关于轴心受压格构柱剪力的计算

一个轴心受压的直柱是没有剪力的。但是当柱子处在临界的微弯状态时,柱子的横截面就产生了剪力,这种剪力就会引起格构柱分肢之间的剪切错动变形,从而降低柱的承载能力。因此,格构柱分肢之间的连缀件正是用来抵抗这种错动变形,所以连缀件的截面尺寸主要是根据这个剪力来设计的。关于这个剪力的计算方法较多,世界各国也各有不同。我国钢结构没计规范(TJ17-74)对轴心受压格构柱剪力值的规定主要是根据西安冶金建筑学院研究的成果。本文将简要介绍格构柱剪力确定的几种方法,提出几点粗浅的看法,并建议一个计算方法。该方法结合了我国对轴心受压构件纵向稳定系数φ的研究成果,使轴心受压格构柱的剪力计算与轴心受压格构柱的稳定计算统一起来,并且提高了计算精度。

Calculation of Shear Foree in Built Up Columns under Axial Compression

There is no shear force in a straight column exposed to an axial compression. But a shear force will arise in the cross section of the column if it is in a critical slightly bending condition. This shear force will induce shear deformation between branches of the column and its bearing ability will be decreased. In order to resist the shear deformation, connecting elements between the branches of the column are used and their cross sections are determined mainly according to the shear force. A number of methods for calculation of the shear force have been presented. In this paper some of them. are introduced and briefly discussed, and a new method for calculation of the shear force is suggested. Considering the results obtained in our country from the investigation of the stability factor against longitudinal bending of a structure under axial compression, this method combines the computations of the shear force with stability analysis for a built up column under axial compression and increases the accuracy of the calculation.