precast bridge deck

8/13/2019 Precast Bridge Deck

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by Sameh,S . Ba(iie, Mantu e, Baishya and Maher K.Tadros

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lnnDvati- Blidle-P~elAASHT07 Standard Article 9.25.1.1 , whichrequires 1.5 in.(40 rnm) clear cover. State agencies, sucb as Missouri,8 use3 in. (75 mm)thick precastpanel pretensioned with.3/8 in.(9.5 mm) diameter strands. One of tbefactorS that is ex-tremely important is tbe condition oftbe bearing ofthe pre-cast panels on the supportinggirders, Research on deck crack-ing by KIuge and Sawyer9 and Fagundo, et al.10has dernon -strated tbat tbe panels must be firmly bedded on groutorconcrete on the supporting girders. In the case of skewedbridges, skewed spans are often cast inplace for the full deptbof the deck. Goldbergll has reported that on lightly skewedspans (15 degrees or less) the panels are sawed tomatch theskew. A mnimum bearing length of 1.0 ft (0.3 m) on theshort side of tbe panel is sometimes required.Research conducted at Pennsylvania Stat~ University byBarnoff et aL,I showed tbat the type of joint used berweendeck precast panels affects neitberdeck behavior nor wheelload distribution. lt also showed that a 6 in. (ISOmm) pro-jection of prestressing strands from the ends of the panel isadequate to anchor fue panel to tbe CIP topping. However,extensive research conducted at tbe University of Texas atAustin by Biescbkel2 showed that under cyclic loading therewas no significant difference in tbe cracking pattem or crack-ing width between the bridgebuilt witb precast panels wherethe strands projecting outside the panel, and the bridge builtwitb precast panels, where the strands were not projectingoutsidethe panel.Research conducted at the University ofFlorida by KIugeand Sawyer9 showed tOOtn most cases the provided devel-opment length was less tban tbe AASHTO specification re-quirements. Therefore, the research recommended

t rCIron:1gteel perpenccularto t(J.eprestress-ing strandsshould not be less tban No. 3 (9.5 mm)bars at 12in. (300mm) oncenterlines,R sear h at University of Nebraska Inordet to evaluate the performance of a conven-tional precast, prestressed stay-in-place bridge deck,systein,I) a fulI-scale test was performed in thestructurallaboratory of University of Nebraska,Omaba campus. An 8.0 x 20 ft (2.4 x 6.0 m)bridgedeck system was tested using two 4.0 x 11.5 ft(1.2 x 3.5 m) precast p(eStressedpaoels, each 3 in.(75 rnm) thick. The bridge deck system was de-signed for a girder spacing of 12 ft (3.6 m) with 4ft (1.2 m) cantileveT00 either side.The total thick-ness ofthe bridge deck system was 9 in. (230mm)where the top 6 in. (150 mm)was C[P reinforcedconcrete. Tbe design strength of the precast panelwas 10,000 psi (70 MPa) andthe topping strength

- hat do Florida, Texas, Pennsylvatia, WestVir-ginia, Indiana, Kentucky, Missouri and several: . otheFstates have jn common with engmeeringday? The successful implementation of partiat-depth.,cast--place (CIP) decks with stay-in-place (SIP) precast con~ete panel systems. Design, detailiqg, field implementationd test results are now available. -


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Fig.,2- Cross-section 01 thewas 4000 psi (28 MPa). The precast panels were erected be'tween the steel girders andowoo


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n ---.----'f270 ksi (1900 MPa). The strands are pro-vitkd io twolayersaod uoiformlyspacedat12in. (300 ~~) as shown in section A-A,fic::.4, A mmmum clcar concrete cover ofI in. (25 rnrn) is used for both the top andbottorn laycrs of strands.- Inorder to maintain the~8in. (200 mm) gapover the girders, 28 No. 6 (19 mm) rein(orc-- ingbarsare used in two layers,as showninectionC~C,.Fig. 4. Tbese bars also have an18in. (460 mm) embedment Iength to trans-mitthe prestressing force and compression:;:force-fromnepartof the paqel to the next 'noverthe gaps. Tomaintain continuity in thelongitudinal direction between the adjacenthear keys and reinforced _.pOcketsare provided. Reinforcedpocke~are'spacedat2.0 ft (0.6 m) in the center. In rderto avoid forming in the field,a 20 gage Flg. 4-,.. SetlonsA~A. EI-B,and C:-C-6 x 6 in. (ISO x ISOmm) sheet metal stockis used as a s~~in-place form at the pockets. Tbe panel iseinforced longitdinally-with No. 4 (13 mm) bars spaced .at 2 ft at the location of the pockets. The No. 4 bars werepliced using an inhovative confinement technique to pro-vide for tension development. T'nesplice consists of a loose90 in. No. 4 bar and a spiral whose size is shown in Fig. 5.This technique was separately evaluated with smaUtensionspecimens and found to produce the full bar yield strengthof 60 ksi (410MPa). .Before the precast panels are set on the supporting girders,:;grout barrier is installed along the girder edges~The groutstoppermay be formed trom light gage metal sheets attachedto the top surface of the girder and the bottom surface of theprecast panel using a standard construction adhesive..Once the panels are placed over the girders and adjustedwith the leveling devices, gaps over the girders are groutedwitha t10wablemortarmix to about 1.5in. 40mm belowthe top surface of the panel. The mortar mix should have acompressive strength of 4000 psi (28 MPa) al the time ofcastingfor the topping slab. The mortarprovidesa com-pression block needed to resist the negative movement over[he girders due to loads imposed by the concrete pavingmachine and the self-weight of the concretetopping.A 4.5 in. (115 mm) cast-in-place topping slab reinforcedwith epoxy-coated welded wire fabric is utilized, shown inFig. 2. Notethat the thickness ofthis layer could be reduced

