Seismic Response Analysis Of Large Crossing Transmission Tower-line System Subjected To Near-fault Ground Motions

As a high-rise structure,the transmission tower is a very important lifeline project.When an earthquake occurs,the transmission line is easily damaged and the vulnerability is high.Once the power system fails or is damaged,it will cause the entire area to lose power,seriously affecting people’s normaly life,and severely reduces the function of other lifeline systems or complete paralysis.The recovery time of other lifeline systems after the earthquake will also be greatly constrained,and the national economy will suffer great losses.Due to some objective factors,transmission lines cannot always be built around active faults,or even across active faults.The structures that are built near faults during earthquakes have greater risk of damage.At present,the existing seismic design codes at home and abroad have not yet taken into account the influence of the special near-field effects of near-fault ground motion on the structure.However,little is known about the response analysis of large-span transmission tower-line systems under near-fault earthquakes.This paper uses Abaqus finite element analysis software and dynamic display analysis method to study the response characteristics of large span transmission tower-line systems under near-fault earthquakes.This article mainly studies from the following aspects:(1)The high-frequency and low-frequency ground motion superposition method is used to generate near-field multi-dimensional ground motion acceleration,and a high-frequency ground motion is generated based on the phase difference spectrum theoretical model.The low-frequency pulse part adopts a corresponding speed pulse model,and the corresponding time will be The high-frequency and low-frequency acceleration time courses are superimposed to generate the near-field multi-dimensional ground motion acceleration time course.(2)Based on the basic principles of structural dynamics and the classical response spectrum analysis method,a method for discriminating the most unfavorable direction of near-fault multidimensional ground motion is proposed through theoretical derivation.The near-field multidimensional seismicity of large-span transmission tower-line system is studied through numerical simulation.The accuracy of the most unfavorable discriminant methods.In order to study the applicability of this method,the accuracy of the most unfavorable input direction of the multi-dimensional ground motion in the far field of the transmission tower-line system is demonstrated through numerical analysis.(3)Near-field ground motions have significant differences between their near-field effects and far-field vibrations.The dynamic response law of near-field and far-field multi-dimensional earthquakes in large-span transmission tower-line systems is compared by numerical analysis.The characteristics of seismic responses of large-span transmission tower-line systems with burst directional pulses,slip effect pulses,and near-field vibrations without speed pulses are discussed.The influence of equivalent pulses on the seismic response of large-span transmission tower-line systems is discussed.