weighing 4 to 10 pounds, is attached directly to an Table 1 summarizes the repair methods exposed reinforcing, steel bar during the discussed in this chapter. It also* underwater inspection. This method is indicates a qualitative "likelihood of quick, is simple, and arrests corrosion of success." bars that are completely exposed for up to 2 years (19). !' Active Cathodic Protection Active cathodic protection of partially submerged concrete bridge substructures is not currently practicable. Bridge decks offer a relatively uniform potential for corrosion, while substructures have more complex physics. , When concrete is continuous through all three zones (subterranean, underwater, and atmospheric), the .reinforcing steel is 27 Figure 22. Gun-applied mortar (note deterioration). Figure 23. Gun-applied mortar (note deterioration). Table 1. Summary of repair methods (likelihood of suooess). STAGE OF ABRASION CORROSION FREEZE-THAW CHEMICAL ATTACK DETERIORATION INITIAL STAGE I. Hydraulic 1. Penetration 1. Penetration Training Sealants Sealants (Fair) (Poor) (Poor) BEGINNING OF THE 1. Veneers (Good) 1. Surface Coatings 1. Surface Coatings 1. Veneers (Good) PROPAGATION (Poor) (Poor) 2. Surface Coatings STAGE (Poor) END OF THE I. Jackets (Good) 1. Jackets (Good) 1. Jackets (Fair) 1. Jackets (Good) PROPAGATION 2. Wraps (Fair) 2. Wraps (Fair) STAGE DESTRUCTION 1. Collar 1. Collar (Excellent) 1. Collar (Excellent) 1. Collar (Excellent) STAGE (Excellent) 2. Zinc Anode 2. Grout (Good) 2. Grout (Good) 2. Grout (Good) (Excellent) 3. Seal Crack (Good) 4. Grout (Fair) 28 Chapter Four NEW OR IMPROVED METHODS TO ARREST CONCRETE DETERIORATION "BIAINSTORIIING" SESSION method. The technology necessary to identify a particular stage of deterioration Format for the Session is not within the scope of this project. In order to generate new or improved It was pointed out by the research team methods to arrest concrete deterioration, a that repairs are typically undertaken during "brainstorming" session was conducted with the destruction stage. This may be too late representatives from 'industry and govern• to effectively arrest deterioration. It was mental agencies in attendance. decided by all that the most benefit would be gained if methods could be devised to Essentially, arresting deterioration arrest deterioration in the initiation and means, or at least implies, interfering with in the propagation stages. a progression of events that will occur naturally in a fairly well-defined order but The consensus of the "braintorming" at a varying rate, depending on the panel was that there is little difference intensity of the various factors involved. between the rate of deterioration caused by On the basis of this premise, the approach hot or cold salt water. The representatives to the brainstorming session was to outline from the U.S. Navy mentioned several to the participants tlie causes of concrete examples from their own experiences around deterioration, as described below, in a the world confirming this. Therefore, it step-by-step process. It was stated that was decided to eliminate any distinction in deterioration begins with the initiation deterioration rate resulting from stage, progresses through the propagation differences in ambient temperatures. stage, and concludes, with the destruction It was also decided that the most stage. This premise was presented in three cost-effective methods would be those that separate categories: salt water (hot), salt require a minimum of diver time and that are water (cold), and fresh water. easy to apply. Cold water and cumbersome gear limit the abilities of the diver. It was pointed out to the attendees Visibility is limited and in many cases that three points should be considered when nonexistent. This limits the application developing a new or improved method to and the inspection of the preservation arrest concrete deterioration. First, the method employed. Currents and waves are stage of deterioration of the member must be dynamic forces that further reduce the established within the progression of events efficiency of the diver. If everything else that one wishes to arrest. Second, it must is ignored , the diver still has the problem then be decided how best to arrest the dete• of having no leverage. He floats in neutral rioration at that point. Third, it should buoyancy with no benefit of a surface to be determined whether or not it is push against or of body weight to apply. economically feasible to do so. When the Because of all these circumstances the diver basic premises were established the is not the ideal contraction worker and "brainstorming" session was begun with the everything he does is costly, time maximum amount of free participation consuming, and relatively inefficient. encouraged. Refinement of Parameters IDEAS RESULTING FROM THE •BRAINSTORMING' It was decided that what would help the SESSION majority of maintenance engineers throughout the nation most was a quick, easy, and Many ideas were presented and discussed economical method to arrest concrete deteri• at the "brainstorming" session. Following oration without the need for extensive is a summary of those ideas without judgment evaluation. As an example, if 10 percent of as to their future value. the piles of a bridge were to begin to deteriorate, it could be assumed that the Tapes other piles were in the propagation stage of deterioration. It would be best then to Several forms of tapes were suggested look for an economicial method that could be that could be wrapped around a pile to applied to all piles and not just the 10 protect it from its environment. This percent that show deterioration. system was well received because it was envisioned to be convenient for a diver to Extensive evaluation could very well apply. The tape would be supplied on a raise the cost of arresting deterioration in hand-held spool that the diver could easily selected piers beyond that of arresting it grasp. Several materials were mentioned as in all piers by a sufficiently economical being suitable for use as tapes. 29 • Mastic tape would provide a good • A floating inner tube device with a chemical barrier and would aid in filling skirt beneath it would be helpful in irregularities in the concrete surface. arresting ice abrasion due to a fluctuating With elastic properties, it would fit a water level. variety of shapes. • Litmus-paper-type indicators that • Bituminous tape would provide an turn different colors would aid in the excellent chemical barrier. Its sticky identification of the type of chemical texture would adhere , to the concrete attack that is occurring. This method would surface. be quick and economical In comparison with a laboratory analysis of water samples. • Hardening tape that is pliable during its application and later sets up • A chemical filter similar to an like a cast would offer abrasion resistance. intrusion fence at a contruction site could be used to screen ions. • Plastic tape would offer chemical resistance. • A bubbler curtain similar to those used at marinas could be used to stop ice • A two-part system of tapes and/or formation. coatings would combine the best of each component. • A vulcanized rubber wrap could protect against chemical attack. Sealants and Coatings • An asphalt coating would seal the Several coatings were suggested as concrete surface. being beneficial in arresting concrete dete• rioration. It was realized that some of • The concrete surface could be these materials cannot be applied under greased to make it hydrophobic. water. The attendees later discussed methods to dewater the application surface. • An electric charge could be applied Suggestions included: to the concrete to drive out ions. • Cycloaliphatic polyurethane silicone • The concrete could be encased in elastometric membrane is a vapor permeable fresh water to provide a hospitable environ• coating that expands into pores when it is ment in contact with the concrete surface. wetted. However, it is not abrasion resistant and biological growth will rupture • A sacrificial pier could be built the membrane. around the structural pier to isolate it from the aggressive environment. • Silica gel, which is now used on submerged glass as an antifouling agent, would discourage biological growth from rupturing sealing membranes. • A coating with low cohesion and high •BRAINSTORIURG- IDEAS TBKD WARRANT FDRTBBR adhesion will not become completely INVESTIGATION dislodged when biological growth is pulled from its surface. Of the numerous ideas that were developed at the brainstorming session, two • Liquid plastic coatings might be appeared to have significant potential to formulated to exhibit ideal qualities. the research team. This conclusion was reached through an evaluation process made • Silicone latex emulsions are water by each member of the research team and a repellant. weighting process resulting in a consensus opinion. • Flaked glass in a mastic tape would stop oxygen ingress. Those ideas are (1) the development of a multiple tape system and (2) the develop• • Sacrificial coatings would stop ment of a procedure for applying coatings chemical attack. and sealants. Multiple Tape System Other Methods It seems feasible that if materials could be found that would resist each of the Various other methods were also four causes of deterioration, they could be discussed at the brainstorming session; formulated into separate or composite tapes these included the following: that could be wrapped around a pile or column to isolate it from its environment. The system has been conceptualized as being • A.^dewatering cofferdam would permit applicable to piles and columns only. It the app3?ication of surface sealants to would be of little use for walls and mass concrete which normally could not be applied concrete. under water. This would certainly increase the variety of sealants available. The It should be stressed that these tapes device would be a small, clamp-on, have not been developed, what is described light-weight unit. here is the basis for a potential system. 30 These tapes would.be on plastic spools increase the tensile strength of the tape. about 1 ft. wide and would have buoyancy It should also have QC overlap lines. compensator bags built: into them so that a diver could wrap them around a pile with Plastic Foam Tape ease while maintaining their neutral buoyancy. The tapes would be applied in a spiral pattern. Each layer would alternate Laboratory tests indicated that the between left-hand and right-hand spirals. extent of damage to a concrete sample as a Each wrapping sequence, would begin at its result of freezing and thawing is directly lower limit of application and progress up proportional to the rate of cooling. the pile so that upper' layers would overlap Through the use of plastic foam tape, an lower ones and the joints would tend to attempt is made to reduce the exodus of "shed water." thermal energy from the concrete and allow water to migrate from the capillaries to Abrasion Tape internal voids or the surface before it freezes. Abrasion tape should be pliable during its installtion. Ideally, it should have a This tape should be thick and pliable compressive strength at least as high as the with a high thermal resistivity factor. It abrasive material. Seven to 10 ksi would be should have a moderate amount of chemical a minimum compressive stress. It should resistance and may be sticky on its face to have a moderate tensile strength to resist aid in its application and have a strong being dislodged. It should be smooth on its backing to Increase the tensile strength of back side to minimize local turbulance, and the tape. It should also have QC overlap the tape may be sticky on its face to aid in lines. its application. For economy, it • can be formulated without chemical resistance for fresh water Conductive Tape and with chemical resistance for salt water. It can also be resistant to the effects of freezing and thawing. This property of the Conductive tape is envisioned as a tape may also be a specification to order pliable tape that would impart cathodic option; however, its cost benefit should be protection. It would conduct electricity investigated. either by means of embedded wires, or more perfectly, by means of the electrical The tape could harden by hydration. conductivity of the material itself. This Because tape by nature would be a relatively may be accomplished with conductive mastic thin layer of material, plastic or or woven graphite fiber. It is possible fiber-reinforced hydraulic cement might be a that the tape may only be required above the good choice. This tape might be in the form waterline and that a single wire would be of plastic packets filled with hydraulic required below the waterline. This is cement on a plastic backing. The packets because the water provides the electrolyte would slowly dissolve in the water trapped to distribute the charge. between layers of tape and release the hydraulic cement so that it may hydrate. A problem that will have to be solved Thorough mixing of the cement would be is the venting of gases that will be doubtful, however. produced. Chlorine gas, which will be one by-product, is so active it will eat away Other methods of hardening are also epoxy. This may be overcome if the top seal available. A two-component tape, as with is gas permeable. epoxy, might be useful; however, thorough mixing of the components again is doubtful. The tape should be sticky on its face Plastic cloth impregnated with epoxy would and have a strong backing to aid in its have good strength characteristics but would application. It should also have QC overlap be more labor intensive. A high-strength lines. cloth might also work. Permutations Additionally, all tapes described herein should have a "quality-control-of- Each of these four tapes would be overlapping-joint" inspection line (QC formulated to protect against the four forms overlap line) located 2 in. from each edge. of deteriora tion independently. In a This will allow a quick construction naturally occu rring environment, however, a acceptance inspection after each layer of combination of several forces is usually at tape is applied. work to deter iorate concrete. For this reason, a comb ination of the tapes described Rubberized Asphalt Tape above would af ford the best protection. Figure 24 shows which tapes would be Rubberized asphalt tape should be a used for combined attack. The important thick pliable tape that is made of element in this figure is the 'order of chemically inert material. Rubberized application. For example. Box 3 prescribes asphalt is specified here; however, other that abrasion tape be placed over rubberized materials may prove beneficial. It should asphalt tape for combined abrasion and be sticky on its face to aid in its chemical attack.. This tape system would be application and have a strong backing to ineffective if it were reversed. 