北美规范与中国规范关于冷弯薄壁型钢C形截面受压构件设计的比较

对比了北美规范CSA S136-07和中国规范GB 50018-2002中关于冷弯薄壁型钢C形截面轴压构件的名义轴压强度。首先介绍了北美规范和中国规范计算名义轴压强度的方法，然后针对控制构件名义轴压强度的2个主要参数，即屈曲应力和有效截面面积，对2本规范进行了深入对比，最后对典型C形墙架柱名义轴压强度进行了比较。研究结果表明：2本规范具有相同的屈曲应力，但依据2本规范计算的有效截面面积却不同；一般来说，根据GB 50018-2002计算的翼缘有效宽度远小于根据CSA S136-07计算的结果，然而依据CSA S136-07计算的腹板有效宽度则略小于依据GB 50018-2002计算的结果；2本规范名义轴压强度不同主要由C形截面翼缘和腹板有效宽厚比不同引起；当翼缘的宽厚比不小于17．8时，构件名义轴压强度的不同主要由翼缘有效宽厚比控制，根据GB 50018-2002计算的名义轴压强度小于根据CSA S136-07计算的结果；当翼缘的宽厚比小于17．8时，构件名义轴压强度的不同则主要受腹板有效宽度控制，依据GB 50018-2002计算的名义轴压强度略大于依据CSA S136-07计算的结果。

On North American and Chinese Standards for Design of Cold-formed Steel C-section Compressive Members

Nominal axial compressive strengths of cold-formed steel C-sections evaluated by the North American standard CSA S136-07 and the Chinese standard GB 50018-2002 were investiga-ted .The procedures of evaluating the nominal axial compressive strength associated with both standards were analyzed and compared .The study results show that discrepancies between the two standards are primarily resulted from the difference in evaluating the effective area subjected to local buckling .For the C-section compressive members ,the flange effective width calculated by the Chinese standard is much smaller than that of the North American standard ,w hereas the web effective width evaluated by the North American standard is slightly less than that of the Chinese standard .For typical C-section wall studs ,the difference on the nominal axial strength is primarily influenced by the flange and web width-to-thickness ratios .When the flange width-to-thickness ratio is not less than 17 .8 ,the difference on the nominal axial compressive strength is dominated by the difference of flange effective width between the two standards and the nominal axial compressive strength evaluated by GB 50018-2002 is less than that of CSA S136-07;when the flange width-to-thickness ratio is less than 17 .8 ,the difference on the nominal axial compres-sive strength is then primarily governed by the difference of web effective width between the two standards and the nominal axial compressive strength evaluated by GB 50018-2002 is slightly greater than that of CSA S136-07 .