冷弯型钢檩条的有效截面

Effective section of cold-formed steel purlins

冷弯型钢檩条按(GB50018—2002)计算,截面大多达不到完全有效,需对其作屈曲后的强度计算。而翼缘非全部有效的卷边槽钢、Z形钢毫无对称性,使应力分析计算十分复杂。本文针对承受重力荷载檩条的特点,论证畸变屈曲对设计不起控制作用,从而得出翼缘和腹板全部有效比较宽松的条件,现有卷边槽钢和Z形钢规格大部分全部有效。提出的公式既可简化计算,又可节省钢材。

Cold formed thin walled steel purlins, calculated according to Chinese Design Code (GB50018—2002), mostly can not have their section fully effective. Lipped channel and Z section with compression flange not fully effective, have no more any symmetry, so that their stress analysis become quite complicated. In conformity to the working conditions of purlins subjected to gravity load, this paper revealed that distortional buckling does not play a decisive role in this case and thereby releasing the severe restriction on the effectiveness of plate elements, making the calculation simple and the design less costly in material consumption.