圆管截面两铰圆弧纯压拱的平面外稳定性及设计方法

拱的平面外稳定极限承载力设计一直没有成熟的设计方法及规范指导。通过分析两铰圆管截面圆弧钢拱的平面外弹性屈曲性能,指出Timoshenko未考虑翘曲的经典解与有限元分析结果吻合很好。在弹塑性平面外稳定性分析的基础上,借鉴单轴对称截面轴心受压构件的弯扭屈曲设计方法,提出以面外屈曲荷载对应的正则化长细比为参数进行面外稳定性设计的方法。借鉴我国GB 50017—2003《钢结构设计规范》中柱子曲线的表达式,建立纯压两铰圆管截面圆弧拱稳定承载力的实用计算公式及设计曲线。

OUT-OF-PLANE STABILITY DESIGN OF PIN-ENDED CIRCULAR STEEL ARCH UNDER PURE COMPRESSION

A finite beam element model is established to study out-of-plane elastic buckling behaviors and elasto-plastic stability behaviors of pin-ended circular steel arch with circular sections.Firstly,elastic buckling of arches subject to hydrostatic pressure is studied and compared with classic buckling theroy.It is pointed out that the finite element analysis resuIts are in good agreement with the Timoshenko classical solutions.Secondly,on the basis of elastic-plastic stability analysis,referring to the stability design method of monosymmetric section axially loaded compression members,equivalent slendemess of pin-endad circular steel arch subject to hydrostatic pressure are deduced from the expression of out-of-plane elastic buckling load.Combined with the column curves in current Chinese"Code for Design of Steel Structures"(GB 50017-2003),the design formula of ultimate load-carrying capacity as well as out-of-plane stability design curves are presented.