Manual of AASHTO

8/3/2019 Manual of AASHTO

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MANUAL FOR CONDITIONEVALUATION OF BRIDGES1994

Prepared by theAASHTO Subcommittee on Bridges and Structures Copyright 1994 by the American Association of State Highway and Trans-portation Officials. All Rights Reserved. This book, or any part thereof, mustnot be reproduced in any form without the written permission of the publisher.ISBN: 1-56051-067-6

Published by theAmerican Association of State Highway and Transportation Officials444 North Capitol Street, N.W., Suite 249Washington, D.C. 20001


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AASHTO EXECUTIVE COMMITTEE1992-1993

VOTING MEMBERSOfficers

President:Vice President:Secretary:Wayne Muri, MissouriHoward YerusaIim, PennsylvaniaClyde E. Pyers, Maryland

Regional RepresentativesRegion IRegion 1/Region IIIRegion IV

Charles O'Leary, New HampshireWayne Shackelford, GeorgiaKirk Brown, Illinois(vacant)NON-VOTING MEMBERS

Immediate Past President: A. Ray Chamberlain, ColoradoExecutive Director: Francis B. Francois. Washington. D.C.


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HIGHWAY SUBCOMMITTEE ON BRIDGES AND STRUCTURES1 9 9 3

JAMES E. SIEBELS, COLORADO, ChairmanG. CHARLES LEWIS, GEORGIA, Vice ChairmanSTANLEY GORDON, Federal Highway Administration, SecretaryALABAMA, Fred ConwayALASKA. Steve Bradford. Ray ShumwayARIZONA. William R. Brucsch, F. Daniel DavisARKANSAS, Veral PinkertonCALIFORNIA. James E. RobertsCOLORADO, A.J. SiccardiCONNECTICUT, Gordon BartonDELAWARE. Chao H. HuD.C.. Charles F. Williams, Jacob PatnaikFLORIDA, Jerry PotterGEORGIA, Paul LilesHAWAII, Donald C. OrnellasIDAHO, Richard JobesILLINOIS, Ralph E. AndersonINDIANA, John 1. WhiteIOWA, William A. LundquistKANSAS, Kenneth F. HurstKENTUCKY, Richard SutherlandLOUISIANA, Norval KnappMAINE, James Chandler, Theodore KarasopoulosMARYLAND, Earle S. FreedmanMASSACHUSEITS, Joseph P. GillMICHIGAN, Sudhakar KulkarniMINNESOTA. Donald J. FlemmingMISSISSIPPI, Wilbur Frank MasseyMISSOURI, Allen F. LaffoonMONTANA, James C. HilINEBRASKA, Lyman D. FreemonNEVADA, Floyd I.MarcucciNEW HAMPSHIRE, James A. MooreNEW JERSEY. Robert PegeNEW MEXICO, Martin A. GavurnickNEW YORK, Michael J. Cuddy, Arun ShiraleNORTH CAROLINA, John L. SmithNORTH DAKOTA, Forest DurowOHIO, B. David HanhilammiOKLAHOMA, Velda M. GoinsOREGON, Terry J. ShikePENNSYLVANIA, Mahendra G. PatelPUERTO RICO, Jorge L. Melendez. Jorge L.

AcevedozRHODE ISLAND, Kazem FahhoumandSOUTH CAROLINA, Benjamin A. MeetzeSOUTH DAKOTA, Clyde H. JundtTENNESSEE, Clellan Loveall, Ed WassermanTEXAS, Luis YbanezU.S. DOT, Stanley Gordon (FHWA), Nick E.Mpars (USCG)

UTAH, Dave ChristensenVERMONT. Warren B. TrippVIRGINIA, Malcolm T. KerleyWASHINGTON, Allan H. WalleyWEST VIRGINIA, James SothenWISCONSIN, Stanley W. WoodsWYOMING, David PopeALBERTA, Bob RamsayMANITOBA, W. SaltzbergMARIANA ISLANDS. Elizabeth H. Salas-Balajadia

NEW BRUNSWICK, Garth RushtonNEWFOUNDLAND. Peter LesterNORTHWEST TERRITORIES, Jivko JivkovNOVA SCOTIA, Stan NguanONTARIO, Rajit S. ReelSASKATCHEWAN, Lome J. HamblinMASS. METRO. DIST. COMM., David LenhardtN.J. TURNPIKE AUTHORITY, Wallace R. GrantPORT AUTHORITY OF NY & NJ, Joseph K.Kelly

NY STATE BRIDGE AUTHORITY. WilliamMoreau

BUREAU OF INDIAN AFFAIRS-DIVISION OFTRANSPORTATION, Wade Cosey

U.S. DEPARTMENT OF AGRICULTURE-FOREST SERVICE, Steve L. BunnellMILITARY TRAFFIC MANAGEMENTCOMMAND. Robert D. Franz

U.S. ARMY CORPS OF ENGINEERS-DEPT. OFTHE ARMY, Paul C.T. Tan

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TABLE OF CONTENTSPage

ACKNOWLEDGEMENT xi1. INTRODUCTION 1

1.1 PURPOSE 11.2 SCOPE 11.3 APPLICABILITY............................................ I1.4 QUALITY MEASURES 11.5 BRIDGE MANAGEMENT SYSTEMS I1.6 DEFINITIONS AND IMPORTANT REFERENCES 1

1.6.1 Definitions........................... 11.6.2 Important References 2

2. BRIDGE FlLE (RECORDS) 52.1 GENERAL.................... 52.2 COMPONENTS OF BRIDGE RECORDS 5

2.2.1 Plans 52.2.1.1 Construction Plans 52.2.1.2 Shop and Working Drawings 52.2.1.3 As-Built Drawings 5Specifications 5Correspondence 5Photographs 5Materials and Tests 52.2.5.1 Material Certfication 52.2.5.2 Material Test Data 62.2.5.3 Load Test Data 6

2.2.6 Maintenance and Repair History 62.2.7 Coating History 62.2.8 Accident Records 62.2.9 Posting 62.2.10 Permit Loads 62.2.11 Flood Data 62.2.12 Traffic Data 62.2.13 Inspection History 62.2.14 Inspection Requirements 62.2.15 Structure Inventory and Appraisal Sheets 62.2.16 Inventories and Inspections 62.2.17 Rating Records 72.3 INVENTORY DATA 72.3.1 General 72.3.2 Revised Inventory Data 8

2.4 INSPECTION DATA 82.4.1 General 82.4.2 Revised Inspection Data 9

2.2.22.2.32.2.42.2.5

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2.5 CONDITION AND LOAD RATING DATA 92.5.1 General 92.5.2 Revised Conditions and Load Rating Data ;.......... 92.6 LOCAL REQUIREMENTS 93. INSPECTION 113.1 GENERAL 113.2 TYPES 113.2.1 Initial Inspections 113.2.2 Routine Inspections 113.2.3 Damage Inspections 123.2.4 In-Depth Inspections 123.2.5 Special Inspections 133.3 FREQUENCY 133.4 QUALIFICATIONS AND RESPONSIBILITIES OF INSPECTION PERSONNEL 133.4.1 General 133.4.2 Inspection Program Manager 133.4.3 Inspection Team Leader 133.5 SAFETY 143.5.1 General 143.5.2 Personnel Safety.................................................................................................. 14

3.5.3 Public Safety 143.6 PLANNING, SCHEDULING AND EQUIPMENT 143.6.1 Planning 143.6.2 Scheduling 153.6.3 Equipment 153.6.3.1 Access Methods and Equipment 153.6.3.2 Inspection Methods and Equipment 153.7 INSPECTION FORMS AND REPORTS 153.8 PROCEDURES 163.8.1 General 163.8.1.1 Field Measurements 163.8.1.2 Cleaning 173.8.1.3 Guidelines for Condition Rating of Bridge Components 173.8.1.4 Critical Deficiency Procedures 173.8.2 Substructure 173.8.2.1 Abutments 173.8.2.2 Retaining Walls 183.8.2.3 Piers and Bents 183.8.2.4 Pile Bents 193.8.2.5 Bridge Stability and Movements :........................................... 193.8.2.6 Dolphins and Fenders 203.8.3 Superstructure 203.8.3.1 Steel Beams, Girders and Box Sections 213.8.3.2 Reinforced Concrete Beams and Girders 213.8.3.3 Prestressed Concrete Beams. Girders and Box Sections 213.8.3.4 Timber Systems 223.8.3.5 Floor Systems 223.8.3.6 Trusses.... 223.8.3.7 Cables 233.8.3.8 Diaphragms and Cross Frames 233.8.3.9 Lateral Bracing, Portals and Sway Frames 233.8.3.10 Rivets, Bolts and Welded Connections 243.8.3.11 Pins and Hangers 24

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3.8.3.12 Bearings 253.8.3.13 Paint , 253.8.3.14 Utilities 253.8.3.15 Arches 263.8.4 Decks.............................. 263.8.4.1 Concrete Decks 263.8.4.2 Prestressed Concrete Deck Panels 273.8.4.3 Steel Decks 273.8.4.4 Timber Decks 283.8.4.5 Expansion Joints 283.8.4.6 Railings, Sidewalks and Curbs 283.8.4.6.1 Railings 283.8.4.6.2 Sidewalks and Curbs 293.8.4.7 Bridge Drainage 293.8.4.8 Lighting 293.8.4.9 Deck Overlays 293.8.5 Approaches 293.8.5.1 Pavement 293.8.5.2 Drainage 293.8.5.3 Traffic Safety Features 293.8.5.4 Embankment Slopes 303.8.6 Signs 303.8.7 Waterways 303.8.8 Box Culverts as Bridges 313.8.9 Corrugated Metal Plate Structures 313.8.10 Encroachments 313.9 SPECIAL STRUCTURES 323.9.1 Movable Bridges , 323.9.2 Suspension Spans 333.9.3 Cable-Stayed Bridges 333.9.4 Prestressed Concrete Segmental Bridges 333.10 UNDERWATER INSPECTIONS 343.10.1 Routine Underwater Inspections 343.10.2 In-Depth Underwater Inspections with Divers 343.11 FATIGUE PRONE DETAILS 343.12 FRACTURE CRITICAL MEMBERS 35

