The Study On The Effect Of The Lateral Braces On The Out-of-plane Stability Of Circular Arches

The lateral stiffness of single-ribbed steel arch without braces is very small,so it is very prone to torsional-flexural overall buckling under loads.The buckling load of the steel arch is much smaller than the straight beam with the same span,so the strength of components have not been fully utilized.It is a effective way to apply the lateral braces on the steel arches for increasing the overall stability.In regard to the theoretical study of the stability of the arch,most scholars have focused on torsional-flexural overall buckling of single-ribbed arches without braces under uniform radial loads,and the assumptions used by researchers is very different,so the stability theory of arch is not as mature as the straight beam's.So far,because of the lack of the researches on the lateral braces'influence on overall stability and corresponding design approaches,its stability is not the correct estimate. In this paper,the task is making a comprehensive analysis of the lateral brac es'influe-nce on the overall stability.In this paper,the finite-element method is used to analyze the influence of single-lateral brace and multi-lateral braces on the overall stability of dual-axis symmetric I-section steel arches. When layouting single-lateral brace on the steel arch,the author researched the changing of the lateral brace's position and the lateral brace's stiffness on the influence of the overall stability and the relationship of lateral brace's position, load position and the stability of the steel arch. When layouting multi-lateral braces on the steel arch,the author researched the influence of the lateral braces'number,the late-ral braces'stiffness and the lateral braces'position on the stability of the steel arch and got out-of-plane effective length factor of the steel arch in accordance with the form of Euler's critical load of axial compression members.Through this study, the author hoped to improve the study of arches'stability and obtained results had reference value in the engineering design.