Out‐of‐Plane Dynamic Stability of Unreinforced Masonry Walls in One‐Way Bending: Parametric Study and Assessment Guidelines

A numerical rigid body model for the out‐of‐plane response of unreinforced masonry (URM) walls connected to flexible diaphragms is validated against the shake table test results presented in a companion paper. It is demonstrated that the model is able to reproduce the observed rocking behavior with reasonable accuracy, particularly the intensity of shaking resulting in collapse of the walls. The validated model is used to undertake a parametric study investigating the effects of numerous parameters on out‐of‐plane wall stability. Ground motion variability is accounted for by using a large suite of motions. Based on the results of the modeling, an updated out‐of‐plane assessment procedure is proposed. The procedure, which could be incorporated into ASCE 41, provides reference curves of h / t versus S a (1.0), along with correction factors for axial load, wall thickness, ground‐level walls, and exposure.