4. MATERIAL TESTING 374.1 GENERAL 374.2 FIELD TESTS 374.2.1 Concrete Field Tests 374.2.1.1 Strength Methods 374.2.1.2 Sonic Methods 374.2.1.3 Ultrasonic Techniques 384.2.1.4 Magnetic Methods 384.2.1.5 Electrical Methods 394.2.1.6 Nuclear Methods 394.2.1.7 Thermography 394.2.1.8 Radar 394.2.1.9 Radiography 394.2.1.10 Endoscopes 404.2.2 Steel Field Tests 404.2.2.1 Radiography 404.2.2.2 Magnetic Particle Examination 40

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4.2.2.3 Eddy Current Examination 414.2.2.4 Dye Penetrant Examination 414.2.2.5 Ultrasonic Examination 424.2.3 Timber Field Tests 424.2.3.1 Penetration Methods 424.2.3.2 Electrical Methods 434.2.3.3 Ultrasonic Techniques 434.3 MATERIAL SAMPLING 444.4 LABORATORY TESTS 454.5 INTERPRETATION AND EVALUATION OF TEST RESULTS 454.6 TESTING REPORTS 45

5. NON-DESTRUCTIVE LOAD TESTING 476. LOAD RATING 496.1 GENERAL 496.1.1 Assumptions................. 496.1.2 Substructure Consideration 496.1.3 Safety Criteria 496.1.4 Application of Standard Design Specifications 496.1.5 Nonredundant Structures 50

6.1.6 Load Rating for Complex Structures 506.2 QUALIFICATIONS AND RESPONSIBILITIES 506.3 RATING LEVELS 506.3.1 Inventory Rating Level 506.3.2 Operating Rating Level 506.4 RATING METHODS 506.4.1 Allowable Stress (AS) 506.4.2 Load Factor (LF) 506.5 RATING EQUATION 506.5.1 General 506.5.2 Allowable Stress 516.5.3 Load Factor 516.5.4 Condition of Bridge Members 516.5.5 Bridges with Unknown Structural Components 526.6 NOMINAL CAPACITY (C) 526.6.1 General 526.6.2 Allowable Stress Method 526.6.2.1 Structural Steel 526.6.2.1.1 Combined Stresses 526.6.2.1.2 Batten Plate Compression Members 65Wrought Iron 65Reinforcing Steel 65Concrete 666.6.2.4.1 Bending 666.6.2.4.2 Columns 666.6.2.4.3 Shear (Diagonal Tension) 676.6.2.5 Prestressed Concrete 67

6.6.2.6 Masonry 676.6.2.7 Timber 676.6.3 Load Factor Method 686.6.3.1 Structural Steel 696.6.3.2 Reinforced Concrete 696.6.3.3 Prestressed Concrete 69

6.6.2.26.6.2.36.6.2.4

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6.7 LOADINGS 696.7.1 Dead Load (D) 696.7.2 Rating Live Load 696.7.2.1 Wheel Loads (Deck) 716.7.2.2 Truck Loads 716.7.2.3 Lane Loads .. 716.7.2.4 Sidewalk Loadings 716.7.2.5 Live Load Effects (L) 716.7.3 Distribution of Loads 716.7.4 Impact (I) c . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . 716.7.5 Deflection 716.7.6 Longitudinal Loads 716.7.7 Environmental Loads 726.7.7.1 Wind 726.7.7.2 Earthquake , 726.7.7.3 Thermal Effects 726.7.7.4 Stream Flow 726.7.7.5 Ice Pressure , 726.8 DOCUMENTATION OF RATING 72

7. ADDITIONAL CONSIDERATIONS 737.1 GENERAL 737.2 CORRELATION OF INSPECTION, TESTING AND LOAD RATING DATA 737.3 FATIGUE EVALUATION OF STEEL BRIDGES 737.4 POSTING OF BRIDGES 737.4.1 General 737.4.2 Posting Loads 737.4.3 Posting Analysis 757.4.4 Regulatory Signs 757.4.5 Speed Limits 757.5 PERMITS........... 757.5.1 General 757.5.2 Routine Permits 757.5.3 Controlled Permits 757.5.4 Escorted Permits 757.6 HISTORIC BRIDGES 767.7 SPEC~AL CONDITIONS 76

APPENDIX A 77APPENDIX B 89APPENDIX C 119COMMENTARY 123INDEX 135

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AcknowledgementThis work was sponsored by the American Association of State Highway and Transportation Officials. in cooperationwith the Federal Highway Administration. and was conducted in the National Cooperative Highway ResearchProgram which is administered by the Transportation Research Board of the National Research Council. This researchwas performed under NCHRP Project 12-23 by A. G. Lichtenstein and Associates, Inc.Subconsultants to Lichtenstein on this project were Imbsen & Associates and Dr. Fred Moses of Case WesternReserve University, who made major contributions to Sections 6 and 7.

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1. INTRODUCTION

1.1 PURPOSEThe purpose ofthis Manual isto serve asa standardand to provide uniformity in the procedures and poli-cies for determining the physical condition, mainte-nance needs and load capacity of our Nation'shighway bridges.

1.2 SCOPEThis Manual has been developed to assist BridgeOwners by establishing inspection procedures and

load rating practices that meet the National BridgeInspection Standards (NBIS). The Manual has beendivided into seven sections, with each section repre-senting a distinct phase of an overall bridge inspectionand load rating program.Section I contains introductory and backgroundinformation on the maintenance inspection of bridgesas well as definitions of general interest terms, Keycomponents of a comprehensive bridge file aredefined in Section 2. The record of each bridge in thefile provides the foundation against which changes inphysical condition can be measured. Changes incondition are determined by field inspections. Thetypes and frequency of field inspections are discussedin Section 3 as well as specific inspection techniquesand requirements. Conditions at a bridge site mayrequire more elaborate material tests, and varioustesting methods are discussed in Section 4. Fieldload testing is a means of supplementing analyticalprocedures in determining the live load capacity ofa bridge and for improving the confidence in theassumptions used in modeling the bridge. This isdescribed in Section 5. Section 6 discusses the loadrating of bridges and includes optional rating meth-ods. The evaluation of fatigue and other special con-ditions are discussed in Section 7.The successful application of this Manual isdirectly related to the organizational structure estab-lished by the Bridge Owner. Such a structure shouldbe both effective and responsive so that the uniquecharacteristics and special problems of individualbridges are considered in developing an appropriateinspection plan and load capacity determination.

1.3 APPLICABILITYThe provisions of this Manual apply to all highwaystructures which qualify as bridges in accordancewith the AASHTO definition for a bridge (see Article1.6.1). These provisions may be applied to smallerstructures which do not qualify as bridges.

1.4 QUALITY MEASURESIn order to maintain the accuracy and consistencyof inspections and load ratings, bridge owners shouldimplement appropriate quality control and quality

assurance measures. Typical quality control proce-dures include the use of checklists to ensure unifor-mity and completeness and the review of reports andcomputations by a person other than the originatingindividual, Quality assurance measures may includethe periodic field review of inspection teams andtheir work.

I.S BRIDGE MANAGEMENTSYSTEMS (BMS)Bridge Management Systems may be used as a

tool in allocating limited resources to the inspection,maintenance, rehabilitation and replacement of brid-ges. The integrity of BMS is directly related to thequality and accuracy of the bridge inventory andphysical condition data obtained through field inspec-tions. A good data base is the foundation of an effec-tive BMS.

1.6 DEFINITIONS AND IMPORTANTREFERENCES1.6.1 DefinitionsAASHTO: American Association of State High-way and Transportation Officials, 444 North CapitolStreet, N.W., Suite 249, Washington, D.C. 20001.Bridge: A structure including supports erectedover a depression or an obstruction, such as water,highway, or railway, and having a track or passage-


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2 MANUAL FOR CONDITION EVALUATION OF BRIDGES 1.6

way for carrying traffic or other moving loads, andhaving an opening measured along the center of theroadway of more than 20 feet between undercopingsof abutments or spring lines of arches, or extremeends of openings for multiple boxes; it may alsoinclude multiple pipes, where the clear distancebetween openings is less than half of the smallercontiguous opening (from the AASHTO Transporta-tion glossary).Bridge Management System (BMS): A systemdesigned to optimize the use of available resourcesfor the inspection, maintenance. rehabilitation andreplacement of bridges.Bridge Owner: An organization or agencyresponsible for the inspection and load rating of high-way bridges.Condition Rating: The result ofthe determinationof the functional capability and the physical conditionof bridge components including the extent of deterio-ration and other defects.FHWA: Federal Highway Administration, U.S.Department of Transportation.Load Rating: The determination of the live loadcarrying capacity of an existing bridge using existingbridge plans supplemented by information gatheredfrom a field inspection.MUTCD: The Manual of Uniform Traffic Con-trol Devices.National Bridge Inspection Standards (NBIS):Federal regulations establishing requirements for

inspection procedures, frequency of inspections,qualifications of personnel, inspection reports, an dpreparation and maintenance of bridge inventoryrecords. The NBIS apply to all structures defined asbridges located on or over all public roads.NICET: National Institute for Certification inEngineering Technologies.Quality Control: Procedures that are intended tomaintain the quality of a bridge inspection and loadrating at or above a specified level.Quality Assurance: The use of sampling to verifyor measure the level of the entire bridge inspectionand load rating program.Structure Inventory and Appraisal Sheet (SI&A): A summary sheet of bridge data required byNBIS. A copy of the SI&A sheet is contained asAppendix AI.1.6.2 Important ReferencesAASHTO, Standard Specifications for HighwayBridges, Washington, D.C. 1989 with annualinterim updated specifications.

