Seismic Behaviour Factor for Unreinforced Concrete Block Masonry Walls Retrofitted by RC Layers

This paper reports on experimental and numerical investigations of the seismic behaviour of unreinforced concrete block masonry (URCBM) structural walls, externally retrofitted on one, or both sides, by reinforced concrete (RC) layers. The behaviour factor (R) components are extracted from nonlinear static pushover analyses of full-scale masonry walls having different aspect ratios. It is found that R-value of masonry shear wall increases with an increase in the aspect ratio of the wall. Also, application of RC layers to the wall has a profound effect on the behaviour factor, as it directly affects both ductility and ultimate capacity of the wall. Finally, based on findings presented, R-values of 2.0, 2.5 and 3.0 are proposed for URCBM, one-sided and two-sided retrofitted concrete block masonry shear wall construction, respectively.