31 Abrasion Abrasion Abrasion Tape Corrosion - BOX 1 - Corrosion Abrasion Tape over Conductive Tape Conductive Tape Freeze-Thaw - ,BOX 2 - - BOX 4 - Freeze- Abrasion Tape Plastic Foam Tape Thaw over over Plastic Foam Tape Plastic Foam Tape Conductive Tape Chemical Attack - BOX 3 - - BOX 5 - - BOX 6 - Chemical Abrasion Tape Rubberized Asphalt Tape Rubberized Asphalt Tape Attack over over over Rubberized Asphalt Tape Rubberized Asphalt Tape Conductive Tape Plastic Foam Tape Figure 24. Combined attack: propagation etage corrective action. Corrosion BOX 7 Abrasion Tape Abrasion & over Freeze Thaw Plastic Foam Tape over Conductive Tape Freeze-Thaw BOX 8 BOX 9 Abrasion & Chemical Abrasion Tape with Chemical Abrasion Tape with Chemical Attack Resistance over Resistance over Conductive Tape Plastic Foam Tape Chemical Attack 1 BOX 10 Rubberized AsphaU Tape Freeze-Thaw over and Corrosion Plastic Foam Tape over, Conductive Tape BOX 11 Abrasion, Abrasion Tape with Chemical Freeze-Thaw Resistance over Rubberized and Corrosion Asphalt Tape over Plastic Foam Tape over Conductive Tape Figure 25. Three and four combined attack. 32 Figure 25 takes this concept a step Top and Bottom Seals further by describing tape systems to combat the simultaneous onslaught of three or four different types of deterioration. It may be Top and bottom _8eals present two noted that Box 11 addresses all four of the interesting problems that were discussed causes of deterioration discussed in this previously: wick action and the venting of report. gases. It would appear that both problems could be solved by developing a watertight Limits of Application bottom seal and a vapor-permeable top seal (see Fig. 27). The top seal would simply keep water out. With this arrangement, To be effective the tapes do not need gases and water vapor can be vented. This to extend completely from the mud line to 10 would cause the pile to dry out, thus ft. above the level of extreme high tide. reducing electrical conductivity and Economy of materials will be achieved if chemical activity. Some problems remain, each tape is applied where it will do the however. Even if the overlapping joint and most good. The order of tape application is the bottom seal were watertight, water would also an important consideration so that still percolate through the concrete optimum use is achieved. Starting from the capillaries producing wick action. In this outside and proceeding Inward through each case the vapor-permeable top seal would only layer, the limit of application of each tape aggravate the situation. is described below and presented in Figure 26. A method to seal the capillaries deep below the water surface would be beneficial. Abrasion tape i s best placed on the One possible solution might be placing outside to provide a, hard shell protection chemicals at the bottom of the bottom seal for the underlying layers. It will be so that they would be drawn up into the needed in two zone At the mud line, it capillaries, react with the concrete, and will need to extend from just above the mud reduce its permeability. line to some depth below the mud line to compensate for the scouring action that Typical Installation occurs at a pile during periods of high water velocity. At the waterline, the tape should extend just beyond the limits of Figure 28 depicts what is described in extreme low tide to extreme high tide. Box 11 of Figure 25. This system is intended to arrest all four causes of Rubberized asphalt tape would be concrete deterioration. The dimensions required next if chemical attack is a shown are for illustrative purposes only. problem. It would extend from the mud line to the top of the splash zone and would also Tape Applicators protect any underlying layers. As mentioned in Chapter Three, wick action will draw in In an effort to minimize diver effort, water and chemicals at the bottom of a various tape applicators were considered. repair and expell water vapors from the top, The simplest is shown in Figure 29 and leaving a high concentration of chemicals at consists of an axle through the spool and the concrete surface. To arrest this two "0" shaped handlebars set at 90 degrees action, effective top and bottom seals will to each other. A hand brake, much like that need to be designed. on a bicycle, is provided on one handlebar and would be capable of locking similar to a Plastic foam tape would be needed next parking brake. This would allow the diver to protect the concrete from falling air the ability to release the spool and not temperatures. This would necessitate an have It float away. As mentioned application zone from just below the extreme previously, the spool itself would have low tide line to the top of the splash zone. buoyancy compensation' to compensate for changes in depth and the weight of the tape Conductive tape would be the innermost remaining on the spool. All materials would layer because it needs to be in direct have to- be corrosion resistant and contact with the concrete surface. It would chemically inert. be required from below the mud line to the top of the splash zone. The diver operates the applicator by holding the handlebars and swimming spirally The economy of labor can be maximized up the pile. Because a second diver is by reducing the number of tapes used. required on any diving operation, this Possibly, conductive tape and rubberized worker follows behind pulling the tape taut asphalt tape could be,offered alternately as and assures a uniform overlapping joint. a composite. Limiting the number of tapes The second diver then applies pressure with will also reduce the stress on the diver by a device much like a rolling pin to squeeze reducing the number of descents that will be out trapped water. required. As a result, the total economy will be a trade-off between labor and A second applicator, shown in Figure materials, i.e., using four separate tapes 30, has the rolling pin built into the or one combined tape. frame. The diver grips the device near the roller and swims forward, guiding the tape and squeezing out trapped water at the same time. The second diver in this operation acts as a construction Inspector, reducing TOP OF METAL BANDING SPLASH ZONE 12 IN SEVERAL LAYERS AT TOP EXTREME HIGH TIDE 12 IN PILE • EXTREME LOW TIDE 12 IN TAPE DEEP , SEVERAL LAYERS PENETRATING AT BOTTOM SEALER Figure 26. Limita of application. Figure 27. Top and bottom seal details. -HANDLE WITH HAND BRAKE -TAPE SEE FIGURE 27 FOR DETAILS SPOOL PILE- /ATERLINE ABRASION TAPE OVF) Figure 29. Tape applicator. PLASTIC FOAM TAPE RUBBERIZED ASPHALT TAPE CONDUCTIVE TAPE 12 IN. DIA. SPOOL HANDLE CONCRETE SURFACE 4 IN. ROLLER SEE FIGURE 27 FOR DETAILS Figure 28. Multiple tape installation Figure 30. Tape applicator. example. 36 the complexity of the operation by a step pile could be steam cleaned below the for each tape that is applied. waterline. Acid etching might be possible with this device. The pile could then be Both the tapes and the tape allowed to dry for a couple of days. Hot applications are an attempt to envision air or infrared light could aid in the something that would appear feasible. Field drying operation. The application of a wide tests will be required in order to determine variety of sealants and coatings would be their true potential. possible because these materials can be applied in-the-dry. The form could even be Oewatering Cofferdam flooded with a sealant to allow it time to soak into the concrete pores with slight hydraulic pressure. The dewatering cofferdam device was first described at the brainstorming session This device could also be used as a as a small clamp-on unit. It would reusable form for the pouring of concrete. facilitate several operations. First, a Curing times for all these materials can be ADJUSTABLE JOINT FRICTION CLAMP ASSEMBLY NEOPRENE PAD STRUCTURAL TUBING 5^ INSPECTION PORT HORIZONTAL FIXED JOINT CASINO PRESSURE HOSE INFLATABLE SEAL Figure 31. Dewatering cofferdam. 36 extended over several days. In subsequent excessive member weight. Inspection ports discussions, it was decided that diver time were provided for quality assurance and all could be minimized, if not eliminated, by metal parts should be either galvanized requiring the device to be completely steel or aluminum. It is realized that much operational from the surface. This would development work remains in order to make mean that the bottom seal would have to be this design a working model. installed without tlie aid of a diver. Figure 31 shows the dewatering Sprayers cofferdam in place around a pile. To do this without a diver, the pile is first cleaned. This may be done by scraping below and sandblasting above the waterline. If In an effort to minimize the buoyancy the dewatering cofferdam is to be used as a force exerted on the dewatering cofferdam, reusable concrete form, a plastic form the inside clearance had to be only a few inches. Working in such a small space lining that is not shown in the figure is became the next concern. Methods of attached to the pile. This form liner will applying sealants and coating were also provide additional curing after the discussed. form is removed. The casing and any banding is then assembled around the pile. One possibility would be a fan sprayer, The inflatable bottom seal is placed shown in Figure 32, on a hollow shaft at a around the pile and its two ends are right angle to it, which could be inserted inside the cofferdam. Other possibilities connected. The seal is snapped onto the include a roller or a brush on a hollow casing and retracted from the pile face. shaft which would supply the sealant at the The casing is then lowered into position and lower end. temporarily secured. The friction clamp is assembled next, bolted in place, and the casing drawn up snug against the bottom of the clamp. The bottom seal is inflated. The seal may be either pneunatic or hydraulic in nature, depending on which is most advantageous. The water is then pumped out from within the casing. FLEXIBLE PRESSURE To remove the dewat ering cofferdam, the HOSE pressure release valve located above the surface is opened, all owing the inflatable seal to deflate. It is retracted from the pile face by means of straps, After the casing has flooded, the friction clamp IS removed and the casing lifted out of the water and dismantled. I f the cofferdam was used as a concrete form, quick-release latches (not shown) will need to be thrown to release the vertica 1 joints so that the casing can be removed. SEMI-RIGID STEM To minimize the cost of the device and maximize the versatility, the casing should be constructed in 4-ft. sections with horizontal fixed joints to accommodate tidal, wave, and splash zone variations. It also should have vertical adjusting joints. This would allow one casing to fit a range of pile sizes. The length of the inflatable seal will depend on the pile size. The bottom section can come in two models, one for square piles and one for round piles. The size of the round pile bottom section would also depend on the pile size. SPRAY The number of 4-ft. sections that will be needed will depend on condition at the site. The area to be covered with sealants would extend from 1 ft. below the level of extreme low tide to the top of the splash Figure 32. Fan sprayer. zone. Beyond this, a 1 ft. sump zone would allow for condensation. The remaining length can be used above the splash zone as a free board. Design and details were also considered. Initial computations were run on the friction clamp to assure strength and torsional stability without the need for 37 Figure 33 depicts a sprayer apparatus As an alternative to the above design, which would be assembled around the pile the device may simply consist of an before the dewaterlng cofferdam was pumped adjustable frame of similar configuration dry. This device is adjustable to with a flexible hose snapped to it. The accommodate a range of pile sizes. The hose would be disposable. This alternate is device would be lowered to the bottom of the proposed to alleviate anticipated problems cofferdam, and then would begin spraying as due to- clogged , spray jets and stuck slip the device is raised back to the top. The joints. The alternate design would minimize device would require a single lifting cable, down-time and eliminate the repetitive and the pressure hose that supplies sealants cleaning operation. from the surface would be attached to it so that the hose will be retracted as the device is raised. The stand-off wheels maintain the optimum spraying distance. DEWATERING LIFTINO CABLE PRESSURE HOSE COFFERDAM CASINO PILE ADJUSTABLE STAND-OFF SLIP SPRAY LINKAGE WHEEL JETS Figure 33. Sprayer apparatue inside deuatering cofferdam. 38 Chapter Five CONCLUSIONS, RECOMMENDATIONS AND RESEARCH NEEDS CONCLUSIONS often limited because a structure which reduces scour and abrasion in one area may Inspection Techniques have a reverse effect elsewhere in the channel. Numerous techniques are presently available for the assessment of 2. Penetrating sealants come in a deficiencies in substructure units under wide variety; however, this research did water. With present technology, some are not reveal any which appear to be more suitable than others. Techniques applicable under water. that may someday have application for underwater use with further development 3. Surface coatings are available in include the following. a wide range of properties; however, they have enjoyed only limited success. 