Special Report

Construction of

East Huntington Bridge

Dr. Man-Chung Tang, P.E.Pres+dentDRC Consultants. Inc.Flushing, New York

by

The East Huntington Bridge is a cablestayed structure over the Ohio River

connecting West Virginia and Ohio atEast Huntington. The stayed girder hasa main span of 900 ft (274 m) and a sidespan of 608 ft (186 m) with approachspans at both ends (Fig. 1). This is atwo-lane bridge with a total deck widthof 40 ft (12 m) at the cable stayed portionand 33 ft6 in, (10.2 m) at the approaches,The actual curb to curb roadway is 30 ft(9.1 m) wide.

The cable stayed portion of the bridgegirder has a concrete slab supported bysteel floor beams spaced at 9 ft (2.7 m)on center, These floor beams are framedtransversely into the two longitudinalconcrete edge girders. The cables areanchored in the edge girders.

The 33 ft 6 in. (10.2 m) wide approachat the Ohio side is a single cell concrete

box girder. A transition piece connectsthe box girder to the stayed girder.

The construction plans specified thatthe cable stayed portion of the girdershall be built in precast segments whilethe box sections are to be cast in place.The pylon is also cast in place.

Bidding the ProjectTwo alternative designs, one in con-

crete and one in steel, were developedfor this project. The contractor had theoption to bid either alternative.

The construction scheme suggestedby the designer of the steel alternatefeatures temporary supports in the riverto support the steel girder. These tem-porary supports would be removed aftercables have been installed and stressed.

The designer of the concrete alterna-

32

tive suggested building the cable stayedportion by balanced cantilever con-struction and the box girder approacheson falsework. Ater the box girder is castand post-tensioned the ialsework wouldbe removed. An auxiliary pier would berequired to be left in place to support theend of the cantilever so as to avoid ex-cessive bending before the closure pourbetween the box girder and the cablestayed portion of the main bridge is cast,

Melbourne Brothers of Ohio was thesuccessful low bidder at $23.5 millionfor the concrete alternate. They retainedContech Consultants, Inc. to provide therequired construction engineering.

Construction EngineeringAs in most bridge projects the con-

struction scheme described in the bid-cling documents is a suggested methodto build the bridge. It lacks the requireddetailed information for actual con-struction, The contractor, through a con-sulting engineer, has to investigate allconstruction stages and come up withthe missing information, such as cablejacking forces, camber curves, etc.

Generally speaking, the constructionengineering consists of the followingitems:

1. Establish the construction schemewith the contractor.

2. Perform a stage by stage construc-tion analysis to determine the requiredjacking forces of the cables and to en-

SynopsisThe author describes the various

phases in the construction of the EastHuntington Bridge — a 1966 ft (600m) long prestressed concrete cablestayed structure. The cable stayedportion of the bridge girder was builtusing precast concrete segments. The250 ton (227 t) segments were matchcast off-site using the long line castingmethod. They were then barged to thesite and lifted into position using a 600ton (544 t) floating crane.

The South Approach was con-structed by the cast -in-place can-tilever method. Both the precast andcast-in-place portions of the structureutilized high strength concrete with aspecified 28-day compressivestrength of 8000 psi (55 MPa).

The bridge was completed suc-cessfully based on a well plannedconstruction schedule.

sure all stresses are within the allowablelimitations during each construction op-eration.

3. Determine the casting curve for theprecast segments if applicable.

4. Develop camber curve for eachconstruction stage.

5. Determine any additional require-

Fig. 1. Elevation of East Huntington Bridge.

PCI JOURNALJNovember-December 1987 33

PIER PIER

4-3'- -52'-6°6 (S 15"-3

20-4-I5.5' S k5-3"

PIER

}6 5•9 15 -'°

I +.CLOSURE SuMEN3 `I

PIER TABLE CLOSURE SEGVENT f. I

i } PIER TABLE

FORM TRAVELER

H _. L I I

I II I

Fig. 2. Construction sequence (South Approach).

ment of cable lengths and shim packs forthe cables.

In the case of this bridge, design oferection travelers to erect the precastsegments was also included in the con-struction engineering.

Basically, the construction designproduces a construction scheme whichwill achieve a stress condition andcamber which are prescribed by the de-signer of the bridge for a specific timeafter completion of construction. How-ever, cable stayed bridges are highly in-determinate structures. Depending onthe method of construction, the bridgemay have different stress conditionsunder permanent loads after it is com-pleted.

