Seismic performance and analysis of resilient high-strength SRAC walls

This paper proposed a new type of resilient concrete wall consisting of steel fiber reinforced recycled aggregate concrete (SRAC) and weakly bonded ultra-high strength bars (UHSBs). Five specimens were fabricated and tested under reversed cyclic lateral force and constant axial load to investigate the seismic performance of the proposed resilient SRAC walls. Experimental parameters included the presence of steel fibers, the concrete strength, the volumetric ratio of the stirrup used in the boundary elements, and the axial load ratio. All test walls exhibited a stable increase of lateral resistance up to 2% drift ratio, while residual drift ratios were only about one-tenth of the transient drift ratios. Test results also indicated that adding steel fibers and increasing concrete strength could mitigate the development of cracks while increasing axial load could delay the development of UHSBs tensile strain and cracks. In addition, the residual drift ratios and corresponding design objectives, as recommended in FEMA 356 and previous studies, were introduced to evaluate the resilience of the proposed SRAC walls. All test specimens could meet the optimal performance design objective. Parallel to the experimental work, a method for simply calculating the skeleton curve and a model to evaluate the hysteretic loops of the proposed walls are presented. The calculated skeleton curves and hysteretic circles agreed well with the test results.