4,5-1 ~. - . . - .~e

Spiral. 3 0.0. . l ' pileb. et,ZS win 4iamoter

~ ,ij. S'et..'Fig. 5.-'Reinfon:ed pocket detaii.

0- _.._----- -..------ -_..

ECTION A.A

'~,.ro.~ .'. ~~... ..~ z - 7',. 'a-r.OSECTION B-B'f ~'I ; i~l O,.

'~1.1S' 7~. i2 '- '''''' ':0a-r.O ~. tb 35in. (90 mm}depending on the-girder spacing. Tbiswould alJow for 2.5 in. (65 mm)of clear cover to protect thereinforcement from eorroson.0ndling nd shippingIt is recommended thatthe panel be lifted at the location o.the girder lines. This can be achieved with two techniques.Tbe first technique involves using multiple lift points withspreader beams '~ shown in Fig. 6(a).Each lifting positionwould have two lifting points nearthe sides of the panel.'For very wide andlor ver)t thinpanels. itmay be advisableto use the second technique.This involves using astrongback (stiffening frame) attached to the panel atthe location of the girder tines, shown in Fig. 6(b). The'

strongback can be a structural steel orprecast concrete mem-ber. lt would be attached to the precast panel before the panelis removed trom the forros and removed after the panels areplaced on the girders and shimmed to the required elevation.Structural performanceFull-scale testing was conducted on the performance-thestructure.15 Transverse continuity 'fprestressing reinforce-ment over the girder lines resulted in full arching actioo.Tests showed that this system hadalmost twice the capacityof a comparable conventional SIP system.

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onclusion. Thesystem was proven to havethefo.Uowing adv.antages:. t.It'eliminates field forroing .for deckoverhangs.2.. For rebabilitation of bridgedeckS;it saves the time and laborn'eededto rearrange tbe shear con-nectors. 'Ibis is due to the opti--mized spaing.between the rein-forcement'in the gaps.3.It saves time alJ,dlabor be-cause the SIP, panel covers theentire width oftbe bridge. There-

fore, there is noneed to handle alarge l1umber of pieces as in thecase afthe conventional SIP pre-cast panels.f

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(a)

(b)

~Attachment

t -'~C c:'c' Cc c' cC C' Cc c',c ,c CCc c::;':'.-,'., . ','~.~Pn:cast panel

r- Strongback(steelorprecastconc~temember)

, 4. The SIPprecastpanel can be crownedto fonn a crossslopesurface of the bridge.5. The SIP precast panel is designed to support the pavingmachine loads and a construction load in addition to its self-weight and the topping slab self-weight. Therefore, there isno need to support the overhang during casting of the top-ping slab.6. Tbe materials used in the production of the panel arenon-proprietary and are inexpensive.7. The reinforced pockets in the transverse direction be-tween the precast panel help toprovide continuity in the lon-gitudinal direction, resulting in minimization of the reflec-tive cracks at the transverse joints.

, 8.Thesystemhasafar superiorperforman~ thanthecon-ventional SIP panel system under cyclic load.9. Tbe system has almost double the flexural capacity ofthe conventional SIP panel system.This anicle was prepared from a presentation givenat the ACI Conventionin AtIanta, Ga., Fa1l1997.Acknow~gments .The research reponed herein was perfonned under NCHRP Project 12-4land Daniel P. Jenny Research Fellowsbip, PrecastlPrestressed Concretelnstitute. Additional support has been provided by tbe l.fniversity of Ne-braska-Lineoln Center for Infrastructure Researc::h, Kiewit Construct ionCompany and HDR Engineering, Ine. Special thanks are d~.to WiIliam -Dowd, Philip E. Rossbaeh, and Hussein Khali1 of HDREngineering Inc.in Omaba., Neb.; and Sharad Mote, Frank Watt, Jerry Thoendel and GaryPietrok ofKiewit Engineering Company, Omaha, Neb. These individualsmade signifieant eontributions to the development ofthe system described.Amin Einea, research assistant professor at the University of Nebraska-Lincoln, otTered suggestions and assistance with he experimental programo 'The following statT and graduate researcb assistants belped with the project:Deborah Derrick , Jim Peoples, Hussam Kakish, SherifYehia.References,

