0. aashto lrfd bridge construction specification, 3rd, 2010

ISBN: 978-1-56051-452-7 Publication Code: LRFDCONS-3

.

American Association of State Highway and Transportation Officials

444 North Capitol Street, NW Suite 249 Washington, DC 20001

202-624-5800 phone/202-624-5806 fax www.transportation.org

2010 by the American Association of State Highway and Transportation Officials. All rights reserved. Duplication is a violation of applicable law.


iii

EXECUTIVE COMMITTEE 20092010

Voting Members

Officers:

President: Larry L. Butch Brown, Mississippi

Vice President: Susan Martinovich, Nevada

Secretary-Treasurer: Carlos Braceras, Utah

Regional Representatives:

REGION I: Joseph Marie, Connecticut, One-Year Term Gabe Klein, District of Columbia, Two-Year Term REGION II: Dan Flower, Arkansas, One-Year Term Mike Hancock, Kentucky, Two-Year Term REGION III: Nancy J. Richardson, One-Year Term Thomas K. Sorel, Minnesota, Two-Year Term REGION IV: Paula Hammond, Washington, One-Year Term Amadeo Saenz, Jr. Texas, Two-Year Term

Nonvoting Members

Immediate Past President: Allen Biehler, Pennsylvania AASHTO Executive Director: John Horsley, Washington, DC


iv

HIGHWAY SUBCOMMITTEE ON BRIDGES AND STRUCTURES 2009

MALCOLM T. KERLEY, Chair KEVIN THOMPSON, Vice Chair

M. MYINT LWIN, Federal Highway Administration, Secretary RAJ AILANEY, Federal Highway Administration, Assistant Secretary

KEN KOBETSKY, AASHTO Liaison KELLEY REHM, AASHTO Liaison

ALABAMA, John F. Buddy Black, William Tim

Colquett, George H. Conner ALASKA, Richard A. Pratt ARIZONA, Jean A. Nehme ARKANSAS, Phil Brand CALIFORNIA, Kevin Thompson, Susan Hida,

Barton J. Newton COLORADO, Mark A. Leonard, Michael G. Salamon CONNECTICUT, Julie F. Georges DELAWARE, Jiten K. Soneji, Barry A. Benton DISTRICT OF COLUMBIA, Nicolas Galdos, L.

Donald Cooney, Konjit Connie Eskender FLORIDA, Marcus Ansley, Sam Fallaha, Jeff Pouliotte GEORGIA, Paul V. Liles, Jr. HAWAII, Paul T. Santo IDAHO, Matthew M. Farrar ILLINOIS, Ralph E. Anderson, Thomas J. Domagalski INDIANA, Anne M. Rearick IOWA, Norman L. McDonald KANSAS, Kenneth F. Hurst, James J. Brennan, Loren

R. Risch KENTUCKY, Mark Hite LOUISIANA, Hossein Ghara, Arthur DAndrea, Paul

Fossier MAINE, David B. Sherlock, Jeffrey S. Folsom MARYLAND, Earle S. Freedman, Robert J. Healy MASSACHUSETTS, Alexander K. Bardow, Shirley

Eslinger MICHIGAN, Steven P. Beck, David Juntunen MINNESOTA, Daniel L. Dorgan, Kevin Western MISSISSIPPI, Mitchell K. Carr, B. Keith Carr MISSOURI, Dennis Heckman, Michael Harms MONTANA, Kent M. Barnes NEBRASKA, Mark J. Traynowicz, Mark Ahlman,

Fouad Jaber NEVADA, Mark P. Elicegui, Todd Stefonowicz NEW HAMPSHIRE, Mark W. Richardson, David L.

Scott NEW JERSEY, Richard W. Dunne NEW MEXICO, Raymond M. Trujillo, Jimmy D.

Camp NEW YORK, George A. Christian, Donald F. Dwyer,

Arthur P. Yannotti NORTH CAROLINA, Greg R. Perfetti NORTH DAKOTA, Terrence R. Udland OHIO, Timothy J. Keller, Jawdat Siddiqi

OKLAHOMA, Robert J. Rusch, Gregory D. Allen, John A. Schmiedel

OREGON, Bruce V. Johnson, Hormoz Seradj PENNSYLVANIA, Thomas P. Macioce, Harold C.

Hal Rogers, Jr., Lou Ruzzi PUERTO RICO, (Vacant) RHODE ISLAND, David Fish SOUTH CAROLINA, Barry W. Bowers, Jeff

Sizemore SOUTH DAKOTA, Kevin Goeden TENNESSEE, Edward P. Wasserman TEXAS, David P. Hohmann, Keith L. Ramsey U.S. DOT, M. Myint Lwin, Firas I. Sheikh Ibrahim UTAH, (Vacant) VERMONT, Wayne B. Symonds VIRGINIA, Malcolm T. Kerley, Kendal Walus,

Prasad L. Nallapaneni, Julius F. J. Volgyi, Jr. WASHINGTON, Jugesh Kapur, Tony M. Allen,

Bijan Khaleghi WEST VIRGINIA, Gregory Bailey, James D. Shook WISCONSIN, Scot Becker, Beth A. Cannestra,

William Dreher WYOMING, Gregg C. Fredrick, Keith R. Fulton

GOLDEN GATE BRIDGE, Kary H. Witt N.J. TURNPIKE AUTHORITY, Richard J.

Raczynski N.Y. STATE BRIDGE AUTHORITY, William J.

Moreau PENN. TURNPIKE COMMISSION, James L. Stump U.S. ARMY CORPS OF ENGINEERS

DEPARTMENT OF THE ARMY, Christopher H. Westbrook

U.S. COAST GUARD, Hala Elgaaly U.S. DEPARTMENT OF AGRICULTURE

FOREST SERVICE, John R. Kattell, Scott F. Mitchell

ALBERTA, Tom Loo NEW BRUNSWICK, Doug Noble NOVA SCOTIA, Mark Pertus ONTARIO, Bala Tharmabala SASKATCHEWAN, Howard Yea TRANSPORTATION RESEARCH BOARD

Waseem Dekelbab

2010 by the American Association of State Highway and Transportation Officials.

All rights reserved. Duplication is a violation of applicable law.

v

ABBREVIATED TABLE OF CONTENTS

The AASHTO LRFD Bridge Construction Specifications, Third Edition, contains the following 32 sections:

1. Structure Excavation and Backfill 2. Removal of Existing Structures 3. Temporary Works 4. Driven Foundation Piles 5. Drilled Shafts 6. Ground Anchors 7. Earth-Retaining Systems 8. Concrete Structures 9. Reinforcing Steel 10. Prestressing 11. Steel Structures 12. Steel Grid Flooring 13. Painting 14. Stone Masonry 15. Concrete Block and Brick Masonry 16. Timber Structures 17. Preservative Treatment of Wood 18. Bearing Devices 19. Bridge Deck Joint Seals 20. Railings 21. Waterproofing 22. Slope Protection 23. Miscellaneous Metal 24. Pneumatically Applied Mortar 25. Steel and Concrete Tunnel Liners 26. Metal Culverts 27. Concrete Culverts 28. Wearing Surfaces 29. Embedment Anchors 30. Thermoplastic Pipe 31. Aluminum Structures 32. Shock Transmission Units


WIN7Rectangle

vii

FOREWORD

The first broadly recognized national standard to design and construct bridges in the United States was published in 1931 by the American Association of State Highway Officials (AASHO), the predecessor to AASHTO. With the advent of the automobile and the establishment of highway departments in all of the American states dating back to just before the turn of the century, the design, construction, and maintenance of most U.S. bridges was the responsibility of these departments and, more specifically, the chief bridge engineer within each department. It was natural, therefore, that these engineers, acting collectively as the AASHTO Highways Subcommittee on Bridges and Structures, would become the author and guardian of this first bridge standard.

This first publication was entitled Standard Specifications for Highway Bridges and Incidental Structures. It quickly became the de facto national standard and, as such, was adopted and used by not only the state highway departments but also other bridge-owning authorities and agencies in the United States and abroad. The title was soon revised to Standard Specifications for Highway Bridges and new editions were released about every four years. AASHTO released the 17th and final edition in 2002.

