Construction and Design of Prestressed Concrete Segmental Bridges

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Construction and Design

of

Prestressed Concrete Segmental Bridges

Walter Podolny, Jr., Ph.D., P.E.

Bridgc Division ()Hicc

or

Ellgineering h'dcr;ti II iglll\'d Y :\dmillisl ratioll L' .S. Depart illenl 01 Tr;lIls[Jortalioll

Jean

M. Muller

(:llaillll;11I (lilhe Board Figg alld ),[uJkr Ellgincers, [Ill.

BR1T"

LEM".

-9 AUG

1982

82/19656

A Wiley-Intersdence Publication

John

Wiley

&

Sons

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Reproduction or translation of any part of this work beyond

that permitted by Section 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright

owner is unlawful. Requests for permission or further

information should be addressed to the Permissions

Department. john Wilt·)' & Sons, Inc

Library of Congress Cataloging in Publication Data: Podoln)', Walter.

Construction and design of prestressed concrete segmental bridges.

(Wiley series of practical construction guides ISSN 0271-6011)

"A Wiley-Interscience publication." Includes index.

I. Bridges, Concrete-Design and construction.

2. Prestressed concrete construction. I. Muller, jean M.

II. Title. III. Series.

TG355.P63 624.2 81-13025

ISBN 0·471-05658-8 AACR2

Printed in the United States of America 10 9 8 7 6 5 4 3 2

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..

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...

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Series Preface

The Wiley Series of Practical Construction Guides provides the working constructor with up-to-date

information that can help to increase the job profit

margin. These guidebooks. which are scaled mainly for practice, but include the necessary theory and design. should aid a construction con tractor in approaching I\ork problems I\'it h more knowledgeable confidence, The guides should be useful also to engineers. architects. planners. specification writers. project managers, superin tendents, materials and equipment manufacturers and, the source of all these callings, instructors and their students.

Construction in the United States alone will reach $250 billion a year in the early I980s. In all nations, the business of building will continue to grow at a phenomenal rate, because the population proliferation demands !1('I\ living. I\'orking. and recreational facilities. This construction will have to be more substantial. thus demanding a more

professional performance from the contractor. Be fore science and technology had seriously affected the ideas, job plans, financing, and erection of structures, most contractors developed their know-how by field trial-and-error. Wheels, small and large, were constantly being reinvented in all

St'C(ors. bccause there ,\as no interchange of

knmdedge. The current complexity of cOlIStru{'

tion. even in more rural areas, has revealed a dear need for more proficient. professional methods and tools in both practice and learning,

Because construction is highly competitive. sOllle practical technologv is necessarily proprietary. BUI

most practical day-to-day problems are common to the whole construction industry. These are the subjects for the Wiley Practical Construction Guides.

M. D. MORRIS. P.E.

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Preface

Prestressed concrete segmental bridge construc tion has evolved, in the natural course of events, from the combining of the concepts of prestress ing, box girder design, and the cantilever method of bridge construction. It arose from a need to Qvercoml: construnion difficulties in spalIning deep valleys and river crossmgs without the use of conventional falsework, which in some instances may be impractical, economically prohibitive, or detrimental to environment and ecology.

Contemporary prestressed, box girder, seg mental bridges began in Western Europe in the 1950s. Ulrich Finsterwalder in 1950, for a cross ing of the Lahn River in Balduinstein, Germany, was the first to apply cast-in-place segmental con struction to a bridge. In 1962 in France the first application of precast. segmental, box girder COll

struction was made by Jean Muller to the Choisy Le-Roi Bridge crossing the Seine River. Since then the concept of segmental bridge construction has been improved and rdined and has spread from Europe throughout most of the world.

The first application of segmental bridge con struction in North America was a cast-in-place segmental bridge on the Laurentian Autoroute near Ste ..\dele. Qllebec. in 1964. This was fol lowed in 1967 by a precast segmental bridge cross ing the Lievre River near ~otre Dame du Laus, Quebec. In 1973 the first U.S. precast segmental bridge was ope lied to traffic in Corpus Christi. Texas, followed a year later by the cast-in-place segmental Pine Valley Bridge near San Diego, California. As of this date (1981) in the United States more than eighty segmental bridges are completed, in construction, in design, or under consideration.

Prestressed concrete segmental bridges may be identified as precast or cast in place and cat egorized by method of construction as balanced cantilever, span-by-span, progressive placement, or incremental launching. This type of bridge has

extended the practical and competitive economic span range of concrete bridges. It is adaptable to almost any conceivable site condition.

The objective of this book is to summarize in one volume the current state of the art of design and constrllction methods for all I ypc,; of segmelHal bridges as a ready reference source for ellgillcer ing faculties, practicing engineers, contractors, and local, state, and federal bridge engineers.

Chapter I is a quick review of the historical evo lution to the current state of the art. It bITers the student an appreciation of the way in which seg mental construction of bridges developed, thc factors that influenced its development, and the various techniques used in constructing segmental bridges.

Chapters 2 and 3 present case ,tudies of the pre dominant methodology oi constructing segmental bridges by balanced cantilever in both cast-in-place and precast concrete. Conception and design of

the superstructure and piers, respectively, are dis cussed in Chapters 4 and 5. The other three ba sic methods of constructing segmental bridges progressive placement, span-by-span, and incre mental launching-are presented in Chapters 6 and

i.

Chapters 2 through i deal essentially with girder type bridges. However, segmental construction may also be applied to bridges of other types. Chaprer 8 discusses application of thc segmcntal concept to arch, rigid frame, and truss bridges. Chapter 9 deals with the cable-stayed type of bridge and Chapter 10 with railroad bridges. The practical aspects of fabrication, handling, and erection of segments are discussed in Chapter II. In selected a bridge type for a particular site, one of the more important parameters is economics. Economics, competitive bidding, and contractual aspects of segmental construction are discussed in Chapter 12.

Most of the material presented in this book is not

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viii Preface

original. Although acknowledgment of all the many sources is not possible, full credit is given wherever the specific source can be identified.

Every effort has been made to eliminate errors; the authors will appreciate notification from the reader of any that remain.

The authors are indebted to numerous publica tions, organizations, and individuals for their assistance and permission to reproduce photo

graphs, tables. and other data. Wherever possible. credit is given in the text.

WALTER PODOLNY, JR. JEAN M. MULLER Burkt, 1'h-~i1/i(J Pans, France january 1982 .."iiliiI...__•_ _ _ _ _ _ - - - · - - 

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_:t9

Bear River Bridge, Canada, 108

2,2 Bendorf Bridge, German" 35 3.1 () J FK ;"'lell1orial Cause\\ay,

2.3 Saint Adele Bridge, Canada, 37 U.S.A., 109

2,4 BOllguen Bridge in Brest and ;) .11 Saint Andre de Cubzac Bridges,

Llcroix Falgarde Bridge, France. 113

France, 38

:U2

Saint Cloud Bridge, France, 114

2.5 Saint Jean Bridge over the 3.13 Sallingsund Bridge,

Garonne River at Bordeaux, Denmark, 122

France. 41 3.14 B-3 South Viaducts, France, 124

2.6 Siegtal and Kochertal Bridges. 3.15 Alpine ~Iotorway Structures,

Germany, 43 France, 129

2.7

Pine Valley Creek Bridge, 3.16 Bridge over the Eastern Scheidt,

U.S.A.,46 Holland, 134

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x Contents

3.17 Captain Cook Bridge, 5.5 Piers with Double Elastomeric

Australia, 136 Bearings, 241

3.18 Other Notable Structures, 139 5.6 Piers with Twin Flexible Legs, 253

References, 147 5.7 Flexible Piers and Their Stability

During Construction, 263

4 Design of Segmental Bridges 148 5.8

5.9

Abutments. 271

Effect of Differential Settlements

4.1 Introduction, 148 _{on Continuous Decks, 276}

4.2 Live Load Requirements, 149 _{References, 280}

4.3 Span Arrangement and Related

4.4 4.5 4.6

Principle of Construction, 149 Deck Expansion, Hinges, and Continuity, 151

Type, Shape and Dimensions of the Superstructure, 159

Transverse Distribution of Loads

6 Progressive and Span-by-Span

Construction of Segmental Bridges

6.1 Introduction, 281

6.2 Progressive Cast-i n- Place

Bridges, 283

281

Between Box Girders in ~1ultibox 6.3 Progressive Precast Bridges, 289

4.7 4.8

Girders, 164

Effect of Temperature Gradients in Bridge Superstructures, 170 Design of Longitudinal Members for Flexure and Tendon