AASHTO, Manual for Bridge Maintenance, Wash-ington, D.C., 1988.AASHTO, Guide Specifications for Strength Evalua-tion of Existing Steel and Concrete Bridges, Wash-ington, D.C., 1989.

AASHTO, Transportation Glossary, Washington,D.C., 1983.

AASHTO, Guide Specifications for Fatigue Evalua-tion of Existing Steel Bridges, Washington, D.C.,1990.

AASHTO, Guide Specifications for Strength Designof Truss Bridges (Load Factor Design), Washing-ton, D.C., 1985.

AASHTO, Guide Specifications for Fatigue Designof Steel Bridges, Washington, D.C., 1989.AASHTO, Guide Specifications for Fracture CriticalNon-Redundant Steel Bridge Members, Washing-ton, D.C., 1986.

AASHTO, Standard Specifications for MovableHighway Bridges, Washington. D.C., 1988.

Federal Highway Administration, U.S. Departmentof Transportation, Inspection of Fracture CriticalBridge Members, Washington, D.C., 1986.

Federal Highway Administration, U.S. Departmentof Transportation, Bridge Inspector's TrainingManual 90, Washington, D.C., 1990.

Federal Highway Administration, U.S. Departmentof Transportation, Bridge Inspector's Manual forMovable Bridges, Washington, D.C., 1977.

Federal Highway Administration, U.S. Departmentof Transportation. Culvert Inspection Manual,Washington, D.C., 1986.

Federal Highway Administration. U.S. Departmentof Transportation, Non-Destructive Testing Meth-ods for Steel Bridges, Washington, D.C., 1986.

Federal Highway Administration, U.S. Departmentof Transportation, Recording and Coding Guidefor the Structure Inventory and Appraisal of theNation's Bridges, Washington, D.C., Dec. 1988.

Federal Highway Administration, U.S. Departmentof Transportation, Technical Advisory-Revisionsto the National Bridge Inspection Standards(NBIS), T5140.21, Washington, D.C., Sept. 1988.

Federal Highway Administration, U.S. Departmentof Transportation, TechnicalAdvisory-EvaluatingScour at Bridges, T5140.23, Washington, D.C.,Oct. 1991.

Federal Highway Administration, U.S. Departmentof Transportation, Manual of Uniform Traffic Con-trol Devices, Washington, D.C., 1988.


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1.6 MANUAL FOR CONDITION EVALUATION OF BRIDGES 3

Federal Highway Administration, U.S. Departmentof Transportation, Underwater Inspection of Brid-ges, Washington, D.C., 1989.Minor, J. K., et. al., Condition Surveys 0 / ConcreteBridge Components, NCHRP Report 312, Trans-portation Research Board, National ResearchCouncil, Washington, D.C., Dec. 1988.

Ritter, Michael A., TimberBridges-Design Construc-tion, inspection, and Maintenance, EM 7700-8,Forest Service, U.S. Department of Agriculture,Washington. D.C. June 1990.U.S. Government, National Bridge Inspection Stan-dards, Code of Federal Regulations, TItle 23, Part650, Subpart C, Oct. 1988.


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2. BRIDGE FILE (RECORDS)

2.1 GENERALBridge Owners should maintain a complete, accu-rate and current record of each bridge under theirjurisdiction. Complete information. in good usableform, is vital to the effective management of bridges.Furthermore, such information provides a recordwhich may be important in legal action.A bridge record contains the cumulative informa-tion about an individual bridge. It should provide afull history of the structure including damages andall strengthening and repairs made to the bridge. Thebridge record should provide data on the capacity ofthe structure, including the computations substantiat-

ing reduced load limits, if applicable.A bridge file describes all of the bridges underthe jurisdiction of the Bridge Owner. It containsone bridge record for each bridge and other generalinformation which applies to more than one bridge.Items which should be assembled as part of thebridge record are discussed in Article 2.2. Informa-tion about a bridge may be subdivided into threecategories: base data which is normally not subjectto change; data which is updated by field inspection;and data which is derived from the base and inspec-tion data. General requirements for these three cate-gories of bridge data are presented in Articles 2.3,2.4. and 2.5. respectively.2.2 COMPONENTS OF BRIDGERECORDSSome of the components of good bridge recordsare described below. It is recognized that, in manycases (particularly for older bridges), only a portionof this information may be available. The componentsof data entered in a bridge record should be datedand include the signature of theindividual responsiblefor the data presented.

2.2.1 Plans2.2.1.1 Construction PlansEach bridge record should include one full-size orclear and readable reduced-size set of all drawingsused to construct or repair the bridge.

2.2.1.2 Shop and Working DrawingsEach bridge record should include one set of allshop and working drawings approved for the con-struction or repair of the bridge.2.2.1.3 As-Built DrawingsEach bridge record should include one set of finaldrawings showing the "as-built" condition of thebridge complete with signature of the individualresponsible for recording the as-built conditions.

2.2.2 SpecificationsEach bridge record should contain one completecopy of the technical specifications under which thebridge was built. Where a general technical specifica-tion was used. only the special technical provisionsneed be incorporated in the bridge record. The editionand date of the general technical specification shouldbe noted in the bridge record.

2.2.3 CorrespondenceInclude all pertinent letters, memorandums,notices of project completion, daily logs during con-struction, telephone memos and all other relatedinformation directly concerning the bridge in chrono-logical order in the bridge record.

2.2.4 PhotographsEach bridge record should contain at least twophotographs, one showing a top view of the roadwayacross and one a side elevation view of the bridge.Other photos necessary to show major defects, orother important features, such as utilities on thebridge, should also be included.

2.2.5 Materials and Tests2.2.5.1 Material CertificationAll pertinent certificates for the type, grade andquality of materials incorporated in the constructionof the bridge such as steel mill certificates, concretedelivery slips and other manufacturer's certificationsshould be included in the bridge record. Material

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6 MANUAL FOR CONDITION EVALUATION OF BRIDGES 2 . 2

certifications should be retained in accordance withthe policies of the Bridge Owner and the applicablestatute of limitations.2.2.5.2 Material Test DataReports of non-destructive and laboratory tests ofmaterials incorporated in the bridge during construc-tion or subsequently should be included in thebridge record.2.2.5.3 Load Test DataReports on any field load testing of the bridgeshould be included in the bridge record.

2.2.6 Maintenance and Repair HistoryEach bridge record should include a chronologicalrecord documenting the maintenance and repairs thathave occurred since the initial construction of thebridge. Include details such as date. description ofproject, contractor, cost, contract number and relateddata for in-house projects.

2.2.7 Coating HistoryEach bridge record should document the surfaceprotective coatings used including surface prepara-tion, application methods, dry-film thickness, andtypes of paint, concrete and timber sealants and otherprotecti ve membranes.

2.2.8 Accident RecordsDetails of accident or damage occurrences includ-ing date. description of accident, member damageand repairs. and investigative reports should beincluded in the bridge record.

2.2.9 PostingEach bridge record should include a summary ofall posting actions taken for the bridge including loadcapacity calculations, date of posting and descriptionof signing used.

2.2.10 Permit LoadsA record of the most significant special single-trip permits issued for use of the bridge along withsupporting documentation and computations shouldbe included in the bridge record.

2.2.11 Flood DataFor those structures over waterways, a chronologi-cal history of major flooding events including high

water marks at the bridge site and scour activityshould be included in the bridge record. where avail-able.2.2.12 Traffic DataEach bridge record should include the frequencyand type of vehicles using the bridge and their histori-cal variations, when available. Average Daily Traffic(ADT) and Average Daily Truck Traffic (ADIT) aretwo important parameters in fatigue life determina-tion which should be routinely monitored for eachbridge and each traffic lane on the bridge. Weightsof vehicles using the bridge, if available, should also

be included in the bridge record.2.2.13 Inspection HistoryEach bridge record should include a chronologicalrecord of all inspections performed on the bridgeincluding the date and type of inspection. The originalof the report for each inspection should be includedin thebridge record. When available, scour evaluationstudies, earthquake data, fracture critical information,deck evaluations and corrosion studies should be partof the bridge record.

2.2.14 Inspection RequirementsTo assist in planning and conducting the fieldinspection of the bridge, a list of specialized tools andequipment as well as descriptions of unique bridgedetails or features requiring non-routine inspectionprocedures or access should be provided. Specialrequirements to ensure the safety of the inspectionpersonnel and/or the public should be noted, includ-ing a traffic management plan.

2.2.15 Structure Inventory and AppraisalSheets

The bridge record should include a chronologicalrecord of Inventory and Appraisal Sheets used by theBridge Owner. A sample Structure Inventory andAppraisal Sheet is shown in Appendix AI.2.2.16 Inventories and InspectionsThe bridge record should include reports andresults of all inventories and bridge inspections suchas construction and repair inspections.


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2.2.17 Rating RecordsThe bridge record should include a completerecord of the determinations of the bridge's load-

carrying capacity.2.3 INVENTORY DATA2.3.1 GeneralThe bridge inventory data provides informationabout a bridge which is generally not subject tochange. As a minimum, the following informationshould be recorded for each bridge:(1) Structure Number. The official numberassigned to the structure by the Bridge Owner.(2) Name. The full name of the bridge. Other

common names by which it is known may be placedin parentheses following the official name.(3a) Year Built. Year of original construction.(3b) Year Reconstructed. The year(s) duringwhich major reconstruction or widening occurred.(4) Highway System. State whether or not thebridge is located on the Federal Aid System. Describethe type of Federal aid system and show the RouteNumber where applicable.

