Effect of Bridge Skew on the Analytical and Experimental Responses of a Steel Girder Highway Bridge

Abstract

AbstractThis study examines the effect of bridge skew on the load rating and natural frequencies of a steel girder skewed highway bridge. The analytical load rating was determined based on a line-girder model and the AASHTO bridge design specification. The experimental load rating was determined based on a series of calibrated-weight truck runs. The analytical natural frequency was determined based on correlating the single span response to a continuous span response. The experimental natural frequency was obtained based on the free vibration response from the calibrated-weight truck. The frequency associated with the first spike of the frequency domain plot was identified using a Fast Fourier Transformation. The results show that the analytical load ratings and natural frequencies differed from the experimental values primarily due to effect of bridge skew, which caused the actual load path to be significantly shorter than the bridge span length that was used in the analytical calculations.