实腹圆弧钢拱的平面内稳定极限承载力设计理论及方法

拱的平面内稳定极限承载力设计一直没有成熟的规范指导。本文用有限壳单元模型先分析了工形截面两铰圆弧钢拱的平面内弹性屈曲性能,与拱的经典屈曲理论作了对比,指出了必须同时考虑长细比和矢跨比对屈曲荷载的影响。然后分析了两铰圆弧钢拱受静水压力和其它荷载作用下的弹塑性屈曲性能,指出了典型破坏机理为拱两侧1/4跨附近形成塑性铰导致结构失效。利用拱的弹性屈曲荷载定义了拱的正则化长细比,用Perry-Robertson公式的形式,建立了拱的稳定系数与正则化长细比的关系,提出了受静水压力的两铰圆弧钢拱的平面内稳定极限承载力设计方法,并用轴力和弯矩的两项相关公式提出了受其它荷载作用下的平面内稳定极限承载力设计方法。

Design theory and method for in-plane ultimate strength of circular arches

A finite shell element model is established to study the buckling and ultimate strength of two-hinged I-sectional circular steel arches.The elastic buckling of arches subject to hydrostatic load is investigated without displacement assumptions and the obtained results are compared with classic buckling theory.It is confirmed that both rise-to-span ratio and slenderness ratio influence the elastic buckling load. The elasto-plastic nonlinear buckling of arches with different parameters subject to different load cases is also studied to find the failure mechanism and the ultimate strength.Based on the numerical results,the ultimate strength design of arches is proposed with the arch feature integrated in.The relationship between the arch stability coefficient and the arch normalized slenderness ratio is established in the form of Perry-Robertson formula.For other load cases,the interaction formula composed of compression and bending is proposed for the design of arches.