To avoid overstresses under ser-vice load condition, the stresses in thestructure have to stay within a certainrange at the time the structure is corn-

pitted. Creep, shrinkage and relaxationeffects must also be considered duringand after the construction period.

The analysis was based on criteriaspecified by the engineer. During con-struction, the allowable stress in the ca-bles is 57 percent of its ultimate tensilestrength and the allowable tensile stressin the concrete is 6 VIT except at theprecast segment joints where no tensilestress is allowed. The engineer also pro-vided the upper and lower bounds forthe permanent stresses in the girderwhich would be acceptable for the finalservice condition of the structure.

Box Girder Approach SpansFor the actual construction of the box

girder approach spans a scheme dif-ferent than that suggested by the en-gineer was selected.

34

I's DY%K)AG 7-FEAZEAR 8A.00E, SYMM.

!2x0.6" o OR5,06°aSTRAVO TENDONS

i5 x 0.6' aSTRAND TENDONS

SECTION NEAR FI TTN YES

Fig. 3. Cross section and tendon arrangement (South Approach).

Instead of building this portion of thebridge on falsework, the actual con-stniction used the balanced cantilevermethod employing formtravelers. Theneed of an auxiliary pier for the can-tilever at the closure pour was elimi-nated by reducing the cantilever fromthe original 184 to 154 ft (56 to 47 m) asshown in Fig. 2.

This eliminated the danger of pos-sible collision against the auxiliary pierby river traffic which could have seriousconsequences. The tendon layout in thisportion of the girder was modified to ac-commodate segmental cantilever con-struction (Fig. 3). Despite the stringentquality requirement of 8000 psi (55MPa) concrete specified for this portionof the bridge, construction proceededsuccessfully.

The layout of the segments is shownin Fig. 2. The pier tables are 36 ft 9 in,(11.2 m) long. They were constructedatop relatively small knee brackets.Formtravelers were then assembled ontop of the pier table. The typical seg-ments are 15 ft 3 in. (4.1 m) long.

The pier table was built off center ec-centrically on the pier. This reduced theunbalanced load at each side of the can-

tilever to a half segment. The weight ofthe formtraveler was approximately 150kips (667 kN).

The knee brackets were designedonly to support the weight of the piertable. As the cantilevers grew longer theunbalanced moment also increased.Sand jacks and vertical tiedowns wereused to support the superstructure at thepiers to transfer the unbalanced bendingmoment from the superstructure to thesubstructure. This eliminated the heavybrackets which are common in mostcantilever constructions.

The advantage of using sand jacks,aside from being less expensive, is thatthey are easy to install and dismantle.However, certain deformation charac-teristics of sand jacks during loading andunloading cycles must be taken intoconsideration to control the bridgecamber during construction. This wasdone by plotting the as-built camber andcomparing it to the theoretical camber todetermine the rotation of the bridge dueto the sand jack settlements so that theelevations of the new segment could beset properly.

The above procedure was success-fully utilized on this bridge.

PCI JQURNAUNovember-December 1987 35

^ITACK CABLE ANCHORAGE FOOTING

Ti: GNE

TEMPORARYSTRUTS

(a) t (b)

Fig. 4. Elevation and cross section of pylon.

Pylon ConstructionThe portion of the main pier below

the bridge girder was completed under aseparate contract. Construction of thepylon started after the last lift of the piershaft was cast.

The pylon has the shape of an in-verted Y (Fig. 4). The inclined pylonlegs were cast in lifts of approximately18 ft (5.5 m). Because the legs were in-clined it was necessary to place struts

between them in order to reduce thebending moment due to the inclination.The struts were designed to be capableof applying a horizontal force to thetower legs to reduce the dead loadbending moment.

The legs were also cast with an out-ward camber to compensate for the deadload deflection due to the inclination.The pylon stem, at the top, was cast inlifts of approximately 15 ft (4.6 m). This

mANCHORS

Fig. 5. Backstay cable anchorage. \\\\\

36

40'- i 0"

LrTI t- :i -. r

Fig. 6a. Typical cross section of precast segment.

stem has an H-shape cross section. Allcables are anchored at the middle part ofthe H-section (Fig. 4b). In order to easethe process of accurately setting thecable anchorages at the tower head, thecontractor used a prefabricated lightsteel frame to support the anchorages.

