Dynamic Loading of Curved Steel Box Girder Bridges due to Moving Vehicles

This paper presents a simplified method for determining the dynamic loading of curved steel box girder bridges due to vehicles moving across rough bridge decks. The curved single box girder bridges are divided into a number of thin-walled beam elements. The curved multi-box girder bridges are modeled as a curved grillage system. The analytical vehicle, simulated as a non-linear vehicle model with 11 degrees of freedom, is the HL-93 truck as described in the American Association of State Highway and Transportation Officials (AASHTO) specifications. Truck parameters include the body, suspensions, and tires. The bridge deck surface is simulated using a stochastic process (power spectral density function). The dynamic loading of 28 three-span continuous single box girder bridges and 216 three-span continuous multi-box girder bridges, with span lengths ranging from 22,83–30,48–22,86 m to 64,01–85,34–60,01 m is analyzed. The analytical results show that the torsion impact factors for curved box girder bridges can be relatively high, while moment, shear, and deflection impact factors are normally less than those of corresponding straight box girder bridges due to restricted vehicle speed on curved bridges. The proposed simplified impact equations are appropriate for the design of both curved single box and multi-box girder bridges.