以往在分析箱形吊臂腹板的局部稳定性时,认为腹板与盖板交接的纵向棱边为铰支。本文则考虑盖板的约束作用,提出约束效用系数η。η的大小由盖板的旋转刚度所决定,即由盖板对腹板的厚度比、宽度比和应力状态所决定。文中对腹板的初始缺陷的影响作了分析,最后推荐确定安全储备的公式。为计算方便,给出了图表,并有计算实例。 In the past when analyzing the local stability of the box boom webs, it is considered that the longitudinal edges of the webs and the cover plate are hinged. In this paper, the restraint effect of the cover is considered and the constraint utility coefficient η is proposed. The size of η is determined by the rotational stiffness of the cover plate, which is determined by the thickness ratio, width ratio and stress state of the cover plate to the web plate. The paper analyzes the influence of the initial defects on the web and finally recommends the formula for determining the safety reserve. For the convenience of calculation, a chart is given, with calculation examples.