Fore and hackstay cables were used tostabilize the tower during the canti-lever construction of the main bridge.The forestay cable consists of two 55'/2 in. (13 mm) diameter strands bundledtogether. It was anchored at the lowerend by looping around the approachpier foundation. The backstay cableutilized the final end cables by extend-ing them to anchor at a concrete blockwhich was tied down by piles and earthanchors (Fig. 5).

The specified concrete strength forthe tower was 6000 psi (41 MPa) at 28days. However, for part of the pylon thecontractor elected to use the same 8000psi (55 MPa) concrete mix which wasused for the approach spans because hehad since gained experience with thisconcrete mix.

A tower crane was used for materialtransport at the tower. This tower cranewas supported by piles driven adjacentto the pier. The crane was also attachedto one of the tower legs. It introduced tothe tower legs additional forces andmoments which were included in thestress analysis of the pylon.

Cable Stayed GirderExcept for a portion of the girder at

the end of the side span, which has anenlarged cross section that was cast onfalsework, the cable stayed portion of

the girder consists of 40 ft (12 m) wideand 45 ft (13.7 m) long precast segments.This typical cross section consists of two5 ft (1.5 m) deep and 3 ft 6 in. (1.2 m)wide edge girders (Fig. 6a). The deckslab is 8 in. (203 mm) thick supported by33 in. (838 mm) deep steel floor beamsspaced at 9 ft (2.74 m) centers. The steelbeams are connected to the concreteslab and edge girders by shear studs.

The specified 28-day compressivestrength of 8000 psi (55 MPa) for the gird-er elements was achieved without dif-ficulty. The segments were match cast.Due to the relatively small number ofsegments (a total of 27), a long linecasting method was chosen. It is easierto match the casting curve by using thelong line method. It requires lesssophisticated formwork and elevationcontrols than for the short line method.After two starter segments were cast,which were to be located at the pylon,the balance of segments were cast in twolines.

To ensure that no undesirable settle-ment occurred during casting, curing andstorage, the forms and segments weresupported by two lines of footing lo-cated underneath the edge girders. Theconcrete footing was cast on a com-pacted sub-base. The top surface of thefooting was graded according to thecasting curve of the precast concrete seg-ments.

Soil between the footings was removedto facilitate easy removal of the segmentsby tractors (Fig. 6h). The slab form wassupported by the steel floor beams andthese steel beams were supported bytimber piles during casting of the seg-ments.

PCI JOURNAL/November-December 1987 37

Fig. 6b. Casting bed arrangement of precast segment.

Fig. 7. Barge crane for segment erection.

38

FOR MTRAVELER

FORESTAY CABLEBACKSTAY CABLE

Fig. 8. Final construction scheme.

PCI JOURNAL/November-December 1987 39

Fig, 9. Arrangement of erection equipment.

A casting curve was provided by theengineer in the bid documents based onthe suggested construction method. Butthe actual construction loads and con-struetion schedule are seldom the sameas assumed by the design consultant.This changes the creep and shrinkagedeformation of the structure. A newcasting curve had to be calculated. Thebridge girder for this structure is soflexible that deviations in the construc-tion sequence, in the constructionschedule, or in the weight of the form-traveler would cause a noticeablechange in the casting curve.

A new casting curve was obtainedbased on the selected construction se-quence, Unfortunately, it was decidedthat the method of segment erectionshould be modified because of economyafter several segments had been cast ac-cording to the first casting curve. Therevised construction scheme yielded anew casting curve which was differentfrom the original scheme, it becamenecessary to manipulate the construc-tion procedure to produce a new castingcurve which matched closely the oneused for the already cast elements. Thiswas quite a tedious task due to the limi-tations of allowable stresses in the ca-bles and in the very flexible bridgegirder.

Fortunately, a very sophisticatedcomputer program was available toperform this task. Numerous castingcurves were generated by the computer

based on manipulation of cable forcesand closure pour procedures. A finalcasting curve was obtained which ade-quately matched the casting curve usedfor the previously precast segments.

Segment ErectionThe bid documents suggested that the

erection of segments be done with agantry supported by erection cables.Stress analysis, casting curve andcamber curves based on this schemewere developed. An erection travelerwas designed to perform this task. Be-cause no tensile stress is allowed at theprecast segment joints, the bridge girderhas a very small capacity to resist bend-ing.