6.4 6.5 6.6 Span-by-Span Cast-in-Place Bridges, 293 Span-by-Span Precast Bridges, 308

Design Aspects of Segmental 4.9

Profiles, 173

Ultimate Bending Capacity of

Progressive Const ruction, 314 References, 319

Longitudinal Members, 190

4.10 Shear and Design of Cross 7 Incrementally Launched Bridges 321

Section. 193 _7.1 _{Illlrodunioll.321} 4.11 4.12 4.13 4.14 4.15 4.16 4.17 4.18 4.19

Joints Between Match-Cast Segments, 199

Design of Superstructure Cross Section, 202

Special Problems in

Superstructure Design, 203 DeAections of Cantilever Bridges and Camber Design, 205

Fatigue in Segmental Bridges, 210

Provisions for Future Prestressing, 212 Design Example, 212 Quantities of Materials, 219 Potential Problem Areas, 220

7.2 7.3 7.4 7.5 7.G 7.7 7.8 7.9 7.10

Rio Carolli, Venezuela, 323 Val Resle! Viaduct, Italy, 327 Ravensbosch Valley Bridge. Holland, 329

Olifant's River Bridge, South Africa, 331

Various Bridges ill France. 333 Wabash River Bridge, U.S.A., 335

Other ~otable Bridges. 338

Design of Incrementall) Launched Bridge~. 34::1

Demolition of a Structure by

Incremental La~nching, 352

References, 352

References, 224 ₈ _{Concrete Segmental Arches, Rigid}

Frames, and Truss Bridges 354

5 Foundations, Piers, and Abutments 225

8.1 Introduction, 354

5.1 Introduction, 225 8.2 Segmental Precast Bridges over

5.2 Loads Applied to the Piers, 230 the Marne River, France, 357

5.3 Suggestions on Aesthetics of Piers 8.3 Caracas Viaducts, Venezuela, 363

and Abutments, 232 8.4 Gladesville Bridge, Australia, 371

5.4 Moment-Resisting Piers and 8.5 Arches Built in Cantilever, 374

Their Foundations, 234 8.6 Rigid Frame Bridges, 382

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Contents xi

8.7 Truss Bridges, 392 11 Technology and Construction of

References. 399 Segmental Bridges 465

9 Concrete Segmental Cable-Stayed Bridges 400 Il.l

11.2

Scope and Introduction. 465 Concrete and Formwork for

9.1 Introuuction,400 Segmental Construction. 466

9.2 Lake Maracaibo Bridge, 11.3 Post-tensioning Materials and

Venezuela. 405 Operations, 470

9.3 Wadi Kuf Bridge, Libya. 407 11.1 Segment Fabrication for

9.1 Chaco/Corrientes Bridge, Cast-In-Place Cantilever

Argentina, 408 Construction, 475

9.5 \lainbrticke, GermallV, 410 11.5 Characteristics of Precast

9.6 Tiel Bridge. ~etherlands. 412 Segmellts and \Iatch-Cast

9.7 Pasco-Kennewick Bridge. Epoxy Joints. 485

C.S.A., 418 11.6 \1anufacture of Precast

9.8 BrolOnne Bridge, France. 41!:l Segments, 493

9,9 Dalluhe Canal Bridge, 11.7 Handling and Temporan

:\ll~lri;l, '1~7 :\ssclllhh of Preca,1

9.10 ~()table Examples of Segments, 507

Concepls, 4:W 11.8 Placing Precast Segments, 50!}

Referellces, 439 References. 517

10 Segmental Railway Bridges 441

12 Economics and Contractual Aspects of

IO.l Illtl'OdllUioll 10 Panicubr Segmental Construction 518

IO,':! 10.:l

IO,,!

:\spects of Rail\Va~ Bridges and Field of Applicatioll, 441 La VOlllte Bridge over the Rholle Ri\'('l'. Frallct'. 4·12 \Ior:llld Bridge III L\om,

Frallce,442

Cerg\ POlltoise Bridge Ileal'

l~.l

12.2

12,,~

Bidding Procedures, 518 Exam pies of Some Interest illg Biddillgs alld Costs, 523 j lit I CI,C ill EITlticll(\ ill

Concrete Bridge~, 528 References, 535 ":Iris, Frallce, ·'·H

10,5 :-'!allle La Vallee and Torn 13 Future Trends and Developments 536

!(Ui

10.7 1O.H

10.9

Bridges for the ~e\V Express Lille lIeal' Paris, Fl'allce, 444 Clichy Bridge Ileal' Paris,

Frallce, ·l!q

Oidaill's Bridge, SOllth :\frica, '1:)2

[ncremental" Lallllched R;lil\\';!\ Bri( for the High-Speed Line, Paris to Lmlls, France, 45:~

Segll1ental Raih,'av Brid~es ill

1:3.1 1:),2 1:3,:~ 1:3.4 LL") 13,6 Introductiol1,536 ~!aterials, 536 Segmental Application to Bridg;e Decks, 542

Se~l11enlal Bridge Piers and

Substructures, 543

Application to Existing or :\ew Bridge I) pe~, ij·H

Summary, 548 References, ;")49

Japall,457

to, 1() Special Oe'iign A~peets of Index of Bridges 551

Segmenral Railwav Bridges, 458 Index of Personal Names 555

10.11 Proposed Concepts for Future Index of Firms and Organizations 557

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1 Prestressed Concrete Bridges

and Segmental Construction

1.1 INTRODUCTION

1.2 DEVELOP!'v1ENT OF CANTILEVER CONSTRUCTION 1.3 EVOLUTION OF PRESTRESSED CONCRETE

1.4 EVOLUTION OF PRESTRESSED CONCRETE BRIDGES 1.5 LONG-SPAN BRIDGES WITH CONVENTIONAL PRE

CAST GIRDERS

1.6 SEGMENTAL CONSTRUCTION 1.7 VARIOUS TYPES OF STRUCTURES

1.7.1 Girder Bridges 1.7.2 TnJsses

1.7.3 Frarn(>, with Slant I.(>~,

1.7.4 Concrete Arch Bridges 1.7.5 Concrete Cable-Stayed Bridges

1.8 CAST-IN-PLACE AND PRECAST SEGMENTAL CON STRUCTION

1.1 Introduction

The conception, development, and worldwide ac ceptance of seglllental c()n~trllcti()n in till' field

or

prestressed concrele bridges represents one 01 the most intere~ting and illlport;lIlt achievelllents in civil engineering durillg the past thirtv \ears. Rec ognized to<i;l\ in all COlllltries ;111d particlilariv ill the United States as a sale, praCTical, and econolllic construction method, the seglllental concept prob ably owes its rapid growth and acceptance to its founding, frOl1l the I)eginning, on sound construc

tion principles sllch as cantile\'er construction. Using this method, a bridge structure is made up of concrete elements usually called segments (either precast or cast in place in their final position in the structure) assembled by post-tensioning. If the bridge is cast in place, Figure 1.1, travelers are used to allow the various segments to be con structed in successive increments and progressively

1.8.1 Characteristics of Cast-in-Place Segments 1.8.2 Characteristics of Precast Segments 1.8.3 Choice between Cast-in-ptace and Precast

ConstnJction

1.9 VARIOUS METHODS OF CONSTRUCTION 1.9.1 Cast-in-Place Balanced Cantilever 1.9.2 Precast Balanced Cantilever 1.9.3 Span-by-Span ConstnIction 1.9.4 Progressive Placement ConstnIction

1.9.5 Incremental Launching or Push-Out ConstnJction 1.10 .\PPUCATTONS OF SEGMDITAL CONSTRUCTTON

IN THE UNITED STATES

1.11 APPLICABILITY AND ADVANTAGES OF SEGMEN TAL CONSTRUCTION

REFERENCES

prestressed together. II the bridge is precast, seg Illent.s are Illanufactured in a special casting vanl or factory, transported to their final position, and placed ill the structure bv various tvpes

or

lallnch-FIGURE 1.1 Cast-in place form traveler.

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2 Prestressed Concrete Bridges and Segmental Construction

FIGURE 1.2. Olcron Vi'HIlIct, scgllH'llIal (ollSlrllclioll ill progress. 011\' t"pical

P)('CISI seglllt'llt placcd jll tile 01('1"011 Vi;,dllCl.

