In-construction Wind Environment Simulation And Multi-case-based Wind Effect Analysis Of Outer-attached Tower Crane To Frame Core-tube Super High-rise Buildings

With the development of economy and society,the number of super high-rise buildings is increasing and the height is increasing.As a typical wind-sensitive structure,the wind-resistant safety of super-tall buildings is particularly critical.As a slender and flexible structure in a complex environment at high altitude,the wind-induced response of the tower crane attached to the construction equipment is more complex,and it is prone to collapse under the action of strong wind.At present,most of the existing researches focus on the completed buildings,and the research on the surface wind load characteristics of super high-rise buildings and attached tower cranes in the construction stage is almost blank.However,in the construction stage,there are a large number of window openings,construction safety net and large construction equipment attachment due to the lack of curtain wall installation,resulting in more complex surface wind field distribution in the construction stage of super high-rise buildings.The surface wind field characteristics of the attached tower crane under the influence of the attached building are not clear yet.In order to conduct a detailed study on the surface wind pressure and wind field characteristics of super high-rise buildings and external attached tower cranes during construction period,this paper conducts a large amount of analysis based on CFD numerical simulation platform and combines the construction technology of super high-rise buildings in the external frame-core tube structure system.The following tasks are mainly completed:(1)A simplified partition model of super high-rise frame core tube structure was established during the construction period,and the influence of various factors on the wind field around the building structure was analyzed.First of all,according to the actual construction situation,the simplified model of super-high-rise building partition section during the construction period was established considering the factors such as the lack of curtain wall installation of the main structure,the construction safety net and the leading construction of the core tube.The construction safety net area was simplified into Porous media,and the additional source term method was used to solve the problem according to the Porous Jump boundary conditions.The wind field simulation was carried out on the model with a closed building appearance,the hollow out model with an uninstalled curtain wall,themodel with a construction safety net,and the model with a circular building section,respectively,and compared with the numerical value calculated according to the specification.This paper analyzes the influence of various factors related to the construction characteristics on the flow field around the building.(2)The characteristics of the attached system in construction period were analyzed and the simulation scheme was formed.The wind field simulation model of the attached system was established and the method of solving the problem was summarized.According to the principle of the same windshield area,a simplified CFD analysis model of the external attached tower crane was established by using a triangular prism with isosceles right triangle as the cross-section instead of the Angle steel bar,and an attachment system model was formed.In order to improve the solving accuracy of the complex model,the mixed grid was divided between the inner and outer basins,and the parameter setting and the problems encountered in the solving process were analyzed and summarized.Finally,the wind sensitivity analysis model of the attached tower crane was formed according to the characteristics of the construction stage.(3)The wind environment characteristics of the super-high-rise attachment system during the construction period was analyzed,and the wind-sensitive working condition of the externally attached tower crane was determined.The attached system and the externally attached tower crane were taken as the research object,the wind pressure distribution and the surrounding flow field change of the attached system model and the externally attached tower crane were analyzed at the different wind direction angles and different boom rotation angles.Extract and calculate the overall wind pressure coefficient of the externally attached tower crane,analyze the law of wind load from all directions,and compare the wind load on the surface of the externally attached tower crane under different working conditions,so as to determine the most sensitive working condition of the tower crane to wind load.