Experimental and numerical study on seismic performance of steel reinforced concrete spatial frame with irregular section columns

Abstract In order to research the seismic performance of steel reinforced concrete (SRC) spatial frame with irregular section columns, a 1/4 scaled model of two-bay and five-story spatial frame was constructed and tested under low cyclic reversed loading. The failure pattern, hysteresis curves, ductility, drift angle, stiffness degradation, strength degradation and energy dissipation capacity were analyzed. The results showed that the plastic hinges firstly appeared at the end of beams, which obeyed the design principle of “strong-column weak-beam”. The hysteresis curves were plump, indicating that the spatial frame had excellent energy dissipation capacity, but pinched at the later loading stage. The strength degradation coefficients and displacement ductility coefficients were larger than 0.8 and 4.0, respectively, and the ultimate drift angle reached 1/19, showing that the spatial frame had stable bearing capacity, good ductility and strong ability to collapse resistance. Based on the test, finite element analysis software OpenSees was employed to evaluate the seismic performance of the spatial frame and the influence of loading direction, axial compression ratio and length-width ratio of column limb was analyzed. The research results can provide reference for the application of SRC frame with irregular section columns in earthquake fortification zone.