钢-混凝土组合梁负弯矩区畸变屈曲弯矩计算公式

侧向弯曲屈曲及侧向弯扭屈曲均为钢-混凝土组合梁负弯矩区钢梁的重要屈曲模式,而现有计算方法通常只考虑到侧向弯曲屈曲,未考虑到侧向弯扭屈曲,因此有一定局限性。本文在钢梁腹板对钢梁下翼缘的转动约束刚度及侧向约束刚度的计算公式上,结合弹性介质中薄壁杆件的屈曲理论推导了工形钢-混凝土组合梁负弯矩区的侧向弯曲屈曲弯矩及侧向弯扭屈曲弯矩计算公式。实例分析表明,现有计算方法均存在一定理论缺陷,本文计算方法更为合理;同时,本文计算式比现有文献中同类型计算式更为简洁,便于手算,实用性强并适于工程应用。

The distortional buckling calculation formula of the steel-concrete composite beams in the negative moment region

Lateral bending buckling and lateral flexural-torsional buckling are both important buckling modes for steel-concrete composite beams in the negative moment region,and only the lateral bending buckling is considered in the existing computing method,so there is some limitations.Based on the rotational restraint stiffness and lateral restraint stiffness calculation formulas provided by the steel beam web plate to the lower cloud point flange and the thin-walled bar buckling theory in elastic medium,the calculation formulas of the lateral bending and lateral flexural-torsional buckling moment of the steel-concrete composite beams in the negative moment are derived.The example analysis shows that the existing computing methods all have some theory shortcomings,and the computing method of this paper is more reasonable.At the same time,the calculation formula of this paper is more concise than the calculation formulas of the same type,easy to be applied,so it is suitable for engineering application.