Collision Resistance and Protection Design of Main Bridge of Muping Xiangjiang River Bridge in Changsha
This study presents the collision resistance research and collision protection design of the main bridge of Muping Xiangjiang River Bridge in Changsha.The vessel-bridge collision analysis of the bridge was conducted in LS-DYNA software to determine the collision protection degree of the bridge.Combined with the shock spectrum approximation method,the dynamic responses of the bridge to vessel collision were simulated,the required dynamic performance as well as the collision resistant capacity of the pier was calculated to evaluate the safety of the bridge structure.Considering the insufficient protection of the arch springing and anti-bending performance of the transition pier,a steel-UHPC composite collision protection fender that consists of UHPC walls,inside X-shaped energy-dissipating steel plates,D-shaped collision protection barriers and EPS foam was proposed.The collision resistant behavior of the fender was numerically simulated.The results demonstrate that the structural responses of the bridge under the maximum water level are more significant than those under the minimum water level,exclusive of the peaks of the collision forces.Without the collision protection fender,the main pier has great collision resistant capacity and a degree of safety margin,while the transition pier does not reach the anti-bending requirements.The fender is able to decelerate the impacting speed of a vessel to zero within 1.5 s and effectively prevent the lateral intrusion of the vessel.With a thickness of 10 mm,the inside energy-dissipating steel plates are capable of suppressing 35%of the peak vessel impact force,while allowing the primary peak responses of the bridge to reduce by 40%to 50%.