论文部分内容阅读
为正确估计桥梁结构船撞下的需求,以中国通航水域广泛采用的高桩承台桥梁为对象,从荷载模式的角度开展了驳船等效侧向荷载研究。在构建船撞等效侧向力作用模式过程中,考虑了高桩承台基础的动力特点,将其简化成两自由度体系。基于两自由度模型的振动模态、驳船冲击谱及模态组合方法,推导出了确定驳船撞下桥梁等效荷载的新方法,并在算例中运用提出的方法与现有规范静力法进行了比较。结果表明:基于模态的等效荷载作用模式与规范静力法单点集中力形式存在显著差异;规范静力法精度低,仅简单放大荷载大小,但不改变作用模式时误差仍然较大,说明荷载作用模式在确定桥梁船撞需求与能力时至关重要;采用所提出的荷载模式计算时,结构响应与动力结果吻合较好,且其计算精度对质量比和墩身-桩基刚度比不敏感。
In order to correctly estimate the demand of bridge structure ship crashing, this paper studies the equivalent side load of barge from the perspective of load mode, taking the widely used pile cap bridge in China’s navigable waters as an object. In the process of building the equivalent lateral force mode of ship collision, the dynamic characteristics of foundation of high-pile cap was considered, which was simplified into two degrees of freedom system. Based on the two-degree-of-freedom model’s vibration mode, the barge impact spectrum and the modal combination method, a new method to determine the equivalent load of a barge on a bridge is deduced. The proposed method is compared with the existing standard static method Compared. The results show that there are significant differences between modal equivalent load modes and those of the canonical hydrostatic method. The standard hydrostatic method has low accuracy and only magnifies the load magnitudes, but the error is still large without changing the mode of action. It shows that the mode of load action is very important in determining the requirements and abilities of bridge ship collision. When the proposed load model is used, the structural response is in good agreement with the dynamic result, and its calculation accuracy to mass ratio and pier body to pile stiffness ratio Not sensitive.