Out-of-Plane lateral load capacity of unreinforced masonry walls

ABSTRACT This study tests two full-scale unreinforced masonry (URM) walls under constant axial stress and cyclic out-of-plane lateral loads and proposes mathematical models to predict their rocking and toe crushingstrengths based on the elasticity and plasticity theorems of concrete. The two specimens were designed to simulate a non-perforated URM wall without opening and a URM wall with a door opening. Parallel walls with a length of 590 mm and thickness of 190 mm were constructed at the both ends of the walls in the out-of-plane direction, producing a barbell-shaped section. Test results showed that the URM wall specimens were initially governed by the rocking rotation and then ultimately failed with compressive toe crushing. The value of the equivalent damping coefficient mostly remained constant up to the occurrence of rocking rotation, beyond which it gradually increased. The effect of a door opening on the out-of-plane seismic response of the URM wall was insignificant because the applied lateral loads were resisted mainly by the in-plane action of the auxiliary parallel walls. The proposed models accurately estimated the rocking and toe crushing strengths of URM walls under out-of-plane lateral loads.