Conventional braced frame systems have limited drift capacity prior to brace buckling and related damage leads to deterioration in strength and stiffness. Rocking braced frame systems increase the drift capacity; however, significant higher mode effects and local yielding may result from column uplift. A friction-damped braced frame (FDBF) system with buckling-restrained columns (FDBF-BRC) is being developed to provide significant drift capacity while limiting damage and residual drift without column uplift. The FDBF-BRC system consists of beams, columns, and braces branching off a central column, and buckling restrained columns (BRCs) are incorporated into the system in the first story. The BRCs and friction generated at lateral-load bearings are used to dissipate energy to minimize the overall seismic response of the FDBF-BRC system. Vertically aligned post-tensioning bars provide additional overturning moment resistance and aid in self-centering the system to eliminate residual drift. In this study, a suite of 44 DBE-level ground motions used in FEMA P695 is numerically applied to several FDBF-BRCs to demonstrate the seismic performance of the system. The results show that the FDBF-BRC system has high ductility and energy dissipation capacity, and is an effective seismic resistant system.
展开▼
