Seismic performance of buildings equipped with dual isolation systems

Resumo

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.