The Wind-induced Vibration Response And Local Fire Effect Of The Double-nominal Tower

The transmission tower is a very important part of the transmission line.The safety of the tower affects the operation of the entire transmission line.Transmission towers are high-rise structures,which are susceptible to damage caused by wind,earthquakes,ice disasters,etc.Among them,wind-induced damage and collapse are the most common phenomena.Transmission towers are generally located in wild mountain forests,and there is a possibility of sudden forest fires.The transmission tower is mainly composed of steel materials.Once encountering a forest fire,local instability and collapse will occur.Therefore,it is of great practical engineering significance to analyze the wind-induced vibration response of the transmission tower and the analysis of the bearing capacity under local fire conditions.This article mainly analyzes the wind-induced vibration of the double-nominal tower and studies the influence of the local fire on the tower:(1)This article takes the double-nominal tower with a total height of 330 kV and51.7m as the research object,establishes its finite element model,and conducts static analysis on the dual-height tower under various working conditions to obtain its displacement,axial force and bending moment etc.,to verify the feasibility and rationality of the design scheme of the double-nominal tower in engineering applications.(2)Perform modal analysis on the double-height tower to obtain its first fourth-order frequency and mode.The wind load simulation theory is introduced from the two aspects of basic wind characteristics and wind load calculation.The AR method is used to simulate the pulsating wind through the davenport spectrum,which isrealized by MATLAB software programming.The wind-induced vibration analysis of the double-nominal tower with wind speed of 31m/s and wind direction angle of 0° was carried out to obtain the displacement response of the tower body and crossarm.The wind vibration coefficient of the tower under this working condition is calculated from the time history analysis results.(3)This paper proposes the selection of expressions of material properties for thermal analysis and thermal stress analysis,and proposes to select the fire heating curve BFD-curve.Based on the finite element modeling of the selected eight anchor bolt tower base plate,the temperature field analysis and temperature stress coupling analysis under local fire conditions are carried out,and the characteristics of temperature rise and stress distribution of the structure under local fire conditions are obtained.