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dc.contributor.authorHinkle, Stephen Docken_US
dc.date.accessioned2014-03-14T20:44:07Z
dc.date.available2014-03-14T20:44:07Z
dc.date.issued2006-08-10en_US
dc.identifier.otheretd-08242006-133037en_US
dc.identifier.urihttp://hdl.handle.net/10919/34740
dc.description.abstractAccurate camber prediction in prestressed concrete bridge beams is important to all parties involved in bridge design and construction. Many current prestress loss prediction methods, necessary for proper camber calculation, were developed many years ago and are predicated on assumptions that may no longer be valid as higher strength concrete, wider beam spacing, and longer span lengths become more commonplace. This throws into question which models are appropriate for use in camber calculation by the bridge engineers and contractors of today. Twenty-seven high-strength concrete modified 79 in. Bulb Tee beams with a design compressive strength of 9,000 psi were periodically measured to determine camber growth. Most available models for concrete creep and shrinkage were used to calculate creep and shrinkage strain. The modulus of elasticity equation of each model was used to predict modulus of elasticity of the studied mix. The Shams and Kahn compressive strength and modulus of elasticity equations were modified in order to approximate measured modulus of elasticity. The creep, shrinkage, and modulus of elasticity equations were used as inputs to an incremental time step method. The time-dependent change in beam curvature calculated by the time step method was used to calculate theoretical camber using the Moment-Area method. Predicted camber, using inputs from each considered model, was then compared with measured camber to determine the most accurate camber prediction models. Season of casting was also examined to determine what, if any, affect ambient temperature has on camber growth. For the studied beams, the Shams and Kahn Model for creep, shrinkage, and modulus of elasticity, used as inputs for an incremental time step analysis, were found to most accurately predict camber values. Lower concrete compressive strength was observed for test cylinders from beams cast in summer versus beams cast in winter. Differences in beam deflection based on season of casting showed mixed results.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartHinkle_Thesis.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.subjectshrinkageen_US
dc.subjectprestress lossesen_US
dc.subjectcreepen_US
dc.subjectcamberen_US
dc.subjecttime-dependent deflectionen_US
dc.titleInvestigation of Time-Dependent Deflection in Long Span, High Strength, Prestressed Concrete Bridge Beamsen_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.committeememberWeyers, Richard E.en_US
dc.contributor.committeememberCousins, Thomas E.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08242006-133037/en_US
dc.date.sdate2006-08-24en_US
dc.date.rdate2006-09-14
dc.date.adate2006-09-14en_US


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