Seismic performance of lightly reinforced structural walls for design purposes

Lightly reinforced concrete walls are commonly found in low-to-moderate seismic regions such as Australia. While many theoretical analyses on lateral load-displacement of structural walls have been proposed and widely used, not many have been developed for lightly reinforced concrete walls. The lateral load-displacement behaviour and failure mechanism of lightly reinforced structural walls differ to those of heavily reinforced concrete walls, particularly in terms of tension stiffening effects, possible failure mechanisms and drift capacities. An analytical study on lightly reinforced rectangular concrete walls is presented in this paper. A parametric study was conducted to provide initial insight into the effect of four design parameters (aspect ratio, axial load ratio, transverse reinforcement ratio and longitudinal reinforcement ratio) on the ultimate displacement capacity of reinforced concrete walls. Two analytical models were developed to predict the lateral load-displacement behaviour of lightly reinforced walls consisting of a detailed wall model and a simplified wall model that provides a quick and conservative estimate for initial design checking purposes using displacement-based principles. Both models are shown to provide good agreement with experimental results in the literature.