Research On The Seismic Performance Of The Transmission Tower Based On Opensees

Power transmission tower-line system is an important lifeline project. It makesimportant economic and social significance to ensure its’ safe operation. Transmissiontower is the main load-bearing structure of the system, at present most domestic andinternational transmission towers are angle steel composite structures. Due to thebetter mechanical properties of steel tube, perfect appearance, and the greaterdevelopment of ultra high voltage grid and long span transmission network, steel tubetower and transmission line steel tube tower more and more attention from theengineering and design practitioners workers. In the course of using, in addition tounapplied with static loads, most of its life is bearing dynamic loads, and thusvibration becomes the main reason for the destruction of the transmission tower.Besides，unstable failure occurs under wind loads, earthquake also inflicting severedamage. Therefore, to ensure that the transmission tower structure normal operatingunder earthquake attracted widespread attention of researchers and designers.This paper is based on OpenSees, the open object-oriented finite elementsoftware, takes a actual self-supporting220kV transmission tower as object of study,builds a finite element model of the space frame according to the transmission tower,analyzes of the dynamic characteristics of the transmission tower, and compares theresults with SAP2000to making sure its accuracy and making preparations for thefollowing linear and nonlinear analysis.Secondly, a dynamic analysis and calculation of the self-supporting powertransmission tower is made against four seismic waves and X, Y two directions: linearmodel, material nonlinear model, geometric nonlinear model and double nonlinearmodel. By comparing the data of kinds of conditions from transmission tower ofincluding peak tower vertical displacement, peak velocity, peak acceleration, thedisplacement history, the speed history, the acceleration history, the component axialstress, the paper makes a provident of geometric nonlinear makes little effects on thedynamic response of transmission towers under seismic action and can be ignored the impact of geometric nonlinearity in the transmission tower engineering practice anddesign.Finally, a simplified calculation principle of transmission towers and lines withstrong nonlinear system is proposed. According to the principle, a simplified model ofthe tower line with quality and a simplify model of tower line with force areestablished. Then a dynamic analysis and calculation is made against four seismicwaves and X, Y two directions: linear model, material nonlinear model, geometricnonlinear model and double nonlinear model. By comparing the data of kinds ofconditions from transmission tower of including peak tower vertical displacement,peak velocity, peak acceleration, the displacement history, the speed history, theacceleration history, the component axial stress, the paper can provide evidence forviewing to the effects of line on the transmission tower identifying weak positionsunder earthquake. By comparing the simplified model of the tower line with qualityand the simplify model of tower line with force, the paper proves the former isreasonable and exact.