Effects of building scale on collapse mechanism and story drift for low and middle-rise steel moment frames

This paper presented an analytical study on elasto-plastic seismic response of low and middle-rise steel moment frames composed of square steel tubular columns and H-shaped steel beams under horizontal bi-directional excitation. The analysis assumed three-dimensional frame considering realistic structural behavior such as deterioration after maximum strength. Based on the analysis results, how to address the issues in current seismic design in Japan, where plane frame under uni-directional load has been generally assumed, is proposed.