The body of knowledge related to the design of highway bridges has grown enormously since 1931 and continues to do so. Theory and practice have evolved greatly, reflecting advances through research in understanding the properties of materials, in improved materials, in more rational and accurate analysis of structural behavior, in the advent of computers and rapidly advancing computer technology, in the study of external events representing particular hazards to bridges such as seismic events and stream scour, and in many other areas. The pace of advances in these areas has accelerated in recent years. To accommodate this growth in bridge engineering knowledge, the Subcommittee on Bridges and Structures has been granted authority under AASHTOs governing documents to approve and issue Bridge Interims each year, not only with respect to the Standard Specifications but also to enhance the twenty-odd additional publications on bridges and structures engineering that are under its stewardship.

In 1986, the Subcommittee submitted a request to the AASHTO Standing Committee on Research to assess U.S. bridge design specifications, to review foreign design specifications and codes, to consider design philosophies alternative to those underlying the Standard Specifications, and to render recommendations based on these investigations. This work was accomplished under the National Cooperative Highway Research Program (NCHRP), an applied research program directed by the AASHTO Standing Committee on Research and administered on behalf of AASHTO by the Transportation Research Board (TRB). The work was completed in 1987, and, as might be expected with continuing research, the Standard Specifications were found to have discernible gaps, inconsistencies, and even some conflicts. Beyond this, the specification did not reflect or incorporate the most recently developing design philosophy, load-and-resistance factor design (LRFD), a philosophy which has been gaining ground in other areas of structural engineering and in other parts of the world such as Canada and Europe.

From its inception until the early 1970s, the sole design philosophy embedded within the Standard Specifications was one known as working stress design (WSD). WSD establishes allowable stresses as a fraction or percentage of a given materials load-carrying capacity, and requires that calculated design stresses not exceed those allowable stresses. Beginning in the early 1970s, WSD was adjusted to reflect the variable predictability of certain load types, such as vehicular loads and wind forces, through adjusting design factors, a design philosophy referred to as load factor design (LFD). Both WSD and LFD are reflected in the current edition of the Standard Specifications.

A further philosophical extension considers the variability in the properties of structural elements, in similar fashion to load variabilities. While considered to a limited extent in LFD, the design philosophy of LRFD takes variability in the behavior of structural elements into account in an explicit manner. LRFD relies on extensive use of statistical methods, but sets forth the results in a manner readily usable by bridge designers and analysts.

With the advent of these specifications, bridge engineers had a choice of two standards to guide their designs, the long-standing AASHTO Standard Specifications for Highway Bridges, and the alternative, newly adopted AASHTO LRFD Bridge Design Specifications, and its companions, AASHTO LRFD Bridge Construction Specifications and AASHTO LRFD Movable Highway Bridge Design Specifications. Subsequently, the Federal Highway Administration (FHWA) and the states mandated that LRFD standards be used to design all new and total replacement bridges after 2007. For more information on FHWAs LRFD policy, please visit http://www.fhwa.dot.gov/bridge/lrfd/index.htm.

A new edition of these specifications will be published every two years, followed by an interim edition the immediate year after its release. The Interim Specifications have the same status as AASHTO standards, but are tentative revisions approved by at least two-thirds of the Subcommittee. These revisions are voted on by the AASHTO member departments prior to the publication of each new edition of this book and, if approved by at least two-thirds of the members, they are


viii

included in the next new edition as standards of the Association. AASHTO members are the 50 State Highway or Transportation Departments, the District of Columbia, and Puerto Rico. Each member has one vote. The U.S. Department of Transportation is a nonvoting member.

Annual Interim Specifications are generally used by the States after their adoption by the Subcommittee. Orders for these annual Interim Specifications may be placed by visiting our website, bookstore.transportation.org, or by calling 1-800-231-3475 (toll free within the U.S. and Canada). A free copy of the current publication catalog can be downloaded from our website or requested from the Publications Sales Office.

The Subcommittee would also like to thank Mr. John M. Kulicki, Ph.D., and his associates at Modjeski and Masters for their valuable assistance in the preparation of the LRFD Specifications.

AASHTO encourages suggestions to improve these specifications. They should be sent to the Chairman, Subcommittee on Bridges and Structures, AASHTO, 444 North Capitol Street, N.W., Suite 249, Washington, DC 20001. Inquiries as to intent or application of the specifications should be sent to the same address.

AASHTO Highways Subcommittee on Bridges and Structures February 2010


ix

PREFACE Units

The AASHTO LRFD Bridge Construction Specifications, Third Edition, uses U.S. Customary units only. Per a decision by the subcommittee in 2009, SI units will no longer be included in this edition or future interims.

References If a standard is available as a stand-alone publicationfor example, the ACI standardsthe title is italicized in the

text and listed in the references. If a standard is available as part of a larger publicationfor example, the AASHTO materials specificationsthe standards title is not italicized and the larger publicationin this case, Standard Specifications for Transportation Materials and Methods of Sampling and Testing, 29th Editionis listed in the references.

Unit Abbreviations

Most of the abbreviations commonly used in LRFD Construction are listed below. Also, please note the following: Abbreviations for singular and plural are the same.

Most units of time have one-letter abbreviations. Unit abbreviations are always set in roman type, while variables

and factors are set in italic type. Thus, 2 h is the abbreviation for two hours. Table iFrequently-Used Unit Abbreviations

Unit Abbreviation cubic foot ft3 cubic inch in.3 cubic yard yd3 degrees Fahrenheit F foot ft foot-kip ft-kip foot per hour ft/h foot per minute ft/min foot per second ft/s foot pound ft lb foot pound-force ft lbf foot second ft s gallon gal hour h Hertz Hz inch in. joule J kilonewton kN kilopascal kPa kip per foot kip/ft kip per square inch ksi kip per square foot kip/ft2 megapascal MPa microinch in micron m mile mi minute min (min. for minimum)


x

Table i (continued)Frequently-Used Unit Abbreviations

Unit Abbreviation newton N newton meter N m newton per meter N/m ounce oz pascal Pa pascal second Pa s pound lb pound-force lbf pound-force foot lbf ft pound-force inch lbf in. pound-force per foot lbf/ft pound-force per inch lbf/in. pound-force per pound lbf/lb pound-force per square foot psf pound-force per square inch psi pound per cubic foot lb/ft3 pound per cubic inch lb/in.3 pound per cubic yard lb/yd3 pound per foot lb/ft pound per inch lb/in. pound per hour lb/h pound per square foot lb/ft2 pound per yard lb/yd radian rad radian per second rad/s quart qt second s square inch in.2 square foot ft2 square mile mi2 square yard yd2 year yr

Note: There are no abbreviations for day, degree (angle), kip, mil, or ton.

AASHTO Publications Staff

February 2010


xi

CHANGED AND DELETED ARTICLES, 2010

SUMMARY OF AFFECTED SECTIONS

The third edition revisions to the AASHTO LRFD Bridge Construction Specifications affect the following sections: 3. Temporary Works 5. Drilled Shafts 11. Steel Structures 18. Bearing Devices 30. Thermoplastic Pipe

SECTION 3 REVISIONS Changed Articles

The following Article in Section 3 contains changes or additions to the specifications, the commentary, or both: 3.1.1

Deleted Articles

No Articles were deleted from Section 3. SECTION 5 REVISIONS

The entire Section 5 has been rewritten.


The following Articles in Section 11 contain changes or additions to the specifications, the commentary, or both: 11.3.1.1 11.3.1.4 11.3.1.7

11.4.3.3.2 11.4.3.3.3 11.4.7

11.4.11 11.4.12.2.1 11.4.12.2.3

11.8.3.3.1 11.8.3.6.4

Deleted Articles

No Articles were deleted from Section 11. SECTION 18 REVISIONS Changed Articles

The following Articles in Section 18 contain changes or additions to the specifications, the commentary, or both: 18.1.5.1.1 18.1.5.1.2 18.1.5.2.3 18.1.5.2.4

18.1.5.2.6 18.1.5.2.7 18.3.2.6 18.3.2.8

18.3.4.1 18.3.4.2 18.3.4.3 18.3.4.4

18.3.4.4.1 18.3.4.4.2 18.3.4.4.3 18.3.4.4.4

18.3.4.4.5 18.3.5 18.6.3 18.8.4.1


xii

Deleted Articles

The following Articles were deleted from Section 18: 18.3.4.2.1 18.3.4.2.2 18.3.4.3.1 18.3.4.3.2


The following Article in Section 30 contains changes or additions to the specifications, the commentary, or both: 30.5.2

Deleted Articles

No Articles were deleted from Section 30.


