Seismic Behavior of Beam-Column Sub-assemblages Designed According to Different Evolution Stages of Design Philosophies

Abstract

Over decades, the design philosophy of framed structures had undergone changes from the ordinary gravity load-designed frames to special moment-resisting frames with ductility detailing. Most of the older buildings were designed only for gravity loads. The past earthquakes produced devastating damages to the gravity load-designed structures. This resulted in the remarkable changes in the seismic design philosophy in the form of introducing ductility detailing in the codes of practices. Different codes of practices, namely EURO, ACI, NZ, IS codes, prescribe appropriate detailing practices so as to ensure desired seismic performance. Hence, in the present study, an attempt is made to compare the seismic performance of gravity load designed, seismic load designed without ductility detailing, seismic load designed with ductility detailing which represent the evolution of design philosophies adopted in codes of practices. An exterior beam-column sub-assemblage of typical three-story building is taken up for the study and designed according to the evolution of design philosophies of Indian standard. Experimental investigations are carried out on beam-column sub-assemblages designed according to different evolution stages of design philosophy. The seismic performance of beam-column sub-assemblages of three different design levels, under reverse cyclic loading, is compared in terms of the hysteretic behavior and energy dissipation capacity.