Evaluation of Crack Spacing in Reinforced Concrete Shear Walls

Abstract

Cracking is a very common phenomenon in reinforced concrete (RC) members, dramatically affecting the members’ properties, such as stiffness, deformation capacity, and permeability. However, cracks develop randomly, making their simulation difficult, especially under combined loading conditions. Using numerical simulation results, the width of a crack can be estimated by integrating the cracking strain, along the crack spacing. Cracking strain can be obtained from a finite element analysis with the well-known smeared crack approach. To use such an approach, however, a reliable simulation of the crack spacing is needed. In this paper, a method is proposed to predict the average crack spacing occurring in RC shear walls subjected to lateral demands. The method extends earlier work, which is based on both a strength and fracture energy criteria. The extension allows the method to be applied to RC members under a plane stress condition with orthogonally placed reinforcement. Eleven low aspect ratio RC shearwall specimens from three experimental data sets subjected to 49 different lateral demand levels are extracted from the literature and used to validate the model. From these data sets, a formula to determine the bond strength between the concrete and reinforcing steel is regressed. Evaluation of the model against the experimental data sets indicates that the method can predict the average crack spacing with reasonable accuracy not only in the crack initiation stage, but also in the stabilization stage.