【摘要】 为揭示环境激励下不同测点反映的模态信息情况，在厦门财富中心布置结构台阵获取环境激励下的结构振动响应。采用Welch平均周期图法获得功率谱密度(power spectral density, PSD)曲线，并在此基础上识别结构模态参数。比较不同测点的PSD曲线和模态识别结果，并与有限元结果进行对比。结果表明：1)结构基底、自由场地和基岩场地三个测点PSD曲线在0.1～1.0 Hz频段高度相似，该频段是由场地次级微地震引起的；不同之处在于结构基底测点PSD曲线Z向峰值是结构竖向基频，而自由场地峰值是场地基本频率。2)结构低楼层测点主要反映其测试方向上的模态频率，而高楼层测点能够反映多方向的模态频率。高楼层测点反映的模态信息更丰富，但易受到密集模态的影响。3)有限元结果与实测结果接近，表明有限元模型可以较好地反映结构的真实动力特性。更多还原

【Abstract】 To reveal the modal information reflected by different measurement points under ambient excitation, a structural seismic response observation array was arranged in Xiamen Fortune Center to obtain structural vibration response. The power spectral density(PSD) curves were obtained using the Welch average periodogram method, and the structural modal parameters were identified on this basis. The PSD curves and modal identification results of different measurement points were compared, In additional, a comparison with the finite element model was completed. The results show that: 1) The PSD curves of the structural base, the free site and the bedrock site are highly similar in the frequency range of 0.1-1.0 Hz, which is caused by the secondary microseism of the site. The difference is that the Z-directional peak of the PSD curve at the structural base measurement point is the structural vertical fundamental frequency; while the peak at the free site is the site fundamental frequency. 2) The measuring points on the lower floors mainly reflect the modal frequencies in the test direction, while the measuring points of high floors can reflect the modal frequencies in multiple directions. The modal information reflected by the measurement points on high floors is richer, but it is vulnerable to the influence of dense modes. 3) The measured results are close to the finite element results, indicating that the finite element model is able to reflect the real dynamic characteristics of the structure.更多还原