Seismic Behavior of a 3D Full-Scale Steel-Concrete Composite Moment Resisting Frame Structure

Abstract

This paper shows the feasibility of composite MR frame structures with partially encased columns and partial strength beam-to-column joints to provide strength and ductility. In detail, energy dissipation is concentrated both in column web panels which are not surrounded by concrete and in composite beam-to-column connections. A full-scale two-storey composite building was used to validate the system performance of composite MR frames with partial strength joints. The frame structure was subjected to pseudo-dynamic tests in order to simulate the structural response under ground motions. The ground motion for 10 % chance of exceedence in 10 years earthquake hazard caused minor damage while the one for 2 % chance of exceedence in 10 years earthquake hazard entailed column web panel yielding, connection yielding and plastic hinging at column base joints. An earthquake level chosen to approach the collapse limit state induced more damage and was accompanied by further column web panel yielding, connection yielding and inelastic phenomena at column base joints without local buckling. Successively, the structure was subjected to a final quasi-static cyclic test with interstory drift ratios over 4.6 %. Moreover, test offered additional opportunities to validate the performance of simulation FE models. Exploiting inelastic static pushover and time-history analysis procedures, behavior factors, design overstrength factors and the ductility demand of the structure were estimated.