大跨度桥梁在运营及极端风环境下的多层次振动控制研究

Structural vibration problems for long-span bridges under strong winds are of significant importance, especially when the length of the designed spans is extended substantially currently. Due to the complexity of the mathematical model and the difficulties in simulating the extreme weather scenarios of hurricane/typhoon events, the evaluation of the aerodynamic performances of the bridge structures can be a very tough task. Therefore, it is highly necessary to develop the vibration control methodology for these large span bridge structures. However, until now there is no available vibration control systems developed for such extreme weather scenarios.This project is intended to develop a multi-level vibration control system for large span bridges in the operation and extreme wind environment scenarios by the approaches of theoretical analysis, wind tunnel tests, and field measurements. The objectives include: 1) developing a multi-degree-of-freedom adaptable levertype tuned mass damper (ALT-TMD) system; 2) establishing an adaptive feedforward control algorithm which does not rely on the exact mathematical model; 3) constructing a numerical analysis model of the bridge-ALT-TMD vibration control system and conducting the parametric optimization analysis; and 4) verifying the control effects and feasibility of the vibration control system by wind tunnel tests.

随着大跨度桥梁跨径越来越大，其受强风作用的结构振动问题显得尤为重要。但由于数学模型的复杂性以及真实飓风/台风等极端天气的难以试验模拟，使得大桥在极端风环境下的结构气动性能难以预测，因此，加强大跨度桥梁结构的振动控制是非常必要的，但目前还没有适合极端风环境下大跨度桥梁结构的振动控制系统。本项目拟以理论分析、风洞试验和现场实测为主要手段，开展大跨度桥梁在运营和极端风环境下的多层次振动控制研究，主要包括：1）研发一套可调多自由度杠杆式调谐质量阻尼器(ALT-TMD)系统；2）建立一种不依赖精确数学模型的自适应前馈控制算法；3）建立桥梁结构ALT-TMD振动控制系统的数值分析模型并进行参数优化分析；4）通过风洞试验验证桥梁结构ALT-TMD振动控制系统的控制效果及可行性。

针对运营及极端风环境，本项目开展了大跨度桥梁多层次振动控制研究，通过研发振动控制系统，进而构建其数学分析模型并开展参数优化，为大跨度桥梁的安全运营和科学管理提供理论参考和技术支撑。.主要研究成果如下：.（1）研发了一套具有工作开关的杠杆式调谐质量阻尼器控制系统(ALT-TMD)，能够实现大跨度桥梁在正常运营和极端风环境下的多层次振动控制，在确保桥梁安全的前提下，大大延长TMD的使用寿命。.（2）考虑极端风情况，研发了新型大幅自由振动试验装置，可用于桥梁大幅弯扭耦合振动风洞试验；基于该试验装置，构建了非线性气动力模型，开展了大跨桥梁后颤振试验，研究发现：极端风下桥梁出现明显的“软颤振”，即极限环振动，结构参数和气动参数存在幅值依赖性，线性理论不再适用。.（3）针对桥梁颤抖振现象，开发了极端风下后颤振自适应振动控制算法，提出了考虑非线性气动效应的颤振控制TMD参数设计方法，探究了杠杆式TMD的抖振控制。