螺栓连接四角钢十字和双角钢T字截面的格构式设计方法

Lattice Design Method of Built-up Angle for Cross and T Section with Bolts

现行的GB 50017-2017《钢结构设计标准》规定螺栓连接的双角钢T字截面应按格构式缀板柱进行计算(四角钢十字截面未明确),需满足公式的使用条件,即缀板线刚度不小于分肢线刚度的6倍,但未明确T字截面缀板线刚度的定义和计算方法。规范未考虑普通螺栓连接的滑移引起截面绕虚轴剪切变形增大的影响;作为缀件的螺栓剪切计算也未给出。穿过截面虚轴的连接螺栓等同于格构式轴心受压柱的缀板;用分肢长细比的修正放大考虑剪切变形,截面绕虚轴的换算长细比也相应放大;根据挠曲变形,给出连接螺栓抗剪承载力的计算公式。参照格构式轴心受压缀板组合构件,对四角钢十字和双角钢T字截面分别给出分肢不先于整体压屈破坏的最小分肢长细比。

The current calculate formation of the GB50017-2017“Standard for design of steel structures”with its explanation of provisions stipulates that the built-up angles for T section with bolts are buckled as a uniform builtup lattice columns with battens,at the same time the built-up angles for cross section are not mentioned Satisfying the application conditions of the formula,the stiffness of the batten is not less than 6 times of the stiffness of component angles,however the definition and calculation of the stiffness of the batten with T-section is absent.The bolt-slide which increasing shear deformation of angles around the imaginary axis,is also not taken into consideration in the Standard,meanwhile the calculation method of the shear bolt with battens is not given.The connecting bolts through the imaginary axis are equivalent to the uniform built-up columns with battens;the slenderness ratio of component angles should be corrected with the influence by the shear deformation,at the same time the equivalent slenderness ratio is also corrected correspondingly;according to the flexural deformation,the shear calculation of connecting bolts is given in this paper.Referring to uniform built-up columns with battens,the minimum slenderness ratio of component is given for built-up angle member for cross and T section with bolts to make sure the component angle failure happening after overall buckling failure.