Seismic performance of a Low-Cost base isolation system for unreinforced brick Masonry buildings in developing countries

Unreinforced masonry (URM) buildings are one of the most common type of constructions in developing countries, due to their reduced cost and ease of fabrication. However, the traditional non-engineered nature of these buildings combined with the poor mechanical performance of their structural materials pose a major threat to their earthquake performance, often resulting in heavy damage and losses. This study investigates the possibility of improving the response of typical URM buildings in developing countries, using a novel low-cost fibre reinforced elastomeric isolators (FREIs) developed with recycled rubber (RR). Detailed three-dimensional finite element analyses were carried out on the fixed-base (FB) and base-isolated (BI) configurations of the prototype building subjected to a set of strong recorded ground motions, considering both the design basis earthquake (DBE) and maximum considered earthquake (MCE). The numerical model of the URM building was developed using non-linear shell elements and bilinear springs that respectively simulated the hysteretic behavior of masonry walls and RR-FREIs. Numerical results show a significant reduction in both the accelerations and interstory drifts of the BI configuration when compared to the response of the FB building. The global elastic response and corresponding enhanced seismic performance of the BI building under DBE confirm the effectiveness of the proposed base isolation system in protecting non-engineered URM buildings from seismic events with medium-to-high intensity.