Wind-induced Vibration Response Analysis And Vibration Reduction Control Of High-rise Buildings With Masts

With the continuous breakthrough of building height and span,and the more and more extensive application of light and high-strength materials,the problem of vibration comfort has become more and more prominent and has attracted widespread attention in society.In May,2021,the SEG Building in Shenzhen experienced a large shaking for three consecutive days,which aroused continuous public concern.In order to explore the essential problems behind the shaking of the building,this paper comprehensively used wind tunnel test,numerical analysis and theoretical calculation to carry out wind tunnel test research on the main structure of the building and vortex-induced vibration analysis of the top mast,and calculated the wind-induced vibration acceleration of the building under the combined action of normal wind,and made indepth analysis combined with the evaluation criteria of wind-induced vibration comfort,and obtained the main reason for the wind-induced vibration of the building.By revealing the essence behind the wind-induced vibration of buildings under local excitation,it is helpful to provide guidance for the structural design and operation of high-rise buildings with such masts.The main research contents of this paper are as follows:(1)Wind tunnel test of main structureIn this paper,the wind-induced vibration response of the main structure is studied by rigid pressure wind tunnel test,and the acceleration sensitivity analysis of parameters such as wind speed,structural period and damping ratio is carried out considering the influence of surrounding environment changes,and the vibration response of the structure is evaluated in combination with the current code.The results show that,without considering the mast,the overturning moment of the foundation of the structure is far less than the standard value,the acceleration response changes obviously with wind pressure,structural frequency and damping ratio,and the acceleration of the center of mass and the acceleration of the corner meet the comfort requirements,which shows that the wind load of the main structure is not the main cause of structural vibration.(2)Vortex-induced vibration analysis of the top mastThe vortex-induced resonance(VIR)effect of the top mast is studied by numerical simulation,and the effects of three-dimensional effect,incoming wind speed and wind direction angle on the lift-drag coefficient and vortex shedding frequency are analyzed.At the same time,the equivalent bottom reaction force of VIR of the mast is applied to the top of the structure,and the acceleration response of the main structure with mast is obtained.The results show that the cantilever section of the mast can stimulate periodic vortex shedding near the measured wind speed and cause high-order vortex vibration of the mast.Considering the mast,the acceleration response of the structure exceeds the comfort evaluation limit in different degrees.When the mast damping ratio is 0.3%,the maximum corner acceleration exceeds the H-90 limit in Comfort Evaluation Standard and Control Technical Specification for Wind-induced Vibration of Tall Building(DBJ/T 15-216-2021),and the comfort is poor.It is verified that the main cause of structural vibration is the high-order mode resonance of the main structure induced by vortex-induced resonance of the top mast.(3)Study on structural vibration reduction based on mastThrough numerical calculation,the effects of different vibration reduction schemes,such as before and after dismantling the mast,changing the offset distance of the mast and adding spoiler,on the wind-induced vibration acceleration of the building are analyzed,which provides reference for solving this kind of vortex vibration problem.The results show that the removal of the mast has obvious inhibitory effect on the acceleration of the building;By reducing the offset distance of the mast,the acceleration of the corner of the building can be effectively reduced,and the comfort is good when the mast damping ratio is 1% without offset.Additional cross-shaped and X-shaped spoilers have obvious inhibitory effects on the lift coefficient,frequency and acceleration of the main structure of the mast.For the additional cross-shaped spoiler,when the damping ratio of the mast is 0.3%,the comfort is good when the rib height of the spoiler is 0.1D and 0.3D,and for the additional X-shaped spoiler,the comfort is good in all working conditions.