Seismic performance of buildings equipped with dual isolation systems

Abstract

Nowadays, researchers from the academy and the industry have proposed several novel seismic isolation schemes to improve the seismic performance of structures such as buildings, bridges, and water tanks, among others. One of such schemes consists of including two layers of elastomeric isolators between the building and the foundation to control both floor accelerations and the large displacement at the isolation level. This paper presents a numerical study on the seismic response of buildings equipped with dual isolation systems. A total of three buildings (4, 7, and 10 stories) modeled by using the shear-type representation (i.e., one horizontal degree of freedom per story) are analyzed. Values of the properties of the elastomeric isolators were obtained from typical values in single-isolation buildings. In contrast, the mass of each isolation layer is assumed to be equal to the story mass of the superstructure. Simulated earthquake signals were generated from realizations of a non-stationary stochastic process representing realistic earthquake ground motions recorded on stiff soils. The average seismic response of the structure (peak displacements, peak inter-story drifts, and peak accelerations) is compared against that obtained for the fixed-base condition and the single-layer isolation condition. Possible advantages of the dual isolation system over the traditional single-layer are then discussed.