Seismic Behavior Of Innovative Crimping PEC Column-steel Beam Composite Frame With End Plate-penetrating Bolts Connection

Innovative Crimping Partially Encased Concrete(PEC)Composite Column is a new composite member fabricated by crimping thin-walled built-up sections.Compared with general PEC column,the crimping thin-walled built-up section increases the restraint of concrete to better meets the requirement of bidirectional equal flexural stiffness.The previous research achievements just studied on seismic performance of member,joint connection and inter-storey substructure with PEC column.But the research on seismic mechanism of PEC column-steel beam composite frame structural system is vacancy,so it is mainly study on the structural system in this article.The test specimen of one bay,two storey composite frame composed of innovative crimping PEC column-steel beam with end-plate-prestressed penetrating bolts connection was taken as subject in this article.Considering the loading capacity of the laboratory,a 1:2 scale test specimen conducted under lateral cyclic reversed loading to study its seismic mechanism was designed and fabricated.Meanwhile,the software ABAQUS was adopted to simulate its seismic performance under lateral cyclic reversed loading.Comparing the results of simulate with the results of the experiment to analyze the rationality of the finite model.The axial force is applied to the model to further analyze the influence of axial force on the structure.The results show that the specimen has high load-carrying capacity and large initial lateral stiffness,and the difference of the initial lateral stiffness of inter-story is obvious,but it decreases with damage process due to loading;58% of lateral shear of first story was sustained by PEC column at compression side with overturning moment while lateral shear of second story was sustained by PEC columns evenly,and the deformation mode of inter-story induced by shearing;energy dissipation capacity is mainly provided by steel yielding and concrete crushing at bottom of PEC column and yielding of steel beam adjacent to end-plate and it is evenly distributed along the height of the specimen;the connection owns good rational capacity and force-transfer mode of concrete equivalent strut in panel zone and self-centering function of connection were achieved due to pre-tension penetrating bolts;the failure mode of specimen is induced by the formation of plastic hinge at cross-section of steel beam adjacent to the plate and the root of PEC column;the corresponding inter-storey drift and connection rotation angles all surpassed the inter-story drift limit(1/30)at maximum consideration earthquake level,hence the specimen owns superior seismic ductility;The vertical force parameter enhanced the initial lateral stiffness of the specimen,but its second-order effect accelerated the yield damage process of specimen led to its ultimate loading-capacity reduction.Research results will further enrich the research achievements of PEC column,also provides the theory support for later research and engineering application.