基于演化谱理论的桥梁风致响应非平稳性分析

Nonstationary Analysis of Wind-induced Responses of Bridges Based on Evolutionary Spectrum Theory

基于Priestley演化谱理论,并结合小波变换原理,在理论上推导了非平稳随机过程演化谱估计的小波时域函数加权和法,从小波时域函数的角度建立了演化谱估计时域方法,弥补了传统演化谱估计方法需要小波频域函数这一不足。在此基础上,对实测台风"麦莎"全过程以及润扬大桥悬索桥在台风"麦莎"作用下的抖振响应进行了演化谱估计,分析了台风全过程及其风致响应的时频特性。研究结果表明:小波时域函数加权和法是一种估计非平稳随机过程演化谱的有效方法;台风"麦莎"全过程表现为强度强非平稳、频率弱非平稳,脉动风的脉动能量在整个台风过程中变化较大但主要频率成分变化较小;润扬大桥悬索桥主梁的风致抖振响应表现为强度非平稳、频率平稳,振动能量变化剧烈但频率成分基本不变。

Based on the principle of wavelet tr developed by Priestley, the property that the e weighted wavelet functions in time domain wa shortage of the traditional method that the clos was required, was established to estimate the ansform and the theory of evo volutionary spectrum was equa utlonary spectrum to the summation s deduced. A method, which could overcome the ed-form expression of wavelet in frequency domain evolutionary spectrum of nonstationary stochastic processes. Based on the field measurement data on Runyang Suspension Bridge, the evolutionary spectra of typhoon Matsa and wind-induced vibration in main girder were estimated and the time- frequency characteristics were analyzed. The results show that the proposed method can calculate the evolutionary spectrum of nonstationary stochastic processes accurately and effectively. The fluetuating wind of typhoon Matsa is high and nonstationary in intensity aspect but weak and nonstationary in frequency aspect. The energy of the fluctuating wind varies dramatically with the typhoon passing but the frequency components change little. The wind-induced vibration of the main girder of Runyang Suspension Bridge in frequency aspect. When typhoon passing, frequency components are constant. is nonstationary in intensity aspect and stationary the vibration energy changes obviously but the