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拱结构经常在桥梁、屋顶等大跨结构中使用。尽管这些结构构件容易出现各种失稳现象,但其中短粗拱或细长拱的侧向水平连接失效是由塑性破坏而非平面内或平面外屈曲引起的。通过极限荷载方法分析塑性破坏荷载,以最大限度地发挥截面的塑性能力和出现塑性铰后的内力重分布能力。描述了竖向荷载下圆弧钢拱塑性破坏荷载的计算方法。使用塑性力学中的上限法、下限法和位移协调法来计算塑性破坏荷载,压力致使拱截面的容许塑性力矩减小。确定外荷载与容许塑性力矩之间的非线性关系后,使用迭代法得到塑性破坏荷载。利用有限元方法对分析结果进行检验,二者的分析结果相吻合。最后基于迭代法绘制设计图。
Arch structure is often used in bridges, roofs and other long-span structures. Although these structural members are prone to a variety of instability, the failure of the lateral horizontal connection of stubby arches or slender arches is caused by plastic failure rather than in-plane or out-of-plane buckling. The plastic failure load is analyzed by the ultimate load method in order to maximize the plasticity of the cross section and the redistribution ability of internal force after plastic hinges. The calculation method of the plastic failure load of circular arc steel under vertical load is described. Using the upper limit method, the lower limit method and the displacement coordination method in plastic mechanics to calculate the plastic failure load, the pressure causes the allowable plastic moment of the arch section to decrease. After determining the nonlinear relationship between the external load and the allowable plastic moment, the iterative method is used to obtain the plastic failure load. The finite element method is used to test the analysis results, and the analysis results of the two are in good agreement. Finally, based on the iterative method to draw the design.