1. Assessing deficiencies with the Epoxies, in particular, tend to be highly aid of definitions based on the urgency of complex systems that have had a history of corrective action can be of help to requiring very stringent controls. maintenance engineers. 4. Jackets and wraps have produced 2. A rating modification system varying degrees of success. Monitoring which accounts for variations in the rate the performance of the system is necessary of deterioration due to the history, to determine if it is protecting the pile environment, geography, and future land or simply hiding continued deterioration. use near a bridge site can be applied to Removable forms provide protection during an initial assessment to more consistently curing and allow monitoring at a later depict the true immediacy of correct^ive date. action. 5. When sealing cracks by grouting Substructure Analysis or pressure injection, it is often questionable as to whether or not the 1. State highway agencies usually repair has arrested deterioration. To analyze a bridge substructure only when a insure that the repair is effective, a relatively obvious deficiency exists. monitoring system is necessary. For repairs such as these, epoxy grout has 2. Most states feel that there is no shown the most promise. need to analyze ' the effect that a deficiency has on capacity if repairs are New or Improved Methods to Arrest Concrete promptly executed. Deterioration General Concrete Deterioration 1. Methods that are quick and economical are needed to arrest concrete 1. There are three stages of deterioration without the requirement for deterioration: initiation, propagation, extensive evaluation. and ' destruction. Once it is determined which state of deterioration a structure 2. Diver time and effort should be is in, a repair process can be selected. minimized for use in these methods. 2. Repairs are usually undertaken only after extensive damage has occurred. This is due to financial limitations and RECOMMENDATIONS the hidden nature of underwater deterioration. Inspection ' The development of several testing 3. Deterioration usually occurs devices for underwater use would aid the first in the primary active zone defined maintenance engineer in evaluating the as an area extending from the level of structural strength of bridge extreme low tide to the top of the splash substructures. zone. This accelerated rate of deterioration is due to the high Concrete availability of oxygen, the effects of freeze-thaw, and other factors. 1. A polarization resistance device would be capable of the underwater Methods to Arrest Concrete Deterioration measurement of the actual rate of corrosion of reinforcing steel. 1. Hydraulic training structures such as spurdikes, cofferdams, etc., 2. A test block permanently attached address the primary causes of abrasion. to the substructure in a protected The advantages of these structures are location would serve as a sample of the 38 original concrete poured at the time of New or Improved Methods to Arrest Concrete construction. This block, which could be Deterioration an outcropping on the pier cap, would aid the engineer in calibrating present and 1. The proposed system of tapes and future test equipment. application should be developed to isolate a concrete pile from its environment. 3. Provisions should be made on existing piling as well as at the' time of 2. Development of usable tape construction for an electrical connection applicators will make the tape system an to be made to the reinforcing steel in the attractive alternative. substructure so that the voltage potential readings can be taken to monitor deterioration. This connection should be 3. Development of a dewatering of trade standard quality and be situated cofferdam device will allow many in a protected location. Substructure activities to be performed in-the-dry and units to be equipped should be distributed allow others to be performed that could in shallow as well as deep water. not previously be used at all. Determination of which units will corrode first should not be of great .concern 4. Development of a sprayer for because those which do not corrode will applying sealants and coatings will serve as a negative control. greatly increase the usefulness of the dewatering cofferdam. 4. Research into predicting a time frame of deterioration would be a help to RESEARCH NEEDS the maintenance engineer in predicting when a structure will need repairs. For 1. The entire decision-making process example, if the potential for corrosion of of whether a substructure unit deficiency reinforcing steel could be observed and should be repaired, replaced, or action correlated to the "time to deterioration," deferred should be examined in detail. an approximation could be made as to when Guidelines are needed to aid the engineer corrosion will commence and when it will in establishing various criteria to be become a problem. This could (be used in this process. accomplished with something as simple as a graph with a "family of prediction curves" on which field data points can be plotted. Methods need to be examined to identify the stage of Steel deterioration of a particular bridge substructure. The premise of an initiation, propagation, 1. A steel- strength testing device and destruction stage of would be capable of determining the deterioration can be applied to strength of existing piles under water. all building materials. The This would eliminate the need for coupons methods examined will probably be and strain gages. a combination of structural strength evaluation techniques Timber identified in Chapter Two. 1. A timber cat scanner would be much like that which is currently under An evaluation of viable repair technique options available for development for concrete. the particular stage of deterioration that is found needs Assessment of Deficiencies to be discussed and tailored to be incorporated into the decision 1. The proposed guideline booklet process. Thus, research is (App. G) should be implemented to assess required to develop a method of underwater deficiencies. selection between alternate repair procedures. This method Existing Methods to Prevent Concrete should be based on an objective Deterioration comparison of cost, benefit, probable success rate, and life Materials expectancy. 1. Because the corner bar of a square pile is exposed to basically two Once a repair approach has been planes of attack and failure, it identified, a decision must be deteriorates much faster than do bars that made whether the preservation are located on the side faces. The procedures are warranted at this development of economical and efficient time. A method of analysis of the means to fabricate circular precast piles cost benefit of performing would eliminate this problem. repairs at a later stage of deterioration should be Practices investigated. Economical savings may be realized if repairs are delayed until the optimum time 1. soaking a pile in clean water frame for a specific preservation before driving it in salt water will procedure. The alternative prevent , the pile from soaking up salt water after it is driven. should also be investigated with regard to whether the estimated 40 cost be spent on the repair or 3. in order to Induce the private the money be applied towards sector into developing new products. funding a replacement structure. Including those that were suggested in this report, the need for product 2. Research that would parallel this development should be demonstrated by study would detail prediction, assessment, quantifying the underwater deterioration and prevention of scoiir. Because of the problem. A demand analysis of this sudden and often catastrophic nature of information should reveal the potential bridge failure due to scour, methods need market for particular products. to be examined that would predict and assess the risk of scour and a structure's 4. Because of the enthusiasm susceptibility to scour. These methods, expressed by several states for the which might Include computer modeling, definitions of urgency of corrective would be based on the type of foundation action based on maintenance level and the material, type of substructure design, its modification chart, the proposed guideline susceptibility to scour, hydraulic booklet should be expanded to assess all characteristics of the stream, and elements of the deck, superstructure and statistics of failure. state-of-the-art substructure above as well as below the methods to arrest scour should be waterline. This research may eventually investigated. New or Improved methods to lead to the development of a comprehensive arrest scour should be developed. Bridge Maintenance Management System. REFERENCES 9. Hopkins, P.P., Morgan, I.L., Ellinger, H.D., Kllnkslek, R.V., Meyer, G.A., and Thompson, J.N., "Industrial Tomography American Public works Association, Applications." Transactions on Nuclear History of Public Works in the United Science, IEEE, Vol. NS-28, No. 2 (April States. APWA (197g) p. 106. 19S1) p. 1718. Jones, R., "A Review of the 10. Eslyn, W.E. and Clark J.W., "Wood Non-Destructive Testing of Concrete." Bridges - Decay Inspection and Control." Agriculture Handbook No. 557 Non-Destructive Testing of Concrete and (October 1979) pp. 20-21. Timber, Institution of Civil Engineers, London (1970) pp. 1-7. 11. McGee, D, , The Timber Bridge Inspection Morgan, I.L., Ellinger, H.D., Program in Washington State, PHWA Kllnkslek, R.V., and Thompson, J.N., (1^75). "Examination of Concrete by Computerized Tomography." Journal, 12, Orchard, D.P., Concrete Technology, ACI, Vol. 77, NO. 1 (January-February Vol. 1, Applied Science Publishers, 1980) pp. 23. England (1979) pp. 438-441. 13, Dutruel, F. and Guyader, R., "Etude de Clear, K.C., "Cost Effective Rigid Concrete Construction and la Corrosion des Canalisations en Rehabilitation In Adverse Beton." Monograph No. 7, Center Environment." PHWA, FCP Annual d'Etudes et de Recherches de Progress Report (Sept. 30, 1980) 1'Industrie du Beton Manufacture, Unpublished, pp. 13-15. Epernon (Juln 1975) pp. 55-64. Malhotra, J.M. and Carette, G., 14. Glassgold, I.L., "Repair of Seawater "Comparison of Pull-out strength of Structures - An Overview." Concrete Concrete with Compressive strength of International, Vol. 4, No. 3 (March Cylinders and Cores, Pulse velocity, im) pp. 50-52. and Rebound Number." Journal, ACI, Vol. 77, NO. 3 (May-June 1980) p. 161. 15. Perkins, P.H., Concrete Structures; Repair, waterproofing and Protection. Hardened John Wiley and Sons, New York (1977) p. 6. Malhotra, J.M. Testing 190. Concrete Nondestructive Methods. Iowa State university Press, Ames and 16. ACI Committee 201, "Guide to Durable ACI, Detroit (1976) pp. 50-51. Concrete." Journal, ACI, vol. 74, No. Arni, H.T., "Impact and Penetration 12 (December 1977) pp. 602-604. Tests of Portland Cement Concrete." HRR NO. 378 (1972) p. 55. 17. Geymayr, G.W., "Repair of Concrete in Tropical Marine- Environment." Youshaw, R. and Dryer, c, "underwater Performance of Concrete in Marine Non-destructive Testing of ship Hull Environment, SP-65, ACI, Detroit (1980) Welds." National Research Council, pp. 535, 538. Unpublished, pp. 4-7. 41 18. 'Protection of Concrete Structures." 28. ACI Committee 201, "Guide to Durable Consulting Engineering, Londonidon, vol. Concrete." ACI Journal, vol. 74, No. 41, No. 2 (February 1977) pp. 35-37"~, 41" . 12 (1977) p. 583. 19. Wakeman, CM., storer, J.W., and 29. Biczok, Imre, Concrete Corrosion and Liddell, O.E., '179 Years in Sea Concrete Protection. Chemical Water?" Materials Protection and Publishing Company, inc.. New York Performance, Vol. 12, No. 1 (January (1967) pp. 353-357. 1573) p. 14. 30. Gjorv, Odd, "Durability of Concrete 20. Florida State Maintenance Office, Structures in the Ocean Environment." 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Freeze-Thaw Resistance of Concrete." Chloride Corrosion of Steel in Cement and Concrete Research, Vol. 8, concrete; STP-629, ASTM, Philadelphia NO. 1 (1978) p. b9. (1976) p. 23. 27. Mehta, P.K., "Effects of Cement Composition on Corrosion of Reinforcing Steel in Concrete." Chloride Corrosion of steel in Concrete^ STP-629, ASTM, Philadelphia (1976) p. 14. Appendix A BIBLIOGRAPHY ACI Committee 201, "Guide to Durable Concrete." Journal, ACI, Vol. 74, No. 12 (December 1977) pp. 573-609. American Association of state Highway ACI Committee 212, "Guide for Use of Officials, Manual of Maintenance Admixtures in Concrete." ACI Journal Inspectio- n of Bridges. AASHO, Proceedings, Vol. 68, No. 9 (1971) pp. Washington, D.C. (1970) 71 pp 646-676. 2. American Association of State Highway American Public Works Association, and Transportation Officials, Manual of History of Public Works in the united Maintenance Inspection of Bridges States. A.P.W.A., Chicago (1976) TIF AASHTO, Washington, D.C. (1978) 75 pp. pp. 42 6. Anger, G., Ten-Division Influence Lines Applications." Transactions on Nuclear for Continuous Beams. Frederick Ungar Science, IEEE. Vol. NS-56, No. 2 (April Publishing Co., New York (1956) 247 pp. 1981) pp. 1717-1720. 