I

Ill).; equiplllent. Figure l.~, while prestressing

.!lhincs the ;t;,-,;clIlhly al1d prmides the stnJcturai strellgth.

\1ost carl\' seglllelltal bridges were huill as call' tilc\'crs, where construction procceds ill a S\'l1lIIlet rical fashion from the bridge picrs ill sllccessi\(' ill ('n'lIlcllts to cOlllplete each spall and lil1al!\ the eillire superstructure, Figure 1.3. Later, olher COII ,tructioll methods appeared in conjunction with

FIGURE 1.3. Cantil<'\er (omtrucliol1 applied to pre st ressed concrete bridges.

the scglllelital cOllCept to IUrlhcr it, !icld of appli

C;1t io11.

1.2 Developmerrt oj Cantilever Construction The idea ofcalltile\'er (ollstrllctioJl is anciellt ill the Oriellt. Shogun';, Bridge located ill thc cit\ of' .'\'ikko, Japall, is the eadicst recorded GtlltileHT bridge ,Illd dates b;lck 10 the fOlll'1!J CeIJtlIr~. The Wall<iipol'c Bridge, Figure lA, was built ill tlte sc\'clIteellth century in Bhutall, betweell lndia and Tibet. It is constructed frolll great timbers that arc corbeled OUt IowaI'd each othcr from mas·

si\e abut mellts and thc narrowed illlen al fillall\' capped with a light beam. 1

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3

Development of Call t ilever Constmdion

Tholllas Pope, a :\ew York Clrpenter, was ~() in spired b\' these structures that he used the concept in his "Fhing Le\cr Bridge," In IH [0 he built a 50

ft ([5 rn) model on a scale of ~ in, to I It ([ to 3~ 111)

represellting half of a proposed IHOO ft (549 Ill)

span. It was to be a single wooden structure cr()sS~

ing the Hudson River near New York City, Figure 1.5. According to witnesses the 50 ft ([5 Ill) unsup ported arm withstood a [0 ton (9 1111) weight. Pope

puhlished the design of his daring and interesting concept the following \'ear. Althollgh arched in

form. the optil1listic span was a calltilever beam in principle. with the "fhing levers" projected from great maSOIll'\' abutments, tined out on the :\ew YOl·k side as apartlllents, Pope's presentation of this desigll was anolllpatlied bv rile following couplet":

Lei the broad arc the spaciolls Hudso[J stride And spall Columbia's rivers far [JJore wide COll\ince the world ,\lllcricl hegins To fo'nn Arts. the ;lIlCiClll \\()rk of killgs, Stupendous plan! which llone belorc c'cr

j'otlild.

ThaI half an arc ~hol!ld sund UPOIl rhe

ground

Without support while building, or a rest; This caus'd the theorist's rage and 'iceptic's

jest.

Prefabrication techniques were successfullv combined with cantilever construcriot1 in many bridges near the end of the nineteenth century, as exemplified by such notable structures as the Firth of Forth Bridge, Figure 1.6, and later the Quebec Bridge, Figure 1.7, mer the Saint Lawrence River. These st.rllClU res bear witness to the engineering genius of an earlier generation. Built more re cently, the Greater :\ew Orleans Bridge over the

\Iississippi River, Figure 1.8, represelJls 11lodcm cOlHemporan' long-spall ,Iecl clI1filevcr cOllslrnc

I [()Il.

Because the properties and behavior of pre stressed concrete are related more closetv to those

of structural sleel than those of comelttional rein rorced cOllcrete. the applicatiotl of this material to cllllileH:r construction W~IS a logical step ill the

COil! iIwing developmetlt

or

bridge cngllleeriJlg,

FIGURE l.i. (~uchec Bridgt:.

FIGURE 1.6. Firth of Forth Bridge. FIGURE l.8. Greatcr :-.lew Orleans Bridge.

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-4 Prestressed Concrete Bridges and Segmental Construction

This applicatioll has eyol\'ed over many years by the slIccessive de\'e!opment of mallY concepts and innovations. III order to see how the present slate olthe art has beel1 reached, let us briefly trace the devcloplllelll of presu'essed concrete and in par ticular its applic<ltioll to bridge construction.

1.3 Evolution of Prestressed Concrete The in\'cllIioll of reinforced concrete stirred the Illlagination 01 t'llgilleers in 11I;JJl\ countries. Thev

envisiolled IlIatat relllcndoll s ad va 11\,1 ge could be achie\cd, if the steel could he lensioned to put the ,qrllctllrc in a pennallclli state 01 compression g-1'Catcr thall all\ tellsile stresses g-clleraled by the <tpplied loads. The pre~ellt state of the art of pre stressed concrete has C\ohcd froll1 the erfort and ('x]lericlln' of lIIall\' ell~ille('rs and scielltists o\'cr lhc past nillet\' \cars" I 1 OW('\'('I' , lire concept of pre

stressing is centllries old. Swiss imcstigators ha\'c shown tl1;lt as earh as :!70(l H.C. thc :tnciellt Egyp

tians prestressed their s(,;lgoing \'('sscls long-itlldi nail\'. This h;IS 1)(,(,1l detenl1illcd from pictorial represcntations fOlllld in Fifth Dynast\' tOIllI)s.

The hasic principle or prestressing was used in the era It of cooperage WhCll the cooper wound ropes or !!letal hands aroulld wooden staves to forlll harrels.:l _{When thc I)ands were lightened,}

thcv were under tensile prestress, which created cOlllpression betwecn the SWH'S and enabled thelll

\0 rcsist Iroop tCllsiol1 produced by internal liquid pressure. III other words, the hands and staves

wcre hot h prest ressed hefore thev \\'(Te subjected to all\ sel\'i('(' loads. The woodell cartwheel with ils shrunk-Oil iroll rim is al10ther example of pre stressed cOl1struction.

The (irst all(,lIlpt to introdllcc internal stresses in reinforced (OllCl'('te mel1lbers iJy tensioning the steel reinforcement was made about 1886 whell P. H. Jackson, all engineer ill San Francisco, obtained a Ullited St;ltes patent ()r tightenin~ stcel rods in concrete nJ(:lIliJers serving as Hoor slabs. ] n 1888,

C. E. \N. Dilhrillg of Berlin secured a patent for the Illallufacture of slabs, battens, and small beams for structural engineering purposes by embedding tensiollcd wire in concrete in order to reduce cracking. This was the first attempt to provide pre cast concrete units wit h a tensioned reinforcement. Several structures wcre constructed using these concepts; IHlWe\'er, ollly mild steel reinforcement was available at the time. These structures at first hehaved according to predictions, but because so little prestrcss force could be induced in the mild

steel, the\' lost their properties because of the creep and shrill kage of the concrete. I n order to recover some 01 the losses, the possibilitv of retightening the reinforcing rods after some shrinkage and creep of the concrete had taken place was suggested in 190f\ by C. R. Steiner of the L'nited States. Steiner proposed that the bond of em bedded steel hars be destroyed b\· lightly tension ing the bars while the concrete \\'as still voung and then tellsioning them to a higher stress when the concrete had hardened. Steiner was also the first to suggest the lise of cuned tendons.

In 19:25, R. E. Dill of :\ebraska took a further slep t()\\'anl freeing cOllcrete beams of any lensile stresses In tensioning high-tensile steel wires after the concrete had hardened. Bonding was to he prevented 1)\ suitahh' coating the wires. He explicith llI{'llliollCd the ;!(h';llltage of lIsing st('eI with a high elastic lilllit alld high strength as COll1

pared to onlinan reillforcing hal'S.

In 19:21'1, E. Freyssillct of France, who is credited wit h the !llOdtTll dc\('loplllellt of prest rcssed COI1

nete, started min,!.!; high-strellgth steel wires

ror

prestressil1g. Although Frnssillct also tried tile lIlethod oj pretcllsiol1lllg, where the steci was bOl1ded to the cOl1crete without elld al1chorages, the lirst 1)l;lctlcd applicatioll of this method \\"as ll1ade 1)\ E. H(lH'! ai;olll I~nH. Wide applicatioll 01

the prestressil1g tcchlJiqlle was 1l0! possible ulltil

reliahle al1d ecollol11icailllt'thods (If tellsionillg alld elld allchorage were dc\·ised. From approximately 1939 OIL E. Fn'\ssillet, "fagllt'l, awl othelS d(' \'cloped differcllt 1ll(,tl\()(ls alld procedures. Prc st ress hegall to gail1 SOlllC importallce ahow 1945, while allernatin' prestressing lllethods were beillg devised 1)\, ellgilleers ill \'arious coulltries.

