Minimum thickness for ductile RC structural walls

An important issue in seismic design of concrete buildings concerns the stability of structural walls when subjected to intense earthquake ground motions. Large tensile strains, developed as a result of significant yielding in the wall, are a cause for concern since the stability of the wall depends on the magnitude of the tensile strain imposed on the wall. A critical condition exists where excessive out-of-plane displacement may occur upon load reversal prior to crack closure causing the wall to buckle. The potential for instability can be mitigated by requiring a minimum wall thickness to ensure that the in-plane lateral strength can be fully developed in the reversed direction. A methodology for assessing the minimum wall thickness is outlined in this paper and results are presented for a number of parameters including the ground motion intensity, longitudinal reinforcement ratio, floor weight, wall-to-floor area ratio and number of stories. The minimum wall thickness is compared with recommendations in current building codes.