钢管混凝土构件在输电线路大跨越铁塔中的应用

Application of Concrete-filled Steel Tube Component in Long Span Transmission Towers

输电线路大跨越钢管塔的结构规模较大时,钢管的局部稳定是设计中的难题,径厚比限值的规定是对此问题的具体要求。为符合规定,设计中通常需增大钢管壁厚,从而产生厚板加工困难、层状撕裂、单件质量过大以及经济指标不理想等问题。在舟山370m高塔的设计中,对大尺寸钢管采用了钢管混凝土构件,从根本上解决了上述问题。此类复合构件中,混凝土约束了钢管的变形,防止钢管过早发生屈曲;而钢管的限制又可以避免混凝土过早开裂。采用钢管混凝土构件,大大地减少了钢材的耗量,经济效益较好。因此,对于工程地质条件较好的情况,输电线路大跨越钢管塔的主材采用钢管混凝土构件是一个比较合理的方案。

When a steel tube tower for long span transmission is large in scale, the local stability for the steel tube will become a critical problem. The stipulation for the limit value of diameter-thickness ratio in the National Code is the specific requirement for solving the problem. In order to meet this stipulation, the tube wall thickness is often increased in design, which leads to such problems as difficult processing, lamellar tearing, overweighting and unsatisfactory economic index. In design of the 370 m-high towers for Zhoushan long span transmission project, the concrete was filled in the large-size steel tubes to overcome the above-mentioned problems. In this type of composite component, the concrete restricts the steel tube＇s deformation, which can prevent the untimely buckling of steel tube; while the confinement of the steel tube can avoid the untimely cracking of concrete. The adoption of concrete-filled steel tube component has substantially reduced the consumption of steel material and achieved good economic results. It is, therefore, reasonable to use the concrete-filled steel tube components for the main members of steel tube towers for long span transmission when the engineering geological condition at the site is good.