高铁拱桥刚性吊杆损伤诊断及其节点板焊缝疲劳剩余寿命评估方法

Rigid hanger arch bridges are widely used in long-span high-speed railway bridges due to their good transverse stiffness; the system of rigid hangers and their gusset plates is one of the key systems of the arch bridge, and it is often subjected to the damage such as joint looseness, weld fatigue crack and corrosion; therefore, damage sensitivity for the diagnosis of rigid hangers and the fatigue assessment accuracy for the welds are urgently required to be improved. This project will propose “a two-stage damage diagnosis method combining monitoring and detection” for rigid hangers and the remaining fatigue life assessment method for welds of the gusset plate. The main contents are listed as follows: (1) to propose vibration-based real-time damage diagnosis method for rigid hangers with a high damage sensitivity under ambient excitations, i.e. the LU-DLV method; (2) to propose the ultrasonic wave-based defect reflective echo analysis damage localization and quantification method for detecting local damage on the hanger; (3) to establish the relationship between stress time history of welds of the gusset plate and the fatigue crack size; (4) to propose the monitoring data-based remaining fatigue life assessment method for welds of the gusset plate considering the train load case by using the fracture mechanics theory and S-N curve method. Based on the combination of theoretical analysis, long-term monitoring data analysis, numerical simulations and model experiments, this project will provide a damage diagnosis method for rigid hangers and a remaining fatigue life assessment method for welds of the gusset plate, which has significant benefits for obtaining the real-time in-service condition of the high-speed railway arch bridge’s rigid hangers and then for ensuring the running safety of the bridge.

刚性吊杆拱桥由于良好的侧向刚度较多地用于高铁大跨桥梁，刚性吊杆及其节点板是其关键构件体系之一且常发生节点松动、焊缝疲劳开裂、腐蚀等损伤，刚性吊杆损伤诊断敏感性及其焊缝疲劳评估精度均亟待提高。本项目将提出刚性吊杆“监测+检测两步骤损伤诊断方法”及其节点板焊缝疲劳剩余寿命评估方法。主要内容有：(1)提出环境激励下基于振动信息的对刚性吊杆损伤敏感的实时诊断的LU-DLV法；(2)提出基于超声导波损伤回波分析的刚性吊杆局部损伤精细化定位与定量方法；(3)刚性吊杆节点板焊缝应力时程特征与疲劳裂纹尺寸关系的建立；(4)联合断裂力学理论和S-N曲线提出考虑列车工况影响的基于监测数据的刚性吊杆节点板焊缝疲劳剩余寿命评估方法。本项目结合理论分析、监测数据、数值模拟和模型试验为高铁拱桥刚性吊杆提供损伤诊断及其节点板焊缝疲劳剩余寿命评估方法，对更好地把握高铁拱桥刚性吊杆实时服役状态进而保障安全运营有积极意义。

刚性吊杆拱桥由于良好的侧向刚度较多地用于高铁大跨桥梁，刚性吊杆及其节点板是其关键构件体系之一且常发生节点松动、焊缝疲劳开裂、腐蚀等损伤，刚性吊杆损伤诊断敏感性及其焊缝疲劳评估精度均亟待提高。此外，大跨桥梁柔性吊杆和斜拉索等索类构件的安全服役也面临一些挑战。本项目提出了刚性吊杆损伤诊断方法及其节点板焊缝疲劳剩余寿命评估方法、大跨桥梁柔性拉索损伤诊断和振动控制方法等。主要内容有：(1)提出了刚性吊杆损伤诊断的LU-DLV法，实现了其环境激励下基于振动信息的实时诊断；(2) 提出了吊杆和拉索等构件局部损伤的精细化检测方法，并发明了相应的漏磁检测仪，实现了该类构件局部损伤的精细化定位；(3)提出了大跨高铁钢桁拱桥整体节点关键焊缝疲劳性能评估方法，可用于评价关键焊缝的疲劳寿命及疲劳裂纹扩展过程，为整体节点的维护或更换提供建议；(4)提出了综合考虑应力比效应和加载顺序效应的铆接钢桁桥构件疲劳寿命评估方法；(5)提出了吊杆和斜拉索等拉索模态参数全过程自动化识别方法，可快速识别模态参数且定量其不确定性，避免了人工输入频带信息；(6)提出了基于附加虚拟质量和贝叶斯理论的损伤定位与量化方法，可用于高铁拱桥刚性吊杆及拱肋和主梁的损伤诊断，且能给出损伤诊断结果的概率分布；(7)提出了一种重要连接节点的初始转动刚度理论计算模型，避免了大量实验和模拟工作量；(8)提出了一种环境激励下大跨桥梁吊杆振动控制的方法及相应装置，减振效果良好，且经济性好。本项目为高铁拱桥刚性吊杆提供损伤诊断及其节点板焊缝疲劳剩余寿命评估方法，对更好地把握高铁拱桥刚性吊杆实时服役状态进而保障安全运营有积极意义。且为保障大跨桥梁吊杆和斜拉索等索类关键构件的损伤诊断、振动控制与状态评估等提供了理论、方法和装置支撑。