# Field Measurement Study on Dynamic Characteristics of the Shanghai World Financial Center
## 4 Conclusions  
The dynamic characteristic parameters of the SWFC and their amplitude correlation variation laws were investigated based on the measured data of the vibration response of the SWFC under four earthquakes in Yilan, Taiwan (E1); Kyushu Island, Japan (E2); East China Sea (E3); and Sheyang, Jiangsu (E4). The main conclusions were as follows:  
1. During the four earthquakes, there was a high level of consistency in the vibration responses of the SWFC in the X and Y directions, and the maximum acceleration response amplitudes all occurred in the X direction, which were 1.984, 0.656, 6.573, and 1.027 cm/s\({}^{2}\), respectively.
2. In super tall buildings, the superstructure is highly sensitive to vibration excitation, and the dispersion of vibration response amplitudes and acceleration signals increases with the increase in floor height.
3. The improved E-RDT method was verified and used to identify the dynamic characteristics of the SWFC. The natural frequencies identified in the X-direction of the SWFC were the same as those in the Y-direction, and the first-order natural frequencies were about 0.151 Hz in the X-direction and 0.153 Hz in the Y-direction under four earthquakes; the second-order natural frequencies in the X and Y directions were about 0.46, except for the parts affected by the installation of sensor. Except for the influence of the dampers installed in the SWFC, the first- and second-order damping ratios in the X and Y directions of the SWFC were smaller than 1%, indicating that the stiffnesses of the two directions were similar.
4. As the amplitude increased, the first two natural frequencies of the SWFC decreased in the X and Y directions, and the damping ratios also increased to varying degrees. In contrast to damping ratios, natural frequencies were less sensitive to changes in amplitude.
5. The mode shape of the SWFC under different seismic excitations was essentially the same. The first-order mode shape in X and Y directions increased with the increase of floors and exhibited a non-linear trend, while the non-linear trend of the second-order and third-order modes was more significant but did not always increase.  
Methodology, H.K.; Validation, G.Z.; Formal analysis, H.K.; Investigation, P.Z.; Resources, P.Z.; Writing--original draft, H.K.; Writing--review & editing, X.W. and G.Z.; Supervision, X.W.; Project administration, P.Z. All authors have read and agreed to the published version of the manuscript.  
This paper was partially supported by the Natural Science Foundation of Chongqing (Project number: CSTB2022 NSCQ-MSX1655), the State Key Laboratory of Structural Dynamics of Bridge Engineering and Key Laboratory of Bridge Structure Seismic Technology for Transportation Industry Open Fund (Grant No. 202205) and the National Natural Science Foundation of China (Grant No. 12002069).  
Not applicable.  
All data generated or analyzed during this study are included in this article. All data included in this study are available upon request by contact with the corresponding author.  
On behalf of all authors, the corresponding author states that there is no conflict of interest.