Seismic Analysis of Irregular Buildings With And Without Lead Plug Rubber Bearings (LPRB)

Abstract

Base isolation has become an effective technique that aids in earthquake hazard mitigation and has been in use for the past decade. By properly separating the structure from the horizontal ground motion components, the base isolation system lowers the likelihood of resonance. Isolators are provided at the base of the structures, and decoupling is accomplished by modifying the system's flexibility and adding adequate damping. Structures with irregular plans are gaining popularity owing to their aesthetic appearance as well as architectural designs. The response of such structures to seismic action will be different from conventional structures. This paper aims to study the effect of base isolators on structures with irregular plans, while simultaneously observing the changes occurring when the height of the structures is increased. Three unique plans are chosen, namely plus, L and T shapes, whose responses are studied on 5, 10 and 15-storeyed structures. All the columns in the base-isolated structures are equipped with lead plug rubber-bearing base isolators which is the chosen isolator for this study. The base isolators are designed for each structure specifically so that the behavioural patterns observed are as accurate as possible. From the obtained results, it is discerned that base-isolated buildings exhibited better performances in comparison with fixed-base buildings, and as the height of the structure increases the effect of the base isolator tends to decrease.