VIBRATION OF HORIZONTALLY CURVED BOX BRIDGES DUE TO VEHICLES

The purpose of this paper is to develop a procedure for obtaining the dynamic response of thin-walled curved box girder bridges due to truck loading and to get their basic impact characteristics. The box girder bridge is divided into a number of thin-walled beam elements. Both wa rping torsion and distortion are considered in the study. The analytic al vehicle is the AASHTO HS20-44 truck simulated as a nonlinear vehicl e model with 11 independent degrees of freedom. Four different classes of road-surface roughness generated from power spectral density funct ion for very good, good, average, and poor roads are used in the analy sis. In comparison with the other approaches developed by former inves tigators, the proposed procedure not only facilitates a physical under standing of the general structural response, but also greatly reduces the computing time required and output obtained. The analytical result s show that most impact factors of torsion and distortion are much lar ger than those of vertical bending response. The impact factors of nor mal stress at different points in the same cross section are quite dif ferent. The larger the normal stress, the smaller the impact factor wi ll be. Though the static normal stresses at different positions in the same cross section may be extremely different for a curved box girder bridge, their dynamic normal stresses tend to be uniform. (C) 1998 El sevier Science Ltd. All rights reserved.