System-Level Seismic Performance Assessment of an Asymmetrical Reinforced Concrete Block Shear Wall Building

In this study, a two-story reinforced concrete block scaled building was tested to failure under fully reversed quasi-static displacement-controlled loading. The building’s seismic force-resisting system (SFRS) consisted of eight structural walls in total, with four walls, aligned along the loading direction, placed asymmetrically to result in a center of rigidity eccentricity from the floor center of mass of approximately 20% of the building width, evaluated on the basis of elastic analysis. The other four orthogonal walls were placed symmetrically around the building floor center of mass to provide torsional restraints to the building. As such, the focus of the paper is on evaluating the influence of twist as a system-level aspect on the ductility capacity of the building and the ductility and strength demands of its wall components. This paper presents the details of the building SFRS and wall configurations and characteristics and the main test observations and results. This is followed by analyses of the experimental results that showed that, at the system level, each wall would be subjected to significantly different displacement/strength demands throughout the building’s loading history. These different demand levels are functions of the interaction between the system-level twist response and the resulting displacement demands imposed on each wall component and the subsequent load redistribution following different component damage. The study showed that the variation in the inelastic response characteristics of the different walls comprising the building’s SFRS and wall strength contributions to the overall building capacity and the subsequently mobilized ductility levels are all factors that should be considered when evaluating the overall building SFRS performance.