(5) Location. Location of the bridge must besufficiently described so that it can be readily spottedon a map or found in the field. Normally, the bridgeshould be located by Route number, County, andlog mile.(6) Description of Structure. Briefly give allpertinent data concerning the type of structure.Include the type of superstructure for both main andapproach spans, the type of piers and type of abut-ments along with their foundations. If the bridge ison piles. the type of piles should be stated. If it isunknown whether piles exist, this should be so stated.If data is available, indicate type of soil upon whichfootings are founded, maximum bearing pressures,and pile capacities.

(7) Skew. The skew angle is the angle betweenthe centerline of a pier and a line normal to theroadway centerline. Normally the skew angle wiII betaken from the plans and it is to be recorded to thenearest degree. If no plans are available, the angleshould be measured, computed or estimated. If theskew angle is 0, it should be so stated.(8) Spans. The number of spans and the spanlengths are to be listed. These shall be listed in thesame direction as the log mile. Spans crossing State

highways will be normally listed from left to rightlooking in the same direction as the log mile for theroute under the bridge. Span lengths shall be recordedto the nearest foot and it shall be noted whether themeasurement is center to center (dc) or clear opendistance (dr) between piers, bents, or abutments.Measurements shall be along the centerline of thebridge.(9) Structure Length. This shall be the overall

length to the nearest foot and shall be the length ofroadway which is supported on the bridge structure.This will normally be the length from paving notchto paving notch or between back faces of backwaUsmeasured along centerline.

(10) Bridge Roadway Width. This shall be themost restrictive of the clear width(s) between curbs,railings, or other restrictions for the roadway on thebridge. On divided roadways, the roadway width willbe taken as the traveled way between shoulders; but,also, the shoulders and median width will be given.(1J) Deck Width. The out-to-out width of thebridge to the nearest tenth of a foot.(2) Clearances. A vertical and horizontalclearance diagram should be made for each structurewhich restricts the vertical clearance over the high-

way, such as overcrossings, underpasses, and throughtruss bridges.The minimum number of vertical measurementsshown on the diagram will be at each edge of thetraveled way and the minimum vertical clearance

within the traveled way.The report will state the minimum roadway clear-ance. This will include each roadway on a dividedhighway. When a structure is of a deck or pony trusstype so that no vertical obstruction is present, thevertical clearance shall be noted on the report as"Unimpaired".Vertical measurements are to be made in feet andinches and any fractions of an inch will be truncated

to the nearest inch, i.e., a field measurement of 15'-7 3/4" will be recorded as 15'-7."Horizontal measurements are to be recorded to the

nearest one-tenth of a foot.(13) Wearing Surface and Deck Protective Sys-tem. The type and thickness of wearing surface andthe type of deck protective system should be noted.(14) Curb or Sidewalk Widths. The widths ofthe left and right curbs or sidewalks to the nearesttenth of a foot. If only one is present. the sidewalkshould be noted thus: "[email protected]' (east)." Sidewalks


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on both sides are noted thus: "2 @5.0' ." Ifthere areno sidewalks. note "None."(15) Railing and Parapets. List the type andmaterial of the railing and/or parapet. The dimen-sions of the railing and/or parapet should also berecorded.(16) Bridge Approach Alignment. Note whetherthe bridge is tangent or on a curve. If the bridge ison a curve, state the radius of the curve if plans areavailable for this information. On the older roadsand bridges, a comparison of the alignment with thegeneral alignment of the road should be made. Noteif there are any posted speed restrictions.

(17) Lanes On and Under the Structure. Statethe number of traffic lanes carried by the structureand being crossed by the structure.(18) Average Daily Traffic and Average DailyTruck Traffic. State the ADT and the ADTI, ifknown, along with the date of record. This informa-tion should be updated at intervals of approximately5 years.(19) Design Load. The live loading for whichthe bridge was designed should be stated if it isknown. A structure widened or otherwise altered sothat different portions have different live load designsis to have each live loading specified. If the designlive loading is not known, this should be so indicated.(20) Features Intersected. List facilities overwhich the structure crosses in addition to the mainobstacle. For example, a bridge with the name "Wet-water River" obviously carries traffic over the river;it may also cross over a railroad, other roads, etc.(21) Plans and Dimensions. State what plansare available, where they are filed. and if they areas-built. When plans are available. dimensions andsize of structural components should be fieldchecked. When plans are not on file. sufficient draw-ings should be prepared during field investigationsto permit an adequate structural analysis of the entirestructure, where practical.(22) Critical Features. Special structural detailsor situations, such as scour critical locations, fracturecritical members, fatigue-prone details, pins andhangers, cathodic protection, and weathering steelsshould be emphasized and highlighted for specialattention during field inspections.

2.3.2 Revised Inventory DataWhen a bridge is significantly altered by widening,

lengthening, or by some other manner which exten-

sively modifies the structure, the bridge inventorydata should be updated to reflect the changes madeto the bridge. The bridge inventory data should alsobe updated to reflect changes in wearing surface,railings and other similar items.

2.4 INSPECTION DATA2.4.1 General

Inspection data may be subject to change witheach inspection cycle. In addition to the results ofthe physical condition inspections conducted inaccordance with Section 3, each Bridge record shouldcontain the following inspection information. as aminimum:(1) Waterway. The adequacy of the waterwayopening should be classed as "Not a Factor," "Exces-

sive," "Sufficient," "Barely Sufficient," or "Insuffi-cient." The velocity of the stream should be classedwith reference to its scouring probabilities, such as"Normally High Velocity," "Normally MediumVelocity." A statement also should be made describ-ing the material making up the stream bed.An assessment of the scour vulnerability of the

substructure should be included. If a bridge has beenevaluated as scour critical and is being monitored,or if it has experienced severe scour, or if for otherreasons its structural stability is in question for higherdischarges, the inspection personnel should coordi-nate with hydraulics and maintenance personnel inplacing a painted line on the piling or abutment whichwould indicate a water surface at which concern andextra precaution should be exercised. This type ofindicator could serve as the trigger for closing abridge.When substructures are located within the water-

way, indicate the type and location of substructureprotection devices. If none are provided, this shouldbe so stated.If the waterway is navigational, the type and place-

ment of navigation lights should be noted and a clear-ance diagram of the navigable portion of thewaterway should be made.Bridges may be designed to allow or may experi-ence the overtopping by floods. A statement shouldbe made describing floods that have occurred or thatmay be possible.(2) Channel Profile. A sheet showing the chan-nel profile at the upstream side of a bridge over a


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2. 4 MANUAL FOR CONDITION EVALUATION OF BRIDGES 9

waterway should be a part of the bridge report. Thesketch should show the foundation of the structureand, where available, a description of material uponwhich footings are founded, the elevation of the piletips, and/or the footings of piers and abutments. Thisinformation is valuable for reference in anticipatingpossible scour problems through yearly observationand is especially useful to detect serious conditionsduring periods of heavy flow.Channel cross sections from the current and past

inspections should be plotted on a common plot toobserve scouring or stream instability.Vertical measurements should be made or refer-

enced to a part of the structure such as the top ofcurb or top of railing which is readily accessibleduring high water.Soundings in addition to the single line channel

profile are necessary at some river piers to provideadequate information on scour conditions and howthe piers may be affected. Such requirements willvary with stream velocity and general channel stabil-ity. The necessity of additional soundings must bedetermined by the Engineer. These soundings willnormally be limited to an area within a radius of 100feet from a pier.(3) Restrictions on Structure. Note any load,speed or traffic restrictions in force on the bridgeand if known, record date of establishment and iden-tification of agency who put the restrictions inforce.(4) Utility Attachments. An attachment sheetshould be submitted when there is one or more utilit-

ies on the structure. A utility in the immediate area,though not fastened to the bridge, should also beincluded, such as a sewer line crossing the ROWandburied in the channel beneath the bridge.(5) Environmental Conditions. Any unusualenvironmental conditions which may have an effecton the structure such as salt spray, industrial gases,etc., should be noted in the report.(6) Miscellaneous. Include information onhigh-water marks, unusual loadings or conditions,and such general statements as cannot be readilyincorporated into the other headings. Identify therequirements for miscellaneous structural inspectionssuch as those for sign structures, catwalks and otherspecial features.2.4.2 Revised Inspection DataThe bridge record should reflect the information

in the current bridge inspection report. The date

upon which the field investigation was made shouldbe noted. All work that has been done to the bridgesince the last inspection should be listed. When main-tenance or improvement work has altered the dimen-sions of the structure and/or channel, the newdimensions should be recorded.

2.S CONDITION AND LOADRATING DATA2.5.1 General

This data defines the overall condition and loadcapacity of the bridge and is based on the Inventoryand Inspection data. As a minimum, the followinginformation should be included:

(1) Bridge Condition Rating. Document thebridge condition inspection results includingobserved conditions and recommended maintenanceoperations or restrictions regarding the deck. super-structure, substructure, and if applicable, channel.(2) Inventory and Operating Ratings. A recordshould be kept of the calculations to determine theoperating and inventory ratings of a bridge and wherenecessary the load limits for posting. A general state-ment of the results of the analysis with note of whichmembers were found to be weak, what rating methodswere used, and any other modifying factors whichwere assumed in the analysis, should be given. SeeSection 6 for the load rating procedures.

2.5.2 Revised Condition and Load RatingDataWhen maintenance or improvement work or

change in strength of members or dead load hasaltered the condition or capacity of the structure, theInventory and Operating ratings should be recalcul-ated.