Several steps of cable adjustmentswould be required during segmenterection and launching of the erectiontraveler to meet this criterion. Cableadjustment is a time consuming taskwhich should he minimized in any waypossible.

Due to the subsequent availability ofa large barge mounted crane (Fig. 7), itwas found that an alternative method oferection using the crane would be moreeconomical, faster and safer. A newanalysis was carried out based on anerection scheme using the barge crane(Fig. 8).

The weight of a precast segmentincluding strong hacks for lifting isabout 250 tons (227 t). The barge crane

40

is capable of lifting this segment, withall attendant loads, and placing it in itsfinal position for attachment to thestructure. The segment was supportedby the crane until the stay cables wereattached and stressed (Fig. 9).

Because the crane was mounted on abarge and subjected to wave action ofthe water, movement of the crane duringsegment erection was investigated toensure that the bridge would not be ad-versely affected during this sensitiveoperation. A hinge device was de-veloped to facilitate segment attachmentto the girder while maintaining fullalignment. The hinge mechanism hasseveral hydraulic jacks for fine adjust-ments in all three directions. The hingeelements were attached to the segmentsby Dywidag tendons before erection. Itwas designed as a connecting device toeasily receive the subsequently deliv-ered segment.

The first piece of the bridge deck wascast in place on top of a knee bracingtogether with a short starter segment ateach end, These same starter segmentshad been used as the first segment in thematch casting. The far end ofthe side spanhad a different cross section than theregular segments because it was used as

a ballast to counterbalance the upliftforces created by the longer main span.A stronger girder was also needed to re-sist the higher bending moments at thisregion. This portion of the bridge girderwas cast in place on formwork supportedby falsework before the cantilever seg-ments were erected (Fig. 10).

When a segment was ready, it wasplaced on a barge and floated to the site.The barge crane picked up the segmentand raised it to the appropriate elevationwhere the hinge mechanism at the endsof the segments engaged each other(Fig. 11). In order to ensure perfectmatching, the segments were pulled to-gether for a trial match. This was done atthe beginning for several segments untilall concerned were confident that thesegments would match properly. Thehorizontal jack then pushed the newsegment about 18 in. (457 mm) awayfrom the old segment and epoxy wasapplied to both faces of the matchingjoint.

In the meantime, the cables wereerected and were tensioned while thesegment was still suspended from thebarge crane. A synchronized step bystep operation of cable stressing, re-treating of the horizontal jack as well as

Fig. 10. Falsework support for end segments.

PCI JOURNAL/November-December 1987 41

IL1

II

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1r

stressing of the longitudinal tendonshad been worked out on paper beforethe actual erection.

The axial force applied a predeter-mined pressure across the matchedjoint. Safety shim plates were insertedor removed during all operations so thatthe gap between the segments was keptto about 2 in. (51 mm) at several loca-tions (Fig. 12). This was a safety precau-tion to eliminate the very improbableevent that if the hinge mechanism skid-ded, the impact caused by the collisionof the segments would be limited to anacceptable level. The actual erectionwent very well without any incident.

End Span ClosureThe end span closure pour was lo-

cated between the sixth and seventh ca-bles at the north end of the structure.The bridge girder north of the closuresegment was cast in place severalmonths before the closure took place.This allowed the concrete to age so thatthe effect of creep and shrinkage wasminimized. This portion of the bridgegirder had a heavy solid cross section. Itwas cast on forms supported by localfalsework and was cast in three hori-zontal pours.

Before casting the closure, the northcast-in-place girder was pushed awayfrom the closure to compensate for fu-ture movements at the end bearings. Apredetermined shear force was alsointroduced into the closure segment.Steel beams were used to clamp thebridge girder at both sides of the closurepour in place. The closure segment wasthen formed and cast. Post-tensioningwas applied after the closure segmentattained a concrete strength of 3500 psi(24 MPa).

Once the end span closure was com-pleted, the bridge became a highly in-determinate structure because all false-work columns became elastic supportsof the bridge deck. They must be con-sidered in the structural analysis of the

Fig. 12. Safety shims.

bridge in the subsequent constructionstages.

