Study On Wind Load Characteristics Of A Kilometer-scale Mega-tall Building Considering Wind Direction Changes

With the continuous development of urban intensification,land resources are tense,and residential intensification is deepening.As the height of buildings is constantly refreshing records,more and more super high-rise buildings are constantly emerging,and the kilometer-scale buildings are about to appear.When the structure reaches the kilometer level,it is more sensitive to wind loads.A large number of on-site measured results show that the horizontal wind direction angle changes with height,which may lead to large asymmetric load and torsional response of the structure;in addition,in "Building Structure Load Specification"(GB 50009-2012),when the structure is higher than 550 m,it is impossible to determine the form of the wind profile.The above two factors have seriously affected the accurate assessment of wind load and wind-induced response of the kilometer-scale mega-tall buildings.Therefore,it is necessary to determine the reasonable flow within the height range of kilometer and accurately simulate it to study the wind load and wind-induced response characteristics of the kilometer-scale mega-tall buildings.At present,wind tunnel test and CFD numerical simulation research in this aspect are still few and basically in a blank state.In order to solve the above problems,in this paper,the wind tunnel test method and CFD numerical simulation technology are used to study the wind load characteristics of the three-type section of the kilometer-scale super high-rise building.The main contents in this paper are given as follows:1.In this paper,the exponential law average wind speed profile,the Ekman spiral average twisted angle profile and the turbulence profile in the "Building Structure Load Specification" are used as the target wind field characteristics.The self-designed baffle system is combined with the traditional passive simulation device to generate a kilometer height wind field with a ratio of 1:1000.The adjustment rules of different devices are summarized,and the wind speed statistical characteristics of the wind field at the height of kilometer are analyzed.To lay the foundation for the subsequent study of the deflection wind effect of the kilometer super high-rise buildings.2.Simultaneous pressure measurement tests are carried out on super high-rise buildings with different shapes(square,rectangular and circular).The influence of building shape,wind twisted angle and wind direction angle on wind load characteristics of kilometer super-tall buildings is evaluated.The twsited wind effect is discussed to explore its mechanism of action.3.Based on the RANS method,a numerical simulation method for wind load characteristics of a kilometer-scale building under the action of twistwd wind flow is established.The effects of different twisted wind flow on wind loads of a kilometer-scale building are further studied.And then the mechanism of action is studied by the advantages of CFD numerical simulation visualization.