Collapse Mechanism Of Interstory Substructure Of Innovative Crimping PEC Column-reduced-section Steel Beam Composite Frame With End Plate Connections

PEC column(partially encased concrete composite column) is fabricated by thin-wall composite section with transverse links and concrete is cased between flange and web.The current research indicated that PEC column has high strength and lateral stiffness, and sound energy ductility; PEC column-steel beam joint has simple details for easy construction; while crimping PEC column can reduce unequality of biaxial stiffness and construction difficulty. Up to date, the research on the seismic performance of structural system has not found, so the study on collapse prevention mechanism of the PEC column-steel beam composite frame structure will be of great theoretical significance and engineering practice prospects.To systematic investigate on seismic performance of the PEC column-steel beam composite frame structure, the test specimen of inter-story substructure of crimping PEC column-reduced-section steel beam composite frame with end plates and pretension high-strength penetrating bolts connection was selected as research subject.According to the loading capacity of test insctions in the lab, the specimen with 1:2scale was designed and cyclic lateal loading test was conducted, the hysteretic curves and failure mode were derived. Based on the test results, the specimen’s performance were analyzed, including the loading-carrying capacity, degradation of lateral stiffness,connection mechanical performance, ductility and energy dissipation capacity, drift deformation pattern and failure mode. Meanwhile, the finite element software ABAQUS was adopted to simulate the test specimen and validate its feasibility, and further analyzed on the influence of relevant design parameters.The results indicated that the specimen processed high strength and initial lateral-resisting stiffness; PEC columns have a strong stiffness and inter-story shear was sustained by PEC columns evenly; through-out bolts exhibited partial self-centering functions and effectively realize the force-transfer mechanism of concrete equivalent strut in the panel zone; reduced-section steel beam can mkes the plastic hinge location away from the joint and provided soundly energy-dissipation capacity; the collapse mechanism formed primarily induced by plastic hinge in reduced cross-section of steel beam, and the specimen still owned high strength even when the drift surpassed the interstory drift limit(1/30) of maximum considered earthquake for structure,correspondingly the specimen owns soundly collapse prevention capacity. The research provided theoretical references for further study and application.