Stability Of Circular Arch Made Of Rectangular Cross-section Circular Steel Tube Space Truss Hinged At Both End

As a kind of space spanning structure,steel arch structure is widely used in bridges and large-span buildings.It has the characteristics of simple structure,convenient construction and light weight.This paper studies the out-of-plane and in-plane stability of circular steel tubular space truss arch with hinged rectangular section at both ends,and summarizes the corresponding design methods to provide reference for practical projects.In this paper,the torsional stiffness and lateral flexural stiffness of the space truss arch are deduced theoretically,and the first order elastic buckling load of the arch under the action of radial uniform load and end bending moment load is obtained.Through the elastic buckling analysis of the arch,it is found that Timoshenko’s classical solution of the first-order elastic buckling load under the end bending moment load is not applicable to the space truss arch with small rise-span ratio,so the out-of-plane elastic buckling load formula of the space truss arch under the end bending moment load is modified by the coefficient.In this paper,the out-of-plane stability curve of space truss arch under radial uniform load and end bending moment load is obtained through the pure compression regularization slenderness ratio and pure bending regularization slenderness ratio,and the design method of pure compression and pure bending space truss arch is proposed.On this basis,the elastic-plastic stability and failure mechanism of space truss arch under full-span and half-span vertical uniformly distributed loads are studied,and a conservative lower boundary is provided for the out-of-plane stability bearing capacity through the interaction equation,thus the design method of out-of-plane stability bearing capacity of space truss arch is obtained.The space truss arch is composed of chord and web members.Before the arch reaches the stable bearing capacity,the chord and web members may lose stability and damage,thus reducing the stable bearing capacity of the arch.In this paper,assuming that the chords and webs of space truss arch only bear axial force,the design formula to prevent the chords and webs from destabilizing is derived.In the first-order elastic buckling analysis of space truss arch,the shear stiffness has a great influence on the load of the first-order elastic buckling of space truss arch in plane.In the elasto-plastic analysis,the in-plane stability curve of the space truss arch under the radial uniform load is obtained,and the design method of the in-plane elasto-plastic stability of the pure pressure space truss arch is obtained.Under the action of full-span and half-span vertical uniform load,the space truss arch mainly bears the combined action of axial force and bending moment.Based on the design method of in-plane stability of space truss arch under pure pressure,the design formula of in-plane elastic-plastic stability of space truss arch under compression and bending is proposed.