变截面门式刚架结构极限承载力分析

采用变截面薄腹构件是门式刚架结构轻型化的主要措施之一。如何利用变截面薄腹构件的腹板屈曲后强度并同时保证构件乃至结构的安全度始终是门式刚架结构工程设计的重要内容。根据有效宽度法的基本思想,提出了相关屈曲系数概念,在变截面H钢构件双重非线性数值分析基础上获得的局部屈曲荷载拟合公式,应用于变宽度楔形腹板的有效宽度简化计算公式当中。应用改进后的有效宽度法,进行了变截面门式刚架结构考虑构件局部屈曲影响的极限承载力分析,探讨了腹板平均宽厚比、腹板楔率对结构极限承载力的影响,提出了对变截面门式刚架结构优化设计的工程建议,并具有工程指导意义。

Analysis on the Capacity of Steel Portal Frame with H-section Tapered Members

Based on the previous parameter studies on H- section tapered members with local buckling, the interactive buckling coefficien t is suggested considering the influence of local buckling. Referring to the cod es of lightweight steel structures, the ultimate capacity criteria of steel port al frame with tapered members is established. The capacity of steel portal frame is analyzed by finite element method, in which the modified effective width met hod added interactive buckling coefficient is adopted. According to the results, influence of web width, web thickness and web tapering ratio on capacity of ste el portal frame are focused.