Seismic performance of tubular structures with buckling restrained braces

In this study 36- and 72-story framed and braced tubular structures were designed according to the current design code and their seismic performances were evaluated by nonlinear static and dynamic analysis. According to the analysis results, the tubular structures generally showed high earthquake-resisting capability. The framed tube structure showed lowest stiffness and strength compared with the other model structures. The braced tube structures showed larger strength but lower overall ductility compared with framed tube structures. When bucklingrestrained braces were used instead of conventional braces, strength increased signifi cantly compared with the framed tube, and ductility was enhanced compared with braced tube structures. As the load-displacement relationship estimated by static pushover analysis formed the lower bound of the dynamic analysis results, the response modifi cation factors obtained based on the static pushover curve may safely be used for seismic design.