Study On Joint Force-Bearing Capacity Of Transmission Tower Subjected To Wind Loads

With the rapid development of economy,electric power transportation system has become an indispensable part of people's production and life.The transmission tower line system is the most important carrier and medium of the power transportation system.Because of the external factors such as the terrain environment and the reasonable utilization of resources,the transmission tower that works in the natural environment for a long time often bears the effects of wind,rain and other natural factors.However,wind-induced transmission tower collapse often occurs in coastal areas,so it is necessary to study the change of bearing capacity of failure section nodes under wind load.This paper takes a certain Angle steel transmission tower in the coastal zone as the research object,and mainly carries out the following research contents:Firstly,the transmission tower line system model is established with the finite element calculation software ABAQUS under the research background of practical engineering.Considering the coupling effect between the transmission tower and the guide wire,the influence of the guide wire on the dynamic response of the single tower is studied.The failure mechanism and location of the tower system under wind load are studied and analyzed.The results show that,in general,the flexural stiffness of the single tower and the tower line system is the same as that of the external plane,but due to the coupling effect between the wire and the tower,the flexural stiffness of the tower line system in the direction of the first plane changes greatly.At the same time,the refined model of the failure section node of the tower body was established to study the change of bearing capacity of the node.Secondly,based on the pre-tightening theory of bolts and the finite element model of the failure section node of the tower body,the bearing capacity performance changes of each component of the failure section node under different tightening degrees of bolts are studied in depth.The results show that: under the service load,with the increase of the pre-tightening force of bolt,the stress of each component increases gradually and shows a linear change.Under the action of critical load,with the increase of preload,the stress of screw holes and bolts in the inclined timber position increases,while the stress of screw holes and bolts in the main timber position is almost unchanged.Then,based on the contact theory and the finite element model of the failure section node,the change of the bearing capacity of each component under the complex contact relationship is discussed.The results show that with the increase of friction coefficient,the stress of each component decreases gradually,but the reduction is very small.Finally,based on the basic theory of bolt structure and the failure section node model,the influence of bolt diameter on the bearing capacity of each member of the node is discussed under different bolt diameters.The results show that under the service load,the stress of each member decreases with the increase of bolt diameter,no matter the preferred bolt or the secondary bolt.Under the action of critical load,with the increase of bolt diameter,the stress of inclined timber screw hole and inclined timber bolt increases,while the stress of main timber screw hole and main timber bolt is almost unchanged.