实腹式等截面纯压钢拱的平面内弹性屈曲系数

利用有限单元法对静水压力作用下的圆弧钢拱、沿水平轴分布的竖向均布荷载作用下的抛物线钢拱、沿拱轴线分布的竖向均布荷载作用下的悬链线拱的平面内弹性屈曲进行研究,考虑了屈曲前变形、剪切变形及长细比的影响。得到了三铰拱、两铰拱、固定拱的弹性屈曲系数的数值解。对数值解与传统的经典解进行了对比分析,数值解具有更高的精度。计算结果表明,长细比大约在20~50的范围内时,经典解具有很大的误差,用屈曲系数经典解得到的计算长度系数来进行这类纯压拱的平面内稳定性设计将非常不安全。

In-plane Elastic Buckling Coefficients of Compression Steel Arch with Uniform Section

It investigates the elastic in-plane buckling behavior of pure compression perfect steel arches by using finite element method(FEM).The buckling coefficients of fixed,two-hinged,and three-hinged steel arches are obtained numerically for the following cases: circular arches subjected to hydrostatic pressure;parabolic arches subjected to vertical load uniformly distributed on a horizontal projection;and catenary arches under uniform vertical load along the arch axis.The pre-buckling deformations and shearing deformation are considered in the analysis.Conclusions are drawn from comparisons carried out between numerical results and classical results.The classical elastic in-plane buckling theory of arches is not accurate and the FEM analysis is more powerful and acceptable.Using the effective length factor obtained by the classical theory to design pure compression arches will lead to seriously unsafe results with the slenderness ranged from 20 to 50.