7. Ami, H.T., 'Impact and Penetration 20. Houston, J. T., Atimtay, E. and Tests of Portland Cement Concrete." Ferguson, P.M., "Corrosion of HRR No. 378 (1972) pp. 55-67. Reinforcing Steel Embedded in Structural Concrete." Report No. 112-lF, Center for Highway Research, 8. Biczok, Imre, Concrete Corrosion and University of Texas, Austin (March Concrete Protection. Chemical 1972) 131 pp. Publishing Co., Inc., New York (1967) 543 pp. 21. jarocki, walenty, "The Effects of Low 9. Browne, R.D., "Mechanisms of Corrosion Temperatures on Hydraulic Structures of of Steel in Concrete in Relation to Concrete." Prace Technique institute. Design, Inspection, and Repair of Bulletin No. 299 Warsaw (D66). Offshore and Coastal structures." Performance of Concrete in Marine 22. Jones, R., "A Review of the Environment, SP-65, ACI, Detroit (1980) Non-Destructive Testing of Concrete." pp. 169-204. Non-Destructive Testing of Concrete and Timber, Institution of Civil Engineers, 10. Cook, H.K., McCoy, W.J., "Influence of • London (1970) pp. 1-7. Chloride in Reinforced Concrete." Chloride Corrosion of steel in 23. Lane, R.O., "Abrasion Resistance." concrete; STP-629, ASTM, Philadelphia Significance of Tests and Properties of (1976) pp. 20-29. concrete and Concrete Making Materials, STP-169B, ASTM Philadelphia (1978) pp. 349-352, 11. Dutruel, F. and Guyader, R., "Etude de la Corrosion des Canalisations en 24. Litvin, G.G. and Sereda, P.J., Beton." Monograph No. 7, Center "Particulate Admixture for Enhanced d'Etudes et di Recherches de Freeze-Thaw Resistance of Concrete." 1'Industrie du Benton Manufacture, Cement and Concrete Research, Vol. 8, Epernon (Juin 1975) 66 pp. NO. 1 (1978) pp. 53-60. 12. Eslyn, W.E. and Clark J.W., "Wood 25. Malhotra, J.M. Testing Hardened Bridges - Decay Inspection and Concrete;, Nondestructive Methods. Control," Agriculture Handbook No. 557 Iowa State University Press, Ames also (October 1979) pp. 20-21. Monograph #9 ACI, Detroit (1976) 188 pp. ' 13. Florida State Maintenance Office, 26. Malhotra, J.M. and Carette, G,, Manual for Bridge Maintenance Planning "Comparison of Pull-out Strength of and Repair Metho"dsT VoTT T", Florida Concrete with Compressive strength of D.O.T., Unpublished. 144 pp. , Cylinders and Cores, Pulse velocity, and Rebound Number." Journal, ACI, 14. Geymayr, G.W., "Repair of Concrete in Vol. 77, No. 3 (May-June 1980) pp. Tropical Marine Environment." 161-170. Performance of Concrete in Marine Environment! SP-65, ACI Detroit (1980) 27. McGee, D., The Timber Bridge Inspection pp. 527-556., Program in Washington State, FHWA (1975). 15. Gjorv, Odd, "Durability of Concrete Structures in the Ocean Environment." 28. Mehta, P.K., "Effects of Cement Concrete sea structures. Proceedings of Composition on Corrosion of Reinforcing the Federation Internationale de la steel In Concrete". Chloride Corrosion Precontrainte, London (1973) pp. of steel in Concrete; STP-629, ASTM, 141-145. Philadelphia (1976) pp. 20-29. 16. Glassgold, I.L., "Repair of Seawater 29. Morgan, I.L., Ellinger, H.D., Structures - An Overview." Concrete Klinkslek, R.V. and Thompson, J.N., International. vol. 4, No. 3 (March •Examination of Concrete by 1982) pp. 48-53. Computerized Tomography." Journal, ACI, Vol. 77, No. 1 (January-February 17. Greeves, I.S., 'Underwater 1980) pp. 23-27. Concreting." Civil Engineering and Public Works Review, vol. 68, No. 806 30. Neville, A.M., "Essentials of Strength (1973) pp. 768-789. and Durability of Various Types of Concrete with Special Reference to 18. Heneghan, J.I., "Shotcrete Repair of Sulfur." Journal, ACI, Vol. 76, No. 9 Concrete structures in Marine (Sept. 1979) pp. 973-996, Environment." Performance of Concrete in Marine Environment, SP-65 ACI, 31. Orchard, D.F., Concrete Technology. Detroit (1960) pp. 509-526. Vol. 1, Applied Science Publishers (1979) 375 pp. 19. Hopkins, p.p., Morgan, I.L., Ellinger, H.D,, Klinkslek, R.V., Meyer, G.A. and Thompson, J.N., "Industrial Tomography 43 32. Performance of Concrete in Marine Inspector's Training Manual. OS DOT, EnvironmenFi SP 65, ACI, Detroit FHWA, Washington, D.C. (1970) 181 pp. (1980) 627 pp. 38, U.S. Dept. of Transportation, Federal 33. Perkins, p.H. Concrete Structures; Highway Administration, Recording and Repair, Waterproofing and Protection. Coding Guide for Structure Inventory John Wiley and Sons' , New" York {1!>7/) and Appraisal of the Nation's Bridges. 302 pp. US DOT, FHWA, Washington, DTCI (I977) 38 pp. 34. Powers, T.C., "Freezing Effects on Concrete. Durability of Concrete. 39. Wakeman, CM., Storer, J .W. and SP-47, ACI, Detroit (1575) pp. l-l2. Liddell, O.E., "179 Years in Sea Water?" Materials Protection and 35. "Protection of Concrete structures". Performance, Vol. IT, No: i (January Consulting Engineering, London, Vol. 1973) pp. 14-17. 41, NO. 2 (February 19'/7) pp. 35-41. 40. Woods, Hubert, "Freezing and Thawing." 36. Tyler, Ivan L., "Concrete in Marine Durability of Concrete Construction, Environment." Symposium on Concrete ACI, Detroit (1968) pp. 15-2U. Construction in Aqueous Environments, ACI SP-8, ACI, Detroit (1954) pp. 2-6. 41. Youshaw, R. and Dryer C, "underwater Non-destructive Testing of Ship Hull 37. U.S. Dept. of Transportation, Federal Welds." National Research Council, Highway Administration, Bridge Unpublished, 31 pp. Appendix B RESEARCH APPROACH ADDRESSES AND SAMPLE LETTERS * Tennessee Department of Transportation TO SOLICIT INFORMATION * Texas Highway Department * Vermont Agency of Transportation HIGHWAY AGENCIES * Virginia Department of Highways and O.S.A. Transportation * West Virginia Department of * Alabama state Highway Department Transportation * Alaska Department of Highways * Wyoming Highway Department * California Department of Puerto Rico Highway Authority Transportation * Colorado Department of Highways * Addressees that responded * Connecticut Bureau of Highways * Florida Department of Transportation * Georgia Department of Transportation * Hawaii Department of Transportation * Idaho Department of Highways OTHER AGENCIES * Illinois Department of Transportation * Kansas State Highway Commission * Kentucky Department of Transportation Highway Authorities * Louisiana Department of Highways * Maine Department of Transportation *N.Y. State Thruway Authority * Maryland Department of Transportation •Massachusetts Turnpike Authority * Massachusetts Department of Public •Mackinac Bridge Authority Works * Michigan Department of State Highways and Transportation Railroads * Mississippi state Highway Department Seaboard Coastline Railroad * Montana Department of Highways •Chicago and Northwest TraAsit Company * Nevada Department of Highways Southern Pacific Transit Company * New Hampshire Department of Public •Kansas City Southern Railways Works and Highways Chessle System * New Jersey state Department of AT & Santa Fe Railway Transportation * North Carolina Department of Canadian National Railway Transportation Federal Railroad Administration * Oklahoma Department of Highways •New Zealand Railways * Oregon Highway Division • * Pennsylvania Department of Transportation Ports * Rhode Island Department of Transportation •Port of Los Angeles * South Dakota Department of •Port Authority of NY and NJ Transportation 44 U.S. Government •American Concrete Pile Association, Virginia *FHWA, Bridge Division, Hydraulic Branch •Associated Reinforcing Bar Producers, •U.S. Army, Corps of Engineers, Illinois Waterway Experimentation Station, International Bridge, Tunnel and Mississippi Turnpike Association, U.S. Army, Coastal Engineering Washington, D.C. Research Center, Ft. Belvoir, VA •American Concrete Pipe Association *U.S. Navy, Facilities Engineering Command United Kingdom *U.S. Navy, Civil Engineering Laboratory, Port Hueneme •Transport and Road Research Laboratory S. Coast Guard British Concrete Pumping Association *U S. Geological Survey, Water Corrosion Advice Bureau Resources Division, Denver •Cement and Concrete Association •Engineering and Research Center, •Reinforcement Manufacturers Association Department of Interior •British Precast Concrete Federation •U.S. Geological Survey, National Water •Construction Industry Research and Data Exchange Information Association •National Bureau of Standards U.S. Dept. of Commerce, National Technical information service West Germany •U.S. Navy, Naval Surface Weapons Center, VA Verein Deutscher zementwerke (Technical Association of the Foreign Governments Cement Industry) •Deutscher Beton-Verein (Concrete) Ministry of Works and Development, NZ •Porschungslnstitut Der zementindustrie •National Roads Board, NZ (Research Institute of the Cement •Ministry of Transportation & industry) Communications, Ontario, Canada Bundesverband Der Deutschen •National Road Administration, Sweden Zementindustrie (Cement Industry and Technical Advisory Services) COUNCILS, INSTITUTES, ASSOCIATIONS New Zealand AND CENTERS •Department of Construction, Experimental Building Section U.S.A. •Portland Cement Association Building Research Association •St. Anthony Falls Hydraulic •Department of Scientific and Laboratory, University of Minnesota industrial Research ^lowa institute of Hydraulic Research •Concrete Research Association Center for Transportation Research, •Institution of Engineers University of Texas •National Association of Corrosion Engineers, Texas South Africa ASCE, New York •ACI, Detroit National Building Research Institute •VDH&T Research Council, Virginia National Institute for Transport and •Transportation Laboratory, California Road Research Department of Transportation •Portland Cement Institute •Planning and Research Division, Texas State Department of Highways and Public Transportation Australia •Fitz Engineering Laboratoy, LeHigh university Concrete Institute of Australia •Highway Research Information Service, •Cement and Concrete Association Washington, D.C. •Texas Transportation Institute, Texas ASM University Canada •institute of Transportation and Traffic Engineering, University •Portland Cement Association of California at Berkley •National Research Council •National Ready Mixed Concrete Engineering Institute of Canada Association, MD •National Concrete Masonry Association, Virginia Belgium •Balcones Research Center, University of Texas Union Des Agglomeres De Ciment De •AREA, Washington, D.C. Belgique ASTM, PA (Belgian Cement Congolmerates Brookhaven National Laboratories, New union) York 46 Greece France Groupement Hellenique Du Beton •Federation Francaise De L'industrie Du Beton (Greek Association of Concrete) (French Federation of the Concrete industry) Norway Centre d'Etudes et de Recherches de l'industrie du Beton Manufacture Norsk Betongforening (Norwegian Concrete Association) Thailand Netherlands •international Ferrocement Information Center Betonvereniging - Sekretariaat (Netherlands Concrete Society) Vereniging Van Bentonmortalfabrikanten COMPANIES in Nederland (Dutch Ready-Mixed Concrete Association) U.S.A. •Adhesive Engineering Company, Sweden California (Epoxy) •American Chemical Corporation, Svenska Betonforeningen California (Epoxy) (Swedish Concrete Association) •American Colloid Co., Illinois (Waterproofing) Cathodic Protection Services, TX Finland Chapman Chemical Company (Sonic Tester) Exxon Corp. Suomen Betoniteollisuuden •Fox Industries, Inc. (Pile Jackets) Keskusjarjesto Ry •Froehling & Robertson, Inc., VA (Association of the Concrete •General Electric, N.Y. (Silicone industry in Finland) Admixture) •Gulf Oil Co. •Gulf States Paper Corp., Alabama Italy (Slope Stabilization) •Harco Corporation, Ohio (cathodic Associazione Nazionale Fra i Protection) Produttori Di Manufatti in Cemento Heath International, Inc., Michigan (National Association of Producers (Sonic Tester) and Manufacturers of Cement) •Lee Turzillo Contracting Co. •Maccaferri Gabion, Inc., MD •Mobile Oil Corp. Japan Northeast Electronics, NH (shigometer) •osmose Co., GA (Pile Jackets) Peabody Testing, IL Public Works Research Institute, Japan •Poly-Carb, Inc., Ohio (Epoxy) Raymond Concrete Pile Company •Raymond International Buildiners, Inc., NJ (Erosion Control) Switzerland •Scientific Measurement Systems, Inc. (Cat Scan) Verband Schweizerischer Shell Chemical Co. Transportbetonwerke •SIKA Chemical Corp., NY (Epoxy) (Swiss Ready-Mixed Assoc.) •Smithsonian Science information Exchange, Inc. Denmark •Structural Bonding Company, Michigan (Epoxy) Landsforeningen Dansk •Subsea International, LA Betonvare-lndustri •Symons Corporation (Pile Jackets) (Society Danish Concrete Industry) TAMMS Industries Co., IL Nordisk Vejteknisk Forbunds •The Hinchman Co. (Cathodic Protection) (Danish Roads Federation) •TYE Engineering Company (Hydraulic Research) •ICE Products Research s Development Spain Company (Pile Jacket) Hitchins Vandex Agriipacion Nacional De Los Derivados Del Cemento (National Association of Cement New zeland Producers) Remedial Engineering Morris & Wilson Tedec, Ltd. Stresscrete Industries 46 United Kingdom LIBRARIES Wells, Ltd. •Taylor woodrow Contracting, Ltd. Department of Transportation Library, Washington, D.C. Renesselaer Polytechnic Institute, Canada Library, Troy, NY Byrd, Tallamy, MacDonald and Lewis BC Research (Sonic Testing) Library Trans. Research Board Library, Washington, D.C. UNIVERSITIES Library of Congress, Washington, D.C. Fairfax County Central Library O.S.A. West Virginia University •Arizona University Oniversity of Michigan Massachusetts Institute of Technology STATES VISITED AND Oniversity of Virginia university of Maryland AGENCY PERSONNEL INTERVIEWED •Lehigh university Cornell University Virginia Polytechnic Institute •Pennsyvanla state university MARYLAND LOOSIANA University of California Texas A & M University E. Williams Ensor M. Pani •Oniversity of Minnesota Douglas Hood •oniversity of Texas Sheldon Law •university of Illinois OREGON Larry Lucas South Dakota state University Ed Bodker Connecticut University John Wood Gerald Test Thailand Donald Dean FLORIDA Robert P. Brown •Asian Institute of Technology IDAHO Jack Roberts Julian McCrory James Welch Bill Alford Norway Larry Davis MASSACHOSETTS •University of Trondheim John Wood Jim Gould New Zealand Joseph Donahue Arthur Blunt University of Auckland Jack Shutt Oniversity of Canterbury John Ahem South Africa •oniversity of stellenbosch •Rand Afrikaans oniversity •Oniversity of Natal Oniversity of Cape Town •oniversity of Pretoria ATTENDEES -"BRAINSTORMING" SESSION EXPERTS 1. Mr. Craig A. Ballinger Office of Research Federal Highway Administration •FFM Chang (Hydraulics) •Emmett M. Laursen (Scour) 2. Mr. Douglas H. Beeson •Bryan Mather, Corps of Engineers Project Manager (Concrete) Byrd, Tallamy, MacDonald and Lewis Gordon Beecroft (Oregon Pile Study) Ernst Renstrup, Denmark 3. Mr. Roland H. Berger •Dr. Roger D. Browne (Taylor-Woodrow Advisory Committee Member