Wind-induced Response Of Double Flat Arm Pole And Vorteg-induced Fatigueyof Cylinders During Construction Of Transmission Tower

With the rapid development of China’s electric power industry,the demand for power resources is increasing.For the construction of transmission towers with complex geographical locations,the safety,reliability,economy,construction speed and construction technology of the process are put forward.And therefore the requirements of the lifting equipment used to assemble the transmission tower-double flat arm poles are also getting higher.As a kind of lifting type mast structure,the double flat arm pole is a very soft structure with high height,small cross section and large slenderness ratio.It is more prone to occur wind-induced damage than transmission tower during construction.Therefore,it is necessary to carry out wind tunnel test and wind-induced vibration analysis of the double flat arm pole.At the same time,since the pole and the transmission tower are coupled with each other during the construction process,it is necessary to study the influence of the steel tube tower on the wind-induced vibration response of the poles.The large-span transmission steel tube tower is located in the coastal area of Zhoushan,Zhejiang Province.As the steel tubeof the tower is inclined,the vortex-induced resonance is easy to occur under the action of breeze,which affects the service life of the structure.Therefore,it is necessary to study the wind-induced vortex fatigue effect of steel tubes by conducting the vortex-induced vibration wind tunnel test of circular steel tubes.Firstly,this paper introduced the application background and existing problems of double flat arm pole,and summarizes the research status of wind-induced analysis of high-rise structures and the research progress of vortex-induced vibration and fatigue damage of steel tubes.Secondly,based on the wind tunnel test of double flat arm pole,the shape coefficients of each part of the pole structure are studied and compared with the values given by the code.The shape coefficients of the lattice-type pole structure under different wind direction angles are complemented.Thirdly,based on the wind tunnel test data of double flat arm pole,the dynamic wind load of the pole structure under different attitudes during construction is calculated,and the finite element model of the pole structure under typical working conditions is established.The wind-induced vibration analysis is carried out in the time domain,wind-induced vibration coefficients along various heights of the pole structure are calculated,and further analyzed the equivalent static wind load of the pole structure.Fourthly,this paper establishes a coupling system of double flat arm pole and steel tube tower,then analyzed the wind-induced vibration of the coupled system in the time domain,and compares the results with the response of the individual pole structure to analyze the influence of the steel tube tower on the wind-induced vibration response of the pole structure during the construction process.At the end of the thesis,the vortex-induced vibration wind tunnel test is carried out on the typical slender-ratio circular steel tubular members.Based on the experimental data,the vortex-vibration fatigue damage analysis of the circular steel tube is calculated in the time domain and the frequency domain respectively,and the meteorological data is combined to evaluate the fatigue life of the steel tube components during the design life..