风吸力下檩条承载性能中外规范比较

Comparison of Chinese and Foreign Design Standards on the Bending Behavior of Purlins under Wind Uplift Load

风吸力下冷弯薄壁檩条受力复杂,准确计算其承载性能较困难,中外相关规范的计算规定不尽相同。全面总结了GB 50018、CECS 102、EN 1993-1-3、AISI S100及AS/NZS 4600等规范针对风吸力下冷弯薄壁檩条承载性能的相关设计规定,重点分析了各规范采用的设计方法、计算模型及对屋面系统约束效应的考虑存在的差异,并比较了18组常用C形和Z形截面檩条的计算结果。对比表明,对于风吸力下锁螺钉屋面系统中檩条的稳定承载力,不设拉条时,GB5 0018因未考虑屋面系统的约束效应,计算结果过于保守,EC 3和AISI的计算结果较接近;设2道拉条时,屋面约束效应明显弱化,GB 50018和EC 3的计算结果较接近,AS/NZS的计算结果略大。

It is difficult to calculate the bending bearing capacity of cold-formed purlins under wind uplift load precisely.The design requirements,which are different in Chinese and foreign design standards,such as GB 50018,CECS 102,EN1993-1-3,AISI S100 and AS/NZS 4600,are summarized comprehensively.The differences in design methods,calculation models and considerations on restraint effects of lightweight steel roof systems among these specifications are also discussed.The bending bearing capacity of 18 groups of commonly used C-purlins and Z-purlins calculated according to these specifications are compared.The analysis result shows that for purlins without sag-rod,the calculation results of GB 50018 are conservative because the beneficial effects of restraint from lightweight steel roof systems are neglected,and the calculation results of EC 3 and AISI are close.For purlins with two sag-rods,the calculation results of GB 50018 and EC 3 are very similar,and the results of AS/NZS are slightly larger.