Nonlinear FEM analysis on the lifting strength and stability of the steel box girder-lift mast

The axial load is generated for 64m and 80m lift masts under the state of vertical hoisting, so it is needed to analyze the total strength and stability of the lift mast to ensure the hoisting security before formal application. Critical load of linear elastic buckling is computed for 64m and 80m large lift mast under the condition of inclined steel cables on the top by the use of nonlinear FEM method. Considering geometrical large distortion, the maximum load and stress of nonlinear buckling are calculated by the use of Lagrange-Euler method and. The results indicate that maximum working stress at lift mast's main limb under the condition of finite distortion is less than the material allowable stress, and lift mast under the state of nonlinear buckling state still meets the strength requirements. The maximum limit lift load of mast designed is less than calculated critical load of mast structure according to the linear and nonlinear finite element solution, so the structure of the lift mast meets the demands of both strength and stability and will not lose stability.