During the past thirty \'ears, prestressed con crete ill the Cllited States has growll from a hrall<!-IH':W idea illto all an:cpted lllethod

or

COI1

crete construction. This growth. it result of a l1ew

applicatioll of existing l1latelials and theories, is in itsel f phellolllenai. III Europe the shortage of ma

terials and the cllforced economies in construction gave prestressed concrete a substantial start. De veloplllent in the Cnited States, however, was slower to underway. Designers al1d contractors hesitated mainly because of their lack of experi ence and a reluctance to abandon more familiar

methods of construction. Contractors, therefore, bid t he first prestressed concrete work conserva tively. Moreover, the equipmcnt available for pre stressing and related techlliques was essentially new and makeshift. However, experience was gained rapidly, the quality of the work improved,

..

_..

" , . _ 1\1 {'I

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5

Evolution of Prestressed Concrete Bridges

m " ~~'T

.----

---:::

...

""~~

....

_..

_, \ ~

FIGURE 1.9. Frevssinet\ Esbh Bridge on the '.larne River.

and prestressed concrete became more :md more competitin: with other Illaterials.

1.4 Evolution of Prestressed Concrete Bridges Although France lOok the lead ill Ihe de\Tlopmenl of prestressed concrete. Ill;Ul\ European COUllt ric:;

SIKh as Belgilllll. England, (~erlllall\. Switzerland. and Holl;llld quickh showed interest. As earl:: as 1948. Frcnsinet llsed prest ressed coneret e for I he constructioll

or

fi\'e bridges o\'er the \larne River ,near P;lris, \\ith ~W ft (7t Ill) spans

or

all excep

tiollally light ;l()pC;lrance. Figure 1.9, ,\ Sllne\ made ill (;erlll;lll\ .showed I hat between IIJ49 ;lIld 1953. out 01 ;)00 bridges built. 350 \\ere pre stressed.

I'

~ ~---~ !

I

\...:.i • I ~I

L

I.

2'· 4"

.1

V

....

.'

...

FIGURE 1.11. .-\:\SHTO·PCI I-girder c!'Oss sections.

FIGURE 1.10 \\'allllll Lane Bridge. Philadelphia (COllrtt"\' of the Portland Cement :\ssociation),

Prestressing in the Lnited Slates followed a <Iii

ferent course, Instead of linear prestressing. cir cular prestressing as applied to storage tallks took lhe lead. Lillear prestressillg as applied to be;tllls

did [lOl sian until 1949. The first strllcture of tiJis

tYlw W;l~ a hridge ill \LtdisOlI COllll(\', Telll]essee. followcd ill I~);)() In the well-known HiO ft HH.HO

Ill) spall Walilut LlIle Bridge in Philadelphia, Fig. lire 1.10. Ih the middle

or

1951 it was estimated that 17:'1 brid!.{cs alld 50 buildillgs had heel] Cllll·

strllClcd ill Ellrope ;lIld 110 !llore thall 10 strllClure~

ill the Lilited State~. III 1952 the Portlalld Cellleill .\sS()Ciatloll cOllducted a SUnle\' ill this COUllln' silowill!.{ 100 or Illorc structurcs cOlllpleted or

.r.-

=:

-TI

L

I

f2"

_'I

(14)

6 Prestressed Concrete Bridges and Segmental Constme/ion

under construction. In 195:1 it was estimated that there were is bridges in Pennsyh'ania alone.

After the Walnut Lane Bridge, which was cast ill place and post-tensioned, precast pretensioned bridge girders e\'oh'ed, taking ach'antage of the in herent economies and qualin' control achievable with shop-fabricated members, With few excep tions, during the 1950s and early 1960s, most mul tispan precast prestressed bridges built ill the Cnited States were designed as a series of simple spalls. The\' were designed with standard AASHTO-PCI* girders of various cross sections, Figure Ll1. for spans of approximately 100 ft

(~O,S m), hut more cOlllmonh for spans of 40 to 80

It {I:! 10 :!4 IIlL The a<!\'alltages of a continuous cast-ill-place st ruet ure were ab;lI1doned in I;l\or of the simpler constructioll offered bv plallt produced st;tJ1(brdizcd units.

AI thi~ lillIe, plecast prctensiollcd lll(,llIl)er~

found all outstandillg application in the Lake Pontchartraill crossing Ilorth of ;\cw Orleans, Louisiana. The crossillg consisl eel of more t hall :!:!()O idelltical S(i It (Ii 111) spalls, Figures I,I:! through I. H. Each

SP,lll

\\'a~ Illadc of a sillgle ~()()

tOil 1I1011olith with pretensioned longitudillal gird

"\ltl(,l ;(;]It ;\,,,,,'1011;011 01 State High"';l\ "11(1 TL'"'i'or!.llioll

Offlci"b (1"'CVlOU,h known ", AASIIO. Amcrican A"ocialloll of Slall' IIlghw;l\ Offlci;lIs) "lid Presln'"ed (;OIl(T('I(' illSlitlltC,

r

FIGURE 1.12. Lake l'olltchartraill Brid!-\c. C.S.A. crs alld a reill/()J'Ccd (,Ollcre1 e deck cast ill t egrall\'. resting ill turn Oil a prccast cap alld two pre stressed 'PUll piles. The speed of erectioll \\'as ill credihle. oftell Illore thaI! eight (,()]llpiell' spam

pi;.ccd ill a sillgle da\.

III the middle 19GOs a growIllg COlK('rll \\;IS

'ihoWIl about the s;det\' of highw,tys. Tile AASHTO Traffic Safel\' COllllllit!ee called ill ;1

1~)(ii rcporr1 _{for the ", , , adoptioll and}

llSC of t\\O

Sp;1l1 hridges for overpasses lTOSSillg dilided Illgh

\\'<I\,S , . . to elilllillate the bridge piers nonllalh

placed adjacellt to the ,houlders." Figllrc LIS.

It;

terstat{' high"',l\'s tOd;1\ reqllire oHTpasses witl; two, tl1r('e, aud /<lllr 'pallS of II» to 1HO II (54.9 Ill) or 101lger. III the case of ri\er OJ strealll (Tossings.

(15)

. . . " " . . " " . ,...<,,~.-' ' (a) 33'-0" .. ~---18'-9" (b) FIGCRE 1.14. \erse sectioll.

Lake Ponlch;lItrain Bridge. C.5..-\. (11) Longilwlinal ,e.-lion. (Ii) Trans

7

(16)

STANDARD 4-SPAN INTERSTATE CROSSING

Span tor Skewed Brldge$

Skew Span

30 144'

4!5 177'

60" 2!50'

FIGL'RE 1.15. Standard four-span illlcrstatc clOssing

(COllrleS\ of lilt' POrlbnd Cemcnt .\sso(iat ion 1.

longer spans in the range of 300

rt

(9].5 111) or longer may be required, and there is a very distinct lrend toward l()llger-~pan bridges. I t soon became apparent that the conventional precast pretell ,jollC'd AASHTO-PCI ginlers were limited In their transportable lellgth and weight. TrallSportation mer the higlm<l\s limits the precast girder to a length or 100 to 120 It C~O.5 to :)G.()), depending

upon local regulatiolls.

1.5 Long-Span Bridges with Conventional Precast Girders

As a result of longer spall requirements a study was conducted I)\' the Prestressed Concrete Institute (PCI) in cooperatioll with the Portland Celllel1l As sociation (peA).:' This study proposed thai simple spans up to 140 It (42.7 Ill) and continllous spallS up to ]60 ft (48.H m) be constructed of stalldard precast girders

lip

to 80 ft (24 111) in length joined

1)\· splicing. To obtain longer spans the use of in clined or haullched piers was proposed.

The following discussion and illustratiollS are hased 011 the grade-separalion studies conducted

In PCI and PCA. Actual structures will be illus

64'

trated, where possible. to emphasize the particular design concepts.

The design stud), illustrated in Figure 1.16 uses cast-in-place or precast end-span sections and a two-span unit with AASHTO I girders.s Narrow median piers are maintained in this design, but the abutments are extended into the spans by as much as 40 ft (12 m) using a precast or cast-in-place frame in lieu of a closed or gravity abutment. \\'hen site conditions warrant, an attractive type of bridge can be built with extended abutments.

