公路桥梁多场耦合随机动态响应时空演变规律及分步损伤识别方法研究

With the urgent needs of safety and management of existing bridges in China, focusing on the existing prestressing reinforced concrete highway bridges, the analysis methods and evolution laws of the multi-field coupling dynamic actions of damaged highway bridges under complex environmental and loading condition, damage identification strategy and some other critical issues will be studied in the present study. Firstly, the numerical simulation methods of non-stationary stochastic dynamic response of the vehicle-bridge coupling system under complex circumstances will be studied systematically. Secondly, the model tests on the prestressing reinforced concrete continuous box-girder bride and the prefabricated cable-stayed bridge will be carried out in a test chamber. Spatio-temporal evolution rules of the time- and frequency-region eigenvalues of highway ridges under the coupling dynamic excitation in damage and temperature fields will be ascertained. The effect of damage types, environment conditions, parameters of bridge models and vehicle models on the stochastic dynamic responses of vehicle-bridge system will be investigated. Finally, on the basis of model experiment and numerical simulation, the preliminary damage location will be determined by the time series dynamic responses of bridges and the moving vehicle, and then the probability density functions of damaged element stiffness parameters will be detected using the stochastic dynamic model updating under the load condition of the controlled moving vehicle. Basing on the vehicle-bridge coupling vibration analysis, the two-step detection methods of highway bridges will be proposed in the frame of probability damage detection technique, and a real-world bridge will be tested for verifying the of the practicability of the proposed methods. The achievements of this project will provide solid theoretical foundations and technical supports for rapid damage diagnosis and safety assessment of the wide-ranging highway and urban bridges.

拟针对我国桥梁运营安全与维护管理的重大需求，以运营中的公路预应力钢筋混凝土桥梁为研究对象，围绕复杂环境和运营条件下带损伤公路桥梁的多场耦合动力效应模拟、损伤引起的随机动态响应演变规律和损伤参数识别等关键科学问题开展研究。通过系统研究复杂环境下车桥耦合系统非平稳随机动态响应分析方法，并结合预应力钢筋混凝土连续梁桥及装配式斜拉桥的模型试验研究，摸清损伤与温度场下公路车桥系统多场耦合随机动态响应时频域特征值的时空演变规律，分析结构损伤类型、环境条件、结构参数及车辆参数等对系统随机动态响应的影响；在模型试验和数值模拟基础上，提出基于移动车辆激励下实测动态响应的损伤初步定位方法和桥梁单元刚度损伤概率密度函数反演方法，在概率框架内基于车桥耦合振动响应分析实现公路桥梁损伤分步识别，并通过实桥应用验证其可行性。研究成果将为量大面广的公路、市政桥梁的快速损伤诊断及安全评估提供重要的理论依据和技术支撑。

项目针对国家交通基础设施建设与运营维护的重大需求，以运营中的公路桥梁尤其是预应力钢筋混凝土桥梁为研究对象，围绕复杂环境和运营条件下带损伤公路桥梁的随机动力特性分析方法、演变规律和损伤参数识别等关键科学问题开展了研究。通过系统研究复杂环境下损伤桥梁车桥耦合系统动态响应分析方法，并结合预应力钢筋混凝土梁桥、斜拉桥、悬索桥等不同桥型的模型试验或场地实测数据研究，基本摸清了损伤场与温度场下公路车桥系统多场耦合随机振动响应的时域和频域特征值的时空演变规律。通过数值模拟与试验研究，分析了结构损伤类型、外界环境条件、桥梁结构参数及车辆模型参数等对系统随机动力响应的影响，研究并总结了不同桥梁类型的车桥耦合系统中桥梁响应的异同以及对各变量的敏感性。在上述研究的基础上，利用损伤桥梁响应的时域统计规律和频域特征值及其相互关系，提出了基于移动荷载激励下车桥耦合振动响应分析的公路桥梁损伤参数分步识别理论与方法。此外，项目研究过程中还引入或改进了如计算机视觉、深度学习、GPS等技术，应用于桥梁的动态响应识别和损伤检测，在完成预定研究要点的基础上深化并拓展了研究内容，为量大面广的公路、市政桥梁的损伤诊断与安全评估提供重要的理论依据和技术支撑。