Experimental and analytical evaluation of seismic behavior of ICEB masonry walls under in-plane cyclic loading

The study investigates the seismic behavior of full-scale interlocking compressed earth brick (ICEB) masonry walls under in-plane lateral cyclic loading. Five wall specimens constructed using ICEBs with distinct reinforcement ratios and subjected to investigation under quasi-static reversed cyclic loading, simulating seismic demands on low-rise masonry structures. Key performance parameters, including lateral load capacity, stiffness degradation, ductility, energy dissipation, viscous damping, and failure mechanisms, are measured and analyzed. The dry-stacked interlocking geometry facilitated stable hysteretic behavior, with energy dissipation occurring through inter-brick sliding and friction. Among the tested configurations, the wall with a vertical reinforcement ratio (0.17%) and corner stirrup confinement demonstrated improved post-peak stability and more distributed damage. A wall without stirrups but with a higher vertical reinforcement ratio (0.23%) achieved a comparable peak lateral resistance. However, this substitution effect was limited to lower drift demands below approximately 2.0%. At larger drift levels, stirrup confinement proved more effective in preserving residual strength and mitigating rapid stiffness degradation. Experimental results were further evaluated using TMS 402/602–16 and CSA S304–14 provisions, as well as a unified analytical shear model. The comparison indicates that conventional masonry codes tend to overestimate the lateral capacity of dry-stack ICEB walls due to inherent cohesion assumptions. In contrast, the unified model, when applied within the context of friction-governed dry-stack mechanics, provides a more consistent and conservative prediction of the seismic shear capacity of ICEB masonry walls.