Threshold Stiffness of Discrete Lateral Bracing for Out-of-Plane Buckling of Steel Arches

Abstract

Steel arches are often restrained by elastic lateral braces to improve their out-of-plane stability. Because in real structures, the braces are not infinitely elastic and the strength consideration can have an effect on the stiffness requirement of the braces, it is important for the lateral braces to have sufficient stiffness and to be configured properly. This paper presents an investigation of the threshold stiffness and arrangement of discrete lateral braces required for preventing steel arches from buckling out of their plane. An energy approach is used to derive the elastic threshold stiffness for discrete lateral braces, and the effect of out-of-plane geometric imperfections on the elastic threshold stiffness of the lateral bracing is also studied. The number of lateral braces and the length of the arch segment between adjacent braces are also derived analytically by comparing the in-plane buckling loads of the entire arch and the out-of-plane buckling loads of the arch segment between adjacent braces. The threshold stiffnesses derived in this study agree well with the finite-element results. The agreement between the analytical solutions for the minimum number of lateral braces and the maximum length of the arch segment between the braces and the finite-element results is also very good.