螺栓连接组合角钢的整体稳定及分肢计算

螺栓连接的组合角钢是输电线路工程常用的结构形式，需要计算的内容有：组合断面绕虚轴的整体稳定、连接螺栓的剪力、分肢角钢的受压和受弯、双拼十字断面缀板的强度。然而现行规范 GB 50017-2003《钢结构设计规范》未给出计算公式，其中给出的填板间距更适合焊接或铆接的组合断面。欧洲钢结构规范对于连接螺栓的剪力也未给出计算公式。由于普通螺栓连接的滑动引起承载力降低，对绕虚轴剪切变形较小的组合角钢，可以不考虑填板厚度引起的虚轴回转半径增大；而对绕虚轴剪切变形较大的双拼十字组合角钢，按格构式轴心受压缀板组合构件的原理，对换算长细比加以修正放大，计算整体稳定；根据挠曲变形，给出连接螺栓的剪力和分肢角钢承载力的计算公式。

Overall Stability of Combined Angle Steel Connected with Bolt and Calculation of Component Angle

Combined angle steel connected with bolts is a common structure in power transmission line project, the calculation contents of which include: the overall stability of combination section around virtual axis, the connecting bolt shear, buckling and bending of component angle, strength of battens on star-battened angle member. However, the current code GB 50017-2003 (“Code for design of steel structures”) has not given the calculation formula, in which the battens distance is more suitable for welded or riveted combination section. The steel structure code in Europe also has not given the calculation formula of connecting bolt shear. Aimed to the decrease of bearing capacity caused by the sliding of ordinary bolt connection, and the small shear deformation of combined angle steel on the empty axis, the pads thickness caused by the increases of virtual axis’ gyration radius can be not considered. But for the star-battened combined angle steel around virtual axis with large shear deformation, the equivalent slenderness ratio should be corrected and amplified to calculate its overall stability, according to the combination principle of battened member with lattice type axis compression; the calculate formulas of connecting bolt’s shear and component angle’s bearing capacity are proposed, according to the flexural deformation.