A similar span-reducing concepl is developed in Figure] .17, using either reinforced or prestressed COl1crele for cantilever abutlllents. An aesthetic abutment design in reinforced concrete was de n.-loped for a grade-separation structure on Ihe Tram-Canada Highway near Druml1lolldvilJe in the Province of Quebec, Figure 1.18. This 1'1'0 \ided a :)2~ It (9.9 Ill) span reduction that led 10 Ihe lISe of t\Ve IV Standard AASHTO I girders 10 SP;1I1 97~ It (29.7 111) to a simple, llarrow median pIer.

:\ c<lsi-in-placc reinlorced cOllcrete frame wilh olliward-:-.loping legs provides a stahle. ccnter sup porring struclure that reduces spall lellgth by 29 It (H.H 111). Figure].1 Y. This enables either standard box secriolls or I seclions 84 ft (25.6 Ill) IOllg 10 be w,cd ill Ihe two main spans. This hn'out was used (()J the Hohbema Bridge in Alberta. B.C.. Canada, shown in Figure 1.20. This bridge was builr with precasl challuel girder sectiolls, but could be buih wilh AASHTO I girders or hox secriollS. The me diall frallle with inclined legs was cast ill place.

'I'll(' schematic and photograph in Figures 1.21

and 1.22 show the Ardrossan Overpass in Alberta.

I t is similar to the Hobbema Bridge except that the spans are longer and, with the exception of a casi-in-place footing, the median frame is made up of precast units post-tensiolled together, Figure 1.2 I. The finished bridge, Figure ] .23, bas a

Af:

II

L_~h=::;::::==:;=t:;::===;:::j

\. Precosl or_CO$t-m~ploce_Frome

E.LE.VATION

SECTION A-A

FIGURE 1.16. Extended abutments (courtesy of the Prestressed Concrete Institute,

from reI. G).

.... _{.. -0}

(17)

9

Long-Span Bridges with Conventional Precast Girders

AF'F'ROX . • ,' ..- - - '

ELEVATION

nz:

GIROEA

SECTION

FIGURE 1.17. Call1iincred abulllH.'lIb (coulleS\ u[" the Pre~lresse{l Concrete !ll,lilllte, rrolll rd. 6).

pleasing appearance. The standard units were channel-shaped siringers 64 in, wide and 41 in. deep (1.6 III bv I.tH m). The use of precast ullits allowed erection

or

the entire superstructure, in cluding the median rrame. in onlv three weeks. The bridge was opened to trafficjusr eleven weeks after construction began in the early sumlller of

196(),

lh lise

or

lemporan bents. Fii-iure 1.21. standard units t)O It (18.3 Ill) long can be placed over Ihe median pier alld connected to main span 1I11ih with cast-in-place reinforced concrete splices located near the poim of dead-load contrallexure. FIGURE 1.18. DIll1l11l101Hhille Bridge (collrtesv

or

the Portland (:CIIlI'11l :\"'ociatlOn).

FIGURE 1.19. Median frame cast in place (courtesv of the Prestressed CotHTl'tc Institute. from ref. 6).

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--

.,

Prestressed Concrete Bridges and Segmental Construction

10

FIGURE 1.20, HolJhem,l Bridge. completed structure

l<ollncs\' of the Ponland CCIl1Cllt Association).

This design is slightly morc expensive than PI'('\,I

ous oncs but it prO\ides the mosl open t\'IK' tW() span structure.

The structural arrangement of the Sehastian Inlet Bridge in Florida consists

or

a three-span \I!lit o\'er the lllain challnel, Figure J.~5, The ell<lspall of this three-spall ullit is 100 It (30.5 lll) IOllg and cantileH:rs 30 ft (9 Ill) beyond the piers to support a l~O ft (3G.G Ill) precast prestressed drop-in spall, Figure I.~(). The end-spall seClioll was huilt in two seglllellts witlI a cast-in-place splice with the help 01

a falsework bent. The :\apa River Bridge at V,t1 kjo, California (not to be confused with the \:apa

River Bridge described in Section 2.11), used a prccast concrete calltile\,cr-suspended spall COll cept silllilar to the Sebastian bllet Bridge, at about the same tillle. The olll" differellce was that the cantile\'er girder was a sillgle girder extcllding

from the side pier o\'er the maill pier to the hinge support for the suspended span.

The t\'pe of construction that uses long, standard, precast, prestressed lIllits never quite achieved the recogllition it deserved. As spans in creased. designers turned toward post-tensioned GIst-in-place box girder construction. The Califor nia Division of Highwa;s, for exallIple, has been quite successful with cast-in-place, multicell, post tensioned box girder construction for multispall structures with spans of 300 It (91.5 lll) and even longer. However, this t\'pe of construction has its own Iilllilations. The extensive fOrInwork used during casting often has undesirable effects on the em'ironlllclit or the ecology.

1.6 Segmental Construction

Sq~melltal constructioll lias hecn delilled7 _as_a Illcdtod of COllst ruct ion in w hieh primar\' load supporting lIlclllhers arc composed of indi\'idual lllemhers called segmcllts post-tellsiolled together. rile cOlJcepts dncloped ill the pel-peA studies and desnibcd ill the prcC(:dillg scctioll cOllie under this delillitioll. alld wC' Illight call theln "longitudi

nal" seglilelltal cOllstruction becallse the indi\'idual clelllcilts arc IOllg with respect to their width.

III Europe, llleanwhile, sel{lllelltal constructioll proceeded ill a sligl1th differellt malltler ill COlJ jUllctiotl with box girder dcsil{ll. SCI{InCllts wcre cast ill place ill r<:lathclr short lellgths hut in flll1 loadw;I\ width and depth. T()(bv segmclltal COIl

struction is uSllally understood to hc the type de \clojJcd ill Europe, Howc\cr, as will be shown lalcr, tlte segllH'llts lIced lIot he of full-roadw;l\'

ELEVATION 16'-6' Lf7---L---'---'-;..;;;...I----r1-._ellI: 48 AASHO-PCI eox SECTION SECTIONS A-A

FIGURE 1.21. Median frame precast (collrtes\,

or

the Prestressed Concrete InstifUle, hom reI'. G),

(19)

11

Segmental Construction

FIE:...D SPLICE

SCCTIO~ A-A

FIGCRE 1.24. Field splice for cOlltinuity (courtesy of the Prestressed COll crete lmtitute, from ref. 6),

FIGURE 1.22. Ardross<ln Overpass preca~t llledia II

frame (counes\ of the Portbnd Ccment Association).

width and can become rather IOllg in the 1011 gitudill<l I d ircctioll of t he bridL{l\ dependiIlg OIl the constrlluioll S\stelll lllilized.

Eugene Frevssinet. ill It.H5 to 1941:). was the lil-st

to use precast segmental constructioll for pre stressed COIlClTte bridge;., :\ bl'idge at LUZallL\

over the \bnH: Ri\ ('I' ahout :iO llliles east or Paris.

Figure I. '27, \\;IS followed In a groll p or lin~ precast

bridges mer tlrat rin:!'. Shorth thereafter, Urich Finsterwal<it:r applied Gist-in-place seglllelltal pre stressed cOllstructioll in a babllced cantilever fashion to;1 bridge (l'n-;,illg the Ltl1ll Rin:r at Bal duinsteill. Cenll;lIl\. rhis S\stelll

or

c<lntile\er segmental COIlst rllct iOll rapidlv gained wide ac ceptal1l:e ill (~enllall\. arter cOIlstructioIl of a bridge U'os.,ing the Rhillc at Worllls ill 195:2. as shown ill Figun.: I.~H.' \\ith three spam

or

:):)0.

