Torsional response reduction of plan-asymmetric vertical seismic isolation by appropriate distribution of viscous and viscoelastic dampers. (October 2020)

• Record Type: Journal Article
• Authors: Milanchian, Reza; Hosseini, Mahmood
• Is Part Of: Structures. Volume 27(2020)
• Page Start: 962
• Page End: 974
• Publication Date: 2020-10
• Subjects: Vertical seismic isolation -- Torsional control -- Non-classical damping -- Viscous and visco-elastic dampers -- Runge-Kutta method -- Response history analyses; Structural engineering -- Periodicals; 624.1
• DOI: 10.1016/j.istruc.2020.07.009
• Languages: English
• ISSNs: 2352-0124

Abstract

Abstract: In this article, torsional control has been studied in the plan-mass asymmetric vertical seismic isolation (VSI) system considering the three-dimensionally analytical model. In the 3D VSI, a structure is partitioned by vertical isolation planes into two inner and outer substructures interconnected by links for lateral response reduction. In an ideal analytical model of plan-mass asymmetric VSI, plan-wise distribution of damping and stiffness have been provided for more torsional control. Seismic responses of the non-classically 3D VSI were obtained by Runge-Kutta numerical method, considering a large number of isolation ratios. In this investigation, the mass and stiffness ratios of substructures are defined with respect to the original structure which provides a novel method of graphic presentation for analysis results. In this manner, contour graphs create comprehensive and worthwhile insight into the 3D VSI behavior and can also serve as a design tool for the preliminary design of the system. The results show that in the case that the inner substructure is the flexible one, torsional control is nearly effective in both substructures satisfactorily, regardless of plan-wise damping distribution. However, in the second case that is the outer flexible substructure, torsional control is nearly effective in the stiff substructure while the response in flexible substructure is satisfactory just in a limited range of isolation ratios.