SECTION 1: STRUCTURE EXCAVATION AND BACKFILL

TABLE OF CONTENTS

1-i

1 1.1GENERAL ........................................................................................................................................................... 1-11.2WORKING DRAWINGS .................................................................................................................................... 1-11.3MATERIALS ....................................................................................................................................................... 1-21.4CONSTRUCTION ............................................................................................................................................... 1-2

1.4.1Depth of Footings ...................................................................................................................................... 1-21.4.2Foundation Preparation and Control of Water ........................................................................................... 1-2

1.4.2.1General ............................................................................................................................................. 1-21.4.2.2Excavations within Channels ........................................................................................................... 1-31.4.2.3Foundations on Rock ....................................................................................................................... 1-31.4.2.4Foundations Not on Rock ................................................................................................................ 1-31.4.2.5Approval of Foundation ................................................................................................................... 1-3

1.4.3Backfill ...................................................................................................................................................... 1-41.5MEASUREMENT AND PAYMENT .................................................................................................................. 1-4

1.5.1Measurement .............................................................................................................................................. 1-41.5.2Payment ..................................................................................................................................................... 1-5

1.6REFERENCE ....................................................................................................................................................... 1-6


SECTION 1

STRUCTURE EXCAVATION AND BACKFILL

1-1

1.1GENERAL

Structure excavation shall consist of the removal of all

material, of whatever nature, necessary for the constructionof foundations for bridges, retaining walls, and other major structures, in accordance with the contract documents or asdirected by the Engineer.

C1.1

If not otherwise provided for in the contract, structureexcavation shall include the furnishing of all necessaryequipment and the construction and subsequent removal ofall cofferdams, shoring, and water control systems whichmay be necessary for the execution of the work.

If not otherwise specified in the contract documents, itshall also include the placement of all necessary backfill,including any necessary stockpiling of excavated material which is to be used in backfill, and the disposing ofexcavated material which is not required for backfill, inroadway embankments or as provided for excess andunsuitable material in Subsection 203.02, AASHTO Guide Specifications for Highway Construction.

Subsection 203.02 is located in the AASHTO Guide Specifications for Highway Construction.

If the contract does not include a separate pay item oritems for such work, structure excavation shall include allnecessary clearing and grubbing and the removal of existing structures within the area to be excavated.

Classification, if any, of excavation will be indicated inthe contract documents and set forth in the proposal.

The removal and disposal of buried natural or man-made objects are included in the class of excavation inwhich they are located, unless such removal and disposalare included in other items of work. However, in the caseof a buried man-made object, the removal and disposal ofsuch object will be paid for as extra work and its volume will not be included in the measured quantity of excavation,if:

its removal requires the use of methods orequipment not used for other excavation on theproject,

its presence was not indicated in the contractdrawings,

its presence could not have been ascertained bysite investigation, including contact withidentified utilities within the area, and

the Contractor so requests in writing prior to itsremoval.

1.2WORKING DRAWINGS Whenever specified in the contract drawings, the

Contractor shall provide working drawings, accompaniedby calculations where appropriate, of excavation


1-2 AASHTO LRFD BRIDGE CONSTRUCTION SPECIFICATIONS

procedures, embankment construction, and backfillingoperations. This plan shall show the details of shoring,bracing, slope treatment, or other protective system proposed for use and shall be accompanied by designcalculations and supporting data in sufficient detail topermit an engineering review of the proposed design.

The working drawings for protection from caving shallbe submitted sufficiently in advance of proposed use toallow for their review; revision, if needed; and approvalwithout delay to the work.

Working drawings shall be approved by the Engineerprior to performance of the work involved, and suchapproval shall not relieve the Contractor of any responsibility under the contract for the successfulcompletion of the work.

1.3MATERIALS Material used for backfill shall be free of frozen lumps,

wood, or other degradable or hazardous matter and shall beof a grading such that the required compaction can beconsistently obtained using the compaction methodsselected by the Contractor.

C1.3

Permeable material for underdrains shall conform toAASHTO Guide Specifications for Highway Construction, Subsection 704.01.

Subsection 704.01 is located in the AASHTO Guide Specifications for Highway Construction.

1.4CONSTRUCTION

1.4.1Depth of Footings The elevation of the bottoms of footings, as shown in

the contract documents, shall be considered as approximateonly and the Engineer may order, in writing, such changesin dimensions or elevation of footings as may be necessaryto secure a satisfactory foundation.

1.4.2Foundation Preparation and Control of Water 1.4.2.1General Where practical, all substructures shall be constructed

in open excavation and, where necessary, the excavationshall be shored, braced, or protected by cofferdamsconstructed in accordance with the requirements containedin Article 3.3, Cofferdams and Shoring. When footingscan be placed in the dry without the use of cofferdams,backforms may be omitted with the approval of theEngineer and the entire excavation filled with concrete tothe required elevation of the top of the footing. Theadditional concrete required shall be furnished and placedat the expense of the Contractor. Temporary water controlsystems shall conform to the requirements contained inArticle 3.4, Temporary Water Control Systems.


SECTION 1: STRUCTURE EXCAVATION AND BACKFILL 1-3

1.4.2.2Excavations within Channels When excavation encroaches upon a live streambed or

channel, unless otherwise permitted, no excavation shall bemade outside of caissons, cribs, cofferdams, steel piling, orsheeting, and the natural streambed adjacent to the structureshall not be disturbed without permission from theEngineer. If any excavation or dredging is made at the siteof the structure before caissons, cribs, or cofferdams aresunk or are in place, the Contractor shall, without extracharge, after the foundation base is in place, backfill allsuch excavation to the original ground surface or riverbed with material satisfactory to the Engineer. Materialtemporarily deposited within the flow area of streams fromfoundation or other excavation shall be removed and thestream flow area freed from obstruction thereby.

1.4.2.3Foundations on Rock When a foundation is to rest on rock, the rock shall be

freed from all loose material, cleaned, and cut to a firmsurface, either level, stepped, or roughened, as may bedirected by the Engineer. All seams shall be cleaned outand filled with concrete, mortar, or grout before the footingis placed.

Where blasting is required to reach footing level, anyloose, fractured rock caused by overbreak below bearinglevel shall be removed and replaced with concrete orgrouted at the Contractor's expense.

1.4.2.4Foundations Not on Rock When a foundation is to rest on an excavated surface

other than rock, special care shall be taken not to disturbthe bottom of the excavation, and the final removal of thefoundation material to grade shall not be made until justbefore the footing is to be placed.

Where the material below the bottom of footings notsupported by piles has been disturbed, it shall be removedand the entire space filled with concrete or other approvedmaterial at the Contractor's expense. Under footings supported on piles, the over-excavation or disturbedvolumes shall be replaced and compacted as directed by theEngineer.

1.4.2.5Approval of Foundation After each excavation is completed, the Contractor

shall notify the Engineer that the excavation is ready for inspection and evaluation and no concrete or other footingmaterial shall be placed until the Engineer has approved thedepth of the excavation and the character of the foundationmaterial.



1.4.3Backfill Backfill material shall conform to the provisions of

Article 1.3, Materials. If sufficient material of suitablequality is not available from excavation within the projectlimits, the Contractor shall import such material as directedby the Engineer.

Unless otherwise specified in the contract documents,all spaces excavated and not occupied by abutments, piers,or other permanent work shall be refilled with earth up tothe surface of the surrounding ground, with a sufficientallowance for settlement. Except as otherwise provided, all backfill shall be thoroughly compacted to the density of thesurrounding ground and its top surface shall be neatlygraded. Fill placed around piers shall be deposited on bothsides to approximately the same elevation at the same time.Rocks larger than 3.0-in. maximum dimension shall not beplaced against the concrete surfaces.

