Seismic Strengthening of R/C Buildings Retrofitted by New Window-Type System Using Non-Buckling Slit Dampers Examined via Pseudo-Dynamic Testing and Nonlinear Dynamic Analysis

Abstract

In the present study, a window-type seismic control system (WSCS) using non-buckling slit dampers (NBSDs) was proposed and developed to address the disadvantages of conventional seismic control systems so that it can be effectively applied to existing reinforced concrete (RC) buildings. Materials testing was also conducted to examine the material performance and energy dissipation capacity of NBSD. A full-scale two-story test frame modeled from existing RC buildings with non-seismic details was subjected to pseudo-dynamic testing. As a result, the effect of NBSD-WSCS, when applied to existing RC frames, was examined and verified, especially as to its seismic retrofitting performance. In addition, based on material testing and pseudo-dynamic test results, a restoring force characteristics model was proposed to implement the nonlinear dynamic analysis of a test building retrofitted with NBSD-WSCS. Based on the proposed restoring force characteristics, nonlinear dynamic analysis was conducted, and the results were compared with those obtained by the pseudo-dynamic tests. Finally, in an attempt to commercialize this NBSD-based WSCS, nonlinear dynamic analysis was conducted on the entire RC building with non-seismic details retrofitted with NBSD-WSCS. The results showed that the RC frame (building) with no reinforcement applied underwent shear failure at seismic intensity of 200 cm/s(2), a typical threshold applied in seismic design in Korea. In contrast, in the frame (building) retrofitted with NBSD-WSCS, only minor earthquake damage was expected, and even when the seismic intensity was set to 300 cm/s(2), the maximum intensity that had been observed in Korea, only small or moderate seismic damage was expected. These results confirmed the effectiveness of the seismic retrofitting method using NBSD-WSCS developed in the present study.