Abstract

This study experimentally evaluates the seismic behavior of reinforced concrete squat walls constructed with high-strength lightweight concrete using expanded clay as lightweight aggregate. Four specimens with identical geometry and reinforcement were tested under monotonic and cyclic loading to assess shear capacity, stiffness degradation, and energy dissipation. Results indicate that the lightweight concrete walls tested exhibited comparable shear strength and cyclic performance to normal-weight concrete walls, despite a 40% lower initial stiffness, but also demonstrated superior behavior compared to other lightweight concrete walls documented in literature with similar characteristics. The experimental shear strength exceeded the nominal capacity predicted by the ACI 318 code, suggesting that the code’s lightweight reduction factor may be overly conservative for high-strength lightweight concrete mixtures. Notably, the results demonstrate the influence of aggregate type on concrete mix in shear response. The study contributes to understanding the nonlinear performance of lightweight concrete walls under lateral loads, providing experimental data that could refine design methodologies for such structures in seismic-prone regions. © The Author(s), under exclusive licence to RILEM 2025.