2.6 LOCAL REQUIREMENTSBridge Owners may have unique requirements for

collecting and recording bridge data mandated bylocal conditions and/or legislative actions. Theserequirements should be considered in establishing thedatabase and updating procedures for the bridge file.


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3. INSPECTION

3.1 GENERALBridge inspections are conducted to determine thephysical and functional condition of the bridge, toform the basis for the evaluation and load rating ofthe bridge, as well as analysis of overload permitapplications, to initiate maintenance actions, to pro-vide a continuous record of bridge condition and rateof deterioration, and to establish priorities for repairand rehabilitation programs. Cooperation betweenindividuals in those departments responsible forbridge inspection, load rating, permits, and mainte-nance is essential to the overall effectiveness of

such programs.Successful bridge inspection is dependent onproper planning and techniques, adequate equipment,and the experience and reliability of the personnelperforming the inspection. Inspections should notbe confined to searching for defects which may exist.but should include anticipating incipient problems.Thus inspections are performed in order to developboth preventive as well as corrective maintenanceprograms.The inspection plan and techniques shouldensure that:

o Unique structural characteristics and specialproblems of individual bridges are consideredin developing an inspection plan.

o Current technology and practice are appliedduring the inspection. The intensity and frequency of inspection isconsistent with the type of structure and details,and the potential for failure.o Inspection personnel are assigned in accor-dance with their qualifications. as determinedby the Bridge Owner.Each of the these items is discussed in detail inthe following articles.

3.2 TYPESThe type of inspection may vary over the usefullife of a bridge in order to reflect the intensity ofinspection required at the time of inspection. Thefive types of inspections listed below will allow a

Bridge Owner to establish appropriate inspection lev-els consistent with the inspection frequency and thetype of structure and details.Each type of inspection requires different levelsof intensity. Such items as the extent of access tostructural elements, the level of detail required forthe physical inspection and the degree of testing willvary considerably for each type of inspection.3.2.1 Initial InspectionsAn Initial Inspection is the first inspection of abridge as it becomes a part of the bridge file, but the

elements of an Initial Inspection may also apply whenthere has been a change in the configuration of thestructure (e.g. widenings, Iengthenings, supplemen-tal bents. etc.) or a change in bridge ownership. TheInitial Inspection is a fully documented investigationperformed by persons meeting the required qualifica-tions for inspection personnel and it must be accom-panied by an analytical determination of loadcapacity. The purpose of this inspection is twofold.First, it should be used to provide all Structure Inven-tory and Appraisal (SI&A) data required by Federaland State regulations, and all other relevant informa-tion normally collected by the Bridge Owner. Thesecond important aspect of the Initial Inspection isthe determination of baseline structural conditionsand the identification and listing of any existing prob-lems or locations in the structure that may have poten-tial problems. Aided by a prior detailed review ofplans, it is during this inspection that any fracturecritical members or details are noted, and assessmentsare made of other conditions that may later warrantspecial attention. If the bridge subjected to an InitialInspection is anything other than a newly constructedstructure, it may be necessary to include some or allof the elements of an In-Depth Inspection.

3.2.2 Routine InspectionsRoutine inspections are regularly scheduledinspections consisting of observations and/or mea-surements needed to determine the physical and func-tional condition of the bridge, to identify any changesfrom "Initial" or previously recorded conditions, and

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to ensure that the structure continues to satisfy presentservice requirements.The Routine Inspection must fully satisfy therequirements of the National Bridge Inspection Stan-dards with respect to maximum inspection frequency,the updating of Structure Inventory and Appraisaldata and the qualifications of the inspection person-nel. These inspections are generally conducted fromthe deck; ground and/or water levels, and from per-manent work platforms and walkways, if present.Inspection of underwater portions of the substructureis limited to observations during low-flow periodsand/or probing for signs of undermining. Specialequipment, such as under-bridge inspection equip-ment, rigging or staging, is necessary for RoutineInspection in circumstances where its use providesfor the only practical means of access to areas of thestructure being monitored.The areas of the structure to be closely monitoredare those determined by previous inspections and/orload rating calculations to be critical to load-carryingcapacity. In-depth inspection of the areas being moni-tored should be performed in accordance with Article3.2.4. If additional close-up, hands-on inspection ofother areas is found necessary during the inspection,then an in-depth inspection of those areas should alsobe performed in accordance with Article 3.2.4.The results of a Routine Inspection should be fullydocumented with appropriate photographs and a writ-ten report that includes any recommendations formaintenance or repair and for scheduling of follow-upIn-Depth Inspections if necessary. The load capacityshould be re-evaluated to the extent that changedstructural conditions would affect any previouslyrecorded ratings.3.2.3 Damage InspectionsA damage inspection is an unscheduled inspectionto assess structural damage resulting from environ-mental factors or human actions. The scope of inspec-tion should be sufficient to determine the need foremergency load restrictions or closure of the bridgeto traffic, and to assess the level of effort necessaryto effect a repair. The amount of effort expended onthis type of inspection may vary significantlydepending upon the extent of the damage. If majordamage has occurred, inspectors must evaluate frac-tured members, determine the extent of section loss,make measurements for misalignment of membersand check for any loss of foundation support. A capa-

bility to make on-site calculations to establish emer-gency load restrictions may be desirable. Thisinspection may be supplemented by a timely In-DepthInspection as described below to document more fullythe extent of damage and the urgency and magnitudeof repairs. Proper documentation, verification of fieldmeasurements and calculations and perhaps a morerefined analysis to establish or adjust interim loadrestrictions are required follow-up procedures. A par-ticular awareness of the potential for litigation mustbe exercised in the documentation of Damage Inspec-tions.3.2.4 In-Depth InspectionsAn In-Depth Inspection is a close-up, hands-oninspection of one or more members above or below

the water level to identify any deficiency(ies) notreadily detectable using Routine Inspection proce-dures. Traffic control and special equipment, suchas under-bridge inspection equipment, staging andworkboats, should be provided to obtain access, ifneeded. Personnel with special skills such as diversand riggers may be required. When appropriate ornecessary to fully ascertain the existence of or theextent of any deficiency(ies), nondestructive fieldtests and/or other material tests may need to be per-formed.The inspection may include a load rating to assessthe residual capacity of the member or members,depending on the extent of the deterioration or dam-age. Non-destructive load tests may be conducted toassist in determining a safe bridge load-carryingcapacity.This type of inspection can be scheduled indepen-dently of a Routine Inspection, though generally ata longer interval, or itmay be a follow-up for Damageor Initial Inspections.On small bridges, the In-Depth Inspection, if war-ranted, should include all critical elements of thestructure. For large and complex structures, theseinspections may be scheduled separately for definedsegments of the bridge or for designated groups ofelements, connections or details that can be efficientlyaddressed by the same or similar inspection tech-niques. If the latter option is chosen, each definedbridge segment and/or each designated group of ele-ments, connections or details should be clearly identi-fied asa matter ofrecord and each should be assigneda frequency for re-inspection, To an even greaterextent than is necessary for Initial and Routine


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Inspections, the activities, procedures and findingsof In-Depth Inspections should be completely andcarefully documented.

3.2.5 Special InspectionsA Special Inspection is an inspection scheduled

at the discretion of the Bridge Owner. It is used tomonitor a particular known or suspected deficiency.such as foundation settlement or scour, member con-dition, and the public's use of a load-posted bridge,and can be performed by any qualified person familiarwith the bridge and available to accommodate theassigned frequency of investigation. The individualperforming a Special Inspection should be carefullyinstructed regarding the nature of the known defi-ciency and its functional relationship to satisfactorybridge performance. In this circumstance. guidelinesand procedures on what to observe and/or measuremust be provided, and a timely process to interpretthe field results should be in place.The determination of an appropriate Special

Inspection frequency should consider the severity ofthe known deficiency. Special inspections usually arenot sufficiently comprehensive to meet NBIS require-ments for biennial inspections.

3.3 FREQUENCYEach bridge should be inspected at regular inter-vals not to exceed two years or at longer intervals

for certain bridges where such action is justified bypast reports and performance history and analysis.If the Bridge Owner proposes to inspect some

bridges at greater than the specified two-year interv al,a detailed plan which includes supporting rationalemust be developed and submitted to Federal and Stateagencies for approvaL Such a plan should includethe criteria for classifying structures by inspectionintervals and the intended intensity of inspections ateach interval. It should consider such factors as age,traffic volume. size, susceptibility to collision. extentof deterioration, performance history of the bridgetype, load rating. location, national defense designa-tion, detour length, and social and economic impactsdue to the bridge being out of service. The plan shouldalso outline the details of the types and intensity ofinspection to be applied. The evaluation of thesefactors should be the responsibility of the person incharge of the overall inspection program.

Underwater inspection frequencies are describedin Articles 3.10.1 and 3.10.2.

3.4 QUALIFICATIONS ANDRESPONSIBILITIES OFINSPECTION PERSONNEL3.4.1 General

Qualified personnel should be used in conductingbridge inspections. Minimum qualifications for thetop two levels of responsibility are described below.3.4.2 Inspection Program Manager

At the highest level, the individual in charge ofthe organizational unit that has been delegated theresponsibilities for bridge inspection. reporting, andinventory shall possess the following minimum quali-fications:(1) Be a registered professional engineer; or(2) Be qualified for registration as a professional

engineer under the laws of the State; or(3) Have a minimum of 10 years experience in

bridge inspection assignments in a responsi-ble capacity and have completed a compre-hensive training course based on the BridgeInspector's Training Manual.

