基于动力响应的高速铁路桥墩损伤评估方法研究

On the basis of existing researches that determine whether piers are damaged, the damage location and quantitation method for the piers before beam erection and high-speed railway piers in service is studied, which is an advanced project in the bridge engineering society. Not the complex lateral loads of passing trains, but the deterministic forces, such as, impact loads and sinusoidal loads, are used to excite the piers. The sensitivities of lateral and longitudinal dynamic responses of new piers before beam erection and lateral responses of existing piers to disasters, such as structural damage, member connection deterioration, subsoil deterioration and bearing degradation are analyzed. Basing on the structural characteristics of high-speed railway piers, the optimum arrangements of measurement points and excitation location are determined. The sensitivity-based disaster diagnosis theory for piers is studied. The ultimate aim of this project is to propose a useful method of damage evaluation method for railway piers by theoretical analysis, laboratory experiments and in-situ experiments. The project is cooperated with foreign experts and many useful data about bridge experiments and bridge inspection can be used. In-situ dynamic experiments can be done under the support of other railway projects. The research will benefit the development of the bridge damage identification theory and will lay good foundation for the further theoretical analysis and engineering application.

在既有判断桥墩是否存在损伤的研究基础上，研究架梁前悬臂桥墩和在役高速铁路桥墩损伤定位和定量评估方法这一桥梁工程领域的前沿课题。避开不确定性的通行车辆横向激励，以冲击荷载和正弦荷载等确定性荷载激励桥墩，分析了架梁前桥墩纵横向动力响应及在役桥墩横桥向动力响应对墩身结构性损伤、构件连接弱化、基础弱化和支座劣化等几种形式病害的灵敏度，结合高速铁路桥墩的结构特点确定测点和激励点的最优布置，研究基于灵敏度分析的桥墩结构病害诊断理论。最终目标是通过理论分析、实验室试验和现场试验建立一种高速铁路桥墩损伤评估方法。项目具有国际合作的背景，有利用国内外大量桥梁试验、检测资料及在铁道部项目支持下进行桥梁现场动力试验的便利条件。项目的完成将对完善桥梁损伤识别的基础理论做出贡献，并为进一步的理论研究和工程应用奠定基础。

本项目系统研究了基于动力响应的高速铁路桥梁桥墩健康状态定量评估和损伤识别方法，主要工作及结论如下：.（1）以桥墩简化分析模型为对象，分析了模态参数和纵向线刚度对桥墩基础病害、墩身材料劣化以及桥墩结构性损伤等病害的灵敏度。.（2）提出了以桥墩横向整体振动模态、横向局部振动模态和顺桥向局部振动模态不同组合为输入，探测桥墩病害类型、病害位置和病害程度的系统识别优化计算方法，并通过理论分析和实验室实验进行了验证。.（3）建立了基于自振频率和纵向线刚度指标的桥梁下部结构整体健全度评估准则和针对基础、墩身和支座的病害细部评估准则，提出了桥墩健康状态定量评估程序。.（4）提出了基于冲击响应灵敏度分析的高速铁路桥墩损伤和支座病害探测方法。.（5）建立了基于模态参数的高速铁路桥墩健康档案数据库。.（6）对三座铁路桥梁和两座普通铁路桥梁进行了现场动力试验，以不同模态为输入，用系统识别优化计算方法识别了下部结构的物理参数，依据所提出的评估准则对下部结构的健康状态进行了定量评估。典型病害桥梁现场挖验结果和动力评估结果一致，从而证明了所提桥墩健康状态定量评估方法的准确性和可靠性。.