?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F19300%2F&rft.title=Assessment+of+Partial+Debonding+Practice+for+AASHTO+Type+Girders&rft.creator=Wang%2C+Weijin&rft.description=Pretensioned+girders+have+been+commonly+used+in+bridge+construction+for+years.+However%2C+some+problems+remain+that+hinder+the+further+application+of+longer+and+more+heavily+prestressed+girders.+The+prestressing+force+can+produce+large+stresses+at+both+the+top+and+bottom+surfaces+of+the+girders%2C+especially+near+the+ends+where+self-weight+moments+are+minimal.+Additionally%2C+the+transfer+of+large+prestressing+forces+can+cause+local+cracking.+Partial+debonding+of+straight+strands%2C+harping+strands+and%2For+adding+top+strands+are+three+common+approaches+to+mitigating+such+problems.+However%2C+harping+is+limited+to+those+strands+aligned+with+the+member+web%2C+and+adding+top+strands+affects+the+overall+stress+state+of+the+section.+Comparatively%2C+partial+debonding+is+a+simple+and+preferred+approach.+The+total+prestress+force+is+introduced+to+the+member+gradually%2C+reducing+stress+concentrations+and+associated+end-region+cracking.%0D%0A%09Even+so%2C+partial+debonding+decreases+the+longitudinal+tension+capacity+particularly+when++%0D%0Aa+large+number+of+strands+is+debonded.+Excessive+debonding%2C+therefore%2C+can+also+have+detrimental+effects+of+the+flexure+and+shear+capacity+of+the+girder.+This+thesis+aims+to+quantify+the+effects+of+partial+debonding+on+initial+girder+stresses+and+ultimate+girder+capacity+in+an+effort+to+identify+acceptable+prestressing+strand+debonding+details.%0D%0A%09Two+series+of+AASHTO+Type+III-VI+girders+having+varying+spans%2C+amounts+of+prestressing+and+different+debonding+ratios+are+systematically+analysed+for+their+adherence+and+consistency+with+present+AASHTO+LRFD+Specification+requirements.+The+analyses+use+a+purpose-written+MATLAB+program.+Analytically+obtained+girder+capacities+are+validated+with+initial+design+capacities+from+the+PCI+Bridge+Design+Manual.+An+individual+case+is+presented+in+order+to+illustrate+the+analysis+procedure.+From+this+study%2C+acceptable+partial+debonding+ranges%2C+satisfying+AASHTO-prescribed+stress+limits%2C+are+obtained.+%0D%0A%09Conclusions+indicate+that+the+upper+limit+for+an+acceptable+debonding+ratio+may+be+increased+from+the+AASHTO-prescribed+25%25+to+perhaps+50%25.+However+the+results+also+indicate+that+this+upper+limit+is+a+function+of+span+length+and+may+be+greater+for+longer+spans.+In+many+cases+no+acceptable+amount+of+debonding+was+found+for+shorter+spans.+Further+parametric+study+is+required+to+establish+such+a+relationship+and+to+extend+the+study+to+other+girder+shapes.%0D%0A&rft.date=2013-09-24&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F19300%2F1%2Fwangweijin_etdPitt2013.pdf&rft.identifier=++Wang%2C+Weijin++(2013)+Assessment+of+Partial+Debonding+Practice+for+AASHTO+Type+Girders.++Master's+Thesis%2C+University+of+Pittsburgh.++++(Unpublished)++