Parameter influences on the out of plane seismic collapse of unreinforced masonry panels

This paper presents the results of dynamic analysis applied to cracked rectangular unreinforced masonry panels which are restrained at two or four edges by beams or columns. The method of dynamic analysis treats each panel as an assembly of rigid sub-panels free to rotate at crack interfaces and takes into account progressive crushing at interface corners. The object of the analysis is to evaluate a collapse loading. The influence of a range of parameters is considered including panel geometry, strength and elastic properties of the masonry, the existence of cracks of finite width prior to ground shaking, progressive spalling of mortar joints and possible defective workmanship at the top mortar joint.