Info Seismic fragility of unreinforced masonry buildings with bonded scrap tire rubber isolators under far-field and near-field earthquakes

Abstract

To improve the seismic performance of unreinforced masonry (URM) buildings in the Himalayan regions, including Western China, India, Nepal, and Pakistan, a low-cost bonded scrap tire rubber isolator (BSTRI) is proposed, and a series of vertical compression and horizontal shear tests are conducted. Incremental dynamic analyses are conducted for five types of BSTRI-supported URM buildings subjected to 22 far-field and 28 near-field earthquake ground motions. The resulting fragility curves and probability of damage curves are presented and utilized to evaluate the damage states of these buildings. The results show that in the base-isolated (BI) URM buildings under seismic ground motion at a peak ground acceleration (PGA) of 1.102g, the probability of exceeding the collapse prevention threshold is less than 25% under far-field earthquake ground motions and 31% under near-field earthquake ground motions. Furthermore, the maximum average vulnerability index for the BI-URM buildings, which are designed to withstand rare earthquakes with 9° (PGA = 0.632g), is 40.87% for far-field earthquake ground motions and 41.83% for near-field earthquake ground motions. Therefore, the adoption of BSTRIs can significantly reduce the collapse probability of URM buildings.