Research Laboratory) Byrd, Tallamy, MacDonald and Lewis •Dr. Odd E. Gjorv 4. Mr. Wade F. Casey Chesapeake Division Naval Facilities Engineering Command 47 5. Mr. Thomas L. Copas 10. Dr. Anil K. Rastogi Special Projects Engineer Owens-Cormng Fiberglas Transportation Research Board 11. Dr. Robert J. Reilly 6. Mr. Donald R. Graber Projects Engineer Assistant Principal Investigator Transportation Research Board Byrd, Tall amy, MacDonald and Lewis 12. Mr. Martin C. Rissel 7. Mr. James W. Harland Principal Investigator Acting Advisory Committee Member Byrd, Tallamy, MacDonald and Lewis Byrd, Tallamy, MacDonald and Lewis 8. Dr. Alfred Marzocchi 13. Mr. Philip T. Scola Chesapeake Division Exploratory Research Technical Center Owens-Corning Fiberglas Naval Facilities Engineering Command 9. Mr. Ronald L. Purvis 14. Mr. Schuyler B. Smith Advisory Committee Member Dow Corning Corporation Byrd, Tallamy, MacDonald and Lewis TELEPHONE INTERVIEW Personnel Contacted T.L. Cain Maintenance Engineer Alabama Kenneth McGuire Engineer California Milton Johnson Engineer of Bridge Design Connecticut Jack Roberts Engineer of Maintenance Florida Bob Brown Corrosion Engineer Florida Larry Davis Bridge Maintenance Planning Engineer' Florida Steve L. Pittman Assistant District Engineer, Maintenance Georgia James Welch Bridge Maintenance Engineer Idaho Gayle-Lane Bridge Maintenance Engineer Illinois Charles Reichenbach Bridge Maintenance Engineer, Chief Kentucky Al Dunn Structures Maintenance Engineer Louisiana Everett Barnard Assistant Bridge Maintenance Engineer Maine E. William,Ensor Chief, Bridge Inspector Maryland John N. Grim Assistant Chief Engineer Massachusetts Richard McGinn Structure Maintenance Engineer Massachusetts N.S. Walker Engineer Bridge Maintenance Michigan James R. Newkirk Engineer III Mississippi Alfred Westall Assistant Chief Bridge Engineer Nevada Ed Swierz State Bridge Engineer New Hampshire Rodger Blaisdell Bridge Safety Inspector New Hampshire Warren Sunderland State Bridge Engineer New Jersey Jimmy Lee Head of Bridge Maintenance North Carolina John Wood Bridge Maintenance Engineer Oregon A. Parol a District Bridge Engineer Pennsylvania John Ekiert Acting District Bridge Engineer Pennsylvania Anthony Callia Chief of Bridge Inspection Rhode Island Harry Anderson Engineer Rhode Island Clyde Jundt Bridge Maintenance Engineer South Dakota Ralph Banks Supervising Field Engineer Texas Warren Tripp Chief of Bridge Inspection and Design Vermont D.C. Harrier Assistant Bridge Engineer Virginia Other Agencies ^ Orlando Doyle, Chief Engineer, MacKinac Bridge Authority E. Van Beilen, Head Task Force Special Studies, Ministry of Transportation of Ontario, Canada David Brookings, Bridge Engineer, Kansas City Southern Railway Company Phil Scola, Engineer, Specialized Inspection, Underwater Investigation, Naval Engineering Facilities Command Larry Anderson, Harbor Engineer I, Port of Los Angeles 48 C U T3 ^ Ol 4«J 5CO « *-> o ^& -St °i i- 3 o. o a. 11^ 5 5 3 C O ^ .- u U 01 5>-o c S3 «a to C 3 >i L> l/l C 3 01 4J C c o c -D ; •O Q. OJ E « OJ I 1? 01 a. 01 3 O ••-» i- O lO 4-> ^ E O — -6 ei3 QJ cn OJ > 3 -O 41 >t U> N O) Q C t- (Q U 3 to to £ c a 01 r- >> W « o w -r- -o -O **- to 01 Wl fO o ••- 01 s > . +* o J- 3 01 Wl *i c J= t. 5 oun w -r- • ^ <0 E |C r— CO i_ VI 01 o u Dew in 4/t I/I t/t M S A 01 o c c 01 01 01 O) 4J 4-» 4J 4-* S'::l«52E:;3i W N W * 4-> M 233i5 ' 0) -M 01 3 *-> 3 lo t/> to 01 § St; 00 ^ ^ in X Q. 49 r—1 LOU OJ t- u 5 * E E c •t-»T) 0) « C 1- OJ ro Oi 0) u ••- 1_ O 3 m T) C 01 «*- o- 0( Vt C i- +J 01 o» c - -M >l- O U irt 0> TJ c » o m ^ tt) u U "O r- o u O C 1- w > •J I- R 0) uS5 OCX -4J > u O C r- la 3 >*- 01 >> J= 4-* 01 cn c 4-» U •o oi a. O "O o E C U O S « 3 U C (A 01 I/I O O <0 o> -a •— 01 3 Q. lO o (O v» E — r- 0> ^ a* to ^ c 0) c > »- Ols: I/) 01 >> O i— 3^ 4-1 01 »1 Ol 3 3 C 4-> 0) 01 3 U> W) M t/l o,„ 3 01 01 01 O 3 4J 4-> Ot u o I c c u Si Ifl - •13 4^ 4^ >> o m iD (/> s °^ T) t- 0,- 4-* 1. 5*- is o « c<^ « 3 >>i^ 01 V) U O. g_ t-i (t_ f- II <4- 4-> 01 u< 01 1^ ° u c « 4-1 U 01 5§ —• 4-* 3 la 4-> 60 Appendix C HIGH QUALITY CONCRETE SDGGBSTBD PROCBDDRBS FOR OBTAINING HIGH ABRASION QDALITY CONCRETE AND GOOD CONSTROCTION PRACTICES , The most important concrete property for abrasion resistance is strength. The The durability of concrete under water stronger the concrete is, the less erodable and in the splash zone depends on the mix it will be. Concrete with 5,000 psi is design and the environment in which it will twice as resistant as 3,000 psi. One very serve. Concrete which is designed to be of important concrete property affecting high quality for one environment may strength is the void to cement ratio which deteriorate rapidly in another. An example has been shown to vary inversely with of this would be the use of air-entraining abrasion resistance (22). Care should be admixtures to increase freeze-thaw taken, however, not to increase the cement resistance. Although this is an advantage content to the point where the homogeneity in compensating for the expansion of or the slump is impaired. internal water, it is extremely deleterious when the concrete is exposed to abrasion. When selecting an aggregate, it is This appendix discusses procedures for advantageous to select one that is at least obtaining high quality concrete and good as hard as the abrasive solids. In a case construction practices in response to four where sand is the abrasive, an extremely causes of concrete deterioration (abrasion, hard aggregate, such as quartz, should be chemical attack, corrosion, and used. Angular coarse aggregate exhibits freeze-thaw). ') significantly better abrasion resistance than round aggregate because it bonds more Certain guideli nes should always be tightly to the cement paste. Only a minimum followed when desig ning a mix for use under amount of fine aggregates should be used. water. A plastic mi X of high workability should be used, This is important to Calcium chloride can give concrete high prevent segregation and because mechanical abrasion resistance. Tests have shown that compaction is diffi cult under water. These 2 percent calcium chloride accelerates the characteristics are achieved with a cement early strength of concrete. Samples have content of at least 350 kg/m3 and a slump of been produced that are, on the average, 100 no more than 125 mm (21). percent more resistant to cavitation and 10-25 percent more resistant to abrasion. A low water-cement ratio is also Any admixture that increases strength, such desirable. This will produce high strength as water reducing agents, increases abrasion and low permeability. Permeability is resistance (2fi.) . reduced by reducing the amount of residual water left after hydration, which will cause When pouring concrete to resist voids, pores, and capillaries. abrasion, good construction practices are essential. Proper compaction and curing Prestressed concrete performs quite will help to provide a dense hard concrete. well in a hostile environment. This is The shape of the substructure is also a because it is produced with dense, high factor. A streamline shape will help to strength concrete that is factory cured avoid cavitation and reduce impact from under a high degree of quality control. In moving solids. addition, transverse cracks tend to automatically close because of the CHEMICAL ATTACK longitudinal prestressing force. Adherence to good construction Cement properties, such as permeability practices is always mandatory. Care in and physical and chemical composition, play placing and compacting of the concrete mix an important role in chemical resistance. and proper curing are all important. Strict In most cases, a good quality cement will be compliance to plan dimensions and material resistant to most chemicals; however, there specifications is essential. The use of are a few isolated cases where a concrete epoxy coated bars and piles that have been that is resistant to one type of attack may treated before being driven is also not be resistant to another. An example of recommended. In addition, a method was this would be the tricalcium aluminate (C3A) discovered for which a pile is soaked in content. In order for the concrete ' to clean water before it is driven so that the resist chlorides, it must contain more than pile will not tend to soak up seawater after 8 percent C3A. On the other hand, in order it is driven. for the concrete to resist sulfates, the content should not exceed 8 percent (21, The following procedures are 2fi). Permeability is the most important recommended in order to make concrete factor in resisting chemical attack because durable to the four specific causes of dete• it affects the ability of the ions to rioration. penetrate the concrete. Authors vary on 61 what is the ideal water-cement ratio. Most to protect reinforcing steel from corrosion recommended ratios are from 0.45 to 0.55 for are relatively the same as those to protect moderate and severe exposures respectively it from chemical attack. A dense impervious (22) . concrete is necessary to prevent corrosive agents from reaching the reinforcement. One of the most severe forms of Again this is achieved by maintaining a low chemical attack is due to sulfate ions. water-cement ratio and by the use of Sulfate ions attack tricalcium aluminate, a water-reducing admixtures to ensure normal constituent of concrete. The product compaction. Cement type, which has of this reaction expands and gives rise to significant effect on chemical resistance, cracks. A C3A content of 8 percent or less has no effect on corrosion resistance. A is required to minimize this action. tricalcium aluminate content of greater than 8 percent, which is harmful in the presence Seawater in the mix water has been of sulfates, is helpful in controlling demonstrated as a means to increase sulfate chlorides. Tricalcium aluminate combines resistance. Doses up to 5 percent improve with Chloride ions and takes them out of the 28 day strength also. This method is solution (21)• not recommended, however, because of the added risk of accelerated corrosion. The use of seawater in the mix water, as mentioned before, for sulfate resistance The proper choice of aggregate is is not recommended for reinforced concrete important because it has an effect on because the added chlorides will accelerate porosity. Lightweight aggregates should be corrosion by combining with lime thereby avoided because these aggregates are usually lowering the alkalinity of concrete and porous and allow passage of aggressive making the concrete a better electrolyte. agents to the interior of the concrete. Aggregate should also be hard, clean, dry, Hard impervious aggregate, such as quartz and impervious. It should also be free from and solite, should be used whenever contamination. For example, if the possible. Aggregates should always be clean aggregate was of marine origin, chlorides and dry. Compatibility of the aggregates could be present. Admixtures and corrosion coefficient of expansion with that of the inhibitors have proved useful in preventing cement helps to reduce cracking, which, in corrosion of reinforcement. Certain turn, helps to prevent the ingress of inhibitors have had deleterious effects on aggressive agents. concrete properties. Some are subject to leaching and can establish concentration Admixtures, such as pozzolans, have cells enhancing corrosion. Others can exhibited varied performances, depending on seriously affect the concrete. Corrosion the type of attack. Ply ash, volcanic inhibitors are a fairly new concept and glass, diatomaceous earth, some shales, require more research. clay, and pumice are among the most common pozzolans. Pozzolans increase sulfate Admixtures, such as pozzolans, are resistance by combining with free lime and often times beneficial ~"in inhibiting by reducing porosity. This property is also corrosion. Ply ash exhibits good corrosion advantageous in resisting acid attack. On resistance by increasing the energy required the other hand, pozzolan cements are less to cause corrosion. Host pozzolans reduce resistant to magnesium attack because of the the alkalinity of concrete, which makes the lack ot free lime. Magnesium chloride in steel more susceptible to corrosion; but it seawater reacts with calcium hydroxide also reduces the permeability, which makes (lime) to form magnesium hydroxide which is the steel less vulnerable. insoluable in water and seals the concrete. Without sufficient free lime, the concrete cannot be sealed. Air entraining also By employing the proper procedures when increases sulfate resistance. preparing concrete, a durable concrete will result that will protect the reinforcing steel. Host steel corrosion is the result Other cements, such as gypsum of poor construction practices. (supersulfated) cement, have performed well Insufficient cover and a variety of other in the marine environment, High alumina conditions will all cause accelerated cements also exhibit good durability in corrosion of the reinforcing steel. seawater. These cements ar e less porous than normal portland cements and contain no tricalcium aluminate. Type V (sulfate FREEZE-THAW resisting) cement should be used in waters containing sulfates. The physical and chemical properties of Chemical resistance is often difficult freeze-thaw resistant concrete are extremely to achieve because more than one deleterious important. Many tiroes, even good quality chemical may be present. In this instance, concrete will deteriorate because of the required combination of concrete freeze-thaw. Concrete is especially properties may be difficult to obtain. In susceptible when completely saturated. any case, the good construction practices Therefore, special care and techniques must should always be observed. be used to produce a concrete that is dense, impervious, and difficult to saturate. CORROSION The method for obtaining a dense impervious concrete is, more or less, the The criteria for high quality concrete same as that mentioned previously for other 62 forms of attack. A low water-cement