台风作用下大跨度缆索支承桥梁非平稳抖振多尺度分析及验证

Aiming at solving key problems in non-stationary analysis of wind-induced buffeting research, the wind-induced buffeting response refinement methodology of long-span cable-supported bridge will be investigated by utilizing multi-scale simulation technique, and the methodology will be validated by the wind environment and time-domain structural response recorded by Structural Health Monitoring System (SHMS) during typhoons. The project mainly focuses on the following four aspects: (1) According to the characteristics of wind environment tests on long-span bridges, refinement research would be conducted based on the existing sensors, installations and testing methods, to provide more reliable and effective technologies for the wind environment monitoring of long-span bridges. (2) The field measurement on non-stationary characteristics of typhoons as well as the synchronized structural response will be conducted based on the multi-scale signal analysis technology, the non-stationary power spectrum of fluctuating wind speed of typhoons will be established, and accordingly the dynamic equation of non-stationary buffeting of long-span bridges in typhoons will be established. (3) The effective connecting technique between diverse scaled models in wind-induced calculation will be studied to establish the multi-scale analytical method of wind-induced non-stationary buffeting of long-span bridge, which will be validated by actual measures, and thus to accurately predict the local response of structures. (4) Combining theoretical analysis, numerical calculation and the field measured results, the refinement of non-stationary characteristics and mechanism of wind-induced buffeting of long-span cable-supported bridges will be developed to contribute to the national key projects such as Sutong Cable-stayed Bridge and Runyang Bridge.

针对大跨度缆索支承桥梁风致抖振非平稳研究中存在的若干关键问题，利用台风期间桥梁结构健康监测系统（SHMS）记录的风环境及结构响应时程数据、借助多尺度手段开展桥梁风致抖振的精细分析理论研究，主要内容包括：（1）针对大跨度桥梁风环境测试的特点，对现有测试传感器、安装装置及测试方法进行精细化改进，为大跨度桥梁风场监测提供更为可靠和有效的手段。（2）基于多尺度信号分析技术开展台风及同步结构响应的非平稳特性实测研究，建立台风脉动风速的非平稳功率谱模型，并据此建立台风下大跨度桥梁非平稳抖振的动力方程。（3）研究桥梁风振计算中不同尺度模型的有效衔接技术，建立大跨度桥梁风致非平稳抖振的多尺度分析方法，实现对结构细部响应的精准预测，并采用实测结果进行验证。（4）综合利用理论分析、数值计算和现场实测结果，开展大跨度缆索支承桥梁风致抖振非平稳特性及其机理的精细化研究，并将成果应用于苏通、润扬大桥等国家重点工程。

近年来，我国东南沿海台风灾害频发，严重威胁着大跨度缆索支承桥梁这类柔性风敏感结构的服役安全性与工作性能。多次现场实测表明，台风风场通常表现出明显的时变均值与时变方差特征，因而具有突出的非平稳特性，这便使得传统平稳随机过程假设难以准确描述台风作用下桥梁的风振状态。因此，亟待开展台风作用下大跨度缆索支承桥梁非平稳抖振分析方法研究。本项目针对大跨度缆索支承桥梁风致抖振非平稳研究中存在的若干关键问题，利用台风期间桥梁结构健康监测系统（SHMS）记录的风环境及结构响应时程数据、借助多尺度手段开展了桥梁风致抖振的精细分析理论研究，主要研究内容包括：（1）针对大跨度桥梁风环境测试的特点，研发了新型风速仪支架等系列装置，并通过模型试验对研发装置进行了性能验证，并探讨了结构振动对风场测试精度的影响，为大跨度桥梁风场监测提供了更为可靠和有效的手段。（2）基于多尺度信号分析技术开展了台风及同步结构响应的非平稳特性实测研究，建立了台风脉动风速的非平稳经验演变谱模型，并推导了台风作用下大跨度桥梁非平稳抖振耦合动力方程。（3）提出了一种确定结构多尺度动力分析中子模型尺寸的方法，并通过引入界面协调方程实现了不同尺度模型的有效衔接，据此建立了大跨度缆索支承桥梁非平稳抖振多尺度分析方法，可实现对结构细部响应的准确预测。（4）综合利用理论分析、数值计算和现场实测结果，开展了大跨度缆索支承桥梁风致抖振非平稳特性精细化研究，初步揭示了台风作用下大跨度桥梁非平稳抖振的演化规律。上述研究成果已被应用于苏通大桥、润扬大桥等国家重点工程台风期间的安全性能评估，为指导台风期间大跨度缆索支承桥梁的运营、管养和维护提供了科学有效的理论参考。