Structural and Nonstructural Performance Evaluation of Self-Centering, Concentrically Braced Frames under Seismic Loading

Self-centering, concentrically braced frame (SC-CBF) systems have higher drift capacity than conventional CBF systems prior to damage. To fully demonstrate the effectiveness of SC-CBF systems, a comparison study is performed considering both structural and nonstructural seismic performance. First, two prototype buildings are designed with the same configuration, but different lateral load resisting systems (CBF or SC-CBF exclusively). Nonlinear dynamic analysis is conducted using finite element numerical modeling to obtain seismic responses under a suite of earthquake records with various hazard levels. The numerical results are then utilized to build probabilistic demand models of inter-story drift, floor acceleration, and roof acceleration. Finally, fragility curves for structural and nonstructural components are generated for various performance levels with demands and capacities. The comparison of the fragilities of the two structural systems reveals that the SC-CBF has better seismic performance than the conventional CBF; however, nonstructural components must be designed for higher force demands in the SC-CBF.