基于准静态影响线精确识别的桥梁状态评估理论与试验研究

In recent years, more and more medium- and short-span bridges which have a large quantity and locate in a wide range in China, become so dangerous that needed to detect, and thus it is demanding to develop a quick and precise method for bridge condition evaluation. This research focuses on the critical problems of bridge condition evaluation based on accurate identification of quasi-static influence line, and then carries on an in-depth and systematic research. Based on the wavelet decomposition and reconstruction theory, quasi-static signal is extracted from bridge dynamic response for further influence line identification. Combining the sparse representation, function construction and solution optimization methods, the sparse regularization-based method is proposed for influence line identification. Based on the relationship among influence line, destructive loading and detective loading, the varying pattern of influence line is studied to justify that it is suitable for application to bridge condition evaluation. Through a comprehensively use of multiple influence line in damage sensitivity analysis, damage localization and quantification, a new method of bridge condition evaluation is proposed. A theoretical system of influence line-based bridge condition evaluation is finally founded based on the aforementioned methods. Then a practical software for bridge condition evaluation is developed by software integration. The correctness of theoretical methods and efficiency of engineering software is verified by numerical simulation, laboratory experiment and field testing. The expected outcome will enable us to realize a quick and precise evaluation for bridge condition, and thus it has important theoretical value and broad application prospect.

近年来，在量大面广的中小桥梁中，亟待检测的危桥、旧桥数量不断增加，迫切需要发展快速准确的桥梁状态评估方法。本项目针对基于影响线识别的桥梁状态评估的关键科学问题，拟开展深入系统的研究。根据小波分解与重构理论，提出针对桥梁影响线识别的准静态响应信号提取方法；通过稀疏表示、函数构造和优化求解，建立处理影响线识别不适定性问题的稀疏正则化方法；通过建立影响线与破坏荷载、检测荷载的关系模型，揭示影响线的变化规律及其适用于桥梁状态评估的机理；在损伤敏感性分析、损伤定位和定量方法中综合运用多影响线信息，提出桥梁状态评估新方法；最终建立基于准静态影响线精确识别的桥梁状态评估理论体系，集成以上理论成果并且开发出实用化的桥梁状态评估软件；通过数值模拟、模型试验和实桥测试，共同验证理论方法和工程软件的正确性及有效性。项目预期成果有望实现对中小桥梁服役性能的快速准确评价，具有重要的理论价值和工程应用前景。

面对遍布于公路交通网的众多中小桥梁，快速且准确地评估桥梁服役性能，具有重要的社会意义和经济价值。本项目拟通过解决识别桥梁影响线及其状态评估的难点，提出一套快速且准确的状态评估方法，可满足中小桥梁评估的迫切需求。主要研究内容包括：（1）针对影响线识别的准静态响应信号提取，提出了基于粒子群算法与改进变分模式分解的信号提取方法，具有准确性高、鲁棒性好、适用性广的优点；（2）适用于桥梁影响线精确识别的稀疏正则化：提出了基于基函数字典和稀疏正则化的桥梁影响线自适应识别方法，可准确识别具有复杂曲线形状的影响线；（3）基于影响线变化规律的桥梁状态评估机理，系统研究了钢筋砼梁桥承受不同检测荷载和不同破坏阶段的影响线变化规律；（4）综合多影响线信息的桥梁状态评估，提出了基于D-S证据理论融合多影响线信息实现影响线精确定位，并提出了基于稀疏正则化和挠度影响线改变量识别梁结构刚度与损伤程度的方法；（5）基于影响线识别的桥梁状态评估系统，研发了由移动检测车、信号采集子系统和信号处理子系统所组成的桥梁影响线识别系统，具有简便高效、精度高、成本低的特点。通过数值模拟（有限元精细仿真）、模型试验（钢筋砼连续梁试验）、实桥验证（装有健康监测系统的大跨悬索桥）和系统测试（不同跨径的中小桥梁），共同验证理论方法和软硬件系统的准确性及有效性。本项目执行情况良好。在本基金的资助下，已在重要学术期刊上发表学术论文8篇（其中7篇被SCI/EI收录）；直接培养硕士生5名，并有一人获福建省优秀学术硕士学位论文；获授权国家发明专利3项，软件著作权1项；基于影响线的快速检测技术具有快速简便，可大量节省成本的显著优点，已成功应用于国内五十余座桥梁，获得四家交通部综合甲级检测机构的认可，该成果被写入行业标准《大跨桥梁结构健康监测系统预警阈值设置标准》。