MODEL REDUCTION METHOD FOR BUILDINGS WITH VISCOUS DAMPERS UNDER EARTHQUAKE LOADING

A model reduction method is proposed for an elastic high-rise building with viscous dampers subjected to earthquake ground motion. A set of story stiffnesses of the reduced model is found under the equivalent conditions that the original model without dampers and its reduced model possess the same fundamental natural frequency and fundamental mode shape. A reduced model of the time-dependent earthquake inertia force is also proposed by requiring the equivalence of displacements at representative floor levels in both models without inertia and damping terms. A set of damping coefficients and a set of relief loads of bilinear-type viscous dampers of the reduce model are found under the equivalent conditions that the original model with dampers and its reduced model possess the same lowest-mode damping ratio and energy dissipation mode shape. Numerical examples are presented to demonstrate the efficiency and accuracy of the proposed method. It is concluded that the proposed method can substantially reduce the number of degrees of freedom in the time history analysis within an acceptable accuracy.
Transactions of AIJ. Journal of structural and construction engineering