Durability Test Research And Time-dependent Reliability Analysis Of Steel-concrete Composite Beams

Abstract:Steel-concrete composite beam has the advantages of both steel structure and concrete structure, and it would have vast application prospect. However, we emphasize the security and applicability but ignore the durability of structure in structure design. And this would make the structure failure before its service deadline, and lead to a grate economic loss.This article aim at the problems in studying the durability of steel-concrete composite beam,analyse the mechanical performance degradation rule of corroded steel-concrete composite beam by artificial climate accelerated corrosion test.The time-dependent reliability as well as endurance life is also studied in the article.The main contents include:(1) Study the mechanical performance degradation rule of corroded bolt by dry and wet cycles accelerated corrosion test,and build its strength degradation model and constitutive relation model,depend on which the computational formula of bolt’s shear bearing capacity design value is revised.(2) Through dry and wet cycles accelerated corrosion test,this article study the mechanical performance change rule of push-out specimens after their bolts are rusting.The change rules of push-out specimens’failure mode,ultimate bearing capacity,slipslip,stiffness and ductility are analysed.(3) By dry and wet cycles accelerated corrosion test,study the change rules of corroded steel-concrete composite beams’ultimate bearing capacity,cross section strain,slipslip,stiffness and ductility.The flexural capacity computational formula of partial shear connection steel-concrete composite beam whose bolts are rusting is built through bringing in k(p),which means the decreasing coefficient of shear connection degree.The formula proves to be practical by comparing the experiment values and the theoretical calculation results.(4) Considering the steel beam’s corrosion,concrete performance degradation and the decrease of shear connection degree caused by bolts’corrosion,build the resistance time-varying model of steel-concrete composite beam, put forward the analysis method on time-dependent reliability and endurance life of steel-concrete composite beam.This article also calculates the ttime-dependent reliability index, as well as the endurance life of a highway simply-supported steel-concrete composite beam,and analyses the influence factors of its reliability.