Analysis of the out-of-plane capacity of unreinforced masonry infill walls

Abstract

To determine the out-of-plane capacity of unreinforced masonry (URM) infill walls, simplified methods from design codes are used in most practical applications. The estimations of these simplified methods are very inaccurate since essential parameters are neglected. To realistically determine the out-of-plane capacity, parameters like geometry, restraints, vertical loads and dynamic effects need to be considered. In the present work a nonlinear time-history analysis which takes those important parameters into account is presented. Real earthquake time histories are applied and increased until collapse of the wall. To investigate the influence of the considered parameters, geometry, axial load and restraint stiffness are varied in the analysis. Collapse strength and the corresponding maximum accelerations are compared with commonly used design methods. The comparison shows that the out-of-plane capacity of URM infill walls is usually much higher than the capacity estimated by simplified design models.