均匀受压圆弧拱平面外弹塑性稳定设计方法

Out-of-plane inelastic stability and strength design of circular arches in uniform compression

作为建立压弯钢拱平面外稳定承载力设计方法的第一步,综合考虑拱截面形式、初始几何缺陷、残余应力、矢跨比及拱脚条件的影响,通过弹塑性有限元分析,对均匀受压圆弧拱的平面外稳定承载力进行了数值分析,获得了平面外稳定设计曲线。研究表明:保向力作用下钢拱的平面外初始刚度及稳定承载力明显低于向心力作用下的相应结果,是一种较为不利的工况;相比几何初始缺陷和残余应力,矢跨比和拱脚条件对均匀受压圆弧拱平面外稳定承载力影响较大;通过引入拱正则化长细比,统一了不同矢跨比和拱脚条件的均匀受压圆弧拱的平面外稳定设计曲线的表达式;对于热轧圆钢管截面、焊接箱形截面、焊接工字形截面圆弧拱,可以采用GB 50017—2003《钢结构设计规范》中的b类、c类和d类截面的柱子曲线计算其平面外稳定承载力。

By considering the factors such as arch section types, initial geometric crookedness, residual stresses, rise-to-span ratio and support conditions, this paper presented the out-of-plane stability design curves for circular arches under uniform compression. It can be not only applied in the practical design of arch under uniform compression directly, but also involved in the design of arch under the combination of uniform compression and bending. It indicates that load with constant direction which causes lower out-of-plane load-carrying capacity of arches is more adverse than one with direction pointing to a constant center. Compared with initial geometric crookedness and residual stresses, rise-to-span ratio and support conditions much more affect the out-of-plane load-carrying capacity. However, stability design curves for arches with different rise-to-span ratio and support conditions are unified by using the normalized arch slenderness. Finally, out-of-plane stability design method of arches with hot-rolled pipe section, welded box section and welded I section is proposed by employing stability design curves for columns of type b, c, d in Chinese code （GB 50017—2003） respectively.