C1.4.3

Embankment construction shall conform to therequirements of AASHTO Guide Specifications forHighway Construction, Subsection 203.02. The fill atretaining walls, abutments, wingwalls, and all bridge bentsin embankment shall be deposited in well-compacted,horizontal layers not to exceed 6.0 in. in thickness and shallbe brought up uniformly on all sides of the structure orfacility. Backfill within or beneath embankments, withinthe roadway in excavated areas, or in front of abutmentsand retaining walls or wingwalls shall be compacted to thesame density as required for embankments.

Subsection 203.02 is located in AASHTO Guide Specifications for Highway Construction.

No backfill shall be placed against any concretestructure until permission has been given by the Engineer.The placing of such backfill shall also conform to therequirements of Article 8.15.2, Earth Loads. The backfillin front of abutments and wingwalls shall be placed first toprevent the possibility of forward movement. Jetting of thefill behind abutments and wingwalls will not be permitted.

Adequate provision shall be made for the thoroughdrainage of all backfill. French drains, consisting of at least2.0 ft3 of permeable material wrapped in filter fabric toprevent clogging and transmission of fines from thebackfill, shall be placed at each weep hole.

Backfilling of metal and concrete culverts shall bedone in accordance with the requirements of Sections 26, Metal Culverts, and 27, Concrete Culverts.

1.5MEASUREMENT AND PAYMENT

1.5.1Measurement The quantity to be paid for as structure excavation

shall be measured by the cubic yard. The quantities forpayment will be determined from limits shown in thecontract documents or ordered by the Engineer. Nodeduction in structure excavation pay quantities will bemade where the Contractor does not excavate materialwhich is outside the limits of the actual structure but withinthe limits of payment for structure excavation.


SECTION 1: STRUCTURE EXCAVATION AND BACKFILL 1-5

Unless otherwise specified in the contract documents,pay limits for structure excavation shall be taken as:

the horizontal limits shall be vertical planes18.0 in. outside of the neat lines of footings or structures without footings,

the top limits shall be the original ground or thetop of the required grading cross-section, whichever is lower, and

the lower limits shall be the bottom of the footingor base of structure, or the lower limit ofexcavation ordered by the Engineer.

When foundations are located within embankmentsand the specifications require the embankment to beconstructed to a specified elevation that is above the bottomof the footing or base of structure prior to construction of the foundation, then such specified elevation will beconsidered to be the original ground.

When it is necessary, in the opinion of the Engineer, tocarry the foundations below the elevations shown in thecontract documents, the excavation for the first 3.0 ft of additional depth will be included in the quantity for whichpayment will be made under this item. Excavation belowthis additional depth will be paid for as extra work, unlessthe Contractor states in writing that payment at contractprices is acceptable.

1.5.2Payment Unless otherwise provided, structure excavation,

measured as provided in Article 1.5.1, Measurement, willbe paid for by the cubic yard for the kind and classspecified in the contract documents.

Payment for structure excavation shall include fullcompensation for all labor, material, equipment, and otheritems that may be necessary or convenient to the successfulcompletion of the excavation to the elevation of the bottomof footings or base of structure.

Full compensation for controlling and removing waterfrom excavations and for furnishing and installing orconstructing all cofferdams, shoring, and all other facilitiesnecessary to the operations, except concrete seal coursesthat are shown in the contract documents, and their subsequent removal, shall be considered as included in thecontract price for structure excavation, unless the contractdocument provides for their separate payment.

Unless otherwise specified in the contract documents,the contract price for structure excavation shall include fullpayment for all handling and storage of excavated materialsthat are to be used as backfill, including any necessarydrying, and the disposal of all surplus or unsuitableexcavated materials. Any clearing, grubbing, or structure removal that is required but not paid for under other itemsof the contract documents will be considered to be includedin the price paid for structure excavation.


1-6 AASHTO LRFD BRIDGE CONSTRUCTION SPECIFICATIONS Unless the contract document provides for its separate

payment, the contract price for structure excavation shallinclude full compensation for the placing and compactingof structure backfill. The furnishing of backfill materialfrom sources other than excavation will be paid for at thecontract unit price for the material being used or as extrawork if no unit price has been established.

1.6REFERENCE AASHTO. 2008. AASHTO Guide Specifications for Highway Construction, Ninth Edition, GSH-9, American Association of State Highway and Transportation Officials, Washington, DC.


SECTION 2: REMOVAL OF EXISTING STRUCTURES

TABLE OF CONTENTS

2-i

2 2.1DESCRIPTION .................................................................................................................................................... 2-12.2WORKING DRAWINGS .................................................................................................................................... 2-12.3CONSTRUCTION ............................................................................................................................................... 2-2

2.3.1General ....................................................................................................................................................... 2-22.3.2Salvage ....................................................................................................................................................... 2-22.3.3Partial Removal of Structures .................................................................................................................... 2-32.3.4Disposal ..................................................................................................................................................... 2-3

2.4MEASUREMENT AND PAYMENT .................................................................................................................. 2-4


SECTION 2

REMOVAL OF EXISTING STRUCTURES 4

2-1

2.1DESCRIPTION This work shall consist of the removal, wholly or in

part, and satisfactory disposal or salvage of all bridges,retaining walls, and other major structures that aredesignated to be removed in the contract documents.Unless otherwise specified, the work also includes anynecessary excavation and the backfilling of trenches, holes,or pits that result from such removal. It also includes allcosts for environmental and health monitoring systems or programs as may be required.

2.2WORKING DRAWINGS

Working drawings showing methods and sequence of

removal shall be prepared:

when structures or portions of structure arespecified to be removed and salvaged,

when removal operations will be performed overor adjacent to public traffic or railroad property,or

when specified in the contract documents. The working drawings shall be submitted to the

Engineer for approval at least ten days prior to the proposedstart of removal operations. Removal work shall not beginuntil the drawings have been approved. Such approval shallnot relieve the Contractor of any responsibility under thecontract documents for the successful completion of thework.

When salvage is required, the drawings shall clearly indicate the markings proposed to designate individualsegments of the structure.


2-2 AASHTO LRFD BRIDGE CONSTRUCTION SPECIFICATIONS 2.3CONSTRUCTION

2.3.1General

Except for utilities and other items that the Engineer

may direct the Contractor to leave intact, the Contractorshall raze, remove, and dispose of each structure orportion of structure designated to be removed. Allconcrete and other foundations shall be removed to adepth of at least 2.0 ft below ground elevation or 3.0 ft below subgrade elevation, whichever is lower. Unless otherwise specified in the contract documents, theContractor has the option to either pull piles or cut themoff at a point not less than 2.0 ft below groundline.Cavities left from structure removal shall be backfilled tothe level of the surrounding ground and, if within thearea of roadway construction, shall be compacted tomeet the requirements of the contract documents forembankment.

Explosives shall not be used except at locations andunder conditions specified in the contract documents. All blasting shall be completed before the placement of newwork.

2.3.2Salvage

Materials which are designated to be salvaged under

the contract documents, either for reuse in the project or forfuture use by the Owner, shall remain the property of the Owner and shall be carefully removed in transportablesections and stockpiled near the site at a locationdesignated by the Engineer. The Contractor shall restore orreplace damaged or destroyed material without additionalcompensation.

Rivets and bolts that must be removed from steelstructures to be salvaged shall be removed by cutting theheads with a chisel, after which they shall be punched ordrilled from the hole, or by any other method that will notinjure the members for reuse and will meet the approval ofthe Engineer. Prior to dismantling, all members or sectionsof steel structures shall be match-marked with paint inaccordance with the diagram or plan approved by theEngineer.

All bolts and nails shall be removed from lumberdeemed salvageable by the Engineer as part of the salvageof timber structures.


SECTION 2: REMOVAL OF EXISTING STRUCTURES 2-3

2.3.3Partial Removal of Structures When structures are to be widened or modified and

only portions of the existing structure are to be removed,these portions shall be removed in such a manner as toleave the remaining structure undamaged and in propercondition for the use contemplated. Methods involving theuse of blasting or wrecking balls shall not be used withinany span or pier unless the entire span or pier is to beremoved. Any damage to the portions remaining in serviceshall be repaired by the Contractor at the Contractor'sexpense.

Before beginning concrete removal operationsinvolving the removal of a portion of a monolithic concreteelement, a saw cut approximately 1.0 in. deep shall be made to a true line along the limits of removal on all facesof the element that will be visible in the completed work.

