Seismic Response of Coupled Long-Period Structures with Maxwell-Type Dampers Subjected to Long-Period Ground Motions observed in the 2011 off the Pacific Coast of Tohoku earthquake

Abstract

We clarify the seismic response of coupled long-period structures with Maxwell-type dampers subjected to long-period ground motions. The simulated long-period ground motions induced in anticipated Nankai earthquake are used for analyses. By varying damping coefficient c_m and stiffness k_m of dampers, the minimal relative displacements for 2DOF systems are computed to analyze the dependence of long-period components of the ground motions on the effectiveness of optimal structural control by installing dampers from view of five points : frequency ratio ω_f/ω^s₁ defined as the value of dominant angular frequency of a ground motion ω_f compared with 1st natural angular frequency of the systems ω^s₁ , mass ratio μ (m₂/m₁), frequency ratio γ (ω₂/ω₁) defined as the ratio of natural angular frequency for system 2 ω₂ by that for system 1 ω₁, stiffness ratio of dampers n defined as the ratio of damper's stiffness k_m by system 1's stiffness k₁ and damping ratio ζ defined as the ratio of damping coefficient c_m by system 1's damping coefficient. Furthermore, we analyze long-period components of the ground motions recorded at 506 K-NET and KiK-net stations in the 2011 off the Pacific Coast of Tohoku earthquake, which are possible to affect seismic response of coupled long-period structures with Maxwell-type dampers.