By analyzing and comparing the cross-sectional properties of steel poles, the annular cross-section exhibits the best stress-bearing characteristics, followed by the hexagonal section, and then the dodecagonal section. The more sides, the better the stress distribution and the lower the material consumption, but the greater the processing difficulty.
Due to the gradually changing wall thickness of the steel poles, they need to be divided into several sections. The number of flanges in a single pole should not exceed four. However, this is limited by transportation and the processes of molding and hot-dip galvanizing. Therefore, the length of each pole section should ideally be around 10m. When the wall thickness is large (>22mm), the section length should be appropriately reduced based on the processing plant's equipment capabilities; otherwise, pressing will be impossible.
The design must fully consider environmental requirements such as flood control, fire prevention, wind protection, and ice prevention. For example, in sections crossing or near rivers, steel pipe poles and narrow-base towers should be used, with foundation pile depths reaching up to 12 meters to improve resistance to erosion and impact.
In late April 2026, State Grid Beijing Electric Power completed the post-disaster upgrade project for the power grid in four districts of northern Beijing. In sections crossing or near rivers, 257 high-strength poles, including steel pipe poles and narrow-base towers, were used, and equipment foundations were deepened or raised, significantly improving resistance to water erosion and impact. For example, along the 10kV Liuliang Road in Liulimiao Town, Huairou District, the diameter of the newly erected steel pipe pole foundation piles was expanded to 1.8 meters and the burial depth reached 12.2 meters, with each foundation using nearly 1900 kg of steel reinforcement and 40 cubic meters of concrete. In Miyun District, 203 sets of boat-shaped protective piers were innovatively applied to river-crossing and river-adjacent sections, improving foundation stability by more than 60% compared to circular protective piers.
Continuous optimization was also carried out in structural design. For example, the steel pipe poles for three-circuit transmission lines achieved symmetrical arrangement of curved arms and crossarms, achieving force balance on both sides, reducing the bending moment borne by the pole body, and helping to reduce the overall height of the steel pipe poles.
The design must take into account the installation conditions. The geological conditions must be investigated before installation. No one is allowed to stand around the installation site during the installation process. Staff must concentrate and all departments should cooperate closely.