U型截面钢拱稳定性相关问题研究

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

现有研究采用径向荷载模式研究U型拱的平面内失稳,本文通过对径向荷载与实际的竖向荷载模式的有限元分析,发现采用径向荷载代替竖向荷载,固支拱在矢跨比0.05到0.35时,误差不大,且偏于安全;固支拱矢跨比0.4到0.5和销轴支座拱,径向荷载偏于危险,且矢跨比越大,误差率越大.针对钢拱的局部屈曲等问题,本文提出加设缀板形成间断闭合截面的方法,并与加设隔板的方法进行比较研究,发现加设缀板优于加设隔板,可更好提高钢拱平面外稳定性,而且用料少、施工简单.加设隔板、缀板对提高平面内承载力效果并不明显.最后,采用回归分析给出竖向荷载下圆弧拱的平面内屈曲荷载计算公式.

Radial load mode is adopted in the study of the instability of U-section steel arch in the most existing research. In this article, radial and vertical load models are studied using finite element analysis. It shows that the fixed arch＇s results of the radial load are more conservative when f / l=0.05 to 0.35, and the error is small. In addition, radial load is dangerous when f / l=0. 4, 0.45and 0.5 of fixed arches, so do all pin bearing arches, and the bigger rise-span ratio, the greater error. To prevent buckling of steel arch, this paper proposes a method using a discontinuous-closed cross section with adding batten plate, and it can be an effective way to enhance the out-plane stability of U-section steel arch. Compared with the U-section steel arch with clapboard, the proposed method can get greater buckling load with less material. Provided with batten plate, clapboard is not good for improving implane instability. Finally, this paper puts forward a calculation formula for the in-plane buckling vertical load.