桥梁在冲刷和船撞共同作用下的生命周期内时变损伤研究

Flood induced scour and ship collision are the major reasons leading to bridge failure. A scoured bridge has the potential to be collided by a ship at the same time. Therefore, it is meaningful to investigate the security of a bridge during its life time under the combination of scour and ship collision. In this project, we aim to build a mathematical model of collision force by deriving the differential equation of vibration considering fluid dynamics and the coupling effect of fluid and solid for a bridge under scour and ship collision, and then solving it and validating the accuracy of the model through experiments; The collision force was monitored under different cases of scour and ship collision in multiphysics numerical and indoor experiments by using a collision force measurement system, investigating the effect of scour depth, angle of scour hole, and the bottom depth of the scour hole on the collision force, quantifying the influence degree of scour properties on the collision force. Based on equivalent static loads and dynamic analysis method, the probability of failure theory and calculation method will be investigated for the bridge under the combination of scour and ship collision, respectively. The results can be used for predicting the collision force of bridges under scour and ship collision; it also can be used to guide the design of bridge to resist the effects of the combination of scour and ship collision, which has higher theoretical value and social economic benefit.

洪水冲刷和船舶撞击是造成桥梁破坏的主要原因，桥梁有可能遭受冲刷和船撞共同作用，因此研究桥梁生命周期内在冲刷和船撞共同作用下的安全性意义重大。本项目拟以冲刷和船撞共同作用下的桥梁为研究对象，通过理论分析，建立船桥碰撞系统振动微分方程，考虑流体动力学及流-固耦合作用并对船撞力求解，构建冲刷和船撞共同作用下的船撞力数学模型，并通过试验进行验证；基于多物理场数值实验和室内试验，监测桥梁模型在不同冲刷和船撞情况下的船撞力，探索冲刷坑深度、坡度、底部宽度对船撞力的影响规律，定量分析冲刷坑深度、坡度、底部宽度对船撞力的影响程度；基于静力等效、动力分析方法，对桥梁在冲刷和船撞共同作用下的生命周期内失效概率进行理论分析，提出失效概率计算方法。研究成果为桥梁在冲刷和船撞共同作用下的船撞力预测提供科学依据；同时为桥梁抵抗冲刷和船撞的安全设计提供理论指导，将具有重要的理论价值和社会经济效益。