In-plane stability behaviours and design of web-opened steel arch

This paper proposes an innovative web-opened steel arch and investigated its buckling behaviours and strength design method. The web-opened steel arch is composed of two circular steel tubes as chords that are connected through discontinuously webs at a certain interval longitudinally. It is well known that the web-opened steel arch combines the advantages of both arches and web-opened beams, and find its wide application in spatial roof structures. First, the sectional shear stiffness of the web-opened steel arch is derived, and accordingly in-plane elastic buckling load considering sectional shear deformation under a radial uniformly distributed load is obtained as a theoretical solution. Moreover, the finite element model for predicting the elastic buckling load of the web-opened steel arch is established and the corresponding parameter investigation of the web-opened steel arch is conducted. Further, a comparison of the elastic buckling load is made between finite element results and theoretical solutions, verifying the accuracy of theoretical solution of the elastic buckling load. Secondly, a strength design method of the web-opened steel arch subjected to a full-span uniformly distributed load is established by a design curve regarding the normalized slenderness ratio and stability coefficient. Finally, an interaction design formula of the web-opened steel arch under a combined action of axial compression and bending moment on its section is proposed for its in-plane global stability capacity design.