Main Span Closure andTransition Segment

The main span closure connects thecable stayed precast girder to the cast-in-place box girder. Because the cablestayed girder is 40 ft (12 m) wide and thecantilevered box girder is 33 ft 6 in. (11.2m) wide, a special section is required tofacilitate this transition (Fig. 13). Vari-ous construction schemes were studiedfor this transition segment. Finally, thecontractor decided to cast this transitionsegment in three stages. The last pour,which was 3 ft 6 in. (1.2 m) long, was theclosure segment.

Because no temporary supports wereused, the cantilevered box girder wasnot capable of supporting the transitionsegment by itself. Steel girders were

PCI JOURNAL/November-December 1987 43

lnof

3-6•270" 3-0CLOSURE- 10--Q" 5 6" -CLOSURE

B r Hr-i___

^^ I I

^ I .

it it

A j CfL 6RIDGE i I A

M II j^ a

____ I

I I I1 1 I Ij ll

J^ l

C-I.P. PRECAST SEGMENT B C.LP CABLE STAGED2 I GIRDER

PARTIAL DECK PLAN

3 6° 27'- Q" 3 - 0

TOP OF DECK -

naIA

cFrT1nN A-A

BRIDGE16-9 f 20-6"

^- r^ Q oM ^

^Sl

:Ma,VA RIES ! VARIES _ '•a Min.

SECTION B - B

Fig. 13. Transition segments.

44

CAST-IN-PLACE CLOSURE PRECAST CABLE STAYEDCANTILEVER GIRDER

GP `^ CP^^

STEEL FRAME ? [TIEDOWNS

JACKSIGMENTL

JACKS 1l

SHIM BLOCKS

SHIM BLOCKS CLOSURE (PRECAST SEGMENT)

CLOSURE POUR IJ

IIT 1.1

CLOSURE POUR 2

Fig. 14. Closure procedure.

PCI JOURNALINovember-December 1987 45

TOWER LEG

THRUST BLOCK

TENDONS GIRDER -,'1

H i Il

Fig. 15. Horizontal restraining device.

placed across the gap which supportedthe formwork and distributed part of thesegment weight to the cable stayedgirder (Fig. 14),

Before the closure pour was cast, aseries of jacking operations introducedto the girders a set of predeterminedbending moments and shear force whichwere locked in after the closure wascast. This operation was necessary toachieve the given permanent load con-dition as prescribed by the design engi-neer. In addition to this operation, ad-justment of several cables before andafter the closure was necessary.

CablesPermanent cables consist of 0.25 in. (7

mm) diameter wires with highamplitude (Hi-Am) sockets. They werepreassembled and delivered to the sitein coils.

To erect the cable, the coil was placednear the tip of the cantilever. The cablewas pulled out of the coil and laid on thebridge deck. The anchorages were thenpulled through the anchorage pipes atthe tower and at the edge girders bywinches. Stressing of the cables tookplace at the edge girder. The cableswere stressed in pairs at each segmentto avoid twisting of the deck.

The cables were grouted with cementgrout after completion of all requiredadjustments. The grouting was done in

lifts to avoid excessive hydrostatic pres-sure which could cause cracking of thepolyethylene (PE) pipe.

Tedlar tape was wrapped on top of thePE pipe after grouting was completed.This wrapping provides a temperatureshield and an additional layer of protec-tion for the cables.

Horizontal Restraint at TowerThe final bridge has a pair of hori-

zontal bearings to restrain the relativemovements between the girder andtower. But they are designed for rela-tively small forces which are muchlower than the possible horizontal loadsduring construction. Therefore, tempo-rary restraints had to be installed tostabilize the bridge deck against unbal-anced loadings acting on the girder.

There were two groups of loads thatrequired the installation of restrainers atthe tower. The first was caused by un-balanced vertical loads between thecantilevered girders. Although the seg-ments are arranged symmetrically, thesegment at one cantilever must beerected before the corresponding seg-ment at the other cantilever can beerected, so that an unbalanced momentcannot be avoided. An additional unbal-anced live load of 5 psf (0.24 kPa) ofbridge deck was also assumed for designpurposes.

The second group of loadings is

46

caused by unbalanced horizontal windload acting laterally to the bridge deck.This wind load was taken as 50 percentof the balanced wind loads based on theassumption that it was very unlikely thatwind will act on one side of the canti-levers only. These two groups of load-ings are to be added to each other, thus,resulting in a maximum restraining forceof 800 kips (3636 kN) at one side of thedeck.

