Critical Speed Variations for Damaged Bridges

This paper investigates the variation of critical vehicle speeds arising from damaged beam – moving oscillator interaction, especially in the presence of damage. The traversing speeds of the moving oscillator that result in local maxima of the vertical displacement, the velocity and the acceleration responses of the beam and the oscillator are termed the critical speeds. The variations of critical speeds of a two degree of freedom oscillator are observed for a wide range of damage location and extent for two different types of damage on a simply supported beam. Significant variation of critical speeds is observed due to the presence of damage in the beam. The nature of the variation of the critical speeds is observed to be dependent on the nature of damage. The findings are useful for engineers to identify vehicle speed regions of interest in relation with design, Structural Health Monitoring and response control of bridge-vehicle interaction process.The first author acknowledges Science Foundation Ireland Centre Marine and Renewable Energy Ireland (MaREI) centre funding 12/RC/2302