Wind-induced Collapse Of Long-span Transmission Tower-line System

Due to the tall, large span, and slender characteristics of tower-line system, the main design load is wind. At the same time, the collapse of the transmission tower-line system under wind load is often occurred. Most collapsed cases show that overall instability and local failure of transmission tower is one of the main failure modes. At present, the member buckling effect is not considered for the wind resistance study, which will overestimate the bearing capacity of structures. Therefore, Establishing an accurate structural model to study the collapse mechanism of transmission tower line system under wind load is of great scientific significance.Transmission tower-line system finite element model is established using ABAQUS. The wind-induced vibration response of the transmission tower-line system is calculated, and the collapse mechanism of the transmission tower-line system under wind load is studied.The work of this paper is divided into the following parts:Firstly,combined with the structural characteristics of the transmission tower and wind-induced collapse of the transmission tower, frame element is used to established the transmission tower finite element model, which can simulate the mechanical properties of member before and after instability. Transmission line system is built using frame element and truss element. Dynamic characteristic analysis is calculated.Secondly, based on the characteristics of wind field and the structure of transmission tower, the simulation method of fluctuating wind is studied. Fluctuating wind speed time history is simulated for further study. The figure coefficient of transmission tower is simulated by fluent and compared with that of the standard.Thirdly, wind-induced vibration response time history analysis of transmission tower line system is carried out under wind angle of 0 degrees and 90 degrees. Based on the dynamic response time history, the wind vibration coefficient is calculated, and compared with that of the standard.The end, whether the structural bearing capacity can keep balance with the wind load is defined to be the dynamic damage criterion of transmission tower and iteration non convergence time is defined to be the structural collapse moment. The collapse of transmission tower and tower-line system under different wind direction is simulated. The collapse mechanism is summarized and the most disadvantageous wind angle of attack is obtained.