371, and :~,iO II (100. 11:~. :111<1 HH Ill). :\Iore thall

300 such slrucllllT'i, with spalls ill excess of ~51) It

(76 m), werc constl'llued bctweell 19:,)() al1d 1965

FIGURE 1.23. Completcd Ardrossan Ovcrpass (courtesy of the Portland CClllent Association).

in Europe.:l _{Since thell the concept has spread}

throughollt the world,

Precast seglllenr,ll construction also was evolving during this period, In 1952 a single-span COUllt: bridge near Sheldon. :\cw York. W;15 designed hv

the Frey'isillet COlllpam. Although tbis bridge W;IS

constructcd

or

longitudinal Luher than the Euro peall transversc seglllents, it represents the hrst practical applicatioll of lllatch castillg, The bridge girders were divided into three IOllgitudinal seg lllelits that were cast end-to-etld, The center seg IIlelll. wa, cast first aiid then the end segments were cast directh agaillst it. Ke\'s were cast at the joints so that the three precast eieIllcnts could be joined at the site ill tbe S,lIlle positioll they h;id in the pre casting \;tnL Lpon shipment to the job site the three eleillcllts of a girder were post-tensioned to gether with cold joints. HI,It

The first major application of lllatch-cast. pre cast segmelltal cOllstruction was no[ consummated

(20)

SeClIOn A·A

100' 180' _-~---.~---100' ... ~

'I'

C65' _35'

I,

_~<L.r

1~9'

.._3_0'.· 35' 65'

FIGURE 1.26. Sebastian I nJet Bridge (courtesy of the Prestressed Concrete Ifl

stitute, from ref. 6) .

FIGURE 1.25. Sebastian Inlet Bridge (courtesy of the

Portland Cement Association),

ulltil ]962. This struClure, designed by Jeall r-.luller and built by Entreprises Campenon Bernard, was the Choisy·Ie-Roi Bridge over the Seine Rin'r south of Paris, Figure 1.29. This concept has been refined and has spread from France to all parts of the wodd.

The technology of casl-in-place or precast seg mental hridges has advanced rapidly in the las! decade. During its initial phase the balanced cantilever method of construction was used. Cur relltly, other techniques such as spall-b:/-span, in cremental laullching, or progressive placelllent also arc available. Any of these cOl1struction methods iliaI' call on either cast-in-place or precast segments or a combination of both. Consequently, a variety of design cOIJcepts and cOllstruction lllethods are now available to economically pro duce segmental bridges for almost anv site condi tion.

Segmental bridges mav be classified broadh' b\ four criteria:

1. The ultimate use of the bridge-that is, high way or railwa\' structure or combination thereof. Although man\' problems are com mon to these two categories, the considerable increase of live loading in a railway bridge poses special problems that call for specific so lutions.

2. The type of structure in terms of statical scheme and shape of the main bending mem bers. Many segmental bridges are box girder bridges, but other types such as arches or cable-stayed bridges show a v..·ide \'arietv in shape of the supporting members.

3. The use of cast-in~place or precast segment~ 01

a combillation thereof. 4. The method of construction.

The sections that follow will deal brie/l\ with til(' last three classifications.

1.7 Various Types of Structures

hOlll the point

or

view of their statical schellle.

there ale essentialh' five categories of structures:

(I) girders, (2) trusses, (3) rigid frames, (4) arch

frallJes. and (5) cable-staved bridges.

1.7.1 GIRD':lm J5WJ)U-:S

Box girders in the JJl;~jorit\ of cases are the most ef'ficient and economical design for a bridge. Whell constructed in balanced GlIltile\'er, box girder derks were initially made integral with the pier~

while a special expansion joint was provided at the center of' each span (or every other span) to allow

(21)

13

Various Types of Structures

n

:iii

~;,s

"3':"'.": _ ..

..

I~'-O"

J

i

FIGURE 1.29. Choisv-Ie-Roi Bridge. FIGURE 1.27. Luzane\( Bridge over the Marne Ri\'cr

for volume changes and to control differential deflections between individual cantilever anTIs. [t is now recognized that continuitv of the deck is desir able. and l110st structures are now continuous over several spans, bearings being provided between deck and piers for expansion.

Todav, the longest box girder bridge structure that has been built in place in cantilever is the

Korol' Babelthuap crmsing in the Pacific rrust ter

ritories with a center span

or

790 ft (24 [ m), Figure

& Widmann). 1.:)0.12 A box girder bridge has been proposed for

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FIGURE 1.32. Saint Cloud Bridge. France. FIGURE 1.35. Rip Bridge, Brisbane, Australia.

...

_...

_ ,oj n longitudinal section 100' 100' I I

DO

r---~

,I.

-

Typical sections at span center

and over main piers

c-~ ..

FIGURE 1.3 I. Tht' (;n'at Belt I'If>jl'ct.

the Creal Belt pJ(~jecl ill Denlllark \\'ith a JOiO fl (:126 111) clear main spall, Figure I.;~ I, The box girder design has bcell applied wilh equal suc c('ss 10 Ihe cOllstruction of difficult and spectacular stl"ll(:lurcs such as the Saint Cloud Bridge o\('r the Seine Ri\cr lIcar Paris, Figure J,3:!, or 10 I he

constructioll 01' c!e\';tted structures in \('1'\ CO!l gestcd urban areas slIch as the B<) \'iaducls Ileal

Paris, Figure 1.:1:).

1.7.2 lRl'SSFS

Whcll spall lellglh illcreases, Ihe I\']lied box girder hecollles hea\"i' ami diHicult 10 build. For Ihe pur pose or rcdu~:illg dead weighl while silllplir\"illg casl ing or VtT\' dccp wch sect ions. a t russ wit h opell webs is a \cr:-' saiisraCl0rV type that call he C()ll\"C

!Iiellth' huilt ill call1ilever, Figure J,;)4. The tech llological lilllilatiolls lie ill the complication

or

COIl

!IectiolJs between prestressed dia~()lIals and chords. An otllslanding example is the Rip Brid~c

in Brisb;lIIC, Australia, Figure 1.;):1.

'.'.6ii''',;

• I ' 'otl

"0<... ~ .... _,, __ .

FIGURE 1.33. B-3 \'iaduCls, France.

The cantilever method ha" potential applications hel\\'een the optimum spall length'. Ollvpical hox girders for the low ranges and of SI;l\Td hridges for the high ranges.

1.7."3 /-/(A,\1/-;S JrlrJI SI..·/'\']" U~(;.'·;

Whcll tile configuration of the sitc allows, the lise 01 inclillcd legs reduce" the dfcctin' span length.

(23)

---~

15

Various Types of Structures

Nt;

I

I ! -~

~ / ~~ '"

FIGt:RE 1.36.

Pro\·isiollal Ilack ,!;t\"S or ;t tClllporan pier ;1I-e

lleeded 10 permil cOllslructioll III LIlltilcHT. Figure

1.3(). ["his requircllIcllt 111;1\ ,olllclill1cS presclIl

diflindl\ ..\11 illtercstillg c,ample

or

,tiel! a ,chcme is (hc BOllhollllllC Bridge oycr 1/](' BL!\ct RiV"tT ill

Frallce. Figme 1.:17.

The sciIeme is a trallsilioll hClweell the bo, girder with \enied picrs alld Ihe true arch. where the load is clrried Il\ 1he drch rill, ;tiOllg I he pres sure lille with lIlinillllllll hClldillg while the deck is supporlcd In spandrel col ti III II s.

,~

'I

...

~;~:~~~~

...

-=<!I!'.;~~:~§~".

"'."l:n

_{:,.~,: ~'*:~r-:~:i'~.,}

FIGURE 1.37. BOllholl1tlle Bridge.

I ~ ;1 , I .: I{~ ~ .:: ; __ I I' ...- / I" __ , , ~- 1/ :; Lung-spall fratlle.

1.7.1 (.'O.W.RI:TF . INCH IWI/)(;/:·S

COllCITte arches are an ecollolllicti w;!\, to Iransfer

loads to the ground where foundation cOl1ditiol1s are adequate to resist horil.ollul loads. Eugene Fre\ssinet prepared a design for a 100{) meter

(:~2HO ft) clear span 40 v"{'ars ago. Because of con struction difficlllties. however. the maximulTI span built to date (1979) has been no IIlore than I ()O() II

C~()() Ill). Construction Oil falsework is made difficult and risb bv the effect of strong winds d II ri ng construct ion.

flle lirst outstanding concrete arch was built at

PIOllg~lstei bv Freyssinet ill 1928 with three fiOO ft

(I H;) Ill) spans. Figure 1.:~H. Real progress was

achie\"ed only when free calltilever and provisional ,Ll\ llIelhods were applied to arch constrtKtion. Figure 1.39. The world record is pn:sentlv the Kirk Bridge ill Yugoslavia. Imilt in cantilever and COl1l

FIGURE 1.38. P!ougastel Bridge. France.

