Investigation of reinforcement curtailment in tall lightly reinforced structural concrete walls

Recent studies have investigated the impact of minimum longitudinal reinforcement limits on the ductility of the plastic hinge region of reinforced concrete (RC) walls, resulting in revised minimum reinforcement limits in design standards. The objective of this research was to investigate the influence of the longitudinal reinforcement distribution or termination rules for the additional reinforcement at the end regions of the wall up the wall height on the response of taller lightly RC walls. A model utilizing a displacement-based fiber element was developed and validated against tested walls with a range of longitudinal reinforcement contents. Pushover analyses were then conducted on a 20-story wall prototype to investigate the sensitivity of key design parameters, including axial load pattern, curtailment heights of the longitudinal reinforcement in the plastic hinge region, reinforcement content at wall base, reinforcement strain-hardening ratio, and the length over which the reinforcement curtailment occurred. The results indicate that the current minimum reinforcement provisions in ACI 318–19 are insufficient to prevent reinforcement yielding outside the plastic hinge region at the wall base.