Mechanical Analysis of Iced Tower Collapse Accident in Tianshui Area of Gansu Province

In order to explore the cause of iced tower collapse accident of a 330 kV transmission line in Tianshui area of Gansu Province, a two-tower three-span coupling structure system based on the actual structural parameters of the fault section of the line is established in this paper. Based on the equivalent density method, the ice loads of the towers and the overhead lines are simulated, and the static analysis of the iced tower-line coupling system is completed. The simulation of the natural wind time-history load is achieved by means of the exponential wind profile method and the harmonic synthesis method, and it is superimposed with the ice load to complete the solution of the mechanical response of the tower-line coupling system under the combined load. Based on the results of simulation analysis, the causes of local failure of #94 Tower and overall collapse of #95 Tower are explained from the mechanical perspective.