ULTIMATE DRIFT RATIO OF NON-DUCTILE COUPLING BEAMS

摘要

Seismic performance of coupling beams designed according to non-seismic provisions is examined. Coupling beam specimens in 1/4 scale were tested under cycles of end shear. Characteristics of the specimens include high main reinforcement ratio, about 3-4%, and large spacing of links with 90-degree hooks. Based on the test data, 140mm is recommended to be the optimal spacing of links. Furthermore, coupling beams must not be heavily reinforced. Since this would lead to substantial reduction in the displacement ductility and ultimate drift ratio. Finally, an empirical relationship is proposed to estimate the ultimate drift ratio of non-ductile coupling beams.