上海中心施工过程动力特性的数值模拟与监测

Numerical simulation and monitoring of dynamic property of Shanghai Tower under construction

为分析上海中心在施工阶段的模态变化,对其在施工阶段的动力特性进行长期监测,介绍某次环境激励下的振动测试,分析施工活动对模态识别的影响,并提出应用短时傅里叶变换技术选取合适监测数据以减少施工活动干扰,提高识别精度。最后,将识别结果与考虑实际施工过程的Midas/Gen有限元模型计算结果进行比较。研究结果表明:施工阶段下结构的加速度振动幅值随施工阶段明显增大;模态频率实测结果低于数值模拟结果;应用短时傅里叶变化技术选取合适监测数据能有效减少施工干扰;基于环境振动的施工阶段模态参数识别可用于修正上海中心的初始有限元模型,为今后运营阶段的健康监测提供更精确的基准模型。

A long-term health monitoring project on Shanghai Tower’s dynamic property under construction was conducted. Given a detail introduction of an ambient vibration test, a short-time Fourier transformation （STFT） technique was proposed to select the data with less construction activities interference to improve the identification accuracy. Then, identification results were compared with those of the finite element model of Midas/Gen. The monitoring results indicate that root mean square acceleration response of structure increases with the construction proceeding; modal identification results are lower than the FE results; STFT technical can improve the identification precision by selecting measurement data with less construction interference, which shows that modal parameters identified under construction can be used to update the Shanghai Tower’s FE model for obtaining a more accurate baseline model for future health monitoring.