Structural health monitoring of Shanghai Tower during different stages using a Bayesian approach

The dynamic characterization of structures is essential for assessing their response when subjected to dynamic loads in structural health monitoring. It mainly comprises the modal parameters, that is, the natural frequencies, damping ratios and mode shapes. These modal properties are attracting more attention when structures are under construction or operation for the researchers, structure owner and engineers. This paper presents the work on the operational modal analysis of a super tall building-the Shanghai Tower with a height of 632 m situated in Shanghai, China. A recently developed fast Bayesian method is utilized to perform modal identification, providing an effective means to identify the modal properties and assess their accuracy. In this study, ambient vibration tests are implemented in different construction stages. The corresponding modal properties and their associated uncertainties are identified and investigated, with interesting trends observed. Finite element models are also established to obtain the modal parameters in different stages and compared with the identified results. After the main structure is completed, a field test covering the eight corners of the core wall in a typical floor is performed to investigate the mode shapes. Afterward, a 12-h measurement is performed with the information of temperature and humidity recorded simultaneously. The variation of modal properties with changing environment is studied. The results obtained will be beneficial for understanding the modal properties of this super tall building and provide a baseline for future structural health monitoring.