T形截面钢压杆整体稳定计算的折算长细比法

Equivalent Slenderness Ratio Method for the Stability Caculation of T-Struts

T形截面轴心压杆绕其对称轴发生弯扭屈曲.当压力作用于截面的剪切中心时,T形截面压杆仅发生弯曲屈曲或扭转屈曲.尽管T形截面压杆绕对称轴屈曲时,剪切中心加载时的屈曲荷载大于轴心加载时的屈曲荷载,但若其具有初弯曲、初偏心及残余应力等缺陷,当压力由形心移至剪切中心时,压杆的整体稳定设计承载能力将会降低.提出了一种T形截面压杆设计计算的新方法———折算长细比法,并将该方法与陈绍蕃提出的计算方法、现行规范中的计算方法以及有限元法进行对比后指出新方法合理、简捷,值得推广应用.

T-struts subject to centroid compression buckle flexural-torsionally about their axis of symmetry. When the force is applied at the shear center of the section, T-struts buckle either flexurally or torsionally without coupling of flexure with twisting. Although the buckling load about the symmetry-axis of shear center loading is greater than that of centroid loading, the design capacity of T-struts with defect such as fabrication error, load eccentricity and residual stress decrease by shifting the working line of a T-section compression chord to the shear center. This article presents the equivalent slenderness ratio method, a new method for the design of T-struts subject to compressive force, introduces another three methods including the one presented by Chen Shaofan, the one in code and the one in ANSYS, contrasts the calculation results of those four meth- ods and recommends the implementation of equivalent slenderness ratio method in the design of T-struts subject to compressive force.