Behavior of torsionally coupled buildings isolated by super-elastic bearing subjected to earthquakes

Abstract

Performance of torsionally coupled buildings isolated by Shape Memory Alloy based Super-elastic isolation bearing is presented considering stochastic and recorded seismic excitations. The stochastic responses of isolated buildings are analyzed considering random earthquakes. The optimal choice of the pertinent isolator parameters are obtained through a bi-objective optimization that minimizes the angular acceleration of the building and the base displacement of the isolator simultaneously. Effectiveness of the Super-elastic bearing is also verified against recorded ground motions considering possible variations in eccentricity, ratio of uncoupled rotational to translational frequencies of the superstructure (frequency ratio) and the isolator. The super-elastic bearings are observed to be less efficient for isolating torsionally coupled building but helps in eliminating residual deformations in the isolators when compared with the conventional elastomeric bearing.