Numerical Simulation of Seismic Responses of Complex Shape Super High-Rise Steel TV Tower

The structural height and antenna mast height of Ningxia super high-rise steel TV tower (NXTVT) is 216 m and 104 m, respectively. The shape of NXTVT resembles a small-bottom, large-top, and slender-waist-middle vase, which consists of three storey segments with 28 floors in total. Its discontinuous arrangement of floors leads to the uneven distribution of mass and stiffness, so that the overall design of this building is very complex and requires a high demand of seismic performance. Firstly, ANSYS code is employed to investigate the dynamic characteristics of NXTVT. Numerical simulation indicates the rotation effect is very significant, while the third and eight modes are rotation. Then, the response of this building under frequent earthquake is analyzed using both the response spectral analysis and time-history analysis, respectively. The seismic response of main structure is larger using the spectral analysis, while by resorting to the time-history analysis the whiplash effect can be brought out clearly. Accordingly, the seismic performance should be evaluated based on the simultaneous considerations of both results. Finally, the overall performance analysis and design proposal under multi-dimensional earthquakes are promoted. The elastic analytical results demonstrate that the deformation meet the requirements of code for seismic design of buildings. Likewise, the analysis methodology and conclusions drawn in this study have reference value in the calculation of super high-rise steel towers utilizing commercial finite element program.