Old concrete shall be carefully removed to the linesdesignated by drilling, chipping, or other methods approved by the Engineer. The surfaces presented as a result of thisremoval shall be reasonably true and even, with sharp,straight corners that will permit a neat joint with the newconstruction or be satisfactory for the use contemplated.Where existing reinforcing bars are to extend from theexisting structure into new construction, the concrete shallbe removed so as to leave the projecting bars clean andundamaged. Where projecting bars are not to extend intothe new construction, they shall be cut off flush with the surface of the old concrete.

During full-depth removal of deck concrete over steelbeams or girders which are to remain in place, theContractor shall exercise care so as not to notch, gouge, ordistort the top flanges. Any damage shall be repaired at the direction of the Engineer and at the expense of theContractor. Repairs may include grinding, welding, heat-straightening, or member replacement, depending on thelocation and severity of the damage.

2.3.4Disposal

Any material not designated for salvage will belong to

the Contractor. Except as provided herein, the Contractorshall store or dispose of such material outside of the right-of-way. If the material is disposed of on private property,the Contractor shall secure written permission from theproperty owner and shall furnish a copy of each agreementto the Engineer. Waste materials may be disposed of in anOwner's site when such sites are described in the contractdocuments.

Unless otherwise provided in the contract documents, removed concrete may be buried in adjacent embankments,provided it is broken into pieces which can be readilyhandled and incorporated into embankments and is placedat a depth of not less than 3.0 ft below finished grade andslope lines. The removed concrete shall not be buried inareas where piling is to be placed or within 10.0 ft of trees, pipelines, poles, buildings, or other permanent objects or


2-4 AASHTO LRFD BRIDGE CONSTRUCTION SPECIFICATIONS structures, unless permitted by the Engineer. Removedconcrete may also be disposed of outside the right-of-way as provided above.

The contract documents shall indicate all knownhazardous material including paint history. Hazardousmaterial shall be properly disposed of and appropriaterecords maintained.


The work, as prescribed for by this item, shall be

measured as each individual structure or portion of astructure to be removed. Payment will be made on the basisof the lump-sum bid price for the removal of each structureor portion of structure as specified in the contractdocuments.

The above prices and payments shall be fullcompensation for all work, labor, tools, equipment,excavation, backfilling, materials, proper disposal, andincidentals necessary to complete the work, includingsalvaging materials not to be reused in the project whensuch salvaging is specified and not otherwise paid for.

Full compensation for removing and salvagingmaterials that are to be reused in the project shall beconsidered as included in the contract document prices paidfor reconstructing, relocating, or resetting the items involved, or in such other contract pay items that may bedesignated in the contract documents; no additionalcompensation will be allowed therefore.


SECTION 3: TEMPORARY WORKS

TABLE OF CONTENTS

3-i

3 3.1GENERAL ........................................................................................................................................................... 3-1

3.1.1Description ................................................................................................................................................. 3-13.1.2Working Drawings ..................................................................................................................................... 3-13.1.3Design ........................................................................................................................................................ 3-23.1.4Construction ............................................................................................................................................... 3-23.1.5Removal ..................................................................................................................................................... 3-2

3.2FALSEWORK AND FORMS .............................................................................................................................. 3-23.2.1General ....................................................................................................................................................... 3-23.2.2Falsework Design and Construction .......................................................................................................... 3-3

3.2.2.1Loads ............................................................................................................................................... 3-33.2.2.2Foundations ...................................................................................................................................... 3-33.2.2.3Deflections ....................................................................................................................................... 3-33.2.2.4Clearances ........................................................................................................................................ 3-33.2.2.5Construction ..................................................................................................................................... 3-4

3.2.3Formwork Design and Construction .......................................................................................................... 3-43.2.3.1General ............................................................................................................................................. 3-43.2.3.2Design .............................................................................................................................................. 3-53.2.3.3Construction ..................................................................................................................................... 3-53.2.3.4Tube Forms ...................................................................................................................................... 3-63.2.3.5Stay-in-Place Forms ......................................................................................................................... 3-6

3.2.4Removal of Falsework and Forms ............................................................................................................. 3-63.2.4.1General ............................................................................................................................................. 3-63.2.4.2Time of Removal ............................................................................................................................. 3-63.2.4.3Extent of Removal ........................................................................................................................... 3-7

3.3COFFERDAMS AND SHORING ....................................................................................................................... 3-83.3.1General ....................................................................................................................................................... 3-83.3.2Protection of Concrete ............................................................................................................................... 3-83.3.3Removal ..................................................................................................................................................... 3-8

3.4TEMPORARY WATER CONTROL SYSTEMS ................................................................................................ 3-93.4.1General ....................................................................................................................................................... 3-93.4.2Working Drawings ..................................................................................................................................... 3-93.4.3Operations .................................................................................................................................................. 3-9

3.5TEMPORARY BRIDGES ................................................................................................................................... 3-93.5.1General ....................................................................................................................................................... 3-93.5.2Detour Bridges ........................................................................................................................................... 3-93.5.3Haul Bridges ............................................................................................................................................ 3-103.5.4Maintenance ............................................................................................................................................. 3-10

3.6MEASUREMENT AND PAYMENT ................................................................................................................ 3-103.7REFERENCES ................................................................................................................................................... 3-11


SECTION 3

TEMPORARY WORKS

3-1

3.1GENERAL 3.1.1Description

This work shall consist of the construction and

removal of temporary facilities that are generally designedby the Contractor and employed by the Contractor in theexecution of the work, and whose failure to perform properly could adversely affect the character of the contractwork or endanger the safety of adjacent facilities, property,or the public. Such facilities include but are not limited tofalsework, forms and form travelers, cofferdams, shoring,water control systems, and temporary bridges. Appropriatereductions in allowable stresses and decreases in resistancefactors or imposed loads shall be used for design whenother than new or undamaged materials are to be used. Tothe extent possible, calculations shall include adjustmentsto section properties to account for damage or section loss.

Unless otherwise permitted, the design of thetemporary works shall be based on AASHTO LRFD BridgeDesign Specifications load factors specified in Articles3.4.1 and 3.4.2, and all applicable load combinations shallbe investigated. Such investigation shall includeconstruction loads; member capacity based on fieldcondition which account for section loss, deterioration ofcapacity, and any alterations of the structure; support conditions during all construction phases; and theappropriate distribution of construction stockpiled materialsand construction equipment.

C3.1.1 FHWA issued Technical Advisory T5140.24 on

October 29, 1993, concerning Bridge Temporary Works. The Secretary of the U.S. Department of Transportation was directed by Congress to develop specifications and guidelines for use in constructing bridge temporary works. The falsework collapse of the Maryland Route 198 Bridge over the Baltimore/Washington Parkway and the fact that no national standard code or specification was available on bridge temporary works precipitated the mandate.

The guide specifications, handbook, and certification program are useful in conjunction with this Section of these Specifications. States are encouraged to review these publications and incorporate appropriate portions into their specifications. The Construction Handbook (see below) is a useful instructional tool for field inspection personnel.

The following publications are useful reference documents in the preparation of specifications for the design, review and inspection of temporary works:

Synthesis of Falsework, Formwork, and

Scaffolding for Highway Bridge Structures, Nov. 1991 (FHWA-RD-91-062)

Guide Standard Specifications for Bridge Temporary Works, Nov. 1993 (FHWA-RD-93-031)

Guide Design Specifications for Bridge Temporary Works, Nov. 1993 (FHWA-RD-93-032)

Certification Program for Bridge Temporary Works, Nov. 1993 (FHWA-RD-93-033)

Construction Handbook for Bridge Temporary Works, Nov. 1993 (FHWA-RD-93-034)

Steel Bridge Erection Guide Specification, 2007 (NSBA S10.1)

3.1.2Working Drawings

Whenever specified in the contract documents or

requested by the Engineer, the Contractor shall provideworking drawings with design calculations and supportingdata in sufficient detail to permit a structural review of theproposed design of a temporary work. When concrete isinvolved, such data shall include the sequence and rate ofplacement. Sufficient copies shall be furnished to meet the needs of the Engineer and other entities with review authority.The working drawings shall be submitted sufficiently inadvance of proposed use to allow for their review; revision, if needed; and approval without delay to the work.



