Vibration of Thin-Walled Box-Girder Bridges Excited by Vehicles

This paper presents a procedure for obtaining the dynamic response of thin-walled box-girder bridges due to truck loading. The box-girder bridge is divided into a number of thin-walled beam elements. Both warping torsion and distortion are considered in the study. The analytical vehicle is the American Association of State Highway Transportation Officials (AASHTO) HS20-44 truck simulated as a nonlinear vehicle model with 11 independent degrees of freedom. Four different classes of road-surface roughness generated from power spectral density function for very good, good, average, and poor roads are used in the analysis. The proposed procedure has been checked against the folded-plate method studied by former investigators. The comparison between these two methods is very good. The analytical results show that the dynamic response of vertical bending moment is caused mainly by several vibration modes, and that of torsion and distortion is greatly affected by the higher modes.