ratio contents from 3 percent to 7 1/2 percent, reduces capillary size and continuity, thus depending on the severity of exposure and reducing the permeability of the concrete. normal aggregate size. Air content alone is Reduced capillary size also lowers the not enough to resist freeze-thaw damage. freezing point of pore water due to surface Void spacing is also important. If voids and thermodynamic forces. A water-cement are too far apart, the water will not be ratio of 0.40 to 0.45 is recommended. In able to migrate to the voids. Authors moderate climates this ratio can be raised recommend void spacings between 0.005 in. slightly to 0.50 to 0.55. A low tricalcium and 0.008 in. (2fl, IS, . aluminate content also helps to produce a more dense concrete (iQ, 21, i2). Silicone admixtures have shown promise in combating freeze-thaw. Silicones The type of aggregate used is also increase the freeze-thaw durability greatly significant in freeze-thaw resistant and at the same time increase the concrete concrete. The aggregate should be nonporous strength. Water-reducing admixtures reduce and dry. Nonporous aggregates are less the capillary size and porosity, thus likely to become saturated at a later date. yielding a more durable concrete. Dry aggregates are needed to ensure that the aggregate is not saturated when placed; Porous particle admixtures have been however, when properly cured, saturated used experimentally with promising results. aggregate is not usually a problem. This is Porous particles with at least 30 percent because of self-desication during early total porosity and pore diameters between hydration. Transpiration also helps to keep 0.3 and 2 microns have significantly the aggregate dry by allowing water to increased freeze-thaw resistance. automatically migrate from a wet to a dry Commercially fired clay-brick and area. Most freezing and thawing occurs in diatomaceous earths show the most promise; the splash zone where transpiration will be however, diatomaceous earths can cause a factor. Aggregate size has a great effect alkali-silica reactions and should be used on frost resistance. Large aggregates cause with caution. Porous particles have excess expansion during freezing. advantages over air-entrainment because the Coefficients of expansion can also cause control of air-entrainment over narrow problems if the aggregates and the cement limits is difficult. The amount and spacing paste expand at different rates. of entrained air are dependent on many factors, such as mix composition, Certain admixtures have been useful in temperature, and time taken during mixing resisting the effects of freeze-thaw. The and finishing operations. When using porous most common are air-entraining admixtures. particles, spacing is easily controlled by Air entrainment provides added space for particle size and concentration. The water to migrate during freezing. Too much limiting size of particles should be between entrained air can lower the strength, 0.4 and 0.8 mm due to the pore structure of however. Strength reduction in most cases the brick. Beyond this point, the internal rarely exceeds 15 percent (2i). Most of the pore volume is insufficient (II). effects of air entrainment are advantageous. Freeze-thaw durability, workability, lower water content, and less segregation are The effects of freeze-thaw can be among a few. Three air entraining reduced, but they are very difficult to admixtures in extensive use are: wood eliminate. Any concrete can be damaged when resin, detergents, and sulfonated hydro• it is completely saturated. Cyclic freezing carbons of petroleum. These admixtures and thawing will inevitably cause should be administered in doses that provide microcracks and strength reductions in about 4 1/2 percent air by volume (24). The concrete. American Concrete Institute suggests air Appendix D CONCRETE DETERIORATION Freeze-Thaw Water level falls and water on outside surface of concrete freezes. Then INITIATION STAGE water level rises and ice on outside surface of concrete thaws. Abrasion 1. Slow at first due to smooth hard PROPAGATION STAGE surface 2. Cavitation produces water hammer Abrasion 3. Waterline abrasion due to grinding of ice sheets Deterioration is faster in this 4. Mudline abrasion stage due to: a. Due to rolling or impacting a. A rougher surface texture solids b. Exposure of softer interior b. Tension stresses due to concrete turbulent underpressure. Ice sheets abrade cover. 63 Freeze-Thaw 3. Ettringite attracts a large number of water molecules causing further Freezing of water in concrete pores expansion causes Internal pressure. Theories to explain scaling from freeze-thaw are as 4. Expansive forces cause cracking. follows: Magnesium Sulfate 1. Pressure developed by expulsion of 1. Magnesium sulfate attacks hydrated water from saturated aggregate aluminum to form ettringite, but particles also attacks hydrated silicates to 2. Hydraulic pressure developed in form gypsum, nearly insoluable capillaries just below the magnesium hydroxide and silica gel. concrete surface. 2. Ettringite that is formed is 3. Accretion of moisture to ice unstable m magnesium sulfate and crystals in capillaries below the forms more gypsum. surface 4. Osmotic pressures caused by Magnesium Chloride concentration of salt in capillaries immediately beneath the 1. Magnesium chloride -reacts with concrete surface calcium hydroxide as follows: 5. Cracking and crazing provide MgCl2 + Ca(0H)2-*-Mg(0H)2 + channels for moisture to reach CaCl2 underlying capillary ice 2. CaCl2 is readily soluable and is 6. Cyclic temperature fluctuations easily leached cause creep, fatigue, and 3. Mg(0H)2 precipitates and seals differential expansion of concrete slowing corrosion. aggregate and mortar. Chlorides Carbonic Acids 1. Chlorides reduce alkalinity of the Carbonic acids react with calcium concrete paste and reduce hydroxide to form calcium passivity of steel carbonate and take twice as much Chlorides tend to make the moisture. concrete a better electrolyte [CO2 + H20-^H2C03l + promoting the corrosion of the Ca(0H)2-»CaC03 + 2H2O reinforcement. Additional free moisture may migrate into the concrete Ammonium Ions depending on the concrete ambiency 3. Acids reduce alkalinity, not 1. React with calcium necessarily strength 2. Reduce strength of concrete 4. Reduces passivity of steel. Corrosion Sulfates 1, Corrosion begins slowly Attacks free lime to form calcium 2. Corrosion products actually sulfate (gypsum) which occupies inhibit corrosion twice the initial volume Corrosion products expand and Gypsum and hydrated calcium crack cover. aluminate form calcium Appendix E METHODS TO ARREST DETERIORATION - CASE HISTORr WORK SHEET CASE HISTORY 1 Deficiency ^S^^f'f WORK SHEETS 2. Method of repair (se^ /^/g6//tg Owner :r-OMMO ^asev<>g7W^>l/^7-- yV/^h^j^^ 7. Owner evaluation Date &-(£-&/ a. Struct'l Integrity Restored? ^ b Deter Arrested? /Ya c. Cause Eliminated',^ d Life or anticipated life of methods Sivp'^r e Owners evaluation <^^yi^rv^.>°^->-xryi 's-rjpe^^aan ne,oos/r'=i Researcher's conments ^rShMX^Jf^^y^ ^>yyo<=.^ i^jrMOtJT 01 METHODS TO ARREST DETERIORATION - CASE HISTORY WORK SHEET D. METHODS TO ARREST DETERIORATION. - CASE HISTORY WORK SHEET 1. Deficiency zew^ Deficiency CVag^oj/^/./ ojir- ^^SAffs ^—af't.^in xa^S CaM^^iaM o/' 'fP^ALtjsxf JAJ s/=l^sm 2. Method of Repair ^^j' r^M-rj^A (sjtx fix, y) Date (/^^A^ify^A^ Method of Repair f=^ae,c J^rtrr /set j'lai^Me 9) Date A«S M70i Date 3. Substructure construction /R/^^ fi^js/r- Date /93 5. Location ^our£ // Ofsa A^tra Poui-u^/r-r-jr^y/^ 5. Location /Pnii^^ ai^rff - J-AtfM f^fTZt'^ft Tf?<^/f/ Owner ^autsi^M yO^>»>.jfW»^7-—a£— 6. Owner Lac/isjMf^ /Djr^M-rM^M-r >-f/aM^^ys 7. Owner evaluation Date /g>-C-g/ 7. Owner evaluation Date /0-&-B/ a. Struct'1 Integrity Restored?/^'^ b Deter Arrfested^ /V^ a. Struct'1 Integrity RestoredT.^^ b. Deter Arrfested? r^y c Cause E1iminated7A^ d. Life or anticipated life of methods c Cause E1iminated7/14 d Life or anticipated life of methods^a«os6> e Owners evaluation yiii. f^^/iSJS. _ e Owners evaluation L/A/.'^jSM-r/^ i^/ta^ i^of^s. uts^O. 8. Researcher's mmnnpntt Cffr/T7"*Tir ilT t'lVKfri ZS—Of^TW/^v 8. Researcher's comments //V Tvyg- ^fo-o,—^ METHODS TO ARREST DETERIORATION - CASE HISTORY WORK SHEET METHODS TO ARREST DETERIORATION - CASE HISTORY WORK SHEET 1. Deficiency rZni:rjrnsjo/^ n/r /fsa^/fs .S^LjtS^ ^o^s- 1 Deficiency (Zo^/mSJ>oM ^ersAtrr /// S^t-ASH |gO/V.a 2. Method of repair /^VC \^^j>f (ssr ^/g 2. Method of repairX'ya^ jACMT-spaxy M,jra(fio/£ilS^^^Jji!'f<:f^eK 3. Substructure construction BSMT Date /ya^ 3. Substructure construction /^,t.B- •°t--ivr Date /'93>2 Environment S/f^CK-rtM I^tct f/oeexl. 4. Znvirorment_^^^ri 5. Location /P„,.ts // oy&i? ^iSiSS.—^^CM^/?T/^^/f/ 5. Location X^tvt ay»Ji ^^>re cai^/zTViVa//v Owner Za.y/j/^^>i /:>BrAtfT/^S//-r or—i^/a'i^i^yS- 6. Owner /^y,'/^st.e^ ,^er<^'/K . e Owners evaluation .r>orr,^,'^ - S^-g-^t za-^£. y^.f-r»^o. 8. Researcher's coirments Uss^ui L jife<^ ^-f-g^-s x-zTV-y 8. Researcher's cornnents TZ^^s- m/skT fk^'?^ j^j.'t-T-oys'.i'—j.^^^ S6 |5 •z N at ? = i ^1 1. S T- 41 >1 U i Jl o t. 1 oj V) 1^ c5 o i 5 —J t ^ s !! . O "O if S S ii V 5 Jl ^ 66 i *• VI SHEE T 1) •3 0) C. 1VI •M >- « o 1 N ;AS E I IO N - c 1 S J V 1 O VI ER I ( h- o 0 I 2 » UJ 1. I. O 1. J C r- f— oh- s. U 1 z & HV- 5 -: t O 5 e cie n T3O 5 a £ si CM 0) a -0a1 «to- 3 0) «*- 4-> O I 1/1 01 01 1 I i. r- <0 1 —4J ^ i ! i 5 1 1 VI ^1 -15 t— t— 01 Appendlx F SUBSTRUCTURE ANALYSIS METHODS TO ARREST DETERIORATION - CASE HISTORY WORK SHEET SYRO, TALLAMY, V 1 Deficiency -ZV-^ jqao^rj^ ^x£Fxs--T»^t'—C^f-?,^fr<' .0^0::."'::::. SUBJECT ^-sz^^-z--^ ch«..d.y_ 2. Method of Repair a^^^jr frgg /-i^s n ^/a) Date C^^,^^^ y^y^^^yysys ^^^^^^^ Sheet No L _ of . 3. Substructure construction ^ji_if ^(Tn^ Date Uvfr^,^ 4. Environment y,^-nrjr - 5. Location yg? o^.r--c cuaz—m^tr t^.g->s Owner ^^jgy^^^a DefMr^^y^^r of 7>.<^y^-«»^7-,-i r/g/V 7. Owner evaluation Date 7-/^-3/ .— /y^fii,tys^€.£ a. Struct'1 Integrity Restored!/Vi) b Deter. Arrfested^ >-^!: c. Cause EliminatedT/^/^ d. Life or anticipated life of methods ^Pjvn' e Owners evaluation JTV M^ira TM/J ajf/n^-.^ /-^o^ Dsy^£> ^y:>M£3 iQ^^c-ryoy^ £>/v y^t.ys - O Bl^)'- > - /• ?S •yg'TT/fif—Ci^i^f^ae. y^/?£^ ^iSSU/^eo y^ery^ C^'y^/'yce SJyOy 8. Researcher's conments Coi.i.^jt ^i^^-r /^avt-^eg-o pe-/iiaa/c^^ A M . ^ ^ Jp^^ y y^S-^y^y^^y^a.yy^^ METHODS TO ARREST DETERIORATION -.CASE HISTORY WORK SHEET 1. Deficiency (Zojv/i03,ajj r>^ /^M^/rs. //v •TJ'I.^SM ^O^£- y^Ae^ — / 2. Method of repair ..^^/ga ^^-r^z,(^/ta /9f.?o^0ate (J^^^^^^ 3. Substructure construction a^y^-r Date 1. Environment S^^rmi^ ytyyanfjf do y^r) jO/y^y^ey^yt. /=y^g- ' Z/^ = <¥.Z,^ ^^<9 " 5. Location yg>i^yg- // „^ex Lyttre /=i:,y^e.uMT/^^'y' 6. Owner ^oL>trj^y^^ Dii-MxrjKr^ e>^ /V/S.»M^>'J 7. Owner evaluation Date /£>-&-fi/ a. Struct'l Inteqnty Restored? /Vo b Deter Arrested? Cause Elimfnated^/^ d Life or anticipated life of methods Sjjo^v Owners evaluation y>^My.y^^.. jf<^g-gy;-fg • 3K i. Researcher's cownents /a,r»^a^. Ol Ol BYRD, TALUMY, ^WCDONALD i LEWIS ^3 BYRO, TALLJ>MT, M«OONAU) 8 LEWIS PROJECT fiPP^/^Ol X f_ SUBJECT S^e^TR^c^r^'^e: ^ ANALYSIS OF PILE F^T^n^TZ^ Made by Date .No <|< _ Checked by Date BF.NT SKETCH - CONDITION Pile Spacing (L) = g'-O" Number of Piles + . Skew Pile Size /2 ' ^ [ 1 Abutment (End Bent) - Span Length Beam Spacing Intermediate Bent-Span Length 2ciai 3oo' Dead Load Reaction/Beam (D.L./BEAM) azr + c ZS = o So (Sec Note 4 ) Live Load Reaction (L L ) for H Truck (from chart) •= /3 C "(See Notes 1,2*3) D.L. Continuity Distribution Factor = / / O L L. Continuity Distribution Factor + (See Note 5) "•L ""^tlon \ (•>••• If^^CA ' ^''"-^ Cont. Dist Fact.)/^a' L L. Reaction =• (L L.) x (L.L. Cont Dist. Fact.) /y./v' Capacity (INVENTORY) ^ BUCKLING OR BEARING Capacity (OPERATING) J (is V Sf^^^^3 eauMi. (»6K6RA<_ COKiOi-noN oi^Pvuilfti Capacity Available for L.L (Capacity Inventory) - (D L Reaction) •= iVfi^INV MiN SPACJNS Qe:Twee^4 TRUCKS = ' Capacity Available for L L =• (Capacity Operating) - (D.L Reaction) = OPER AU. TIMQEA Pil-Ei I'l-"* -1 KiLM Capacity Factor = (Capacity Avail L.L.) •.(L.L. Reaction) 2 "-tC-f INVENTORY » HOOPS) iMV ,i«,fciof>e« 3 3^"^ OPERATING Ration = (capacity Factor Operating) • (Capacity Factor Inventory) A 38 RATINGS INFUU^NC^ COEFFICIENT CALC11UAT\0N INVENTORY RATIO OPERATING H Truck - INV F X 15 36 06 T-o, CASS. « I NOTES 1 If the cap Is of any other inaterlal than t1i*er, multiply llveload by Impact factor 2. L L. H Truck from AASHTO. t 3. For unequal longitudinal spans, L.L. reaction to be average of intermediate reaction 1 for the two considered spans, but not less than end reaction for larger span i-o" T. i-o T 4. D.L./Beam to be for BOTH SPANS FOR INTERIOR CAP '1' 5. If the cap simply supported with a splice, do not use continuity factors for 0 L. and 1 L L. e * Skew Is 0° when cap Is perpendicular to roadway centcrllne. Therefore COS = 1. ' I 3goO < m'T.yghf.e gggfycignr Co-^g -niut-*.) F-1 OTRO, TALwiMY, M4C0ONALO S LEWIS PROJECT AREA «fi.»AA«NiNS = S'-1L.-r<' - 78 i-'V F-4 01 « 61 Appendix Q PROPOSED GUIDELINE BOOKLET TABLE OF CONTENTS Introduction Instructions Inspection Forms Scour around Piles Undermining of a Footing Section Loss of a Concrete Pile Section Loss of a Steel Pile Section Loss of a Timber Pile General Deterioration of Concrete General Deterioration of Timber Settlement INTRODUCTION The number of different types of substructure elements and the types of deficiencies which occur to them are relatively limited. There is, however, a wide diversity of opinion on how the significance of a deficiency should be judged. Most jurisdictions responsible for the underwater Inspection and repair of bridge substructure elements, have developed their own subjective "rule of thumb" guidelines for the rating of a deficiency which may or may not be written In any appreciable detail. These "rule of thumb" guidelines may often appear arbitrary, but they are of substantial significance as they are generally based on the judgement of experienced bridge engineers. The purpose of this booklet is to provide a guided, objective method to measure the threat to the Integrity of a structure from a maintenance viewpoint. This booklet is not to be construed as a replacement for the rating system now used to rate the substructure condition for Item 60 of the Federal Highway Administration's (FHWA) "Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation's Bridges" (SI&A), but rather as an adjunct to It. The SI&A rating system is required for consistency of approach for funding eligibility from a reconstruction viewpoint. The methods presented herein are only meant to provide a more consistent approach to the process of assessing deficiencies from a maintenance viewpoint. 