Residual seismic performance of damaged reinforced concrete walls

Structural engineers face a dilemma in assessing the residual seismic capacity of damaged buildings after an earthquake, especially for buildings with lightly to moderately damaged elements that might not need repair but require to be assessed for their performance in aftershocks and future major earthquakes. The main purpose of this paper is to investigate the influence of pre-damage levels on residual seismic capacity of reinforced concrete (RC) wall tests, by conducting quasi-static, cyclic loading tests of reinforced concrete shear walls. A comparison of the reduction in stiffness, deformation capacity, and strength to existing guidelines regarding residual seismic evaluation is investigated. This study presents experimental results of eleven 1/4 scaled RC wall tests that were divided into three series based on the wall reinforcement ratio and the shape of the wall boundary elements. Within each series, the effect of four levels of initial damage on the wall performance was investigated. The specimens were designed to fail in shear to represent the shear walls in Onagawa nuclear power plant buildings in Japan. The results showed that no significant deterioration in ultimate strength and maximum deformation capacity due to slight to severe previous damage. RC walls with flange boundary elements had relatively greater stiffness degradation due to prior damage than walls with boundary columns.