Study On Wind-induced Catastrophic Mechanism Of Transmission Tower-line System Under Strong Typhoon Load

China has a vast territory and the power resources of China are highly regional,leading to the uneven distribution,Transmission line is a vital means of power transmission.The transmission tower-line system is characterized by long-span,lightweight,tall and flexible,and it is very sensitive to wind loads and vulnerable to typhoons.Therefore,it is significant to ensure that the transmission tower-line system located in a complex and harsh natural environment perform well,which is important to the national economy.A transmission tower-line system in the southern coastal area of China is taken as an example in the research.Taking the characteristics of transmission tower into account,the beam type element has been selected for simulating the members.Then the finite element model of transmission tower-line system has been proposed combining the mechanical performance of transmission lines.The dynamic characteristics of the single transmission tower and tower-line system has been analyzed and compared.The influence of the transmission line on the dynamic characteristics of the transmission tower is researched.In order to obtain the key parameters of the transmission tower-line system,the field measurement has been adopted.The reasonable and feasible measurement scheme to collect the acceleration response of the transmission tower under natural environment excitation has been put forward taking the finite element method analysis for reference.And then the parameter has been identified by Stochastic Subspace Identification(SSI)method.Based on the obtained wind speed of typhoon,the maximum of the average speed of 10 minutes is selected for establishing a non-stationary typhoon wind field.And then the typhoon wind load of the transmission tower-line system can be obtained.The dynamic response of the transmission tower-line system was analyzed to explore its wind-induced collapse mechanism under typhoon loading.According to the similarity theory,considered with the existing experimental conditions,the scale ratio of 1:12 is determined.The subtle model of transmission tower-line system is designed and manufactured to study the wind-induced damage of transmission tower-line system.To meet the needs of the experiment and take the characteristics of the transmission tower-line system into account,a synchronous loading device that can meet the multiple loading need step by step is developed.The static load test was carried to study the bearing capacity of the transmission tower under typhoon load.The displacement of the key nodes and the stress of the key members has been collected.Comparing the model experiment with the finite element analysis results,it is concluded that the damage position and the deformation of the members and joints are analogous,which verifies the reliability of the finite element analysis and the model experiment.The research has been sorted out and summarized at last,and the key points has been proposed for further research.