Study On Aeroelastic Performance Of High-rise Buildings With Varying Unconventional Configurations Based On Measured Urban Wind Field

As typical wind sensitive structure,the wind-induced vibration of super-tall buildings is an important control parameter to measure its safety and comfort.Periodic vortices can generate on the acrosswind directions of the structure when the wind flow passes the structure,and vortex shedding can cause the crosswind vibration of the building.When the vortex shedding frequency is close to the structural natural frequency of acrosswind direction,the wind-induced vibration will increase significantly,and vortex-induced resonance occur.This phenomenon is easy to cause the damage of retaining structure,and the damage or even collapse of the main structure.Therefore,it is necessary to accurately evaluate the acrosswind wind-induced response of high-rise buildings in structural wind resistance design.The wind field characteristics and building shape are important factors which affecting the acrosswind response significantly.In terms of wind field,the average height of buildings and the number of super tall buildings in the city increases significantly with the economic progress,which changes the lower cushion characteristics in the urban boundary layer,and further affects the wind field characteristics.Therefore,it is necessary to study the wind field characteristics of the urban boundary layer through wind field measurement,and investigate appropriate wind speed and turbulence profiles for accurately evaluating the wind load and wind-induced response characteristics of high-rise buildings;In terms of building configuration,due to the function and aesthetic needs,the configration of high-rise buildings is mostly unconventional section shape,while the classical wind resistance theory of super-tall buildings is mainly based on square-section high-rise buildings.Therefore,it is necessary to evaluate the acrosswind response characteristics of high-rise buildings with unconvention configuration through rocking model test,so as to provide basis for engineering design.According to the above,the influence of wind field characteristics of urban boundary layer in dense urban area,wind fields and building shapes on the acrosswind response of high-rise buildings,and the coupling vibration effect of super tall buildings are studied in this paper,based on the field measured data of wind speed in the urban center and the rocking model test.The main work is as follows:(1)The profiles of mean wind speed and turbulence intensity in dense urban area are fitted by the field measured wind speed data in urban center which is suitable for wind resistance design of super high-rise buildings,and the wind field characteristics of urban boundary layer are analyzed.(2)The vertical layered structure of urban boundary layer is determined according to atmospheric stability and friction velocity calculated by using the high-frequency wind speed data collected by ultrasonic anemometer.The characteristics of horizontal and vertical full-scale wind speed spectrum in different sub-layers of urban boundary layer are studied and compared with that in coastal and mountainous areas.The particularity of full-scale wind speed spectrum in urban boundary layer and the difference of full-scale spectrum in different sub-layers are investigated.(3)Using the measured urban wind profiles from the wind field measurement research,and the class B and D wind fields corresponding to the suburban terrain and urban terrain in the structure load code,the effects of wind fields on acrosswind response characteristics of the square-section high-rise buildings are studied.The analysis shows that the crosswind response is obviously affected by aerodynamic damping under suburban terrain and urban terrain.The crosswind aerodynamic damping characteristics of the structure are identified by Van der Pol(GVDP)aerodynamic damping model.Under the measured urban wind field,the crosswind vibration of the structure is mainly the random buffeting caused by turbulence of incoming flow,and the aerodynamic damping can be ignored.(4)Based on rocking model test,the acrosswind displacement response characteristics of high-rise buildings with 12 different kinds of buildings with varying unconventional configurations in suburban terrain and field measured urban terrain are studied.In the suburban terrain,buildings with those above 12 different kinds of shapes are evaluated,the building configurations that are not conducive to the crosswind aeroelastic performance are determined,and the acrosswind displacement response characteristics and aerodynamic damping characteristics of these models are analyzed in detail.Under the field measured urban terrain,building with each shape configuration has good aeroelasic performance,and the acrosswind wind-induced response is mainly dominated by buffeting force.The building shape can be judged by the corresponding aerodynamic performance.(5)The rocking model test is improved to ensure the consistency of the natural vibration frequency and damping ratio of the model in both the along-and across-wind directions.By changing the mass of the model,the coupling vibration effect of square-section high-rise buildings under different Scruton numbers are analyzed.It is found that when vortex-induced resonance occurs in the acrosswind direction,the alongwind wind-induced response increases significantly,and the probability density distribution of displacement response shows hardening non-Gaussian characteristics.In addition,the influence of stiffness ratio on the coupling vibration effect is studied by adjusting the natural frequency ratio of along-wind and across-wind direction.