On May 18, 2021, there was a sense of vibration in the SEG Plaza Building. Shenzhen City initiated an emergency response immediately. The Municipal Emergency Bureau and the Futian District Government organized the property management party to immediately evacuate the people in the building in an orderly manner and closed the building. Manage and carry out necessary traffic control in the surrounding area. The monitoring data of vibration, tilt and settlement of the SEG Plaza Building are released daily on official channels such as "Shenzhen Release". Demonstration and analysis of structural safety and vibration reasons.
Recently, through technical investigations, environmental and equipment operation investigations and tests, the expert team ruled out factors affecting subway operation, construction or blasting of surrounding projects, and operation of air-conditioning units.
Through the key analysis of wind-induced vibration and structural damage, the expert group believes that the coupling of wind-induced vortex-induced resonance of the mast and changes in the dynamic characteristics of the building and the mast has caused the perceived vibration of the SEG Plaza Building.
Under steady-state and specific wind conditions that lasted for a certain period of time, the mast of the building produced a fourth-order inverted asymmetric vortex-induced resonance with a frequency of 2.12 Hz, which stimulated the high-order bending and torsion of the main structure of the building with a frequency of 2.12 Hz Combined modalities, which in turn cause perceptual vibrations in the main structure of the building.
After the building has been in use for more than 20 years, the cumulative damage of the local floor profiled steel plate composite floor and the mast connection point has changed the structural frequency, damping ratio and other dynamic characteristics. The mast and the main structure of the building have a common vibration frequency of 2.12Hz, forming resonance Necessary conditions.
The above-mentioned local cumulative damage only has an impact on the dynamic characteristics of the structure, and does not affect the safety of the main structure.
The expert group believes that removing the mast can effectively solve the problem of perceived vibration in the building. The original lightning protection and navigation mark functions of the mast can be re-arranged on the roof of the building after the mast is removed.
The Shenzhen Municipal Bureau of Housing and Urban-rural Development stated that the demolition project will be implemented in the near future and the damage repair project will be carried out simultaneously. The effective construction period is about 32 days.
If it is affected by extreme weather such as torrential rain, typhoon, high temperature, etc., construction operations will be stopped in due course and the construction period will be postponed.
In order to ensure the safety of people’s lives and properties, strict protection measures will be taken during the demolition, and the SEG Plaza Building and some of the surrounding roads will be closed for management.
Editor in charge: [Ji Xiang]