Application of MR damper in Base-isolated Irregular Building with different variable sliding Isolators

Abstract

Application of Electromagnetic induction (EMI) based passively controlled and some local response governed MR dampers in controlling the isolator displacement in base-isolated Irregular building have been studied and compared with the Lyapunov controller. The Irregular building is hybrid isolated with elastomeric rubber bearings and a variety of sliding isolators subjected to strong near field earthquakes acting bi-directionally in horizontal plane. The shear type base-isolated Irregular building is modelled as three-dimensional linear elastic structure having three degrees-of-freedom at each floor level. Time domain dynamic analysis of the building has been carried out using constant-average acceleration Newmark-Beta method and non-linear isolation forces has been taken care by fourth-order Runge-Kutta method. It is observed that the EMI based passive controller performs better than the Lyapunov controller though it reduces less base displacement but gives lower structural response among all the controllers. Local response governed Hyperbolic and Aly’s controller require only velocity and displacement at controller locations sound simpler in application as compared to Lyapunov controller especially to civil engineering structures like Irregular building. The Hyperbolic controller restrains base displacement comparable to the Lyapunov controller but gives less base shear and story drifts to Irregular building. Variable frequency pendulum isolator (VFPI) and variable curvature friction pendulum system (VCFPS) sliding isolators perform better with MR damper control in comparison to conventional friction pendulum system (FPS) in base–isolated Irregular building.