输电铁塔设计中角钢构件稳定计算问题的讨论

现行输电铁塔结构设计依据的规程、规定引用的是《钢结构设计规范》(GBJ17-1988)的条文,《钢结构设计规范》(GB50017-2003)增加了关于轴压构件扭转失稳和弯扭失稳方面的规定,本文基于新钢规对输电铁塔设计中双角钢十字形、T形截面以及单角钢轴压构件的整体稳定计算做了试算和探讨,得出对于输电铁塔设计中主材选用双角钢十字截面构件扭转失稳将起控制作用、对于单角钢构件绕平行轴的弯扭失稳起控制作用的结论。通过对220kv和500kv双回路直线塔的工程实例计算,按新钢规规定,塔重将增加6％～10％。因此,在输电铁塔结构设计中,关于角钢整体稳定按新钢规条文的具体应用还需进一步探讨。

Discussion on Calculation of Stability for Angles in Design of Transmission Towers

The current code for design of transmission towers accords with "Code for Design of Steel Structures"(GBJ17-1988). And items about torsional buckling and flexural-torsional buckling for central compression members are added to "Code for Design of Steel Structures" (GB50017-2003). Based on "Code for Design of Steel Structures"(GB50017-2003), the overall stability about central compression members which include double angles of cross section, single angle and double angles of T section in transmission towers design, is discussed in the paper. It is concluded that torsional buckling is determinant for double angles of cross section used for chord members, and flexural-tor-sional buckling around the parallel axis is determinant for single angle. Through the calculation of 220kv and 500kvdouble circuit transmission towers which is in accordance with "Code for Design of Steel Structures" (GB50017-2003), the weights of transmission towers increase six to ten percent. Therefore, the calculation of overall stabilhy for angles according to "Code for Design of Steel Structures" (GB50017-2003) should be studied further in design of transmission towers.