The Contractor shall not start the construction of anytemporary work for which working drawings are requireduntil the drawings have been approved by the Engineer.Such approval will not relieve the Contractor ofresponsibility for results obtained by use of these drawingsor any of the Contractor's other responsibilities under thecontract.

3.1.3Design

The design of temporary works shall conform to the

AASHTO LRFD Bridge Design Specifications or the Guide Design Specifications for Bridge Temporary Works, or to other established and generally accepted design code orspecification for such work.

When manufactured devices are to be employed, thedesign shall not result in loads on such devices in excess ofthe load ratings recommended by their Manufacturer. For equipment where the rated capacity is determined by loadtesting, the design load shall be as stated in the Guide Specifications for Bridge Temporary Works.

The load rating used for special equipment, such asaccess scaffolding, may be under the jurisdiction of OSHAand/or other State/Local regulations. However, in no caseshall the rating exceed 80 percent of the maximum loadsustained during load testing of the equipment.

C3.1.3 Article 3.1.3 specifies the use of the AASHTO LRFD

Bridge Design Specifications or the Guide Design Specifications for Bridge Temporary Works, unless another recognized specification is accepted by the Engineer.

The Guide Design Specifications for Bridge Temporary Works is referenced for design loads.

Access scaffolding is covered under the Occupational Safety and Health Administration (OSHA) but stability trusses used for erection of structural steel are designed as falsework.

When required by statute or specified in the contractdocuments, the design shall be prepared and the drawingssigned by a Registered Professional Engineer.

3.1.4Construction

Temporary works shall be constructed in conformance

with the approved working drawings. The Contractor shallverify that the quality of the materials and work employedare consistent with that assumed in the design.

3.1.5Removal

Unless otherwise specified, all temporary works shall

be removed and shall remain the property of the Contractorupon completion of their use. The area shall be restored toits original or planned condition and cleaned of all debris.

3.2FALSEWORK AND FORMS 3.2.1General

The working drawings for falsework shall be prepared

and sealed by a Registered Professional Engineer wheneverthe height of falsework exceeds 14.0 ft or whenever traffic,other than workers involved in constructing the bridge, willtravel under the bridge.

Falsework and forms shall be of sufficient rigidity andstrength to safely support all loads imposed and to produce in the finished structure the lines and grades indicated inthe contract documents. Forms shall also impart therequired surface texture and rustication and shall not detractfrom the uniformity of color of the formed surfaces.

C3.2.1 Falsework is considered to be any temporary structure

which supports structural elements of concrete, steel, masonry, or other materials during their construction or erection.

Forms are considered to be the enclosures or panels which contain the fluid concrete and withstand the forces due to its placement and consolidation. Forms may in turn be supported on falsework.

Form travelers, as used in segmental cantilever construction, are considered to be a combination of falsework and forms.


SECTION 3: TEMPORARY WORKS 3-3

3.2.2Falsework Design and Construction

3.2.2.1Loads The design load for falsework shall consist of the sum

of dead and live vertical loads and any horizontal loads. As a minimum, dead loads shall include the weight

(mass) of the falsework and all construction material to besupported. The combined unit weight (density) of concrete, reinforcing and prestressing steel, and forms shall be assumedto be not less than 0.16 kip/ft3 of normal-weight concrete or 0.13 kip/ft3 of lightweight concrete that is supported.

C3.2.2.1 In the SI units, normal-weight concrete is known as

normal-density concrete and lightweight concrete is known as low-density concrete.

Live loads shall consist of the actual weight (mass) ofany equipment to be supported, applied as concentratedloads at the points of contact and a uniform load of not less than 0.02 kip/ft2 applied over the area supported, plus0.075 kip/ft applied at the outside edge of deck overhangs.

The horizontal load used for the design of the falseworkbracing system shall be the sum of the horizontal loads due toequipment; construction sequence, including unbalancedhydrostatic forces from fluid concrete; stream flow, whenapplicable; and an allowance for wind. However, in no caseshall the horizontal load to be resisted in any direction be lessthan two percent of the total dead load.

For post-tensioned structures, the falsework shall alsobe designed to support any increase in or redistribution ofloads caused by prestressing of the structure.

Loads imposed by falsework onto existing, new, orpartially completed structures shall not exceed thosepermitted in Article 8.15, Application of Loads.

3.2.2.2Foundations Falsework shall be founded on a solid footing, safe

against undermining, protected from softening, and capableof supporting the loads imposed on it. When requested bythe Engineer, the Contractor shall demonstrate by suitableload tests that the soil bearing values assumed for thedesign of the falsework footings do not exceed thesupporting capacity of the soil.

Falsework which cannot be founded on a satisfactoryfooting shall be supported on piling which shall be spaced,driven, and removed in an approved manner.

3.2.2.3Deflections For cast-in-place concrete structures, the calculated

deflection of falsework flexural members shall not exceed 1/240 of their span irrespective of the fact that the deflectionmay be compensated for by camber strips.

3.2.2.4Clearances Unless otherwise provided, the minimum dimensions

of clear openings to be provided through falsework forroadways that are to remain open to traffic duringconstruction shall be at least 5.0 ft greater than the width ofthe approach traveled way, measured between barrierswhen used. The minimum vertical clearance over Interstate routes and freeways shall be 14.5 ft, and 14.0 ft over other classes of roadways.



3.2.2.5Construction Falsework shall be constructed and set to grades that

allow for its anticipated settlement and deflection, and forthe vertical alignment and camber indicated in the contractdocuments or ordered by the Engineer for the permanentstructure. When directed by the Engineer, variable-depth camber strips shall be used between falsework beams andsoffit forms to accomplish this.

Suitable screw jacks, pairs of wedges, or other devicesshall be used at each post to:

adjust falsework to grade, permit minor adjustments during the placement of

concrete or structural steel should observedsettlements deviate from those anticipated, and

allow for the gradual release of the falsework. The Contractor shall provide for accurate measurement offalsework settlement during the placing and curing of theconcrete.

Falsework or formwork for deck slabs on girderbridges shall be supported directly on the girders so thatthere will be no appreciable differential settlement duringplacing of the concrete. Girders shall either be braced andtied to resist any forces that would cause rotation or torsionin the girders caused by the placing of concrete fordiaphragms or decks or be shown to be adequate for thoseeffects. Unless specifically permitted, welding offalsework support brackets or braces to structural steelmembers or reinforcing steel shall not be allowed.

3.2.3Formwork Design and Construction

3.2.3.1General Forms shall be of wood, steel, or other approved

material and shall be mortar tight and of sufficient rigidityto prevent objectional distortion of the formed concretesurface caused by pressure of the concrete and other loadsincidental to the construction operations.

C3.2.3.1

Forms for concrete surfaces exposed to view shallproduce a smooth surface of uniform texture and colorsubstantially equal to that which would be obtained withthe use of plywood conforming to the National Institute ofStandards and Technology Product Standard PS 1 for Exterior B-B Class I Plywood. Panels lining such formsshall be arranged so that the joint lines form a symmetricalpattern conforming to the general lines of the structure. Thesame type of form-lining material shall be used throughouteach element of a structure. Such forms shall be sufficientlyrigid so that the undulation of the concrete surface shall notexceed 0.125 in. when checked with a 5.0-ft straightedge or template. All sharp corners shall be filleted withapproximately 0.75-in. chamfer strips.

Forms for concrete structures using plywood refers to the National Institute of Standards and Technology Product Standards PS 1, Construction and Industrial Plywood.


SECTION 3: TEMPORARY WORKS 3-5

Concrete shall not be deposited in the forms until allwork connected with constructing the forms has beencompleted, all debris has been removed, all materials to beembedded in the concrete have been placed for the unit tobe cast, and the Engineer has inspected the forms andmaterials.

3.2.3.2Design The structural design of formwork shall conform to the

ACI Standard, Recommended Practice for ConcreteFormwork (ACI 347), or some other generally acceptedand permitted standard. In selecting the hydrostaticpressure to be used in the design of forms, considerationshall be given to the maximum rate of concrete placementto be used, the effects of vibration, the temperature of theconcrete, and any expected use of set-retarding admixturesor pozzolanic materials in the concrete mix.

C3.2.3.2 Formwork design refers to ACI 347-78, Recommended

Practice for Concrete Formwork.

