竖向荷载和水平荷载共同作用下钢管拱平面内稳定承载力设计研究

采用二阶弹塑性有限单元法对竖向荷载和水平荷载共同作用下的圆形截面两铰抛物线钢管拱的平面内稳定承载力进行研究。考虑材料非线性、残余应力、初始几何缺陷、矢跨比和长细比等因素对钢管拱平面内力稳定承载力的影响。结果表明：残余应力对其竖向承载力影响很小；初始几何缺陷会显著降低中等长细比钢管拱的承载力；矢跨比和长细比是影响钢管拱承载力的重要因素，但拱的竖向承载力并不随矢跨比和长细比的均匀变化而变化。研究竖向荷载和水平荷载共同作用下两铰抛物线钢管拱达到平面内极限状态时的N-M相关关系，并拟合两铰压弯抛物线钢拱承载力N-M相关关系统一表达式。提出了竖向荷载为全跨均布和半跨均布荷载，同时考虑水平方向荷载作用的两铰抛物线钢拱平面内整体稳定承载力设计建议，可供相关设计问题参考应用。

Design analysis for stability capacity of steel tubular archunder vertical and horizontal loading

Using-second order elasto-plastic finite element method, research on in-plane stability of pin-ended parabolic steel tubular arch under vertical and horizontal loads was conducted. Material nonlinearity, residual stress, geometric imperfections, rise-to-span ratio and slenderness ratio were considered. Residual stress have little effect on the vertical carrying capacity. The existence of initial geometric imperfection can significantly reduce the load-carrying capacity of steel tubular arch for medium slenderness ratio. Rise-to-span ratio and slenderness ratio are important factors affecting load-carrying capacity of steel tubular arch, but load-carrying capacities of the arch are not uniformly changed with uniform changes of rise-span ratio and slenderness ratio. The N-M interaction was established when the pin-ended parabolic steel arch reaches in-plane limit state under both vertical and horizontal loads, through which the unified expression of N-M interaction is produced. In addition, some design suggestions were offered concerning in-plane stability of pin-ended parabolic steel arch when the vertical loads (full cross-uniformly distributed load and half-cross-uniformly distributed load) and horizontal loads are considered. These suggestions can serve as references in relevant projects.