架设在绿化带中的四回路钢管单杆优化设计

近年来，国内许多在城镇及绿化带中的220 kV多回路送电线路工程大量采用钢管单杆结构。有些设计单位未进行详细的设计计算优化工作，对荷载较小的钢管单杆盲目推荐采用Q420 材质高强钢。通过多方案计算比较，建议根据主管壁厚的计算结论确定主管的钢材材质；结合相关节点试验对钢管单杆采用内、外法兰新结构进行简要介绍，建议对于主管管径大于2 m的钢管单杆采用内外法兰新结构。

Optimization Design for Four-circuit Single-pole Steels Erected in Green Belts

In recent years, the single-pole steel structure has been widely used for 220 kV multi-circuit transmission lines constructed in towns and green belts. However, for those single-pole steels subject to small external load, it is not suitable to use the Q420 high-strength steel. Based on the calculation and comparison of different schemes, it is suggested that the steel materials for main pipes should be selected in accordance with the calculated thickness of main pipes. The new inside-outside flange is briefly introduced according to the node test, and proposed to be used for the single-pole steel with the diameter of over 2 m.