Limit Bearing Capacity Analyasis Of The Natural Ventilation Cooling Tower Under Wind Load

Along with the modernization construction in our country,more and more natural ventilation cooling tower were built,for security reasons,in order to verify the importance of nonlinear factors in the analysis of bearing capacity of the cooling tower.In this article,based on the actual engineering project of yang ling buadian cooling tower,the author analysed the nonlinear ultimate bearing capacity of cooling tower.Cooling tower model is established by finite element software,eigenvalue buckling analysis was carried out on the cooling tower,It is concluded that the corresponding critical load,considering the geometric nonlinearity,material nonlinearity and geometry stiffness,analysed the ultimate bearing capacity of the cooling tower under the wind load.1.For the tower,the layered shell element was used to accurately simulate the distribution of circumferential reinforced layer,meridional reinforced layer and concrete layer;adopt the fiber beam element of ABAQUS finite element software to simulate Cooling Tower X pillars;used subroutine's key command to insert steel into the beam elements.The rebar use elastic-plastic servo stiffness of uniaxial constitutive model by user subroutine;The concrete use ignore the tensile strength of concrete model.2.The wind loading of the tower is selected according to the load specification,for there are"Cooling Tower Triangle" and "shutters" in X-pillars,the selection of X pillars' wind loading is considered under closed shutters(which means the wind load maxximum),and equivalent to the corresponding pillar.Then dynamic characteristics analysis is did on the cooling tower to get the order of the first few natural frequencies and mode shapes,and compared with similar projects,the obtained results are also similar,moreover the participation ratio of mass is greater than 90%.3.Under the condition of without considering the nonlinear factors,Eigenvalue buckling analysis of cooling tower under wind load and the weight of combination conditions,It is concluded that the cooling tower each order buckling mode and buckling coefficient,to calculate the critical load.At this point the load factor is 42.5,critical load is G + 42.5 W.4.Nonlinear ultimate load analysis of cooling tower was taken with considering nonlinear material,geometric large deformation and geometrical stiffness,the load-displacement curve of the observation point was known,the G + 2.21 W was the critical load under three non-linearity of the cooling towe.0 degrees on the meridian,the bearing capacity of the tower drum throat a minimum,the largest displacement of X direction;45 degrees on the meridian,the bearing capacity of the tower drum ring beam on the lowest,and the biggest displacement.5.Finally the difference between buckling analysis under linear and nonlinear situation eas compared,considering the nonlinear factors limit bearing capacity decreased by 19.23 than the linear elastic bearing capacity times.Emphasis the importance of nonlinear factors and provide theoretical reference to practical engineering.