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近年来我国多次发生在积雪荷载作用下门式刚架轻钢房屋发生破坏事故。本文分析了积雪荷载在房屋屋面形成的特点和屋面积雪荷载作用下薄壁型钢檩条的破坏特征。探讨了现行设计规范和技术规程中檩条抗积雪荷载设计方法的合理性,指出了计算模型存在的不足。压型钢板屋面在积雪荷载作用下,不宜作为檩条可靠的侧向支撑,檩条计算应按屋面不能阻止檩条侧移和扭转进行强度和稳定计算。通过大量算例计算和分析比较,研究了屋面坡度与扭转翘曲正应力对檩条截面正应力的影响规律和程度,指出了现行设计规范和技术规程中薄壁型钢檩条抗积雪荷载的设计方法的适用性和缺陷。对于目前大量采用的屋面坡度较小的轻钢建筑檩条进行强度和稳定计算时,不宜忽略扭转翘曲正应力的影响。探讨了在屋面积雪荷载作用下门式刚架轻钢房屋发生破坏的原因。提出了薄壁型钢檩条抗积雪荷载作用的设计方法建议。
In recent years, the occurrence of damage to the portal frame light steel houses occurred many times in China under the action of snow load. In this paper, the damage characteristics of thin-walled steel purlin under the action of snow load on the roofing of houses and snow loads on roofs are analyzed. The rationality of the design method of anti-snow load in the current design code and technical regulations is discussed, and the deficiencies of the calculation model are pointed out. Under the action of snow load, the profiled steel plate roof should not be used as a reliable lateral support for purlins. The calculation of purlins should be based on the fact that roofing can not prevent the purlins from swaying and twisting for strength and stability calculation. Through a large number of example calculation and analysis and comparison, the influence law and degree of the positive slope of roof slope and torsional warping on the normal stress of billet section are studied, and the design method of anti-snow load of thin-wall steel billet in current design code and technical regulation is pointed out Applicability and defects. For the intensity and stability calculation of light steel building purlin which is widely used at present, it is not advisable to neglect the effect of normal torsional warping stress. This paper discusses the reason of the failure of portal frame light steel house under the roof snow load. The design method of anti-snow load on thin-wall steel purlin is proposed.