62 The guidelines and modifications presented herein aid inspection personnel in arriving at an initial assessment of a deficiency expressed as a numerical value. This assessment, in turn, indicates the urgency of corrective action. This number prescribes the type of action to be taken in the inspection process as well as by maintenance forces in scheduling work which is to be performed. INSTRUCTIONS On the following pages there are a number of guidelines for types of substructure elements and materials describing various states of deterioration. The steps to be taken in the use of these guidelines are presented below. 1) Inspection personnel are to select the description which most closely depicts the severest example of deterioration found. The number appearing adjacent to the chosen description Is the Initial assessment of the deterioration. 2) The deficiency should then be photographed or sketched for the purpose of documentation in the inspection report. 3) The initial assessment may then be modified based on the threat to the integrity of the structure caused by the effect of supplemental or external factors. Ih this way, deficiencies may first be evaluated by the guidelines shown and then modified by conditions which are unique to a particular area or climate. The right hand chart provided on the back of each form is to be used to perform this function for all deficiencies. 4) The assessment modification should then be algebraically added to the initial assessment to produce the maintenance urgency index. Assessment and modification numbers may be circled to highlight the guidelines used. The statement next to the numbers chosen should be underlined to document the reason'for the selection. 5) Once an urgency Index has been selected, the type of action to be taken in inspection process and by maintenance forces can then be selected. This is done by consulting the chart on the next page. The Administrative level at which the assessment modification should be approved is not addressed here. With the aid of this method, the assessment of underwater deficien• cies of bridge substructures can be performed in an objective manner. Inspection personnel can uniformly arrive at a numerical value to indicate the urgency of corrective action from a maintenance viewpoint. 63 SUBSTRUCTURE CONDITION BELOW THE WATERLINE URGENCY OF CORRECTIVE ACTION MAINTENANCE URGENCY INDEX Maintenance Maintenance Inspection Urgency Index Immediacy of Action Course of Action 9 No repairs needed. 8 No repairs needed. List specific items for special inspection during next regular in• spection. Note in inspection report only. No immediate plans for repair. Examine possibility of increased level of inspection. By end of next season - add to scheduled work.J Place in current schedule - current season - first reasonable opportunity. Priority - current season - review work plan Special notification for relative priority - adjust schedule if to superior is possible. warranted. 3 High priority - current season as soon as can be scheduled. 2 Highest priority - discontinue other work if required - emergency basis or emergency sub• Notify superiors sidiary actions if needed (post, one lane verbally as soon as traffic, no trucks, reduced speed, etc.) possible and confirm in writing. 1 Emergency actions required - reroute traffic and close. 0 Facility is closed for repairs 64 Assessment Modification Chart Based on Threat to Integrity of Structure Modification Description +2 No threat for minimum of 5 years and one or more of the following: 1. Deficiency condition is slowing; 2. External causes of deterioration substantially reduced or eliminated; 3. Deficiency has history in similar circumstances of being self correcting; 4. Deficiency is entirely "cosmetic" in nature and has little or no structural effect.* (Note: May be used for original rating of 2 to 6 inclusive.) +1 No threat for minimum of 3 years and one or more of the following: 1. Deficiency condition is stable; 2. External causes of deterioration have lessened somewhat; 3. Deficiency has history in similar circumstances of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect.* (Note: May be used for original rating of 2 to 7 inclusive.) 0 No threat for minimum of one year and one or more of the following: 1. Deficiency condition worsening at expected or "normal" rate; 2. External causes of deterioration have remained constant; 3. Deficiency has history in similar circumstances of growing worse at consistent rate; 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: May be used for any original rating.) -1 Threat anticipated within one year and one or more of the following: 1. Deficiency condition worsening at increasing rate; 2. External causes of deterioration are Gradually in• creasing; 3. Deficiency has history in similar circumstances of growing worse at gradually increasing rate; 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 inclusive.) -2 Threat is imminent and one or more of the following: 1. Deficiency condition is worsening rapidly; 2. External causes of deterioration are rapidly increasing; 3. Deficiency has history in similar circumstances of growing more severe at rapidly increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 inclusive.) * Structural effect includes redundancy of load path and other factors, 65 SCOUR AROUND PILES 1 1 FLOW p 4' / h3' ; II 1 1 I I I I I I I I _1-L Initial ' Modification Urgency Assessment Index DESCRIPTION: SKETCHES: Initial GUIDELINES DESCRIPTION Modification Assessment No threat for minimum of 5 years and one or more of the following: No scour 9 1. Deficiency condition Is stable; 2. External causes of deterioration substantially No scour 8 reduced or eliminated; +2 3. Deficiency has history In similar circumstances of being self correcting; 4. Deficiency is entirely "cosmetic" in nature and has little or no structural effect. Light scour around piles 7 (Note: May be used for original rating of 2 to 6 inclusive.) No threat for minimum of 3 years'and one or more of Moderate scour around piles 6 the following: 1. Deficiency condition Is worsening slowly; 2. External causes of deterioration have lessened somewhat; +1 3. Deficiency has history in similar circumstances Moderately heavy scour pockets around piles 5 of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect. (Note: May be used for original rating of 2 to 7 4 inclusive.) Heavy scour pockets around piles No threat for minimum of one-year and one or more of the following: Scour pockets have Increased unsupported length dramatically 3 1. Deficiency condition worsening at expected or "normal" rate; 2. External causes of deterioration have remained 0 constant; 3. Deficiency has history in similar circumstances Pile Is completely exoosed 2 of growing worse at consistent rate; 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: May be used for any original rating.) Structure Is threatened 1 Threat anticipated within one year and one or more of the following: Structure Is closed 0 1. Deficiency condition worsening at increasing rate; 2. External causes of deterioration are Gradually in- -1 creasino; 3. Deficiency has history in similar circumstances of growing worse at gradually Increasing rate; 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 Inclusive.) Threat Is imminent and one or more of the following: 1. Deficiency condition Is worsening rapidly; 2. External causes of deterioration are rapidly Increasing, 3. Deficiency has history In similar circumstances -2 of growing more severe at rapidly Increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 Inclusive.) 67 UNDERMINING OF FOOTING 45' Initial " Modification Urgency Assessment Index DESCRIPTION: SKETCHES: Note: Once a pile is exposed, it must also be rated 00 GUIDELINES Initial DESCRIPTION Modification Assessment No threat for minimum of 5 years and one or more of the following: No undermining 9 1. Deficiency condition is stable; 2. External causes of deterioration substantially No undermining 8 reduced or eliminated; +2 3. Deficiency has history in similar circumstances of being self correcting; 4. Deficiency is entirely "cosmetic" in nature and has little or no structural effect. OX to 102 of pile footing area is exposed 7 (Note: May be used for original rating of 2 to 6 inclusive.) No threat for minimum of 3 years and one or more of 102 to 302 of pile footing area Is exposed 6 the following: 1. Deficiency condition is worsening slowly; 2. External causes of deterioration have lessened somewhat; +1 Greater than 302 of pile footing area is exposed. 3. Deficiency has history in similar circumstances 02 to 102 of piles are exposed. 5 of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect. (Note: Nay be used for original rating of 2 to 7 Inclusive.) 102 to 502 of piles are exposed 4 No threat for minimum of (uie-year and one or more of the following: 502 to 902 of piles are exposed. 3 1. Deficiency condition worsening at expected or 02 to 1002 of spread footing is undermined. "normal" rate; 2. External causes of deterioration have remained 0 constant; 3. Deficiency has history in similar circumstances 902 to 1002 of piles are exposed 2 of growing worse at consistent rate; 4. Deficiency has structural effect but has not • seriously reduced structural capacity. (Note: Hay be used for any original rating.) Structure threatened 1 Threat anticipated within one year and one or more of the following: Structure is closed. 0 1. Deficiency condition worsening at increasing rate, 2. External causes of deterioration are gradually in• -1 creasing; 3. Deficiency has history In similar circumstances of growing worse at gradually increasing rate; 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 inclusive.) Threat is imninent and one or more of the following: 1. Deficiency condition Is worsening rapidly; 2. External causes of deterioration are rapidly Increasing; 3. Deficiency has history in similar circumstances -2 of growing more severe at rapidly increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 Inclusive.) 69 SECTION LOSS OF CONCRETE PILE ^ ^ 4" Typical SECTION ELEVATION Initial Modification Urgency Assessment Index DESCRIPTION: SKETCHES: Modification o GUIDELINES Initial DESCRIPTION Assessment No threat for minimum of 5 years and one or more of the following: OX section loss - area In plan' 9 1. Deficiency condition Is stable; 2. External causes of deterioration substantially +2 OS section loss - area In plan 8 reduced or eliminated; 3. Deficiency has history In similar circumstances of being self correcting; 4. Deficiency Is entirely "cosmetic" in nature and has little or no structural effect. OX to 5X section loss - area In plan 7 (Note: May be used for original rating of 2 to 6 Inclusive.) -- No threat for minimum of 3 years and one or more of 6 the following: 5X to lOX section loss - area In plan 1. Deficiency condition Is worsening slowly; 2. External causes of deterioration have lessened somewhat; +1 lOX to 15Z section loss - area In plan or 3. Deficiency has history In similar circumstances Reinforcing bar has section loss. 5 of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect. (Note: Nay be used for original rating of 2 to 7 15X to 20X section loss - area In plan or 4 - Inclusive.) Reinforcing bar has section loss No threat for minimum of one-year and one or more of the following: 20X to 30X section Toss - area In plan or 3 1. Deficiency condition worsening at expected or Reinforcing bar Is free-standinq "normal" rate, 2. External causes of deterioration have remained 0 constant; 3. Deficiency has history in similar circumstances Over 30X section loss - area In plan 2 of growing worse at consistent rate; 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: Hay be used for any original rating.) Structure is threatened 1 Threat anticipated within one year and one or more of the following: 0 1. Deficiency condition worsening at increasing rate; Structure Is closed 2. External causes of deterioration are oradually in- -1 creasino; 3. Deficiency has history In similar circumstances of growing worse at gradually increasing rate, 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 inclusive.) Threat is Imnlnent and one or more of the following: 1. Deficiency condition is worsening rapidly, 2. External causes of deterioration are rapidly increasing; 3. Deficiency has history in similar circumstances -2 of growing more severe at rapidly increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 inclusive.) 