The inspection program manager provides overallsupervision and is available to team leaders to evalu-ate problems. Ideally, the position requires a generalunderstanding of all aspects of bridge engineeringincluding design. load rating. new construction, reha-bilitation. and maintenance. Good judgment isimportant to determine the urgency of problems andto implement the necessary short-term remedialactions to protect the safety of the public. Whenappropriate, the specialized knowledge and skills ofassociate engineers in such fields as structural design.construction, materials. maintenance, electricalequipment, machinery. hydrodynamics. soils. oremergency repairs should be utilized.3.4.3 Inspection Team LeaderThe second level of responsibility is the Inspection

Team Leader. The minimum qualifications of a TeamLeader shall be:

(I) Have the qualifications specified for theorganizational Unit Leader. or


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(2) Have a minimum of 5 years experience inbridge inspection assignments in a responsi-ble capacity and have completed a compre-hensive training course based on the BridgeInspector's Training Manual, or

(3) NICET Level III or IV certification in BridgeSafety Inspection.

The Inspection Team Leader is responsible forplanning, preparing and performing the field inspec-tion of a bridge. There should be at least one teamleader at the bridge at aU times during each inspec-tion.

3.5 SAFETY3.5.1 General

Safety of both the inspection team members andthe public is paramount. Bridge Owners shoulddevelop a safety program to provide inspection per-sonnel with information concerning their safety andhealth including the proper operation of inspectiontools and equipment. This program should embodyapplicable State and Federal legislation governingsafety and health in the bridge inspection work envi-ronment.3.5.2 Personnel Safety

Personal protective clothing should be worn at alltimes including hard hats, vests, safety glasses (whereneeded), and appropriate footwear. Proper hearing,sight, and face protection methods should be prac-ticed whenever using manual and power tools. Allequipment, safety devices, and machinery should bekept in the best possible operating condition.

Inspection vehicles should be operated in accor-dance with the operating manuals provided by themanufacturer. Personnel should be trained in the safeuse of the vehicles and emergency procedures in theevent of equipment failure.Belts, lanyards, harnesses, and other personal

safety equipment should be used in accordance withapplicable standards. All lifelines, belts, lanyards andother equipment should be maintained in good repair.Worn or damaged equipment should be discarded.In addition, inspection personnel should be cautionedto keep safety equipment clean and away from poten-tially harmful chemicals such as gasoline, dye pene-trant and/or oil.

Proper safety precautions should be employedwhen entering confined spaces such as the interiorof a box girder. Air testing, air changes and/or theuse of air packs may be required.Safety programs provide a guide to inspection per-

sonnel but do not substitute for good judgment andcommon sense. It should be recognized that eachbridge site is unique. In situations where unusualworking conditions may exist, specialized safety pre-cautions may be required. Inspection personnelshould have first aid training.

3.5.3 Public SafetyIn the interest of public safety, Bridge Owners

should employ proper procedures for traffic controland work zone protection during the inspection of abridge. The Manual of Uniform Traffic ControlDevices as supplemented by state and local authori-ties should be used as a guide for such procedures.

3.6 PLANNING, SCHEDULING ANDEQUIPMENT3.6.1 PlanningThe key to the effective, safe performance of any

bridge inspection is proper advance planning andpreparation. The inspection plan should be developedbased on a review of the Bridge Record (see Section2), and may require a pre-inspection site visit. Thefollowing items should be considered:(a) Determine the type of inspection required.(b) Determine the number of personnel and type

of equipment and tools necessary to performthe inspection.

(c) Determine which members or locations arenoted in previous inspections or maintenancerecords to have existing defects or areas ofconcerns.

(d) Estimate the duration of the inspection andthe scheduled work hours.

(e) Establish coordination with or notification ofother agencies or the public, as needed.(f) Assemble field recording forms and prepare

appropriate pre-drafted sketches of typicaldetails.

(g) Determine the extent of underwater inspec-tion required and the vulnerability to scour.


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Special needs such as diving or scour studiesshould be identified.(h) Decide whether non-destructive or other spe-cialized testing is appropriate.(i) Determine whether the structure containsmembers or details requiring special atten-tion, such as fracture critical members,fatigue-prone details and non-redundantmembers.G) Determine whether there are structuresnearby which are also scheduled for inspec-tion which require a similar crew with similartools and equipment.

It is advisable for the individual making the inspec-tions to confer with the local highway maintenancesuperintendent or foreman regarding the bridges tobe inspected. The local maintenance person sees thebridges at all times of the year under all types ofconditions and may point out peculiarities which maynot be apparent at the time of the investigation.Stream action during periods of high water and posi-tion of expansion joints at times of very high andlow ambient temperatures are examples of conditionsobserved by local maintenance personnel which maynot be seen by the inspector.3.6.2 SchedulingSo far as is practicable, bridge inspections should

be scheduled in those periods of the year which offerthe most desirable conditions for thorough inspec-tions. Substructures of bridges over streams or riverscan best be inspected at times of low water, andstructures requiring high climbing should beinspected during those seasons when high winds orextremes of temperature are not prevalent. Inspec-tions during temperature extremes should be madeat bearings, joints, etc., where trouble from thermalmovement is suspected. These examples illustratethe importance of proper scheduling.3.6.3 EquipmentBridge inspection equipment consists of thoseitems used for access, and those used to perform

actual inspection tasks. Once the equipment require-ments are established for a bridge, it should becomepart of the bridge record (see Article 2.2.14).3.6.3.1 AccessMethods and EquipmentThe variation in types of structures to be inspectedrequires that a broad range of techniques and equip-

ment be used by the bridge inspectors to gain accessto the structural elements to perform the inspection.The methods and equipment used to gain access tobridge members include ladders, power lift vehicles,power lift staging, rigging and scaffolds, boats,assisted free climbing, and diving equipment.In selecting the use of such equipment the follow-ing items must be considered:(a) The ability ofthe ground, pavement, or bridgestructure to safely support the access equip-ment;(b) The need for traffic control and/or lane clo-sure, depending on the location of the equip-ment. The MUTCD and/or State and localrequirements should be used as a guide inplanning such measures;(c) The presence of utilities. Ifutilities are pres-ent, special care may be required to pre-vent accidents;(d) The need for permits, flagmen and other spe-cial considerations for bridges over railroads.Experienced personnel should be responsible forplanning the use of inspection equipment.3.6.3.2 Inspection Methods and EquipmentThe inspection methods and equipment to beemployed will depend on the type of inspection asdescribed in Article 3.2. In planning the inspection,

a pre-inspection site visit by the Team Leader maybe helpful. If plans are available, the pre-inspectionshould be done plans-in-hand to allow preliminaryverification of structure configuration and details.The pre-inspection should determine means ofaccess, disclose areas of potential concern which willrequire close attention during subsequent inspectionsand form the basis for decisions on timing, weatherconditions, traffic controls, and utility de-energiz-ations,

3.7 INSPECTION FORMS ANDREPORTSInspection forms and reports prepared for fielduse should be organized in a systematic manner andcontain sketches and room for notes. The completedreport should be clear and detailed to the extent thatnotes and sketches can be fully interpreted at a laterdate. Photographs should be taken in the field to


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16 MANUAL FOR CONDITIONEVALUATIONOF BRIDGES 3.7

illustrate defects and cross referenced in the formsand reports where the various defects are noted.Sketches and photographs should be used to supple-ment written notes concerning the location and physi-cal characteristics of deficiencies. The use of simpleelevation and section sketches of deteriorated mem-bers permits the drawing and dimensioning of defectsclearly, without resorting to lengthy written notes.The sources of all information contained in a reportshould be clearly evident, and the date of the inspec-tion or other sources of data should be noted. Areport should be made for each bridge inspectioneven though it may be only a Special Inspection.All signs of distress and deterioration should benoted with sufficient accuracy so that future inspec-tors can readily make a comparison of condition. Ifconditions warrant, recommendations for repair andmaintenance should be included.Bridge Owners should develop and use standard-ized abbreviations, legends and methodologies forsystematic numbering of bridge components to facili-tate note taking and produce uniform results whichare easily understood by all inspection teams andoffice personnel. The use of photographs and sketchesto define areas and extent of deterioration should beencouraged. Nomenclature used to describe bridgecomponents should be consistent. Basic highwaybridge nomenclature is shown in Appendix A2.

3.8 PROCEDURES3.8.1 GeneralThe field investigation of a bridge should be con-ducted in a systematic and organized manner thatwill be efficient and minimize the possibility of anybridge item being overlooked. To achieve this objec-tive, consideration should be given to standardizingthe sequence for inspection of a bridge.Defects found in various portions of the structurewill require thorough investigation to determine andevaluate their cause. The cause of most defects will

be readily evident; however, it may take considerabletime and effort to determine the cause of some defectsand to fully assess their seriousness.If possible, bridges should be observed duringpassage of heavy loads to determine if there is anyexcessive noise, vibration or deflection. If detected.further investigation should be made until the causeis determined. Careful measurement of line, grade,

and length may be required for this evaluation. Seri-ousness of the condition can then be appraised andcorrective action taken as required.Possible fire hazards should be identified includ-ing accumulations of debris such as drift, weeds,brush, and garbage. The storage of combustible mate-rial under or near a bridge. in control houses onmovable bridges, or in storage sheds in the vicinity

of the bridge should be reported.The procedures should include, but notnecessarilybe limited to, observations described inArticles 3.8.2through 3.8.10. Unusual or unique bridges or portionsof bridges may require special considerations andthese should be defined in the inspection plan forthe bridge. Items common to these procedures arediscussed below.3.8.1.1 Field MeasurementsField measurements are made to provide baselinedata on the existing bridge components and to trackchanges such as crack width and length. which mayoccur over time.Measurements may be required on bridges forwhich no plans are available and to verify data shownon plans. Measurements are to be made only withsufficient precision to serve the purpose for whichthey are intended. Unnecessarily precise measure-ments lead to a waste of time and a false sense ofvalue of the derived results. The following limits of

accuracy are generally ample for field measurement:Timber MembersConcrete MembersAsphalt SurfacingSteel Rolled Sections

Nearest 1/4"Nearest 1/2"Nearest 1/2"Necessary accuracyto identifysectionNearest 0.1 footpan LengthsWhen plans are available for a bridge which is tobe load rated, dimensions and member types andsizes will normally be taken from the plans. How-ever, many of the plans for older structures are not

as-built plans, nor do they reflect all changes madeto the bridge. Sufficient checking must be done dur-ing field inspections to insure that the plans trulyrepresent the structure before they are used in struc-tural calculations. Special attention should be givento checking for possible changes in dead load, suchas a change in the type of decking, additional over-lays, and/or new utilities.


