Experimental study on failure modes of a transmission tower reinforced with clamps

Transmission towers frequently collapse under extreme weather conditions such as strong winds. To ensure the stability of existing transmission towers, we propose an innovative clamp reinforcing technique for the main leg and diagonal members of operational transmission towers. This technique employs star-shaped plates with stiffeners, angle steel clamps, connecting plates, and bolts to connect the reinforcing members to the original members of the transmission tower without drilling or welding. It was demonstrated by performing sub-assemblage tests that the ultimate bearing capacity of the reinforced structure can be enhanced by 21.96% compared with the original structure while maintaining a strong synergy between the reinforcing and original members. Finally, a formula for computing the ultimate loads of reinforced compound members under eccentric compression is proposed along with a method for calculating the section coefficient, and 40 sets of eccentric compressed members were employed as samples for verification. The findings of the study can serve as a theoretical analysis basis for the retrofitting design of transmission towers.