DYNAMIC ANALYSIS OF LONG-SPAN TRANSMISSION TOWERLINE SYSTEM UNDER DOWNBURST

The extreme wind loads have caused enormous structural failures around the world, especially in high-rise flexible steel structures such as transmission towers. However, most of the design criteria discussed in the code are for extended pressure system (EPS). Due to the action of downburst, the structure may be damaged by the failure of local members, which may further lead to the collapse of transmission tower. In this paper, a long-span transmission tower-line system project with a span of 2500m and a main tower height of 272m is taken as the research object. The focus is on the dynamic response of suspension tower under the action of downburst. First, the simulation process of downburst wind field and the calculation criteria of wind load are introduced. Second, the whole tower-line system is simulated with refined finite element model, which includes two suspension towers, four anchor towers and other elements. The wind-induced vibration response of the structure is calculated by numerical simulation. Finally, the possible failure modes and bearing characteristics of the tower line system under downburst are obtained, which provides reference for engineering design.