Overall Stability And Deformation Simplified Calculation And Research On Geometric Parameter In Truss With Triangle Section

Truss that its longitudinal length is greater than the vertical length is lattice structure of mading up by many bars. Compared with solid web girder, truss takes less material and is light. Therefore, truss can give full play to the material properties, at the same time gets great performance on service function, the requirement of shape and economic effect.Truss is mainly divided into two forms that is with triangle section frequently in practice:one are made up of one top chord and two bottom chords, the other are made up of two top chords and one bottom chord. Flexural members have been existing calculation formula of overall stability, but are not for truss with triangle section in ’Code for design of steel structures’(GB 50017-2003). Therefore, effective calculations of overall stability and deformation and how influence to the geometric parameters on overall stability are important problems about truss with triangle section in this paper.Relying on the subject of ’the Application of steel pipe in structure’ by Kunming Iron & Steel Holding co., LTD. Truss with triangle section is taken as simply supported beam to research. The research focuses on the following aspects:First of all, making introductions about the characteristics and the application status of the truss, and introducing the basic theory of steel structure stability.Then it is assumed that the chord subjected to bending and web member under shear and torsion in simplified calculating of truss with triangle section, deriving bending stiffness and torsional stiffness; according to a plane web shear stiffness equivalent solid web thickness, deriving shear center position of box section with triangle section. Basing on thin-walled members elastic stability theory, the calculation formula of the critical moment can be obtained and calculation formula of deflection and torsion angle can be obtained under the action of moments and torques through bending stiffness and torsional stiffness about truss with triangle section.Later, basing on the result of using the finite element software ANSYS 13.0 eigenvalue buckling analysis and deformation analysis, the result will prove the accuracy of the simplified calculation formula of the critical moment, deflection and torsion angle.Finally, making researches on geometry parameters and suming up various factors the influence law of overall stability of truss with triangle section, which provides references for the design and application.