A semi-analytical approach for analyzing ground vibrations caused by trains moving over elevated bridges

A semi-analytic approach is presented for the three-dimensional analysis of ground vibrations induced by trains moving over elevated bridges. The train is modeled as two sets of moving loads, with one for the front wheels and the other for the rear ones, the elevated bridge as a series of elastically supported beams, and the ground as a viscoelastic half space. Three key elements are considered in the solution: (1) the analytic solution for the vibration of an elastically supported beam under a series of moving loads, (2) the impedance of the foundation-soil system, and (3) Green's function for an elastic half space under a harmonic point load. Such an approach allows us to consider the structural dynamics of the elevated bridge, the foundation-soil interaction, and the wave propagation characteristics in the half space. From the numerical examples studied, the proposed approach was demonstrated to be accurate and efficient. The framework of analysis described herein can be generalized to solve problems with complex foundations and layered soils. (C) 2004 Elsevier Ltd. All rights reserved.