Effect of construction joints on the seismic performance of RC structural walls

Abstract

A survey of earthquake damage in reinforced concrete (RC) structural walls after the 2008 Wenchuan Earthquake in China showed unexpected phenomena at the location of a construction joint at the base of the wall, suggesting that the construction joint has an impact on the seismic performance. In this study, the test of six medium-scale RC wall specimens (height-to-length aspect ratio 2.1) with and without construction joints at the footing-wall interface were implemented under the pseudo-static reversed cyclic lateral loading, and the failure process, hysteretic response, and energy dissipation capacity were investigated. It showed that wall specimens without a construction joint exhibited better seismic performance than comparable specimens with a construction joint, mainly reflected by a higher lateral load capacity, better energy dissipation capacity, and longer plastic hinge length. A numerical model was developed using the multiple-vertical-line-element-model (MVLEM) to simulate the response of RC walls with construction joints, and walls with different axial load ratios and boundary element reinforcement ratios were studied. Results indicated that the presence of a construction joint reduces the lateral load capacity of RC wall. The influence of construction joint on the lateral load capacity is more obvious when the boundary element reinforcement ratio and axial load ratio are both low. These results show that the presence of construction joints should be considered to accurately predict the response of RC walls subjected to seismic loading conditions.