Study on seismic behavior of widened beam flange connections of steel frame

Based on the experiments of four widened beam flange connection specimens and one traditional joint specimen under low period cyclic loading,failure forms and seismic behavior of direct arc widened beam flange connections and welded side-plate connections were studied by ANSYS software,such as load-displacement hysteretic curve,skeleton curve,ultimate load,ductility and energy dissipation factor etc.The comparability between the results from the analyses and those from the experiments is satisfactory.Results of the research show that through properly designing the section of widened flange,the plastic hinge of beams can be effectively moved outward from welded connection area in both arc widened beam flange connections and welded side-plate connections,and the two kinds of widened flange beam connections have better ductility,bearing capacity and energy dissipation capacity than the traditional connection and may satisfy the demand from current Chinese seismic design code.In addition,because the arc widened beam flange connections have simpler conformation and fewer welds at the section of widened beam flange,which avoid brittle rapture due to the materials becoming brittle in the weld heat-affecting zone,they have better seismic property than the welded side-plate connections.