Experimental Assessment of the In-plane Cyclic Response of Flanged Partially Grouted Reinforced Masonry Shear Walls Failing in Flexure

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Despite the economic benefits of partially grouted reinforced masonry shear wall (PG-RMSW) systems in low-rise buildings, using such a system in mid- and high-rise buildings is still questionable. This is because the literature lacks comprehensive studies investigating different seismic design provisions adopted for PG-RMSWs failing in flexure in the North American masonry design standards (i.e., TMS 402/602-22 and CSA S304-14) to design rectangular and flanged PG-RMSWs. Most of the conducted studies targeted fully grouted reinforced masonry shear walls (FG-RMSWs). They were then adopted for PG-RMSWs with some modifications and conservatism that do not always reflect the actual case. Accordingly, this study aims to experimentally explore and quantify the influence of increasing the shear span-to-depth ratio (M/(Q×dv)) on the in-plane cyclic response of flanged PG-RMSWs made with concrete masonry units and failing in flexure. In this regard, two flanged PG-RMSWs with similar cross-section dimensions and details of reinforcement and different shear span-to-depth ratios (2.54 and 5.08) designed to fail in flexure were tested under a constant axial load, quasistatic cyclic displacement and cyclic top moment. It can be shown that increasing M/(Q×dv) for flanged PG-RMSWs can result in an overall enhanced behavior compared with those with lower M/(Q×dv). In particular, it results in the enhancement of the behavior of the tested walls in terms of propagation of damage, displacement ductility, stiffness degradation, axial compressive strain, curvature, flexural and shear contribution in displacement, and finally, energy dissipation and hysteretic damping. This shall contribute to the supporting evidence that PG-RMSWs can perform well in mid- and high-rise buildings. Furthermore, this allows for the modification of clause 16.8.5.2 in CSA S304-14 to allow partial grouting of plastic hinges of PG-RMSWs of high shear span-to-depth ratio (M/(Q×dv)).