Enhancing the wind-resistant capacity of transmission towers with buckling-restraint-reinforced angle-steel-members (BRR-ASMs)

Abstract

The collapse of numerous transmission towers highlights the importance of improving the stability of angle steel components. However, the current reinforcement methods for angle steel components of transmission towers often suffer from drawbacks such as installation complexity and the need for damaged reinforcement angle steel. This study proposes a new type of buckling restrained reinforced angle steel member (BRR-ASM) for reinforcing the angle steel on the existing main tower legs of transmission towers. The buckling performance of the proposed BRR-ASMs were investigated based on compression tests. Three different reinforcement types were considered as full-length BRR(F-BRR), half-length BRR(H-BRR), and partial BRR(P-BRR), which can increase the bearing capacity of primary member by 101.3 %, 57.04 %, and 49.80 %, respectively. The corresponding constitutive models of the BRR-ASMs were established for the convenience of finite element analysis on structures with BRR-ASMs. Through wind-induced response analysis on a realistic transmission tower-line system, the enhancement of BRR-ASMs on wind-resistant capacity was evaluated. Consequently, the ultimate wind speed of the transmission tower-line system increased from 34 to 38 m/s. The buckling failure on the main tower leg members is effectively prevented. Considering the high reinforcement efficiency and low economy cost, the P-BRR scheme is recommended for engineering practice.