大跨度桥梁模态频率识别中的温度影响研究

针对由环境激励响应辨识得到的桥梁模态频率会受到温度影响的问题,通过建立模态频率-温度分布模型,对香港汀九大桥长期振动和温度分布测试数据进行了分析研究。研究结果表明:不仅环境温度波动会引起模态频率的变化,大跨度桥梁结构上不同部位温度分布的模式对模态频率也有显著影响。对多种建模方法分析比较的结果表明:支持向量机(SVM)的非线性回归模型可以有效地消除引起模态频率变化的环境温度和温度分布模式因素的影响。给出了运用SVM的非线性回归算法消除温度影响的具体方法以及运用这种方法对汀九大桥600 h连续测试数据的处理结果。

Research on Temperature Influences in Long-Span Bridge Eigenfrequencies Identification

Aimed at the problem that consecutive time series of eigenfrequencies identified from ambient exciting bridge structure responses are always influenced by temperature,a problem being paid much attention by bridge monitoring and health estimation applications,a research work with modeling eigenfrequency and temperatures was performed upon long term acquisitions of vibration and temperatures from the Ting Kou Bridge in Hong Kong.The research results show that eigenfrequencies vary not only followed atmospheric temperature fluctuation but also associated remarkably with the temperature distribution patterns over the structure.To eliminate temperature complications from eigenfrequency time series,an approach based on SVM nonlinear modeling algorithm was proposed in the paper.The effect of its application of 600 hours test data from Ting Kou Bridge was also described.