Research On Overall Stability Of Tower Crane Jib Structure And The Development Of Calculation Software

With the rapid development of the national economy,due to the needs of the construction of large-scale and super high-rise building construction projects and nuclear power projects,the working range requirements of the tower cranes have gradually increased,and the tower crane jib structure has been changing towards to the goal of large-scale,lightweight and softening.Therefore,the problem of the stability of the jib is becoming more apparent.At the same time,the use of the tie rods causes the jib to withstand multiple non-conserving forces outside the lifting plane,the calculation of the stability of the jib becomes more complicated,which leads to greatly increase in the amount of modeling and calculation of the designer during the engineering design period.Therefore,this paper will combine the latest version of the national standard?Tower Crane Design Specification GB13752-2017? and relevant research results in recent years to improve the stability theory of double suspension point jib.Then,this paper developed a calculation software about tower crane jib Stability based on the theory above.In order to improve the shortcomings of the existing theory,this paper adds the influence of the self-weight of the jib and the eccentricity of the lifting point to the existing out-of-plane buckling characteristic equation.The structural degradation of the jib of the double-hedge horizontal tower crane under different working conditions was analyzed,and the degradation results of the calculation model of the boom were judged according to the axial force of the two tie rods.For the stability analysis in the hoisting plane,the elastic support is added on the basis of the traditional simple support model.The new displacement equation of the double lifting point jib in the hoisting plane is derived by the angular displacement method.The result is more reasonable.In addition,this paper introduces the stability calculation method of the new structure with a single waist rope jib structure.In order to improve the efficiency in the tower crane design process,the lattice arm is usually equivalent to the solid belly component.Therefore,this paper summarizes and compares the equivalent inertia moment calculation theory of the existing lattice structure,and summarizes the triangle.The two methods of calculating the equivalent moment of inertia of the triangular and quadrilateral cross-section lattice structure are summarized,namely the converted slenderness ratio method and the equivalent stiffness method.At the same time,considering the characteristics of the jib-type of luffing jib tower crane,this paper introduces the calculation method of the equivalent moment of inertia of the uniform variable section,step variable section and symmetric variable section boom.Finally,combined with the above content,the C# language and Matlab language mixed programming technology is used to build the calculating software.The software combines the advantages of Visual Studio in user interacting and the advantages of Matlab in data processing.The platform can finally calculate the critical axial force of the jib instability,the critical load and the calculated length factor under various jib types,multiple working conditions and various jib sizes.And a calculation report can be generated to provide a reference for the tower crane designer.The research results of this paper will be of great significance to improve the efficiency and computational accuracy of designers.