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3.8 MANUAL FOR CONDITION EVALUATIONOF BRIDGES 17

Measurements sufficient to track changes in jointopening. crack size or rocker position may need tobemade and recorded. Measurements tomonitor sus-pected or observed substructure tilting or movementmay be required. In these cases it is necessary thatpermanent markings be made on the structure andrecorded in field notes by the inspector to serve asa datum for future readings. A log of the readingsshould be kept in the inspection file, and updatedwith the readings after each inspection cycle.Direct measurement of the surface area. depth andlocation of defects and deterioration is preferred tovisual estimates of "percentage loss."

3,8.1.2 CleaningIt is a good inspection practice to clean selectedareas to allow close "hands on" inspection for corro-

sion. deterioration or other hidden defects. Debris,vegetation. fungus, marine growth, vines, litter, andnumerous other obscuring coverings can accumulateand hide problem areas.On metal structures, particularly on fracture criti-cal members. it may be necessary to remove alliga-tored,cracked and peeling paint for proper inspection.Metal structures with heavy plate corrosion willrequire chipping with a hammer or other means toremove corrosion down to the base metal in order tomeasure the remaining section. Provisions should bemade to recoat such areas exposed during the inspec-tion which are critical to the structural integrity ofthe bridge.On concrete structures, leaching, lime encrustationand debris may cover heavily corroded reinforcing,cracks or other deterioration. Debris on piles canobscure heavy spaIling or salt deterioration and vege-tation (particularly vines) can obscure large defectssuch as cracks or spalls.Timber structures are particularly susceptible totermites and decay in areas where debris causes awet/dry condition. Inspectors should give particularattention to cleaning and carefully inspecting suchareas. especially when they are present near end grain.

3.8.1.3 Guidelines for Condition Rating ofBridge ComponentsGuidelines for evaluating the condition of bridgecomponents should be developed to promote unifor-mity in the inspections performed by different teamsand at different times. Coding systems, similar to the0-9 numeric system used by the FHWA. have proven

to be effective in establishing such uniformity mcondition evaluation.3.8.1.4 Critical Deficiency ProceduresCritical structural and safety-related deficienciesfound during the field inspection and/or evaluationof a bridge should be brought to the attention ofthe Bridge Owner immediately. if a safety hazard ispresent. Bridge Owners should implement standardprocedures for addressing such deficiencies,including: Immediate critical deficiency reporting steps Emergency notification to police and the public Rapid evaluation of the deficiencies found Rapid implementation of corrective or protec-tive actions A tracking system to ensure adequate follow-up actions Provisions for identifying other bridges withsimilar structural details with follow-up inspec-tions.

3.8.2 SubstructureAn inspection of the substructure of a bridge isgenerally comprised of an examination and recordingof signs of damage, deterioration. movement and, ifin water, evidence of scour.3.8.2.1 AbutmentsThe footing of the abutment should be investigatedfor evidence of significant scour or undercutting.Probing is normally performed if all or part of theabutment is located in water. Those underwater situa-tions which require diving to establish the structuralintegrity are described in Article 3.10. Typical evi-dence of abutment scour for spill-through abutmentsis an observable instability of the slope protectiondue to removal of material at the toe of slope.Particular attention should be given to foundationson spread footings where scour or erosion is morecritical than for a foundation on piles. However. be

aware that scour and undercutting of a foundation onpiles can also occur. Any exposed piling should beinspected in accordance with the applicable proce-dures listed in Article 3.8.2.4. The vertical supportcapacity of the piles normally should not be greatlyaffected unless the scour is excessively severe, butthe horizontal stability may be jeopardized.


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When erosion has occurred on one face of theabutment only, leaving solid material on the oppositeface. horizontal instability may result. Horizontalinstability may also result from earth or rock fillspiled against abutments or on the slopes retainedby wingwalls.

All exposed concrete should be examined for theexistence of deterioration and cracks. The horizontalsurfaces of the tops of abutments are particularlyvulnerable to attack from deicing salts. In some areas,corrosion of reinforcing steel near the surface canresult in cracking, spalling and discoloration of theconcrete.Devices installed to protect the structure against

earthquakes should be examined for evidence of cor-rosion. broken strands, missing bolts, nuts or cableclamps, and proper adjustment. Check for evidence ofhorizontal or vertical movement of the superstructurerelative to the abutment.Structural steel partially encased in substructure

concrete should be inspected at the face of the con-crete for deterioration and for movement relative tothe concrete surface.

Stone masonry should be checked for cracking inthe mortar joints and to see that the pointing is ingood condition. Check the stone masonry for erosion,cavities, cracking. and other signs of deterioration ofthe stones.Abutments should be checked for evidence of rota-

tion of walls, lateral or longitudinal shifting, or settle-ment of foundations as compared to previous records.Such movement is usually evidenced by the openingor closing of cracks or joints, by bearings being offcenter or at a changed angle. or by changes in mea-sured clearances between ends of girders and theabutment backwall. This type of inspection shouldbe performed after an earthquake has occurred inthe vicinity.Examine the abutment drains and weep holes to

see if they are functioning properly. Seepage of waterat cracks or joints away from the weep holes mayindicate an accumulation of water and improper func-tioning of the weep holes. Mounds of earth adjacentto drains indicate the probable presence of bur-rowing animals.

3.8.2.2 Retaining WallsIf the retaining wall is adjacent to water, the foot-

ings should be examined for scour as described forabutments in Article 3.8.2.1. The toes of all retaining

walls should be examined for soil settlement as wellas for erosion and scour. Loss of full bearing at thetoe can bring about failure of the wall,Exposed concrete and stone masonry should be

examined for the existence and severity of cracksand any deterioration of the concrete, masonry ormortar. The exposed ends of headers of concrete cribwalls should be closely examined for cracks whichcould indicate possible future loss of the interlockingfeature and failure of the wall.Wall faces. tops and joints should be checked for

bulging or settlement since the last inspection. Cracksin the slope behind a wall can indicate settlement ofthe toe and rotation of the wall. Bulges in the facesof sheet pile walls or mechanically stabilized earthwalls can indicate failure of individual anchors.Any exposed piling, whether exposed as a feature

of the wall (sheet pile and soldier pile walls) or byadverse action (scour, erosion or settlement), shouldbe inspected as described in the applicable portionsof Article 3.8.2.4.

3.8.2.3 Piers and BentsPiers and bents located in or adjacent to water

should be inspected for evidence of scour as describedin Article 3.8.2.1 for abutments. Footings in somelocations should also be examined for undercuttingcaused by soil settlement or wind erosion. Exposedpiling should be inspected as described in applicableportions of Article 3.8.2.4.Riprap that has been placed as a countermeasure

against pier scour should be evaluated for stability.It should be verified that the material being observedas riprap is actually riprap. It may be larger materialdeposited at the pier by the stream and may not beproviding adequate protection. The key to makingthe evaluation is the shape of the material. Angularrock is typically specified for riprap while materialdeposited by a stream is usually rounded.Examine all exposed concrete and stone masonry

for the existence and severity of cracks and any dete-rioration of the concrete. masonry or mortar. Areasof special vulnerability are the waterline and splashzones, the ground line, and locations where the con-crete is exposed to roadway drainage, including thetops of piers or bents. Bearing seats, grout pads andpedestals should be examined for cracks. spalls orother deterioration.Steel piers and bents should be checked for corro-

sion, especially at joints and splices. Cable connec-


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tions, bolts and rivets are especially vulnerable to rust.Article 3.8.3 contains a more complete discussion onexaminations of structural steel members.All bents and piers should be checked for lateral

movement, tilt or settlement, particularly after peri.ods of high water, storm or earthquakes. Observebent members, rockers, pins and bearings during pas-sage of heavy loads to determine whether movementsare unusual or as expected.Any material deposited against a bent or pier

which was not provided for in the original designshould be noted. Horizontal instability could resultfrom such loads.

3.8.2.4 Pile BentsThis article covers those bridge supports which

are composed of concrete, steel or timber pilesextending to a cap which may be separate from thebridge superstructure or integral with it.

