U型截面钢拱平面外稳定分析

Out-of-plane stability analysis of U-section steel arch

U型截面钢拱由三块钢板焊接而成,可在截面内浇注混凝土形成钢-混组合结构,从而充分利用底板钢材的抗拉性能.当作用在拱平面内的荷载达到临界值时,拱可能出现平面外屈曲即侧倾问题,而使整个结构发生平面外失稳.如果U型截面钢拱沿整个弧线长度上没有隔板,则会出现两个侧板的局部屈曲.通过建立有限元计算模型,讨论了不同参数,包括截面尺寸,边界条件,有无隔板以及隔板间距情况下钢拱的稳定问题,并对计算结果进行分析,利用最小二乘法拟合,得到钢拱平面外稳定承载力的计算公式,可为工程设计提供参考依据.

Introduced in this paper is a new U-section steel arch which is welded by three steel plates.It can be used as a single section in steel structure,as well as a composite section when concrete cast in hybrid structure.Arch is the preferred structure under bearing pressure,but for certain bending moment,out-of-plane instability,which is also called lateral buckling,in the whole structure will occur,while local buckling in U-shape section may also appear at the same time.In this paper,two kinds of instabilities are discussed,and the finite element numerical model is built.The parameter analysis,such as different section dimensions,boundary conditions,without clapboard along the whole structure,with clapboards in various spaces,is made.Based on the results above,referred to the formula of thin-wall with open slot,bearing capacity formulas,are proposed,which can serve as a reference in the stability design of steel arch.