Study On Interstory Collapse-prevention Mechanism Of Crimping PEC Column(Weak Axis)-reduced-section Steel Beam Composite Frame

PEC column is a new type of partially encased concrete composite column that fabricated with thin-wall composite section with transverse links.The relevant research showed that PEC column has high strength and lateral stiffness, and sound energy ductility; PEC column- steel beam joint has simple details construction; while crimping PEC column can decrease 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(weak axis)—reduced-section steel beam composite frame with end plates and pretension high-strength penetrating bolts connection were taken as subject. According to the loading capacity of test insctions in the lab, the specimen with 1:2 scale was designed and the quasi-static 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 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 vertical load.The results indicated that the specimen processed high strength and initial lateral-resisting stiffness; PEC columns have a powerful stiffness and inter-story shear was sustained by PEC columns evenly; through-out bolts exhibited partial self-centering functions to 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(1/20) of maximum considered earthquake for structure, correspondingly the specimen owns soundly collapse prevention capacity. The research provided theoretical references for further study and application.