Timber piles should be checked for decay, espe-cially in areas where they are alternately wet and dry.The most likely place for this condition to be foundis at the ground line or tidal zone in coastal areas.Often, the earth has to be removed from around thepile to a depth of a foot or so and the timber probed orbored. Holes made for testing which might promotedecay should be filled with treated wooden plugs.The timing of such borings will vary greatly fromarea to area because of climatic variations, specie ofwood used for piling, and the preservative treatmentthat has been given the timber. Although piles mayappear sound on the outer surface, some may containadvanced interior decay. Creosoted piles, for exam-pie, may become decayed in the core area where thetreatment has not penetrated, even though the outsidesurface shows no evidence of deterioration. Sound-ing with a hammer may reveal an unsound pile.Timber piles in salt water should be checked for

damage by marine organisms which will attack tim-ber in the area at and below tide line down to mudline. Footing piles which have been exposed by scourbelow the mud line are highly vulnerable to attack.Attack may also occur in treated piles where checksin the wood, bolt holes, daps, or other connectionsprovide an entrance to the untreated heartwood area.In addition to the above, special attention should

be given to the following:(I) contact surfaces of timber when exploring

for decay;

(2) areas where earth or debris may have accu-mulated;

(3) areas such as the top of piles where thecap bears;

(4) areas where the bracing members are fas-tened; and

(5) checked or split areas.Caps must be examined for decay, cracks, check-

ing, and any evidence of overstress. Further infonna-tion on the inspection of timber members is foundin Article 3.8.3.4.Examine steel and concrete piles both in the splash

zone and below the water surface for corrosionand deterioration.Inspect all submerged piles for deterioration and

loss of section. Special attention should be given toexposed piles in or near salt water. Corrosion ofexposed steel piles may be more active at the terminusof concrete encasements on partially encased struc-tural steel members, at the waterline or tide affectedzone, and at the mudline.When subjected to a corrosive environment, struc-

tural steel substructure elements should be inspectedbelow the waterline and in the splash zone by mannedor unmanned underwater surveillance. Coastalstreams may be brackish due to tidal effects for sev-eral miles upstream and should be considered a poten-tially corrosive environment until confinnedotherwise. Additional information on underwaterinspections is given in Article 3.10.Observe the caps under heavy loads to detect

unusual movement or any excessive deflection. Steeland timber caps should be observed for any rotationalmovement resulting from eccentric connections.Bracing members must be checked to see that they areadequate. sound, and that they are securely fastened.Bearings are designed to move freely about theirpins or bearings and, if feasible, should be inspectedcarefully under passage of heavy loads to confirmthat their movement is not being restrained (see Arti-cle 3.8.3.12).

3.8.2.5 Bridge Stability and MovementsThe baseline condition of the structure should be

established during the Initial Inspection and should bethe basis for the future determination of movement.Check for transverse movement by sighting along

the top of railing, edge of deck or along a girder.Similarly, one can check for differential verticalmovements by sighting along the top of railing or


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edge of deck. On large structures or structures oncomplex alignment. it may be necessary to use a levelor transit to detect movement. Differential settlementbetween one side of a bridge and the other may alsorequire checking with a level.

Use of a transit is suggested for checking bents.piers, and faces of abutments and retaining walls forrotational movements or tilt. A plumb bob may beused where heights are not great or where only apreliminary determination is desired.

Vertical movement in the superstructure is usuallyevidence of foundation settlement or rotation of theabutments or piers. Lateral or longitudinal sliding iscaused by high water. ice pressure. earthquake. orother application of horizontal forces. Small. rela-tively equal movements should be noted. but usuallyare of little consequence. Large or differential move-ments should be investigated further to determinethe probable cause with a view toward correctivemeasures being taken.Examine rockers. rollers and hanger elements for

movements or inclinations not consistent with thetemperature. Compare with notes from previousinspections to see if movements or inclinations aresigns of settlement or shifting of foundations.Inspect joints at abutments, bents. piers and at

hinges. Jamming, unusually large openings and ele-vation differentials on opposite sides of the joint areevidences of substructure movement (or bearingfailure).Check abutment backwalls and ends of beams for

cracking, spalling or improper clearances. Causescould be rotation or sliding of the abutment or pres-sure from the roadway pavement against the back ofthe abutment.

Examine abutments. wingwalls, and retainingwalls for distortion, unusual cracking. or changes injoint widths or inclination. This damage could havebeen caused by settlement or a change in pressureagainst the walls. Look for cracks, slipouts or seepagein the earth slopes in front of or behind the walls aswell as for unbalanced, post-construction embank-ment exerting pressure against these walls.

3.8.2.6 Dolphins and FendersDolphins and fenders are used to protect substruc-

ture units from impacts by floating debris or maneu-vering vessels. The term "dolphin" refers to the stand-alone unit placed upstream or downstream from thepier. The term "fender" refers to the protective unit

or cover placed around the pier or abutment face andwhich is frequently attached to the substructure.Piles used in dolphins or fenders are to be

inspected as described in Articles 3.8.2.4, "PileBents."Steel piles, frame members, fasteners. and cables

should be inspected for rust damage, particularly inthe "splash zone." Since both dolphins and fendersmay suffer frequent hits and abrasion, the inspectionmust include a close examination for the results ofthese actions.Timber piles and other timber members should be

examined for decay, insect damage, marine organ-isms, abrasion and structural damage. Check at thewaterline for weathering of material. (See Article3.8.3.4.) Note whether protective treatment needspatching or replacement. Cable ties and bolts shouldbe examined for rust. Catwalks and their fasteningsshould also be examined for decay and other damage.Concrete members should be examined for spall-

ing, cracking, rusting of the reinforcing steel anddamage from abrasion or collisions. For concretesurfaces which have a protective treatment, indicatethe condition of the treatment and the need for patch-ing or replacement.Rubber elements should be examined for missing

parts, deterioration, cracking and other damage toelements or fastening devices. Pneumatic and hydrau-lic elements should be examined for damage and tosee if they are functioning properly under impact.Lighting devices on dolphins or fenders should be

checked for rust, broken or missing lenses. and to seewhether the lights are functioning correctly. Wiring,conduits, and fastening devices should be examinedfor rust, breaks or loose connections.3.8.3 SuperstructureThis article includes discussions covering inspec-

tion of all commonly-encountered types of super-structures composed of reinforced concrete. structuralsteel or timber, including bearings, connectiondevices and protective coatings. The discussion cov-ering inspection of bridge decks, joints, sidewalksand curbs is included in Article 3.8.4. Inspectionof the more unusual types of bridges is covered inArticle 3.9.Girders over a traveled way should be checked for

any damage resulting from being struck by overheightloads passing under the bridge. If feasible. note anyexcessive vibration or deflection as truck loads moveacross the superstructure.


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3.8 MANUAL FOR CONDITION EVALUATIONOF BRIDGES 21

Where the deck obscures the steel top flange orthe steel member is totally encased, the inspector mayrecommend that portions of the covering material beremoved at random locations to determine if signifi-cant section loss has occurred.The inspector should note if flammable materialis stored under or near a bridge and check for theaccumulations of debris, weeds, bushes and, if overwater, driftwood.3.8.3.1 Steel Beams, Girders and BoxSectionsSteel beams girders and box sections should beevaluated as to ~hether or not they are Fracture Criti-cal Members (FCM) or contain fatigue-prone details,as defined in the AASHTO Design Specifications.More information on fatigue prone details and FCMs

may be found in Articles 3.11 and 3.12, respectively.The bridge record should contain a complete listingof all FCMs and the type and location of variousfatigue-prone details found on the structure.Structural steel members should be inspected forloss of section due to rust. Where a build-up of rustscale is present. a visual observation is usually notsufficient to evaluate section loss. Hand scrape areasof rust scale to base metal and measure remainingsection using calipers, ultrasonic thickness meters. orother appropriate method. Sufficient measurementsshould be taken to allow the evaluation of the effectof the losses on member capacity.MemLers should be checked for out-of-planebending in webs or connection plates. Compressionflanges should be checked for buckling.The tension zone of members should be checkedfor cracking near erection or "tack" welds and at

other fatigue prone details.Box members should be entered and inspectedfrom within where accessible. Check enclosed mem-bers for water intrusion. Access points to enclosedbox members should be closed or screened to prevententry of birds. rodents and other animals. Check forcollection of debris. bird/animal excrement and otherdeleterious materials.Check for fatigue cracks which typically beginnear weld terminations of stiffeners and gusset platesdue to secondary stresses or out-of-plane bending.Any evidence of cracking should be carefully docu-mented for evaluation and appropriate follow-up.as necessary.On FCMs perform periodic inspections at a levelof effort sufficient to detect very small cracks.

Inspect uncoated weathering steel structures for:(a) Details or conditions which promote continu-ous wetting of the uncoated steel(b) Bridge geometries which result in salt spray(marine or traffic generated) reaching theuncoated steel(c) Pitting of the surface of the steel indicatingunacceptable degradation of the steel.3.8.3.2 Reinforced Concrete Beams andGirdersAll reinforced concrete superstructures should beinspected for cracking. The locations of the cracksand their size should be carefully noted for futurereference and comparison. An effort should be madeto determine the probable cause of the cracking:shrinkage. overstress. settlement of substructure, orpossible chemical action.Stems ofmembers should bechecked for abnormalcracking an d any disintegration of the concrete. espe-cially over bearings. Diagonal cracks radiating from

the bearings toward the center of span indicateoverstress caused by shear. Vertical cracks extendingupward from the girder soffit near centerline of spanindicate overstress in tension. High-edge pressure atthe bearings may cause spalling in the girder stems.Examine the soffit of the lower slab in box girderstructures and the outside face of the girders forsignificant cracking. Note any offset at the hingeswhich might indicate problems with the hinge bear-ing. An abnormal offset may require further explora-tion to determine the cause and severity of thecondition. Examine the inside of box girders forcracks and to see that the drains are open and func-tioning properly. Check the diaphragms for cracks.If there are earthquake restrainer mechanisms atabutments, bents. or hinges, the inspection shouldcover close examination of these elements for damagedue to corrosion or stress. Vertical, lateral and longi-tudinal movements relative to the substructure should

be noted.

3.8.3.3 Prestressed Concrete, Beams,Girders and Box SectionsPrestressed concrete girders should be examinedfor alignment, cracking, and deterioration of the con-crete. Check for cracking or spaUing in the areaaround the bearings. and at cast-in-place diaphragmswhere creep and humping of the girders may have


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22 MANUAL FOR CONDITION EVALUATIONOF BRIDGES 3.8

had an effect. The location of any cracks and theirsize should be carefully noted for future referenceand comparison. Evidences of rust at cracks can meanpossible damage to prestressing steel.Pretens

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Manual of AASHTO