Spatiotemporal Frequency Variation in Plate-Type Bridges Under Moving Vehicles: Theoretical Study.

This paper uncovers the frequency variation in plate-type bridges under moving vehicles, highlighting the transverse characteristics stemming from the bridge's spatial configuration. First, the mode shapes are determined for plates with two opposite sides simply supported and the other two free (S-F-S-F bridge) by Levy's method. Then, analytical solutions are derived for the frequencies of the vehicle-plate system subjected to a moving vehicle. Through numerical analysis, it is demonstrated that the frequencies of the vehicle-plate system exhibit spatiotemporal variations, contingent upon both the transverse spatial path and longitudinal time-varying distance of the plate traveled by the vehicle. The "edging effect" was identified wherein maximum frequency variation will occur when the vehicle traverses along one side edge of the plate. Moreover, the transverse variation ratio of the plate-type bridge frequency increases with the decrease in the bridge's span/width ratio. These findings underscore the significance of the bridge's transverse characteristics when using the moving vehicle to measure the frequencies of plate-type bridges, particularly for short-span bridges. [ABSTRACT FROM AUTHOR]