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16 Prc'stressed Concrete Bridges and Segmelltal Construction

-

,

FIGURE 1.39.

FIGt:RE lAO. Kirk BridgTs. Yllg()sl;n'i~L

.:

pkted ill 1979 with <l dear ~pall of 1:!HO It (:190 Ill).

Figure lAO.

1.7.5 CO'\"CNEn. LWH.-Sr.1l1.1> filUj)(;},) '"

\\'!Jcn a span is i>eyolJ(l 1he reach of <l COllE'Il1 iOJl,iI

girder bridge. a logical stcp i~ to suspend the deck 1)\ a s\'slem oC pdons alld Sla\'S, Applied 10 sted Sf rUClures Cor the last twellt \' \cars. this approach g'aillcd illlll1ediate acceptallce ill thc field of COIl

crete brid ges wilcli cOllq ruCl ion bccalIIe possihle

l..4sr

ItfCLOS(./'U'

1

FIGURE 1.41. Long-spall concrete cablc-sta yed bridges.

SECOI'fO

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17

Cast-in-Place and Precast Segmental Construction

FIGURE 1.42. Ihotollllt' Bridge. Frallct',

and ecolloll1iGlI ill balallced calltilevel' with a larg-e nUlllber of sta\'s 1IIlifol'lllh' di~tril)ljted ;dollg- the deck. Fig-ure IAI, I'lIe long-cst 'ipall or this type is the Brotolllle Bridge ill Fraw" with a 10;)0 It

ctW

01) dear Illaill'ip,lll mer the Seille River. Figlll'(' 1.42, Single In lOllS alld olle lillc of Sla\s :IIT iOCllCd

along the centl'rlllll' 01 !Ill' hl'ld;..il',

1.8 Cast-in-Place and Precast Segmental C()ns/ruction

1,8,1 Cfl,W, ! CT/JUS TICS OF L1SI',/\',/JI..I<:F

S/·:C.\IF,\

r\

In cast-in-pl:ln: U)lISlrllctioll. \('gTlll'Ili'i ;IlT c;t'il olle

after another illliteir fill:d InelltO!l ill lite stl'llctllt't', Special equipnll'lll is llSed for Ilti" pllrpme. '>11(11 as

traveler's (for c;lIltilcn~1' COIl'ilrllctioll) or f()l'I11work units I1l<)\'ed ;dollg ,t stlpporting g;lllIl'\ (for spall

b~'-spat1 cOllstrllctiOI1), btl'll seg!!l('nt is rcild'ol'ced

with cotH'entional lIntcnsiol1cd steel ;I!ld 'iOllle times by trans\'(:rsc or \crucd pn:'itres'iing or hot h. while the assel!,lbl ~ of>eglllclllS i'i ;1,~~!il'\Td

h_::

J~?~l:

-tellSioning.

-'--''''''~-'---'--''''-:---~~cg'I;ll;~;,re cast end-to-end. it is

not difficult to placc IOllgitlldin.d reilll'on:illg steel across the joillls betweell SCg-lllClllS if the desigll calls for colltinltolls reinforcemctll. Joints !Il<lV be

treated as reqllired for safe trallsfer of all bending and shear stresses alld for water tightlless ill ag gressive eli mates. COllnection betweell ind i\'idual lengths of longitlldillal posHellsiollitlg dllns lll;t\ be made easih' at each joillt alld for each telldon. The method\ essential limitation is that the strength of the concretc is alw<\\s 011 thc critical

path of cOllstruction and II <t!~0it~!ll~,=-Il('csgre,;t~\~_'"

the structure's deformability. particularlv durin/.{ cmi'S'i'lw:tion, DeAections of a typical cas!:ln:,>Sce GlIltile\'cr are often two or three times those of the same camilever made of precast segments.

The local effects of concentrated forces behind the anchors of prestress tendons ill a young con crete (two or four days old) are always a potential source of concern and difficulties,

/.8.2 C/I,/IUCTERISnCS OF PREC.iST SE(;,\l/~'\TS

[n precast segmelltal constrllction. segments are manufactured ill a plant or near the job site. then transported to their final positioll for asselllblY. I nitialh'. joints between segments were

or

comen tional t>Ve: either concrete poured wel joints or dn mortar packed joints. :Vlodern seglllcntal COI1

st ruct ion calls for the lllatch-castillg techllique. as mcd for the Choisv-Ie-Roi Bridge ~lI1d further de \'eloped and refilled. \\'hcreb:; thc seglllents are precast against each other. preferabh in the same "ciati\'(: order thev will have ill the final strllctllrc, \:0 ;uIjllstlllent is therefore llccessarv between ,cgmcnts before assembly. The joints arc cithcr

left <In' (ill ;Ireas where climate permils) or made of

a vel'\' thin fillll of epox:: resin or mineral complex. which docs not alter the lIlatch-casting properties. .l'here is llO lIecd for allv waiting period ror joint

lllre. and final asselllbly of segments bv prest res

~illg 111:1\' proceed as bs! as practicable,

Becausc the joints are

or

negligihle thickness.

1here is u-;uallv no mechanical cOllllect iOIl bet wecn

thc illdi\iduallellgths of tendoll ducts at thejoillt. L'ql:tlh' no attempt is Inade to obtain cOlltinllitv of the longitudinal con\'entional steel through the joints. ,tithollgb se\'eral methods are ~I\'aibhle ~II}(I

han: heen applied slIcccssfulh (as ill the Pasco Kellilewick cable-sl<l\ecl bridge, for exalllplc). Segillellts Illay be precast 10llg ellough ill advallce

01 their asselllbh in the structure to reach 'iufficiellt strellgtll and maturitv and to miuilllize both the deHecriol1S during construction alld the elfeets of cOllcrete shrinkage and creep ill the lill~d

5t ruct u re.

If erection of precast segments is to proceed smoothl\,. a high of geometry control is re quir'ed during match casting to ensure accuracv.

1.1-1. CH01CE BETWEE.V CAST-IX-PLACE ./XD

PRECAST CO,VSTRL'CTIO.v

Both cast-in-place methods and precast methods h;l\e been successful!:' lIsed and produce suhstall

( /

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Prestressed Concrete Bridges and Segmental Construction

18

tially the same final structure. The choice depends on local conditions, includillg size of t he project, time allowed for constructioll. restrictiolls on ac cess and environment, and the equipment available to the successful contractor. Some items of interest are listed helm\':

1. SjJ(w/ of COlis/ruction Basical"', cast-in-place calltile\'er construction proceeds at the rate of one pair of segments 10 to 20 It (:1 to 6 m) long even fOllr to se\'en d;l\s. On the average. Olle pair of travelers permits the completioll of 150 f't (46m) of hridge deck per 111011th, excluding the transfer

from pier 10 pier and fabrication of the pier table.

Oil the otlier hand, precast segmental cOllstructioll allows a cOl1siderablv /'aster erectiol1 schedule. a. For the Oleron Viae! lIct, the average speed of collJpletion of tlw deck was 750 It C22H 1Tl) per lIlont h

for more than a year.

h, For both the B-:1 Viaducts ill Paris and the Long Kev Briclge ill Florida, a typical 100 to I f)() It (:10 to 4:) Ill) spall was erected ill two working cla\s, repres('l1til1g a construction of I:10() It HO() Ill) of fillished bridge per lIlollth,

c. Saillt Cloud Bridge llear Paris, despite t hl' ('x

cept iOllal di fficlilt y of its geolllet n and design schellle. was COllstructed ill exactlv Olll' \Tar, its total area anloullting to 250,()OO sq It (~;L()()() sq

III ).

It is evident, then. that cast-in-place GllJlile\'er COlJ

struction is basically a slow process, while precast seglllental \"ith lllatching jOlllls is ,lI11011g the las test.

2. 1117.'('.111111'111 ill Sf'(,Cla/ Equil'lI/f'IIt f lere t hl' situation is usuallv reversed. Cast-in-place requires usually a lower investment. which IlIa kes it COIlJ

petitive on short structures \\ith long spa ns [ for example, a typical three-span structure with a center span in excess qj approximately :150 f't (J 00 m)].

III long, repetitive structures precast ~egl11elltal

may he 1I10re economical than cast-ill-place. For the Chillon Viaducts with twin structures 7000

n

(2134 111) long in a di I'ficu 11 environmcllt, a detailed com parative estimate showed the cast -ill-place method to be 10% more expensive than the pre cast.

