Experimental study on failure modes and retrofitting method of latticed transmission tower

Abstract

Recent years have witnessed an increasing number of transmission towers collapsing under strong winds. Therefore, a retrofitting technique on diagonal bracings is proposed in this paper to enhance the load-carrying capacity of existing transmission towers based on a thorough exploration of the failure mechanism of transmission towers in working conditions. A pair of double-panel subassemblages of a transmission tower with one’s diagonal members retrofitted and the other not were statically tested to study the failure modes and to evaluate the retrofitting effects. The experimental results reveal that in the original tower subassemblages the diagonal members are vulnerable to buckling, which could lead to structural failure, while in the retrofitted specimen the most vulnerable member is the leg member rather than the diagonal bracings, which is accompanied by a change of the failure mode of the subassemblage. The ultimate lateral and vertical loads applied on the retrofitted subassemblage increase significantly compared with the original subassemblage.