Abstract: This paper derives the concept that bimoment has critical value.According to the concept,an interaction formula that shows the relationship of various critical forces and a torsion angle amplification factor of members is obtained.A new modification of the formula is proposed to solve the problem that the formulas used in the plane and out the plane are disjointed in the present specifjcation.The initial imperfection and elastic-plastic property of the member are presented by an equivalent eccentric ratio.Finally,the formula is illustrated by several examples,e.g.columns and beams.

Key words: critical bimoment, interaction formula of critical forces, bimoment amplification factor, equivalent eccentric ratio, relative slenderness

摘要： 本文在建立临界双力矩概念的基础上,导出弹性杆件各临界力因素之间的相关方程和扭角放大系数,再用等效偏心率反映杆件的缺陷因素和弹塑性效应,提出双向偏心钢压杆的新校核式,避免了现行规范中面内压弯变形和面外弯扭变形校核式之间的不衔接问题。

关键词: 临界双力矩, 临界力因素的相关方程, 双力矩放大系数, 等效偏心率, 相对长细比