Comparative Seismic Performance Assessment of Reinforced Concrete Frame Structures with and without Structural Enhancements Using the FEMA P-58 Methodology

Abstract

Adding energy dissipation devices to reinforced concrete (RC) frame structures is a commonly adopted structural enhancement in seismically active regions. In this paper, a state-of-the-art seismic performance assessment is applied to a typical fixed-base RC frame structure designed based on the current Chinese code. Two additional structural enhancements, including equipping buckling restrained braces (BRB) and designing as a base-isolated structure, are investigated. Nonlinear response history analyses were performed to assess the structural performance parameters under four different seismic hazard levels (i.e., frequently occurring earthquake, design level earthquake, maximum considered earthquake, and very rare earthquake). The seismic performance is quantified in terms of repair times, repair costs, and casualties. The intensity-based assessment method is used, and a comparative analysis is performed for each performance measure. The results show that a base-isolated structure and BRB frame structure can each effectively reduce the repair cost and repair time compared with a fixed-base frame, as the repair mostly come from nonstructural components. In addition, the casualties in the base-isolated structure are the lowest of the three structures. It should be noted that the acceleration response of the BRB frame structure is the largest among the three structures, and that its acceleration-sensitive components are seriously damaged, causing the most casualties.