3. Size alld Weight of S('gmerlts Precast seg JIlemal is limited by the capac:it y or transportation and placing equipment. Segmellts exceeding 250

tons are seldom economical. Cast-ill-place con struction does not ha\'(' the same limitation, al

though the weight alld cost of the travelers are di rectly proportional to the ,,'eight of the heaviest segment.

4, Ell1!lromnfJlI Rfslricliolls BOI h precast and cast-in-place segmelltal permit all work to he per formed from the lOp, Precast. however. adjusts more easily to restrictions such as allowing work to proceed over traffle or allowing access of workmell ami materials to the various piers.

1.9 Variou.~ Methods of Construction Probahh Ihe most signihcant classification of seg lllental hridges is In llll'1 hod or cOllslrUClioll. Al though cOllstruction mel hods ma\' be as varied as the ingenuit\

or

Ihe designers alld contractors, thn Ldl into 10111' hasic categories: (J) halall(ed c<lntiienT, (~) spall-I>\ -span cOllstructioll. (:I) pro gressive placclIlellt COllst ruet iOIl. alld (4) 111 ('r('

lIlcl)tal launchillg or push-oUl construction.

1,9,1 c.'ISr·/.\'·j'j.,l(J, li.1LJ.\'CUl C/.\T/UJUI The h;li;lllccd or frce calli iI('\('1 COllst run ion CO)l

(ejlt \\'as origillalh dcn'loped to elilllilJate Lllsework, TClIJporan sllOrillg Ilot ollh is ('XPCIl

si\'(' hUI call he ;1 hazard ill tile Lise of suddcll

floods, as cOlJfirllJed 1)\ lll;tm f;tilllles. (her Ila\'iga ble waterways or Iran·led highwa\'s or railways, lals('\\ork is either not allowed or ;,('\eIT" re strictcd. Cantiien:r cOllstructiol], \\hetlier cast ill

place or precast, clilliinates slIch difficulties: C()IJ structiolJ ilia\, pro(ced from Ihe permallellt piers, and the Slrllcture is sell-supportillg at all sLtges, The hasic prillciple of the lIIethod \\as outlincd ill Section 1. J (Figme l.~i).

In cast-ill-place COllst ructioll the jonn\\'ork is sllpported from a 1ll00ahie form carrier, Figure

1.1. Detaib of the lorlll Iran·lers arc showll ill Fig lire 1.43. The forllltra\'eier 1IJ00es forward 011 rails

attached to the deck of the completed structure and is anchored to the deck at the rear. With the form t r;J\e!er ill place, a ncw segmellt is formed, cast, and strcssed to the IHe\'iolish constructed segment. I n some instances a covering m<l\ be pro

vided on the form carrier so that work m<ly pro ceed during inclelllent weather, Figure 1.44.

The opcration sequence in cast-in-place bal anced cantilever construction is as follows:

1. Selling lip and <l(Uustillg carrier. 2. Selling up and aligning forms.

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Various Methods of Construction 19

CENTERJACt<

REA~ GANG-BOARD BOTTOM FRAME WORK

FRONTAL UPPER WORKING PLATFORM

!

FRONTAL LOWER WORKING PLATFORM

FIGURE 1.43. Forlll I r;I\\:I('I' IC()t!rtl";\

or

D\ckcrhofT & Widmallll),

3. Placing reinlorcclIlcl1l and tendoll ducts.

4. COIlCl'Cling,

5, lllscriing plt'SlleSs IClldollS illlhc segmcnl and stres'iing

6, RCll1millg I he IOl'll1work,

7. ~[()\'illg I hI.' lorm carrier (0 the llCXI position

and slarling ;1 new C\cle,

Initia!!\', Ihe normal cOl1slruClion time for a segmellt W;IS olle week per fOl'1nwork lIni!. Ad

vances ill precast sq';ll1enul construction ha\c bcen applied ret'el)t!\' 10 the cast-ill-pbce method in order to reduce the nde 0[' operaliolls and in crease the eificiellc\ of the travelers. \'.'jth todav's techllologY' it does Hot seem possible to reduce the

FIGURE 1.44. Bendorf Bridge form tra\-e!er (cour tesy of DvckerholT & Widmann).

cOllStl'llnioll time for a full cycle below two work ing da~s, ;lIHI this ollly for ;1 very simple structure

with constant cross section and a moderate a1l10UIlI

or

reinforcillg' and prestress. For a structure with \;triahle deplh and longer spans, say ;Ibove 250 ft

(75111), the typical nell' is more realistically three to

lour working' <la\·;;.

\Vhe!e a IOllg viaduct type structure is 10 be COIl

strllcted of cast-ill-place segmellts, an auxiliary stee! girder may be used to support the f()rmwork, Figure 1A5, as on the Siegtal Bridge. This

equip-FIGURE 1.45. Siegtal Bridge, use of an auxiliary truss in cast-in-place construction.

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i

ment may also be used to stabilize th~ free-standing pier by the anchming of the auxiliaiy<~teel girder to the completed portion of the structure. Nor mally, in construction using the form traveler pre viously described, a portion of the end spans (near the abutments) must be cast on falsework. I f the auxiliary steel girder is used, this operation may be eliminated. As soon as a double typical camilever is completed, the auxiliary steel girder is advanced to the next pier. Obviously, the economic justification for use of an auxiliary steel girder is a function of the number of spans and the span length.

1.9.2. PRECAST BALA.\'CED C;/]\'TILEVER

For the first precast segmental bridges in Pal'is (Choisy-le-Roi, Courbevoie, and so on, 1961 10 1965) a floating crane was Itsed to transfer the pre cast segments from the casting yard to the barges that transported them to the project site and was used again to place the segments in the structure. The concept of sell-openlling launching gantries was developed shortly thereafter for the COllst ruc tioll olthe Oleron Viaduct (1964 to 1966). Further refined and extellded in its potential, this concept has heen used ill many large structures.

The ereclioll optiollS available Gill be adapted to

almost all construction sites.

I. Crane Placing Truck or cr,l\vler cranes are

used on land where feasible; float.ing cranes Illay be used for a hridge over navigable water, Figur'c 1.46. Where site cOllditions allow, a portal crane may be used Oil the fulllengtb or the deck, prefer ably with a castillg yard aligned with the deck near

FIGURE 1.46. Segment erection by barge-mounted crane, Capt. Cook Bridge, Australia (courtesy of G. Be lofr, Main Roads Department, Brisbane, Australia).

one abutment to minimize the number of handling operations, Figure 1.47.

2. Beam and Winch A1c1hod If access by land or

water is available under the bridge deck, or at least around all permanent piers, segments may be lifted inlO place by hoists secured atop the previ ously placed segments. Figure 1,48. At first this method did not permit the installation of precast pier segments upon the bridge piers, but it has been improved to solve this problem. as will be ex plained later.

3. Launching Gan/rip.I There are essentially

two families of launching gantries, Ihe details

or

which will be discussed in a later chapter. Here we briefly outline their use.

In the first family developed lor the Oleron Via duct, Figures 1.49 and 1.50. the lalllKhing gantrY is slighth more than the typical span length, alld t he gantry's rear support reaction i;. applied ncal the far end of the last completed cantilever. All segments are brought onto the finished deck alld placed bv the launching gant!'y ill balanced can tilever; after cOlllpletion of a calltilever, alter placing the precast segment over the new pier. the launching gantry launches itsclllO the next span to start a new cycle of operations.

In the second family. developed for the De venter Bridge in Holland and for the Rio Niteroi Bridge in Brazil, the launching gal1lrY has a length approximately twice the tvpical span, and the reac· tioll of the legs is always applied abo"e the perIna nent concrete piers, Figures 1.51 amI 1.52.

Placing segments with a launching gamry is now in most cases the Illost elegant ane! efficient method, allowing the least disturbance to the envi ronment.

1.9.3 SPAN-ln'-SPAN COSSTRUC710.\'

'The balanced cantilever construction method was developed primarily for long spans, so that con struction activity for the superstructure could be accomplished at deck level without the use of ex tensive falsework. A similar need in the case of long viaduct structures \\·ith relatively shorter spans has been filled by the development of a span-by-span methodology using a form traveler. The following discussion explains this methodol ogy.13,14,15.16

In long viaduct structures a segmental span-by span construction may be panicularly advanta geous. The superstructure is executed in one direc

Construction and Design of Prestressed Concrete Segmental Bridges