云南漾濞地震大理某高层建筑结构地震响应观测数据初步分析

2021年5月21日21时21分至22时32分，云南漾濞先后发生了M5.6级、M6.4级、M5.0级和M5.2级地震，位于大理的某高层建筑结构地震反应观测台阵获取了这4次地震的结构动力响应，观测数据同步性好，数据质量高。该高层建筑为框架剪力墙结构，地上26层，地下1层，三分量加速度测点共8个分别位于建筑的第1层、4层、7层、10层、13层、17层、20层和25层，数据实时传输至中国地震局工程力学研究所燕郊数据中心。本文对结构台阵的观测记录进行了初步分析，绘制建筑结构观测楼层的三向绝对加速度及其傅里叶幅值谱，检验数据同步性和质量，通过滤波和积分得到相对速度和相对位移，利用功率谱方法分析得到频率响应函数，并利用复模态指数函数方法得到两水平方向前三阶模态频率和振型。通过4次地震结构模态频率和振型的初步对比结果表明:主体结构基本完好，这与现场调查结果吻合。该结构台阵获取的前震、主震和余震反应记录，为后续开展深入的模态参数分析、地震损伤识别以及研究框架剪力墙结构的振动特性和抗震性能提供了宝贵数据。

Preliminary analysis of structural seismic response of a tall building in Dali recorded in Yunnan Yangbi earthquakes

M5.6, M6.4, M5.0 and M5.2 earthquakes struck successively in Yangbi, Yunnan from 21:21 to 22:32 on May 21, 2021 in Beijing time. The structural response observation array of a high-rise building in Dali successfully obtained the seismic response under the four earthquakes. The observation data has good synchronization and high quality. The high-rise building is a frame shear wall structure with 26 floors above ground and 1 floor underground. The structural array has 8 three-component acceleration measuring points arranged on the first, fourth, seventh, tenth, thirteenth, seventeenth, 20th, and 25th floors of the building, and the observation data is transmitted to Yanjiao data center of Institute of Engineering Mechanics, China Earthquake Administration in real time. This paper carries out the preliminary analysis of the structure array records. To check the quality of records, three-dimensional absolute accelerations and their Fourier amplitude spectra are drawn. The relative velocities and displacements are obtained through band-pass filtering and integration. Frequency response functions are obtained by the power spectrum method. Complex mode indicator function are used to obtain the first three modal frequencies and modal shapes in two horizontal directions. The preliminary comparison results of the modal frequencies and modal shapes under the 4 earthquakes show that the main structure is basically intact, which is consistent with the field survey results. The foreshock, mainshock, and aftershock response records obtained by the structure array provide valuable data for subsequent in-depth modal parameter analysis, seismic damage identification, and research on the vibration characteristics and seismic performance of frame shear wall structures.