3.2.3.3Construction Forms shall be set and held true to the dimensions,

lines, and grades of the structure prior to and during theplacement of concrete. Forms may be given a bevel or draftat projections, such as copings, to ensure easy removal.Prior to reuse, forms shall be cleaned, inspected fordamage, and, if necessary, repaired. When forms appear tobe defective in any manner, either before or during theplacement of concrete, the Engineer may order the work stopped until defects have been corrected.

Forms shall be treated with form oil or other approvedrelease agent before the reinforcing steel is placed. Materialwhich will adhere to or discolor the concrete shall not be used.

Except as provided herein, metal ties or anchorageswithin the forms shall be so constructed as to permit theirremoval to a depth of at least 1.0 in. from the face withoutinjury to the concrete. Ordinary wire ties may be used onlywhen the concrete will not be exposed to view and wherethe concrete will not come in contact with salts or sulfates.Such wire ties, upon removal of the forms, shall be cutback at least 0.25 in. from the face of the concrete withchisels or nippers; for green concrete, nippers shall be used. Fittings for metal ties shall be of such design that, upontheir removal, the cavities that are left will be of thesmallest possible size. The cavities shall be filled withcement mortar and the surface left sound, smooth, even,and uniform in color.

When epoxy-coated reinforcing steel is required, allmetal ties, anchorages, or spreaders that remain in theconcrete shall be of corrosion-resistant material or coatedwith a dielectric material.

For narrow walls and columns where the bottom of the form is inaccessible, an access opening shall be provided inthe forms for cleaning out extraneous material immediatelybefore placing the concrete.



3.2.3.4Tube Forms Tubes used as forms to produce voids in concrete slabs

shall be properly designed and fabricated or otherwisetreated to make the outside surface waterproof. Prior toconcrete placement, such tubes shall be protected from theweather and stored and installed by methods that preventdistortion or damage. The ends of tube forms shall be covered with caps that shall be made mortar tight andwaterproof. If wood or other material that expands whenmoist is used for capping tubes, a premolded rubber jointfiller 0.25 in. in thickness shall be used around theperimeter of the caps to permit expansion. A polyvinylchloride (PVC) vent tube shall be provided near each endof each tube. These vents shall be constructed to providepositive venting of the voids. After exterior form removal,the vent tube shall be trimmed to within 0.5 in. of the bottom surface of the finished concrete.

Anchors and ties for tube forms shall be adequate toprevent displacement of the tubes during concreteplacement.

3.2.3.5Stay-in-Place Forms Stay-in-place deck soffit forms, such as corrugated

metal or precast concrete panels, may be used if shown inthe contract documents or approved by the Engineer. Priorto the use of such forms, the Contractor shall provide acomplete set of details to the Engineer for review andapproval. Unless otherwise noted, the contract documentsfor structures should be dimensioned for the use ofremovable forms. Any changes necessary to accommodatestay-in-place forms, if approved, shall be at the expense ofthe Contractor.

3.2.4Removal of Falsework and Forms

3.2.4.1General Falsework or forms shall not be removed without

approval of the Engineer. In the determination of the timefor the removal of falsework and forms, consideration shallbe given to the location and character of the structure, theweather, the materials used in the mix, and other conditionsinfluencing the early strength of the concrete.

Methods of removal likely to cause overstressing ofthe concrete or damage to its surface shall not be used.Supports shall be removed in such a manner as to permit the structure to uniformly and gradually take the stressesdue to its own weight (mass). For structures of two or morespans, the sequence of falsework release shall be asspecified or approved in the contract documents.

3.2.4.2Time of Removal If field operations are not controlled by beam or

cylinder tests, the following minimum periods of time,exclusive of days when the temperature is below 40F, shall have elapsed after placement of concrete beforefalsework is released or forms are removed:


SECTION 3: TEMPORARY WORKS 3-7 Falsework for:

Spans over 14.0 ft 14 days Spans of 14.0 ft or less 10 days Bent caps not yet supporting girders 10 days

Forms:

Not supporting the dead weight (mass) of the concrete 24 h

For interior cells of box girders and for railings 12 h

If high early strength is obtained with Type III cementor by the use of additional cement, these periods may bereduced as directed.

Where field operations are controlled by cylinder tests:

Generally, the removal of supporting forms orfalsework shall not begin until the concrete is found to have the specified compressive strength.

In no case shall supports be removed in less thanseven days after placing the concrete.

Forms shall not be removed until the concrete hassufficient strength to prevent damage to thesurface.

Falsework for post-tensioned portions ofstructures shall not be released until theprestressing steel has been tensioned.

Falsework supporting any span of a continuous orrigid frame bridge shall not be released until theaforementioned requirements have been satisfied for all of the structural concrete in that span and inthe adjacent portions of each adjoining span for alength equal to at least one-half the length of the span where falsework is to be released.

Unless otherwise specified or approved in the contractdocuments, falsework shall be released before the railings,copings, or barriers are placed for all types of bridges. Forarch bridges, the time of falsework release relative to theconstruction of elements of the bridge above the arch shall be as shown in the contract documents or directed by theEngineer.

3.2.4.3Extent of Removal All falsework and forms shall be removed except:

Portions of driven falsework piles which are morethan 1.0 ft below subgrade within roadbeds, or2.0 ft below the original ground or finished gradeoutside of roadbeds, or 2.0 ft below the established limits of any navigation channel.



Footing forms where their removal wouldendanger the safety of cofferdams or other work.

Forms from enclosed cells where access is notprovided.

Deck forms in the cells of box girder bridges thatdo not interfere with the future installation ofutilities shown in the contract documents.

3.3COFFERDAMS AND SHORING 3.3.1General

Cofferdams shall be constructed to adequate depths to

assure stability and to adequate heights to seal off all water.They shall be safely designed and constructed and be madeas watertight as is necessary for the proper performance ofthe work which must be done inside them. In general, theinterior dimensions of cofferdams shall be such as to givesufficient clearance for the construction of forms and theinspection of their exteriors, and to permit pumping fromoutside the forms. Cofferdams that are tilted or movedlaterally during the process of sinking shall be righted,reset, or enlarged so as to provide the necessary clearance.This shall be solely at the expense of the Contractor.

C3.3.1 Cofferdams and shoring consist of those structures

used to temporarily hold the surrounding earth and water out of excavations and to protect adjacent property and facilities during construction of the permanent work.

The Contractor shall control the ingress of water sothat footing concrete can be placed in the dry. TheContractor shall determine if a seal is required, and, if required, shall determine the depth of the seal and the curetime required and shall be fully responsible for theperformance of the seal. After the seal has cured, thecofferdam shall be pumped out and the balance of the masonry placed in the dry. When weighted cofferdams areemployed and the weight is utilized to partially overcomethe hydrostatic pressure acting against the bottom of thefoundation seal, special anchorage such as dowels or keysshall be provided to transfer the entire weight of thecofferdam into the foundation seal. During the placing andcuring of a foundation seal, the elevation of the waterinside the cofferdam shall be controlled to prevent any flowthrough the seal and, if the cofferdam is to remain in place,it shall be vented or ported at or below low-water level.

A concrete seal conforming to the requirements of Section 8, Concrete Structures, shall be placed underwater below the elevation of the footing.

Shoring shall be adequate to support all loads imposedand shall comply with any applicable safety regulations.

3.3.2Protection of Concrete

Cofferdams shall be constructed so as to protect green

concrete against damage from sudden fluctuations in waterlevel and to prevent damage to the foundation by erosion. Nostruts or braces shall be used in cofferdams or shoring systemsin such a way as to extend into or through the permanentwork, without written permission from the Engineer.

3.3.3Removal Unless otherwise provided or approved, cofferdams

and shoring with all sheeting and bracing shall be removedafter the completion of the substructure, with care beingtaken not to disturb or otherwise injure the finished work.


SECTION 3: TEMPORARY WORKS 3-9 3.4TEMPORARY WATER CONTROL SYSTEMS 3.4.1General

Temporary water control systems consist of dikes, by-

pass channels, flumes and other surface water diversionworks, cut-off walls, and pumping systems, includingwellpoint and deep well systems, used to prevent waterfrom entering excavations for structures.

