Longitudinal Vibration and Its Suppression of a Railway Cable-Stayed Bridge Under Vehicular Loads

The paper is aimed at investigating the longitudinal vibration and vibration reduction of a cable-stayed bridge under vehicular loads with emphasis on the longitudinal resonance. To investigate the phenomenon of longitudinal resonant vibration, the equivalent longitudinal excitation for the bridge deck due to moving vertical loads is approximately expressed as longitudinal loads with a sine-wave form. A formula for estimating the longitudinal resonant speed of the cable-stayed bridge is developed. A long-span cable-stayed railway bridge is considered in the case study to calculate the longitudinal response of the bridge under moving loads at different speeds. The numerical results indicate that the longitudinal resonance for the cable-stayed bridge occurs when the speeds of the moving loads approach the resonant speed predicted by the analytical formula. A fluid viscous damper (FVD) is employed to reduce the longitudinal vibration of the bridge under moving loads. The results show that the longitudinal resonant responses of the cable-stayed bridge can be effectively mitigated by the FVD adopted.