Research On Hysteretic Performance Of A New Mentioned Steel Beam-Column Connection Based On Accordion Effect

The steel frame structure has been used more and more widely in the high-rise building structure. Existing research shows that the steel beam-to-column connection performance directly affects the overall behavior of the frame structure when it is under load action, especially under severe earthquake action. The traditional all welded steel beam-to-column connection with poor ductility and large residual stress is one of the most important reasons of brittle failure. Aseismic optimum design of steel beam-to-column connection and the development of new types of beam-to-column connection is the key to improve the seismic performance of high-rise steel frame structure. A new type of reduced beam section(RBS)connection, “Accordion web RBS(AW-RBS)”, has been proposed in this study. The AW-RBS decrease the web contribution in moment strength and a reduced section is developed in the beam. The off-shoring plastic hinge is formed by making the failure position develop on the beam at the corrugated web zone instead of the beam-to-column joint weld. While the corrugated web could provide sufficient shear strength, its contribution to the moment strength and flexural stiffness are negligible. According to the hysteretic experimental test of the AW-RBS connection and the traditional flat web connection,AW-RBS provides 5% story drift without any significant decrease of strength. The inelastic rotation of the new connection is provided mainly by the reliable and ductile rotation at the reduced region rather than in the connection plate or panel zone. The energy dissipation capacity of new proposed connection is superior than the traditional beam-to-column connection. Based on the experimental study and theoretical analysis, this paper studied the energy dissipation and aseismic mechanism of the AW-RBS connection, which could provide the design theory and experimental basis for designing ductile steel frame structure.The primary research contents are presented as follows:(1) Quasi-static test has been conducted on the specimen AW-RBS all welded connection and traditional flat web all welded connection, respectively. Both of the specimens' deformation history ? failure process and the typical failure mode have been achieved. Some indexes, in terms of deformation capacity, energy dissipation, strength degradation, ductility ratio, accumulated energy dissipation ratio and equivalent viscous damping coefficient are analyzed to appraise the seismic performance of AW-RBS T-joints.The failure mechanism of the new proposed connection and how the location of the corrugated web and its geometric parameters effect the connection's hysteretic behavior has been studied.(2)Verified finite element(FE) model of the specimens is built by using FE software ABAQUS. In the FE model, the steel plates use hardening model to simulate the material properties. Boundary conditions, loading scheme, other aspects are as far as possible consistent with the test and the weld is also considered in the FE model. The validity and accuracy of the FE model for hysteretic analysis is verified by comparing the numerical results with experimental results.(3)Based on the verified FE model, parametric analyses of AW-RBS T-joints under cyclic axial loading are conducted to investigate the influence of geometric,such as a, b, c,beam depth h and beam web thickness W_t on its hysteretic performance.