Seismic isolation is a highly effective design strategy to enhance earthquake resistance by reducing the transfer of ground motion to the superstructure. It is widely applied in high-seismicity regions, particularly for buildings with critical functional or strategic importance. This study presents a comprehensive numerical investigation of the seismic performance of masonry wall systems subjected to near-fault earthquakes through a two-level modeling framework. At the global structural level, a total of 32 building models were developed, including fixed-base, sliding-base, and base-isolated configurations. The parametric study considered variations in the number of stories, span lengths, and plan configurations to evaluate the influence of seismic isolation on overall structural response. Nonlinear dynamic analyses under near-fault ground motions were performed to assess base shear, interstory drift, and floor acceleration. At the component level, detailed finite element models of masonry walls strengthened with two to five seismic isolators were developed in Abaqus and subjected to nonlinear cyclic loading. The local response was evaluated in terms of lateral load capacity, hysteretic behavior, energy dissipation, and damage distribution. The results indicate that seismic isolation significantly reduces base shear and floor accelerations at the global level, while increasing displacement demands. Bare masonry walls (unstrengthened) exhibited extensive damage and a maximum lateral force of 3,360 N, while walls with isolators reached 4,803–6,221 N, depending on the number of isolators. Walls with two isolators provided substantial improvement, while additional isolators resulted in diminishing returns, except for the five-isolator configuration, which showed the highest energy dissipation and ductility. Strengthened walls also demonstrated symmetric cyclic responses with minimal local crushing, in contrast to the bare wall, which experienced severe damage in nearly 90% of its area. Overall, the findings demonstrate that properly designed seismic isolation systems can substantially enhance both global and local seismic performance of masonry structures. The study provides practical insights into the optimal number and configuration of isolators for improving structural resilience under near-fault ground motions.
Farivar et al. (Tue,) studied this question.