预应力损失对大跨度pc连续梁桥挠度的影响

《预应力损失对大跨度pc连续梁桥挠度的影响》由会员上传分享，免费在线阅读，更多相关内容在工程资料-天天文库。

1、预应力损失对大跨度PC连续梁桥挠度的影响卜建清崔金灿(石家庄铁道大学，石家庄050043)摘要:研究目的:近年来国内外多座大跨度预应力混凝土连续梁桥在通车一段时间后主跨跨中出现较大的挠度，不但影响了过桥车辆的舒适性和安全性，而且威胁着桥梁的安全，缩短了桥梁的使用寿命。本研究旨在分析预应力损失对大跨度连续梁桥长期挠度的影响规律，为采取有效的设计、施工及加固等措施抑制大跨度预应力混凝土连续梁桥跨中持续下挠提供理论依据。研究结论:(1)大跨预应力混凝土连续梁桥挠度是长期增长的，增长速率不确定，其跨中挠度随跨径的增

2、大而增大，增长率与跨径的大小、预应力损失程度都有着密切关系，且桥梁跨度越大，主跨跨中挠度受预应力损失影响越明显;(2)桥梁顶板纵向预应力损失比底板纵向预应力损失对跨中挠度的影响显著;(3)混凝土收缩徐变及由其引起的预应力损失是引起大跨PC连续梁桥跨中下挠的主要原因;(4)该研究成果可应用于大跨度预应力混凝土连续梁桥优化设计。关键词:大跨度预应力混凝土连续梁桥;预应力损失;收缩;徐变;长期挠度中图分类号:U448．215，U448．35文献标识码:AImpactsofPrestressLossontheDeflec

3、tionforLarge－spanPrestressedConcreteContinuousGirderBridgesBUJian－qing，CUIJin－can(ShijiazhuangTiedaoUniversity，Shijiazhuang，Hebei050043，China)Abstract:Ｒesearchpurposes:Inrecentyearsseverallarge－spanprestressedconcretecontinuousgirderbridgesappearlargedeflecti

4、oninthemainspanafteropenedaperiodoftimeathomeandabroad，whichnotonlyinfluencesthecomfortandsecurityofthepassingvehicle，butalsothreatensthesafetyofthebridgeandshortenstheservicelifeofthebridge．Thisstudyaimstoanalyzehowtheprestresslossaffectlong－termdeflectionof

5、large－spancontinuousgirderbridge，theresearchconclusionsmaybethetheorybasisfortakingeffectivemeasurestocontrolthecontinuousdown－warpinginthedesign，constructionandreinforcementforlarge－spanprestressedconcretecontinuousgirderbridgeacross．Ｒesearchconclusions:Thed

6、eflectionoflarge－spanprestressedconcretecontinuousgirderbridgesislong－termgrowth，anditsgrowthrateisuncertain．Themid－spandeflectionincreaseswiththespanlength，thegrowthratehasacloserelationshipwiththespanlengthandprestresslossdegree，andtheprestresslosseffectism

7、oreobviouswhenbridgespanlengthisgreater．Theprestresslossoftopdeckhasmoreeffectonmid－spandeflectionthanthatofbottomslab．Thecreepandshrinkageofconcreteandtheprestresslosscausedbythesearethemainreasonofmid－spandeflectionlarge－spanprestressedconcretecontinuousgir

8、derbridges．Thisresearchresultscanbeappliedtooptimizationdesignandconstructionforlarge－spanprestressedconcretecontinuousgirderbridges．Keywords:Large－spanprestressedconcretecontinuousgirder