Out-of-Plane Performance of Reinforced Masonry Shear Walls Constructed with Boundary Elements

Reinforced masonry shear walls with boundary elements have been introduced recently as a seismic force–resisting system as alternative to traditional reinforced masonry shear walls with rectangular cross sections. The introduction of the boundary elements enhances the wall’s in-plane performance because of the confinement action of the horizontal steel ties within the boundary elements that increase the compressive strain capacity and thus improve the overall wall displacement ductility. However, the performance of such reinforced masonry shear wall system has not yet been well investigated experimentally or analytically under out-of-plane loading (e.g., blast loads). Therefore, this study evaluated the contribution of boundary elements to the wall out-of-plane performance in terms of enhanced ultimate resistance load and displacement capacities. Three reinforced masonry shear walls with boundary elements, with different reinforcement ratios and distributions, were tested under quasi-static loading to evaluate the wall displacement response, mode of failure, damage state, ductility capacity, and energy absorption. Furthermore, a numerical model was developed and used to generate additional results of walls with similar in-plane or out-of-plane load resistance to those tested experimentally, but with rectangular cross sections, to allow for a performance comparison. The results showed that reinforced masonry shear walls with boundary elements achieved higher ductility capacity and energy absorption levels compared to their counterparts with rectangular cross sections. This study presents key experimental and numerical data that will facilitate quantifying several aspects pertaining to the out-of-plane performance of reinforced masonry shear walls with boundary elements within the next editions of relevant North American codes and standards.