The Study Of Bridge Safety Based On Static Load Test

Bridges as transportation bub,have bccame the tie to economic development for everyarea. It plays an important role in economy’s rapid increases.In China,there are a largenumbers of bridges having entered“aged”stage.Although these bridges have appeared tovarious diseases, they still insisted on working with problems.According to the ChineseMinistry of Communication making the quantitative statisical for the dangerous bridges:thenumbers of dangerous bridges have a tendency to increase in China.So,no matter the bridgeis newly bulit or on building,a part of them face the necessary security research that canensure the structure of bridge keeping safety operation.This paper selects for bonded prestressed concrete test T-beam that is Xiaogeliao Bridgeof Xingfen high speed right amplitude Number3-4and bonded prestressed concrete testbox beam that is Shahe Bridge of Xingfen high speed left amplitude Number33-2carryingout three cycles(three cycles control load including: the load with craking condition、theload with serviceability limit state and the load with ultimate bearing capacitycondition)localized loading at the middle of span,and measures and analyzes thedeflection、residual displacement、strain、stress、cracking condition and cracking widthduring three cycles step loading,in order to evaluate the security for the bridge.At the same,by virtue of the test of bonded prestressed concrete T-beam, this paper not only analyzes theprestressed loss of bonded prestressed concrete,but also studies on undertaking proportionthat transfer to concrete both the anchorage、 the bund force between the prestressedreinforcement and grouting during step loading.The result of studying and analyzing shows:the crack resistance can meet normativerequirements at the condition of craking condition,the stiffness、the crack width can meetnormative requirements at the condition of serviceability limit state and the strength canmeet normative requirements at the condition of tultimate bearing capacitycondition.Namely the safety of design for prestressed concrete T-beam and prestressedconcrete box beam can be guaranteed; calculation formula of the prestressed loss of curvebonded prestressed concrete is1.52times of measured value in Highway reinforce concreteAnd Prestressed concrete bridge Design Code（JTG D62-2004）;the prestressed in bondedprestressed concrete transfers to concrete mainly based on the bund force between theprestressed reinforcement and grouting,and the part of the anchorage transfers to concretecan be neglectable; under repeated load,if ensure the reliable grouting,then the fatiguedamage of the prestressed reinforcement at anchorage section could not happen.