Residual Seismic Capacity of Reinforced Concrete Walls with Unconfined Boundaries

An experimental study was conducted to evaluate the residual seismic capacity of reinforced concrete (RC) walls with unconfined boundaries. Six walls were subjected to constant axial load and cyclic lateral loading protocols. Three walls were tested under one cyclic lateral loading protocol, and the other three walls were tested under two cyclic lateral loading protocols to induce initial damage. Primary test variables were the shear span-depth ratio and the target drift ratio of the initial loading protocols. Test results indicate that the six wall specimens showed a flexural dominated behavior. The residual crack widths measured in the three walls tested with initial damage were only 6% of the crack width suggested by FEMA 306 for the identified damage severity levels. The effective stiffness decreased significantly due to previous damage. Finally, the maximum strength was not considerably affected and the lateral drift capacity was not reduced due to previous damage.