Four large steel brackets were tied tothe edge girder of the deck against eachside of the two tower legs (Fig. 15) byDywidag Threadbar tendons to providethe restraining capacity.

Stage Analysis and CamberControl

All structural analysis was performedusing a computer program, calledCAB B, developed by the author. Creepand shrinkage factors were assumed as2.0 and 0.000020, respectively.

The computer program is capable ofperforming both linear and nonlinearanalyses. However, a study of severalcritical stages indicated that for the se-lected construction scheme, linearanalysis was sufficiently accurate so thatthe complete analysis was carried outaccording to the linear theory. The cablestiffness was modified to consider thesag of the cables.

The computer program checks allstresses at every joint and comparesthem with the allowable stresses. It alsocompares the ultimate bending momentand shear of the girder and tower in eachconstruction stage with the ultimate ca-pacities at the corresponding joints. Anyoverstress or under capacity will beprinted out so that cable forces can beadjusted to alter the stress condition ofthe structure until all stresses are withinthe allowable ranges.

As a result of this construction stageanalysis, a set of camber curves and cor-responding cable forces were given tothe contractor for use at the site. The

contractor surveyed the bridge to obtainthe actual geometry of the bridge at allcritical stages and compared his sur-veying results with the calculatedcamber values. The survey must bedone with minimum effect of tempera-ture. Therefore, it was done during earlymornings before sunrise.

All survey data were transmitted tothe engineering office for immediateevaluation. Excessive deformationswere immediately investigated.

Throughout the construction, the ac-tual surveyed geometry of the bridgematched the predicted camber verywell. Generally, the deviations in de-flection were less than 2 in. (51 mm) ex-cept for very few situations where a de-viation of up to 4 in. (102 mm) was de-tected. Subsequent investigations foundthat the excess deviations were all ex-plainable and mostly due to differencesbetween the actual and the assumedloading conditions.

Aerodynamic InvestigationsWind tunnel tests of the section model

of the bridge were carried out by theUniversity of Colorado for the designengineer before the bidding. A copy ofthe test report was made available to thecontractor and his consultant after thebidding.

Although the original testing did notaddress construction stage behavior ofthe bridge, test results of the sectionmodel had been sufficient to predict theaerodynamic behavior of the bridgeduring various construction stages aftersome modifications. No additional testswere carried out for construction pur-poses.

Calculations for flexural vibrations,torsional vibrations and flutter foundthat no unacceptable wind induced vi-brations were to be expected duringconstruction. Therefore, no additionalmeasures were necessary to stabilize thebridge against the predicted windspeed.

PCI JOURNALiNovember-December 1987 47

Fig. 16. East Huntington Bridge nearing completion. Photo courtesy: Arvid Grant andAssociates,

Closing RemarksThe East Huntington Bridge was

completed successfully based on a wellplanned construction scheme. Thebridge behaved basically as predictedby the calculations. It is a very attractivestructure that blends well with the sur-rounding landscape (see Fig. 16). Thebridge won an award in the 1985 PCIProfessional Design Awards Program.

Acknowledgment"The owners of the bridge are the State

of West Virginia and State of Ohio, withWilliam Domico, director, StructuresDivision of West Virginia Department ofHighways, as manager of the designproject. Luther Wickline and StanMeadows under the direction of EarlScyoc, chief engineer, Construction andMaterials, were responsible for con-struction supervision.

The engineer for the main bridge isArvid Grant and Associates in collab-

oration with Leonhardt and AndraPartners, and project engineers wereConrad Bridges and David Goodyear.

The contractor was MelbourneBrothers. Their project manager wasBrian Danaher and project engineerswere John Macrae and Doc Woodard.

Construction engineering and equip-ment design were done by ContechConsultants, Inc. Project engineerswere Joseph Tse and Nien-ShengChung under the supervision of Man-Chung Tang.

REFERENCES1. Grant, A., "Design and Construction of the

East Huntington Bridge," PCI JOURNAL,January• -February, 1987, pp. 20-29.

2. Tang, M. C., "A Tale of Two Bridges -Penang, Malaysia and East Huntington,Ohio," Major Concrete Bridge Confer-ence, April 1986, New York.

3. Tang, M. C., "Design of Cable-StayedGirder Bridges," ASCE Journal of theStructural Division, STS, August 1972,pp, 1789-1802.

48