Effect of Ductile Shear Wall Ratio and Cross-Section Configuration on Seismic Behavior of Reinforced Concrete Masonry Shear Wall Buildings

Reinforced masonry buildings typically have a load-bearing wall structural system. Thus, the reinforced masonry shear walls must be capable of resisting both vertical forces from gravity loads and lateral forces from seismic and wind loads. Typically, because the walls are subjected to high axial loads, ensuring the ductile response becomes challenging. A possible solution at the component level would be the utilization of walls with confined ends (i.e., walls with boundary elements) to reduce the compression zone and increase the compression strain. Another solution, which is at the system level, is the introduction of a hybrid structural system composed of two types of walls: (1) ductile walls with or without boundary elements to resist the lateral forces and part of vertical forces, and (2) gravity walls that resist only axial loads. This paper proposes a combination of both solutions (i.e., at component and system levels). Additionally, it utilizes a series of linear and nonlinear static and dynamic analyses to evaluate and quantify the effect of cross-section configuration and ductile shear wall area to total floor area (i.e., ductile shear wall ratio) on the seismic response of masonry buildings. The numerical analyses are performed by a macro model detailed to simulate the nonlinear response. The primary objective is to recommend a range of ductile shear wall ratios that optimize the design and overall performance. The study targets mid-rise and high-rise masonry buildings located in regions with moderate seismic hazard. The findings emphasize that utilizing the ductile walls with boundary elements in the proposed hybrid structural system resulted in major favorable enhancements in the structural response and optimization of the design. In addition, the results demonstrate the possibility of vertically reducing and terminating the specially detailed boundary elements, thus promoting ductile reinforced concrete masonry shear wall buildings as a competitive building system. (C) 2020 American Society of Civil Engineers.