Fragility Analysis Of The Long-Span Transmission Tower-Line System Subjected To Wind Loads

The long-span transmission tower-line system is a kind of complex system with strong tower-line coupling effect.It has structural characteristics such as high tower body,large span,and light weight.The construction of long-span transmission tower-line system is large in number and wide in distribution,which is widely used in the feild of power transmission.The structural characteristics of the long-span transmission tower determine that the natural vibration period of it is relatively long,which also makes it more susceptible to the influence of wind load.Wind disaster is one of the largest natural disasters.Both domestic and overseas wind disaster data shows that the transmission tower-line system often collapse subjected to wind load In addition,as wind load is a kind of random load,the probability method should be used to analyze the wind-induced response of the structure.Therefore,it is of great significance to carry out analysis on wind-induced collapse and fragility of transmission tower-line system.At present,there are few studies foucused on the collapse and fragility analysis of transmission tower-line system subjected to wind load.This paper proposed the global damage index(GDI)of transmission tower,based on the incremental dynamic analysis(IDA)method,using ABAQUS software to simulate the collapse of the transmission tower-line system subjected to wind load.Meanwhile,fragility analysis and uncertainty analysis were carried out.The main content of this article is organized as follows:1)A typical long-span transmission line was selected as the case study.And GDI was proposed as the criterion to determine the collapse of the transmission tower.Based on IDA method,the collapse process was simulated with ABAQUS/Explicit,the global damage of the transmission tower was studied when the structure collapsed,and the collapse mechanism was analyzed.2)The fragility analysis of the long-span transmission tower-line system is analyzed,and the wind resistance of the structure is evaluated;at the same time,the impact of different codes(GB and IEC)and different spectrum(Kaimal and Davenport)on the collapse fragility of transmission tower was studied.3)The elastic modulus,Poisson’s ratio,steel yield strength and the radius and thickness of steel tube are selected as the uncertain parameters.The sensitivity analysis of the long-span transmission tower line system was carried out,and the relative influence of each parameter on the critical wind speed was analyzed.4)Fifty sets of random structural-wind samples were generated using the Latin hypercube sampling(LHS)method.The ultimate capacity of the transmission tower was studied when considered the uncertainty of structure and wind load.The influence of structural uncertainty on the collapse resistance of transmission tower is analyzed.