In many countries in the world, when developing UHV transmission lines, steel pipe profiles began to be applied to the iron tower structure, and steel pipe towers with steel pipes as the main material of the tower body appeared. In Japan, almost all of the 1000kV ultra-high voltage lines and towers use steel tube towers, and their research on the design of steel rods is very thorough.
Drawing on foreign experience, domestic steel pipe profiles have also been used in the 5OOkV double-circuit iron tower and the same tower four-circuit tower, which shows its good performance and benefits. Its advantages are manifested in:
First, it can reduce the wind pressure of the tower body (the shape coefficient of the member, the round tube is almost twice as small as the angle steel);
Second, in the case of equal cross-sectional areas, the radius of gyration of the round tube is about 20% larger than that of the angle steel;
The third is to improve the structural carrying capacity.
Generally speaking, the steel tube tower is reduced by 10%-20% compared with the angle steel tower; at the same time, the number of rods can be reduced, the tower period can be shortened, and the structure is easy to be diversified. However, the use of steel pipes also has the disadvantages of limited specifications of steel pipe profiles, poor quality outside, and high price. At the same time, the joints between the steel pipes are complicated in structure and low in processing efficiency.