71 SECTION LOSS OF STEEL PILE 3" f 1 I I HP 10 X 42 SECTION ELEVATION Initial Modification Urgency Assessment Index DESCRIPTION: SKETCHES: GUIDELINES Initial DESCRIPTION Modification Assessment No threat for minimum of 5 years and one or more of the following: 02 section loss - area In plan 9 1. Deficiency condition is stable, 2. External causes of deterioration substantially OZ section loss - area In plan 8 reduced or eliminated; +2 3. Deficiency has history in similar circumstances of being self correcting; 4. Deficiency is entirely "cosmetic" in nature and has little or no structural effect. OX to 5X section loss - area In plan 7 (Note: May be used for original rating of 2 to 6 inclusive.) No threat for minimum of 3 years and one or more of 5X to 15X section loss - area in plan 6 the following: 1. Deficiency condition Is worsening slowly; 2. External causes of deterioration have lessened somewhat; +1 3. Deficiency has history in similar circumstances 15X to 35X section loss - area in plan S of growing no worse; 4. Deficiency Is mostly "cosmetic" in nature and has little structural effect. (Note: May be used for original rating of 2 to 7 35X to SOX section loss - area in plan 4 inclusive.) No threat for minimum of one year and one or more of the following: SOX to 70X section loss - area in plan 3 1. Deficiency condition worsening at expected or "normal" rate; 2. External causes of deterioration have remained 0 constant; 3. Deficiency has history In similar circumstances More than 70X section loss - area In plan 2 of growing worse at consistent rate; 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: May be used for any original rating.) Structure threatened 1 Threat anticipated within one year and one or more of the following: structure is closed 0 1. Deficiency condition worsening at increasing rate; 2. External causes of deterioration are Gradually 1n- -1 creasina; 3. Deficiency has history In similar circumstances of growing worse at gradually increasing rate; 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 inclusive.) Threat is imnlnent and one or more of the following: 1. Deficiency condition is worsening rapidly; 2. External causes of deterioration are rapidly increasing; * 3. Deficiency has history in similar circumstances -2 of growing more severe at rapidly Increasing rate; 4. Deficiency has severe structural effect. (Note: Nay be used for original rating of 4 to 8 Inclusive.) 73 SECTION LOSS OF TIMBER PILE 2" Shell ! I r ~1 SECTION ELEVATION Initital ' Modification Urgency Assessment Index DESCRIPTION: SKETCHES: GUIDELINES Initial DESCRIPTION Modification Assessment No threat for minimum of 5 years and one or more of OX section loss in plan (external) the following: 9 1. Deficiency condition is stable; 2. External causes of deterioration substantially OX section loss In plan (external) 8 reduced or eliminated; +2 3. Deficiency has history in similar circumstances of being self correcting; 4. Deficiency is entirely "cosmetic" in nature and has little or no structural effect. OS to St section loss in plan (external) 7 (Note: May be used for original rating of 2 to 6 Inclusive.) No threat for minimum of 3 years and one or more of 5« to 15X section loss in plan (external) 6 the following: 1. Deficiency condition is worsening slowly; 2. External causes of deterioration have lessened somewhat; +1 15S to 25X section loss in plan (external) 3. Deficiency has history in similar circumstances S of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect. 25X to SOX section loss in plan (external), or (Note: May be used for original rating of 2 to 7 0« to lOX section loss in plan (internal), or 4 inclusive.) OX to lOX section loss in plan (internal + external 1 No threat for minimum of one-year and one or more SOX to 7SX section loss in plan (external), or of the following: lOX to SOX section loss in plan (Internal), or 3 1. Deficiency condition worsening at expected or lOX to SOX section loss in plan (internal + external) "normal" rate; 2. External causes of deterioration have remained 0 More than 7SX section loss in plan (external), or constant; (tore than SOX section loss in plan (internal), or 3. Deficiency has history in similar circumstances More than SOX section loss in plan (internal + external) 2 of growing worse at consistent rate; 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: May be used for any original rating.) Structure is threatened 1 Threat anticipated within one year and one or more of the following: Structure is closed 0 1. Deficiency condition worsening at increasing rate; 2. External causes of deterioration are Gradually 1n- creasina; -1 3. Deficiency has history in similar circumstances of growing worse at gradually increasing rate, 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 inclusive.) Threat is inininent and one or more of the following: 1. Deficiency condition is worsening rapidly; 2. External causes of deterioration are rapidly Increasing; 3. Deficiency has history in similar circumstances -2 of growing more severe at rapidly increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 Inclusive.) 75 GENERAL DETERIORATION OF CONCRETE + = Initial ' Modification Urgency Assessment Index DESCRIPTION: SKETCHES: GUIDELINES Initial DESCRIPTION Modification Assessment No threat fdr mlnlnuun of 5 years and one or more of No deterioration the following: 9 1. Deficiency condition Is stable; 2. External causes of deterioration substantially No deterioration 8 reduced or eliminated; +2 3. Deficiency has history in similar circumstances of being self correcting; 4. Deficiency is entirely "cosmetic" in nature and has little or no structural effect. Light scaling 7 (Note: May be used for original rating of 2 to 6 inclusive.) No threat for minimum of 3 years and one or more of Moderate scaling or light spalling 6 the following: 1. Deficiency condition Is worsening slowly; 2. External causes of deterioration have lessened somewhat; +1 Heavy scaling or moderate spalling or cracking over 3. Deficiency has history in similar circumstances reinforcing steel. 5 of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect. (Note: May be used for original rating of 2 to 7 Heavy spalling with reinforcing steel exposed 4 inclusive.) No threat for minimum of one-year and one or more of the following: Severe spalling with reinforcing steel free-standing 3 1. Deficiency condition worsening at expected or "normal" rate; 2. External causes of deterioration have remained 0 constant; 3. Deficiency has history in similar circumstances Heavy section loss 2 of growing worse at consistent rate; 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: May be used for any original rating.) Structure Is threatened 1 Threat anticipated within one year and one or more of the following: Structure Is closed 0 1. Deficiency condition worsening at increasing rate; 2. External causes of deterioration are aradually 1n- creasina; -1 3. Deficiency has history in similar circumstances of growing worse at gradually increasing rate, 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 inclusive.) Threat is innlnent and one or more of the following: 1. Deficiency condition is worsening rapidly; 2. External causes of deterioration are rapidly increasing; 3. Deficiency has history in similar circumstances -2 of growing more severe at rapidly increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 Inclusive.) 77 GENERAL DETERIORATION OF TIMBER + = Initial ' Modification Urgency Assessment Index DESCRIPTION: SKETCHES: CO GUIDELINES Initial DESCRIPTION Modification Assessment No threat for minimum of S years and one or more of No deterioration the following: 9 1. Deficiency condition is stable; 2. External causes of deterioration substantially +2 No deterioration 8 reduced or eliminated, 3. Deficiency has history In similar circumstances of being self correcting, 4. Deficiency Is entirely "cosmetic" in nature and has little or no structural effect. Light weathering 7 (Note: May be used for original rating of 2 to 6 Inclusive.)_ _ No threat for minimum of 3 years and one or more of Moderate weathering 6 the following: Light splintering 1. Deficiency condition is worsening slowly; 2. External causes of deterioration have lessened +1 Light decay or , somewhat; 3. Deficiency has history in similar circumstances Moderate splintering with gapping or 5 Heavy weathering of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect. (Note: May be used for original rating of 2 to 7 Moderate decay or Inclusive.) Heavy splintering with gapping to heartwood or 4 Moderate biological growth No threat for minimum of one-year and one or more Heavy decay of the following: Heartwood deteriorated 3 1. Deficiency condition worsening at expected or "normal" rate; 2. External causes of deterioration have remained 0 Advanced decay or constant; Heavy biological growth or 3. Deficiency has history in similar circumstances 2 of growing worse at consistent rate; Heavy loss of section 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: Hay be used for any original rating.) Structure Is threatened 1 Threat anticipated within one year and one or more of the following: Structure Is closed 0 1. Deficiency condition worsening at increasing rate; 2. External causes of deterioration are Gradually in- ' creasino; -1 3. Deficiency has history in similar circumstances of growing worse at gradually increasing rate; 4. Deficiency has structural effect. (Note: Hay be used for original rating of 3 to 8 inclusive.) Threat is Innlnent and one or more of the following: 1. Deficiency condition is worsening rapidly; 2. External causes of deterioration are rapidly increasing; 3. Deficiency has history in similar circumstances -2 of growing more severe at rapidly Increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 Inclusive.) 79 SETTLEMENT Initial " Modification Urgency Assessment Index DESCRIPTION.: SKETCHES: 00 GUIDELINES Initial DESCRIPTION Modification o Assessment No threat for minimum of 5 years and one or more of No settlement the following: 9 1. Deficiency condition Is stable; 2. External causes of deterioration substantially No settlement 8 reduced or eliminated; +2 3. Deficiency has history In similar circumstances of being self correcting; 4. Deficiency Is entirely "cosmetic" in nature and has little or no structural effect. Hinor settlement or tlltinq of substructure 7 (Note: Hay be used for original rating of 2 to 6 inclusive.) - - Moderate settlement or tilting of substructure. No threat for minimum of 3 years and one or more of Joints are less than design opening. 6 the following: 1. Deficiency condition is worsening slowly; 2. External causes of deterioration have lessened Ridablllty Impaired. Bearing devices and joints are fully somewhat; +1 open or closed before full design movement has occurred. 3. Deficiency has history in similar circumstances 5 of growing no worse; 4. Deficiency is mostly "cosmetic" in nature and has little structural effect. Thru cracks visible in substructure, no dislocation. (Note: Nay be used for original rating of 2 to 7 Bearing devices and Joints are locked. 4 inclusive.) No threat for minimum of one-year and one or more Thru cracks visible with moderate relative displacement. of the following: Joints spalling from Induced stress. 3 1. Deficiency condition worsening at expected or "normal" rate; 2. External causes of deterioration have remained 0 Thru cracks visible with major relative displacement. constant; Major settlement or tilting substructure. 3. Deficiency has history in similar circumstances 2 of growing worse at consistent rate; 4. Deficiency has structural effect but has not seriously reduced structural capacity. (Note: May be used for any original rating.) Structure Is threatened. 1 Threat anticipated within one year and one or more of t^ie following: Structure Is closed. 0 1. Deficiency condition worsening at Increasing rate; 2. External causes of deterioration are gradually in- creaslnp; -I 3. Deficiency has history in similar circumstances of growing worse at gradually Increasing rate; 4. Deficiency has structural effect. (Note: May be used for original rating of 3 to 8 inclusive.) Threat is imminent and one or more of-the following: 1. Deficiency condition Is worsening rapidly; 2. External causes of deterioration are rapidly increasing; 3. Deficiency has history in similar circumstances -2 of growing more severe at rapidly increasing rate; 4. Deficiency has severe structural effect. (Note: May be used for original rating of 4 to 8 inclusive.) THE TRANSPORTATION RESEARCH BOARD is an agency of the National Research Council, which serves the National Academy of Sciences and the National Academy of Engineering. The Board's purpose is to stimulate research concerning the nature and performance of transportation systems, to disseminate information that the research produces, and to encourage the application of appropriate research findings. The Board's program is carried out by more than 270 committees, task forces, and panels composed of more than 3,300 administrators, engineers, social scientists, attorneys, educators, and others concerned with transportation; they serve without compensation. The program is supported by state transportation and highway departments, the modal administrations of the U.S. Department of Transportation, the Association of American Railroads, the National Highway Traffic Safety Administration, and other organizations and individuals interested in the development of transportation. The Transportation Research Board operates within the National Research Council. The National Research Council was established by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and of advising the Federal Government. The Council operates in accordance with general policies determined by the Academy under the authority of its congressional charter of 1863, which establishes the Academy as a private, nonprofit, self-governing membership corporation. The Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineer• ing in the conduct of their services to the government, the public, and the scientific and engineering communities. It is administered jointly by both Academies and the Institute of Medicine. The National Academy of Sciences was established in 1863 by Act of Congress as a private, nonprofit, self-governing membership corporation for the furtherance of science and technology, required to advise the Federal Government upon request within its fields of competence. Under its corporate charter the Academy established the National Research Council in 1916, the Nadonal Academy of Engineering in 1964, and the Institute of Medicine in 1970. TRANSPORTATION RESEARCH BOARD NON-PROFIT ORG. Narional ReMarch Council U.S. POSTAGE 2101 Conttitulion Avanue, N.W. PAID Washington, D.C. 20418 WASHINGTON, D.C. ADDRESS CORRECTION REQUESTED PERMIT NO. 42970 00 lU u z UJ o 3( U. Z o z >• o X UJ o < < (/)a zt- X •-tie. oo < i-i nt- oz jfMai