Effects Of Tower Crown On Aerodynamic Forces And Wind-induced Responses Of Super High-rise Buildings

As a kind of enclosure structure on the top of super high-rise building,tower crown has different functions and shapes.With the increase of the height of the super high-rise building,the height of the tower crown itself has reached more than 30 m.The wind load is not only the control load in the design of super high-rise buildings,but also one of the important factors that limit the height development of super high-rise buildings.the wind load on the tower crown acts on the top of the super high-rise building and has a great influence on the overall wind load and wind-induced response of the structure.therefore,through small changes to the shape of the structure to reduce the wind load or wind-induced vibration has become one of the research directions of wind-resistant design of super high-rise buildings.In the present study,the wind tunnel tests of 20 tower crowns at square cross-section super high-rise buildings are carried out in an atmospheric boundary layer by using high-frequency force balance technology.The effects of opening,step,slope,and cone shape tower crowns on the aerodynamic force and wind-induced responses of the structure are discussed.The specific work is as follows:(1)This paper introduces the present situation of the research on wind resistance of super high-rise buildings,and expounds the equipment parameters used in wind tunnel test and the data calculation method and principle of high frequency force balance test.(2)Based on the test data,the effects of four kinds of tower crowns on the aerodynamic characteristics of super high-rise buildings in downwind direction and crosswind direction are analyzed,and the variation rules of base moment coefficients of different tower crowns in different wind angles and different upwind directions are given.(3)The values of structural parameters are defined,and the effects of different tower crowns on the base bending moment power spectrum in different upwind directions are discussed.according to the structural parameters,the displacementresponse and acceleration response are calculated,and the influence of tower crown on wind-induced response is analyzed in detail.some suggestions are provided for the shape selection of the top tower crown of super high-rise buildings.