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dc.contributor.authorBowers, Susan Elizabethen_US
dc.date.accessioned2014-03-14T20:36:28Z
dc.date.available2014-03-14T20:36:28Z
dc.date.issued2007-05-08en_US
dc.identifier.otheretd-05122007-195020en_US
dc.identifier.urihttp://hdl.handle.net/10919/32644
dc.description.abstractFull-depth precast concrete panels offer an efficient alternative to traditional cast-in-place concrete for replacement or new construction of bridge decks. Research has shown that longitudinal post-tensioning helps keep the precast bridge deck in compression and avoid problems such as leaking, cracking, spalling, and subsequent rusting on the beams at the transverse panel joints. Current design recommendations suggest levels of initial compression for precast concrete decks in a very limited number of bridge configurations. The time-dependent effects of creep and shrinkage in concrete and relaxation of prestressing steel complicate bridge behavior, making the existing recommendations for post-tensioning in precast deck panels invalid for all bridges with differing girder types, sizes, spacings, and span lengths. Therefore, the development of guidelines for levels of post-tensioning applicable to a variety of bridge types is necessary so designers may easily implement precast concrete panels in bridge deck construction or rehabilitation. To fulfill the needs described, the primary objective of this research was to determine the initial level of post-tensioning required in various precast concrete bridge deck panel systems in order to maintain compression in the transverse panel joints until the end of each bridgeâ s service life. These recommendations were determined by the results of parametric studies which investigated the behavior of bridges with precast concrete decks supported by both steel and prestressed concrete girders in single spans as well as two and three continuous spans. The three primary variables in each parametric study included girder type, girder spacing, and span length. The age-adjusted effective modulus method was used to account for the ongoing effects of creep and shrinkage in concrete. Results from the Mathcad models used in the parametric studies were confirmed through comparison with results obtained from finite element models generated in DIANA. Initial levels of post-tensioning for various bridge systems are proposed based on the trends observed in the parametric studies. The precast decks of the simple span bridges with steel girders and the one, two, and three span bridges with prestressed concrete girders needed only 200 psi of initial post-tensioning to remain in compression under permanent and time-dependent loads throughout each bridgeâ s service life. The precast decks of the two and three span continuous bridges with steel girders, however, needed a significantly higher level of initial compression due to the negative moments created by live loads.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartSusanBowersMSThesis.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectPrestress Lossesen_US
dc.subjectPrecast Panelsen_US
dc.subjectAge-Adjusted Effective Modulusen_US
dc.subjectLongitudinal Post-Tensioningen_US
dc.titleRecommendations for Longitudinal Post-Tensioning in Full-Depth Precast Concrete Bridge Deck Panelsen_US
dc.typeThesisen_US
dc.contributor.departmentCivil Engineeringen_US
dc.description.degreeMaster of Scienceen_US
thesis.degree.nameMaster of Scienceen_US
thesis.degree.levelmastersen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineCivil Engineeringen_US
dc.contributor.committeechairRoberts-Wollmann, Carin L.en_US
dc.contributor.committeememberDavis, Rodney T.en_US
dc.contributor.committeememberCousins, Thomas E.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05122007-195020/en_US
dc.date.sdate2007-05-12en_US
dc.date.rdate2007-06-12
dc.date.adate2007-06-12en_US


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