Out-of-plane elastic buckling of I-section steel arches braced laterally and design of bracing stiffness.

This paper presented the out-of-plane elastic buckling behavior of circular steel arches discretely and laterally braced, and based on FE analysis a threshold value of bracing stiffness for design was proposed. The effects of bracing parameters, including bracing stiffness, brace types, the number and longitudinal location of bracing point, on the arch elastic buckling behavior were investigated carefully. An equation for predicting the threshold value of bracing stiffness was obtained for equally-spaced lateral braces of pin-ended and fixed arches with I-section in pure compression. And the required arch segment length between bracing points to prevent the arch segment from elastic out-of-plane buckling was proposed. It shows that, the closer brace is to the crown of arch, the higher efficiency brance has to prevent out-of-plane buckling of arch. When arches with lateral braces buckle, buckling half-waves increase with the augment of bracing stiffness, while arches with torsional braces always buckle with one half-wave. For equally-spaced lateral braces, a threshold value of stiffness of arches in uniform compression is suitable to the arches under other general load conditions. When segment length meets the requirement mentioned above for arches with I-section, in-plane asymmetric buckling form will take place before out-of-plane buckling of arch segment. [ABSTRACT FROM AUTHOR]