Failure modes of reinforced concrete walls under cyclic loading: Experimental study and prediction method

Abstract

Failure mode identification and prediction of RC walls are of critical importance for seismic strengthening of existing members and target quantification of performance-based seismic design. This paper aims to better understand the failure modes of RC walls under cyclic loading. Firstly, cyclic test was conducted to examine the effect of reinforcement strength (fy = 476 MPa vs 641 MPa), axial load ratio (0.1 vs 0.2), and shear demand to capacity ratio (Vf/vs = 0.38 vs 1.25) on the failure modes of RC walls. Then, the existing experimental data of 168 wall specimens was collected, and the statistical analyses were carried out to obtain the critical parameters for different failure modes, which were used to establish the prediction method for failure modes. Finally, the accuracy of the prediction method was evaluated by the experimental data. The study results show that the larger axial load can both increase the likelihood of concrete crushing as well as various out of plane buckling modes; shear demand to capacity ratio is a critical parameter to affect the failure process and mode of RC walls. The statistical analyses show that when shear span ratio (λ) ≥ 2.7 and Vf/vs ≤ 0.60, the wall specimens fail in flexure; when Vf/vs ≥ 1, or λ ≤ 1.1 and Vf/vs ≥ 0.80, the wall specimens fail in shear, and the wall specimens not within the above ranges fail in flexure-shear mode. The evaluation results show that the prediction method has a reasonable accuracy.