3.4.2Working Drawings

Working drawings for temporary water control

systems, when required, shall include details of the designand the equipment, operating procedures to be employed,and location of point or points of discharge. The design and operation shall conform to all applicable water pollutionand erosion control requirements.

3.4.3Operations Pumping from the interior of any foundation enclosure

shall be done in such manner as to preclude the possibilityof the movement of water through any fresh concrete. Nopumping will be permitted during the placing of concrete orfor a period of at least 24 hours thereafter, unless it be donefrom a suitable sump separated from the concrete work by awatertight wall or other effective means, subject to approval of the Engineer.

Pumping to unwater a sealed cofferdam shall notcommence until the seal has set sufficiently to withstandthe hydrostatic pressure.

Pumping from wellpoints or deep wells shall beregulated so as to avoid damage by subsidence to adjacentproperty.

3.5TEMPORARY BRIDGES 3.5.1General

Temporary bridges shall be constructed, maintained,

and removed in a manner that will not endanger the work orthe public.

C3.5.1 Temporary bridges include detour bridges for use by

the public, haul road bridges, and other structures, such as conveyor bridges, used by the Contractor.

3.5.2Detour Bridges

When a design is furnished by the Owner, detour

bridges shall be constructed and maintained to conform toeither such design or an approved alternative design. Whenpermitted by the Specifications, the Contractor may submita proposed alternative design. Any alternative design mustbe equivalent in all respects to the design and detailsfurnished by the Owner and is subject to approval by theEngineer. The working drawings and design calculationsfor any alternative design shall be signed by a RegisteredProfessional Engineer.

C3.5.2



When a design is not furnished by the Owner, theContractor shall prepare the design and furnish workingdrawings to the Engineer for approval. The design shallprovide the clearances, alignment, load capacity, and otherdesign parameters specified or approved in the contractdocuments. The design shall conform to the AASHTOLRFD Bridge Design Specifications. If design live loadsare not otherwise specified in the contract documents,75 percent of the HL93 loading may be used. The workingdrawings and design calculations shall be signed by aRegistered Professional Engineer.

The design of detour bridges refers to the AASHTO LRFD Bridge Design Specifications, 2007.

3.5.3Haul Bridges

When haul road bridges or other bridges which are not

for public use are proposed for construction over anyright-of-way that is open to the public or that is over anyrailroad, working drawings showing complete design anddetails, including the maximum loads to be carried, shall besubmitted to the Engineer for approval. Such drawingsshall be signed by a Registered Professional Engineer. Thedesign shall conform to AASHTO LRFD Bridge DesignSpecifications when applicable or to other appropriatestandards.

C3.5.3 The design of haul bridges refers to the AASHTO

LRFD Bridge Design Specifications, 2007.

3.5.4Maintenance The maintenance of temporary bridges for which

working drawings are required shall include theirreplacement in case of partial or complete failure. In caseof the Contractor's delay or inadequate progress in makingrepairs and replacement, the Owner reserves the right tofurnish such labor, materials, and supervision of the workas may be necessary to restore the structure for propermovement of traffic. The entire expense of such restorationand repairs shall be considered a part of the cost of thetemporary structure and where such expenditures areincurred by the Owner, they shall be charged to theContractor.


Unless otherwise specified in the contract documents,

payment for temporary works shall be considered to beincluded in the payment for the various items of work forwhich they are used and no separate payment shall be madetherefore.

When an item for concrete seals for cofferdams isincluded in the contract, such concrete will be measured andpaid for as provided in Section 8, Concrete Structures.

When an item or items for temporary bridges,cofferdams, shoring systems, or water control systems isincluded in the bid schedule, payment will be the lump-sum bid for each such structure or system which is listed on thebid schedule and which is constructed and removed inaccordance with the requirements of the contractdocuments. Such payment includes full compensation forall costs involved with the furnishing of all materials andthe construction, maintenance, and removal of suchtemporary works.


SECTION 3: TEMPORARY WORKS 3-11 3.7REFERENCES AASHTO. 1995. Construction Handbook for Bridge Temporary Works, CHBTW-1, American Association of State Highway and Transportation Officials, Washington, DC. AASHTO. 1995. Guide Design Specifications for Bridge Temporary Works, GSBTW-1, American Association of State Highway and Transportation Officials, Washington, DC. AASHTO. 2007. AASHTO LRFD Bridge Design Specifications, Fourth Edition, LRFDUS-4-M or LRFDSI-4. American Association of State Highway and Transportation Officials, Washington, DC. ACI. 1978. Recommended Practice for Concrete Framework, American Concrete Institute, Farmington Hills, MI. CCEER. 2006. Recommendations for the Design of Beams and Posts in Bridge Falsework, CCEER 05/11, Center for Civil Engineering Earthquake Research, University of Nevada, Reno, NV, Jan. 2006. FHWA. 1991. Synthesis of Falsework, Formwork, and Scaffolding for Highway Bridge Structures, FHWA-RD-91-062, Federal Highway Administration, U.S. Department of Transportation, Washington, DC, Nov. 1991. FHWA. 1993. Bridge Temporary Works, TS140.24, Federal Highway Administration, U.S. Department of Transportation, Washington, DC, Oct. 1993. FHWA. 1993. Guide Standard Specifications for Bridge Temporary Works, FHWA-RD-93-031, Federal Highway Administration, U.S. Department of Transportation, Washington, DC, Nov. 1993. FHWA. 1993. Guide Design Specifications for Bridge Temporary Works, FHWA-RD-93-032, Federal Highway Administration, U.S. Department of Transportation, Washington, DC, Nov. 1993. See also AASHTO GSBTW-1, listed above. FHWA. 1993. Certification Program for Bridge Temporary Works, FHWA-RD-93-033, Federal Highway Administration, U.S. Department of Transportation, Washington, DC, Nov. 1993. FHWA. 1993. Construction Handbook for Bridge Temporary Works, FHWA-RD-93-034, Federal Highway Administration, U.S. Department of Transportation, Washington, DC, Nov. 1993. See also AASHTO CHBTW-1, listed above. NIST. 1995. Construction and Industrial Plywood, Voluntary Product Standard PS 1-95, National Institute of Standards and Technology, U.S. Department of Commerce, Gaithersburg, MD. NSBA. 2007. Steel Bridge Erection Guide Specification, S10.1, National Steel Bridge Alliance, Chicago, IL. See also AASHTO NSBASBEGS-1 (2007). SSRP. 2006. Full Scale Load Testing of Sand-Jacks, SSRP-05/06, University of California, San Diego, CA, June 2006.


SECTION 4: DRIVEN FOUNDATION PILES

TABLE OF CONTENTS

4-i

4.1INTRODUCTION ............................................................................................................................................... 4-14.2MATERIALS ....................................................................................................................................................... 4-2

4.2.1Steel Piles ................................................................................................................................................... 4-24.2.1.1Rolled Structural Steel Piles ............................................................................................................ 4-2

4.2.1.1.1Specifications for Steel Properties ......................................................................................... 4-24.2.1.1.2Minimum Dimensions ........................................................................................................... 4-2

4.2.1.2Steel Pipe Piles ................................................................................................................................ 4-34.2.1.2.1Specification for Steel ........................................................................................................... 4-34.2.1.2.2Concrete for Concrete-Filled Pipe Piles ................................................................................ 4-3

4.2.2Timber Piles ............................................................................................................................................... 4-44.2.2.1General ............................................................................................................................................ 4-44.2.2.2Submittals ........................................................................................................................................ 4-44.2.2.3Field Fabrication .............................................................................................................................. 4-44.2.2.4Pressure Treatment .......................................................................................................................... 4-44.2.2.5Required Retentions ......................................................................................................................... 4-4

4.2.3Prestressed Concrete Piles ......................................................................................................................... 4-54.2.3.1Forms ............................................................................................................................................... 4-54.2.3.2Casting ............................................................................................................................................. 4-54.2.3.3Finish ............................................................................................................................................... 4-64.2.3.4Curing and Protection ...................................................................................................................... 4-64.2.3.5Prestressing ...................................................................................................................................... 4-64.2.3.6Shop Drawings ..............................................................................................................................

0. aashto lrfd bridge construction specification, 3rd, 2010

Documents

twoyear term region

transportation officials

year term thomas

highway subcommittee

federal highway administration

violation of applicable

mark ahlman

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