Seismic Wave Propagation in Framed Structures by Joint-Based Wave Refraction Method

Abstract

This paper studies the dynamic behavior of the structural frames subjected to seismic loadings using a joint-based wave refraction method. The beams of the frame are modeled by the Timoshenko beam theory to consider the rotary inertia and shear deformation effects. The whole frame is considered as an assemblage of the waveguides connected with joints and boundary conditions, including discrete spring–dashpots for modeling the foundation supports that are generally treated as discontinuities. The wave refraction matrices at the discontinuities are derived analytically and the final assembled system of equations are solved numerically. The accuracy of the method is validated using an experimental setup and its performance is assessed for a 15-story concrete moment frame subjected to real ground motions. The soil structure interaction effect is also considered in the simulations using discrete spring–dashpot elements. The results show that the wave refraction method can be effectively used as an alternative means for the seismic analysis of the frames. In comparison with numerical methods such as finite element method, the proposed method is computationally efficient, while its accuracy and cost are independent of the loading frequency and the length of waveguides.