Experimental evaluation of the lateral load behavior of squat structural walls

Abstract

This experimental study investigates the lateral load and deformation capacity of low-rise (squat) reinforced concrete structural walls designed to resist seismic actions. An experimental program was conducted to assess the lateral strength, degradation of lateral load at large deformations, and hysteretic energy dissipation characteristics of squat structural walls. One important objective was to provide detailed experimental data for development of analytical modeling methodologies, which simulate shear-flexure interaction behavior for low-rise (squat) structural walls. For this purpose, the experimental program conducted at the Boğaziçi University Structural and Earthquake Engineering Laboratory involved testing of 11 (eleven) squat wall specimens, with different geometries and reinforcement configurations. Eleven largescale specimens were subjected to cyclic horizontal displacements applied at the top, corresponding to increasing drift levels. Other test parameters included the wall aspect ratio, the amount of vertical and horizontal distributed web reinforcement, the amount of longitudinal boundary reinforcement, and the compressive strength of concrete. The test results were evaluated for characterizing the cracking shear force and drift level, the maximum shear capacity and the corresponding drift level, and the drift level associated with a pre-defined collapse limit state, for each of the specimens tested. Conclusions were drawn regarding the shear capacity, deformation capacity, energy dissipation characteristics, strength deterioration characteristics after capacity is reached, and the influence of vertical distributed reinforcement on the lateral load behavior of walls. Experimentally measured shear capacities and lateral load – top displacement envelope relationships were compared with the existing code provisions on design and assessment of reinforced concrete structural walls.