高耸结构建造阶段环境振动测试与模态分析

以建造阶段的广州新电视塔为研究背景,详细介绍了在一般风荷载激励下,对其进行的一次环境振动测试,然后用频域法和时域法两种不同的方法识别出了在测试阶段电视塔的前十阶模态频率及相应的振型和阻尼比,并与SAP2000有限元模型的计算结果进行了比较。结果表明本次频率的测试值和理论值低阶模态频率符合得很好,但高阶存在一定的差异。表明此次环境振动测试结果可以用来修正电视塔的初始有限元模型,从而为今后的健康监测和损伤检测提供较精确的基准模型。

Ambient Vibration Test and Modal Analysis for High-rise Structure under Construction

Taking the Guangzhou New TV Tower (GNTVT) under construction as a test bed, a detailed introduction of a ambient vibration test conducted on it under normal wind excitation is given. Two different modal analysis methods, namely, frequency domain based method and time domain based method are used to identify the modal parameters of the tower. The first ten modal parameters, namely, modal frequencies, mode shapes and damping ratios, have been identified successfully from both methods, and they are compared with those from finite element model of SAP2000. It is shown that several low modes agree well with the analytical ones, but large errors are observed in the higher modes. This shows that modal parameters from this test can be used to update the finite element of the tower, such that a better 〖JP3〗baseline model of the tower can be obtained for future health monitoring and damage detection for the tower.