Performance based seismic design of steel braced frame system with self-centering friction damping brace

摘要

This paper presents a displacement-based seismic design methodology for steel concentrically braced frame (CBF) systems with a special type of bracing element termed self-centering friction damping brace (SFDB). The SFDB is a passive energy dissipation device with its core re-centering component made of stranded superelastic Nitinol wires while enhanced energy dissipation mechanism of the SFDB is achieved through friction. Compared with conventional braces for steel frame buildings, SFDB frame has a few desirable performance characteristics such as minimal residual drifts and its ability to withstand several design basis earthquakes without the need for brace replacement. A displacement-based design procedure for proportioning SFDB is proposed in this paper. A 3-story design example is presented to illustrate the design method. Nonlinear pushover and time history analysis of the 3-story CBF building is performed to validate the effectiveness of the proposed design method. The results of the nonlinear time history and pushover analysis show that with careful design the SFDB frame can achieve a seismic response level comparable to that of the BRB frame while having significantly reduced residual drifts. The SFDB thus has a potential to establish a new type of CBF systems with self-centering capability.