为提高钢拱的平面外稳定性，钢拱的平面外通常布置有一定数目的弹性离散支撑。该文研究了拱顶设置单个弹性支撑作用时，箱形截面钢拱的平面外弹性屈曲性能。首先采用能量法推导得到了弹性支撑作用下，箱形截面纯弯两铰拱和纯压两铰拱的平面外弹性屈曲荷载；其次结合无支撑拱的弹性屈曲性能，获得了弹性支撑的门槛刚度计算公式。该方法的结果与有限元计算结果吻合较好，可以作为离散支撑均匀分布的箱形截面钢拱平面外弹塑性稳定设计的基础。
Arches are usually arranged with lateral bracings to improve their out-of-plane stability. The out-of-plane elastic buckling of box-section arches was analyzed with a single lateral bracing on the crown. The energy method was used to derive the formulas for the out-of-plane buckling loads on lateral braced box-section arches for uniform compression or uniform bending. Then, the out-of-plane elastic buckling solution for arches with no lateral bracings was used to derive the threshold stiffness of the lateral bracings. The out-of-plane buckling loads and threshold stiffnesses of the lateral bracings given by this method agree well with finite element results and can be applied to calculate the the out-of-plane inelastic strength of box-section steel arches with lateral bracings.
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