In-plane cyclic response of high-rise reinforced concrete masonry structural walls with boundary elements

Abstract

The majority of tested Reinforced Concrete Masonry (RCM) shear walls with boundary elements represented walls in low- to mid-rise buildings. In addition, these tested walls had continuous vertical reinforcement with no lap splices, which is impractical in multi-story masonry buildings. Therefore, this study aims to evaluate the structural performance of high-rise RCM structural walls with boundary elements under reversed cyclic loading simulating seismic actions. This is achieved by constructing and testing four half-scale fully grouted RCM shear walls with boundary elements under constant axial load and quasi-static reversed cyclic loading. The walls were designed and constructed with similar geometry and material properties and were tested under the same level of axial compressive stress. The studied parameters are the wall’s shear span-to-depth ratio, the type of boundary elements’ masonry blocks (stretcher or C-shaped), and the lap splicing of vertical reinforcement in the plastic hinge region. The objective is to quantify the cyclic response of ductile RCM shear walls and to provide experimental evidence of its reliable structural performance for higher aspect ratios. Furthermore, the present study investigates the impact of the presence of lap splices in the plastic hinge region on the ductile response of high-rise RCM walls with boundary elements. The tested walls had an enhanced cyclic response due to its end zone confinement. The testing results demonstrated that the shear span significantly influences the distribution and layout of cracks, the lateral stiffness and resistance, and the post-peak response. Using the C-shaped blocks instead of the regular stretcher blocks in constructing the boundary elements enhanced the construction and performance of the walls. Lap splicing of vertical rebars increased the initial lateral stiffness, resulted in a higher rate of stiffness and strength degradation, and slightly limited the ultimate displacement ductility. However, with proper detailing of the splice and confinement of the end zones, the premature tensile bond failure was prevented.