Collapse Mechanism Of Interstory Substructure Of Innovative Crimping PEC Column-steel Beam Composite Frame With Extended End Plate Connections

Partially encased composite(PEC) column is fabricated with H-shape steel section or steel plate composited section with transverse links(for the steel section of non-curling)or steel-plates(for the steel section of curling) and concrete casted between opposing flanges.Up to date, the current researches of PEC column was focus on the member and beam-column joint,and the research on mechanical performance of PEC column—steel beam composite frame structural system is vacancy, consequently studying its seismic performance will be of great theoretical significance and engineering application value.The inter-story substructure of innovative crimping PEC column — steel beam composite frame with end plates-pretension high-strength penetrating bolts connection was selected as subject, the 1:2 scale test specimen was designed and fabricated based on the loading capacity of the instuctions in lab. The test was conducted under lateral low-cycle reversed loading, the hysteretic curves and failure mode were derived. Based on the test results, Analysis obtained including the loading-carrying capacity, lateral stiffness, connection mechanical performance, deformation pattern, force-transfer mechanism of panel zone and failure mode. Meanwhile the software ABAQUS was adopted to simulate the test specimen its mechanical performance to verify the rationality and feasibility of the finite element model, and further analyze the influences of axial force on the behavior of specimen.The results indicated that the specimen processed high strength and initial lateral-resisting stiffness; lateral force was sustained by PEC columns evenly and the drift deformation pattern is shear-type; all joints captured partial self-centering function resulted from pre-tension penetrating bolts and reduce its residual drift; end-plate connection possesses large rotational stiffness and restrainted its rotational capacity; the collapse mechanism formed primarily induced by plastic hinge in cross-section of steel beam adjacent to the plate, and interstory drift and connection rotation both surpassed the interstory drift limit(1/30) of maximum considered earthquake for frame structure,correspondingly the specimen owns soundly ductility and collapse prevention capacity.Research results will further enrich the research achievements of PEC column, also provides the theory support for later research and engineering application.