1. BarnotT, R. M.; OrndortT, 1. A.; Harbaugh, R. B.; and Rainey, D. E.,Full-Scale Test of a Prestressed Bridge with Preeast Deck Planks, PCIJournal, V.22, No. 5, September-October 1977, pp. 66-83. R

2. Biswas, M., Precast Bridge Deck Design Systems;' PCI Journal, Y.31, No. 2, March-April 1986, pp. 40-94.

3. Inverset Bridge System, Design lnstallation and Technical Manual,The Fort Miller Co. Inc., Schuylervil.e, N Y 12871. '

4. Kelly, J. B., Applications ofa Stay-in-Place Prestressed Bridge DeckPanels, PCI Journal, Y. 24, No. 6, November-December 1979, pp. 20-83.

5. PCI Bridge Committee, Precast Prestressed Concrete Bridge DeckPanels, PCI Journal, Y. 32, No. 2. March-ApriI1987,pp, 26-45. f{

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6. PCI Bridge Committee, Tentative Design and Construction Specifi-cat ions for Bridge Deck Panels, PCI Journal, Y. 23, No. 1, January-Feb-ruary 1978, pp. 32-39.7. AASHTO Standard, American Association of State Highway and

Transportation Officials;' Standard Specifications for Highway Bridges,Sixteenth Edition, 1996.I. 8. Bridge Manual of Design Section, Part I, Missouri Highway and

Ag~ 6 - a Handling using muttiple lifting points; (b) Handlingusing strOngback. ',ITransportation Commission, Division ofBridges.

9. Kluge,R. W., and Sawyer, H. A., Interacting Pretensioned ConcreForm Panels for Bridge Decks;' Final Report No. cD610-635F, Depart-;ment of Civil Engineering, Engineering and Industrial Experiment Sta~lion, University ofFlorida, Gainsville, pp. 58. :~

10. FagUndo, F.E.; Tabatabai, H.; Soongswang, K.; Riehardson. 1.M.=andoCall ,is, E.G., Precast Panel Co~posite Brid8~ Decks;' Concrete lnter.natlOnat, Y.7 , No. 5, May 1995 pp A-65. r

11. Goldberg, D., Preeast Prestressed Concrete Bridge Deck PanelsSpeciaJ report prepared by pcr Bridge Committee, PCI Journal. Y. 32No. 2, March-April 1987, pp. 26'-45. {l..

12. Bieschke, L. A., and KJingner, R. E., Effect of Transverse PanetStrand Extensions on the Bebavior of Precas[ Prestressed Panel Bridge,PCI Journal, Y. 33, No. 1, January-February, pp. 68-88. ( .

13. Tadros, M. K., and Baisbya, M. c., Raptd Replaeement of Bridge Decks, National Cooperative Highway R~searcb Program, NCHRP Re;/..'port 407, Washington, D.C. 1998. V';,_J..~. Precast P' stre,ssed Concrete Bridge Desif .nManual, Precast/Pre---1Istressed Concrete Institute, Chieago, 111.,1997. : : :

15. Badie, S.; Baishya, M. C.; and Tadros, M. K.. NUDECK - An .1tEfficientand Econom}cal Precast Bridge ?eek System;' PCI Journal, Sep- .5E:,c.&c

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.tember-October, V. 4 , No. 5,1998, pp. )6-74...: Ti1-f1-

Sameh S. Badie is a research assistantlprofessor with the civil engineering depart-,

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. ment, University-~f Nebraska Lincoln. He r~ceived his PhO from the University of~.-:Nebraska-Lincoln, in 1997. '

Received and reviewed under Institute publ ieatian policies.

;J;., ,Mantu C. Baishya is a research assistanL~1professor with the Center for Intrastructure;1Researeh, University ot Nebraska-Lineoln. tHe is a professional structural engineer for c~the state of Nebraska. He reeeivedhis PhO;from the University of Colorado-BouJder.fin 1993. Maher K.Tadros is Cheryl Prewett Profes-=sor of Civil Engineering, University 01Ne- -=braska-Uncoln. He is past president of the =-ACI-Nebraska ehapter and a member ofseveral ACI technical eommittees, inelud-ing ACI Committee 31~-G, Prestressed ~Concrete.

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precast bridge deck

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