Viscoelastic damper connected to adjacent structures involving seismic isolation

Abstract

The seismic response of multi-storied base-isolated structure to various types of isolation systems connected using viscoelastic dampers to the adjacent dissimilar base-isolated or fixed-base structure is investigated. The multistoried structures are modelled as a shear type structures with lateral degree-of-freedom at each floor, which are connected at different floor levels by viscoelastic dampers. The performance of this combination is studied by deriving the governing equations of motion and solving it in the incremental form using Newmark's step-by-step method of integration. The variation of top floor absolute acceleration of both the buildings and bearing displacement under different real earthquake ground motions is computed to study the behaviour and effectiveness of resulting connected system. It is concluded that connecting the two adjacent base-isolated buildings with the viscoelastic dampers is useful in controlling large bearing displacements in the base-isolated structures thereby eliminating the isolator damages arising due to instability at these large displacements or pounding with adjacent ground structures during earthquakes. The viscoelastic damper connection between adjacent structures is found to be most effective when the adjacent base-isolated and fixedbase buildings are connected. Such scheme is hence useful in upgrading the seismic performance of existing fixed-base structures adjacent to a base-isolated structure.