Measured inelastic response of reinforced masonry building structures to earthquake motions

Experiments were performed to study the dynamic response of reinforced concrete masonry building structures. Two reduced-scale reinforced masonry perforated shear wall structures were subjected to simulated earthquake motions on a shaking table. A third was tested using conventional static methods to provide insight into differences in behavior of systems that are subjected to artificial static forces and those allowed to develop natural inertial forces.

Experimental data were studied to determine trends in nonlinear dynamic response and to evaluate current practice for seismic design and analysis. Common linear models for assessing lateral drift and distribution of story shear among vertical elements were found to be inadequate for response in the nonlinear range. Analysis of measured response identified simplified procedures for evaluating lateral strength and seismic drift of reinforced masonry structures. It was suggested that sufficient lateral strength could be provided in the piers of a perforated wall structure by placement of minimum amounts of vertical reinforcement and selection of horizontal reinforcement by a capacity design approach. The use of a substitute linear method was suggested for assessing the stiffness (based on lateral drift) of a trial structural configuration. A simple, single-degree-of-freedom nonlinear analysis was suggested for use in evaluating the nonlinear displacement response of a trial configuration.