| As an important lifeline structure,the transmission tower-line system plays an important role in the power transmission process.In the seismic design of the transmission tower-line structure,only the horizontal seismic action is generally calculated,and in a few cases,the vertical seismic action is considered,regardless of the rocking component of ground motion.The reason is the lack of measured rocking component data of ground motion available for practical calculations,which has led to a limited in study of structural seismic effects involving the effects of rocking component of ground motion,and the effects of rocking component of ground motion have not received sufficient attention.Especially for the high-flexible structures such as transmission tower-lines,it is of great value to study the seismic effects under the ground-rock coupling.In this paper,the shaking table test and theoretical study on the seismic effect of the transmission tower-line structure under coupled horizontal and tilt ground motion are carried out.In addition,the finite element simulation analysis is carried out on the influence of the transmission line on the seismic effect of the transmission tower-line structure.The main research contents and conclusions are as follows:(1)Using the frequency domain method and the spectral ratio method to process the data of the TCU084 site in Taiwan,respectively,to obtain the corresponding rocking component of ground motion,and then select a more reasonable method for the near field data processing——spectral ratio method.The data obtained by the method is used for the next structural seismic effect analysis;(2)Taking the structure of a transmission tower-line as a prototype,establish a 1:30 scale transmission tower-line structure which is single tower model and three tower with two line model,and carry out shaking table test under coupled horizontal and tilt ground motion.According to the results of the shaking table test,it can be seen that the transmission line will have a certain weakening effect on the seismic effect of the transmission tower structure,and the seismic response which is parallel to the line in the vibration direction is different from the seismic response which is perpendicular to the line in the vibration direction.After considering the rocking component of ground motion,the seismic response of the transmission tower-line is improved significantly,and the asymmetric displacement effect is obvious;(3)Establishing the multi-mass model of the scale model,deducing the dynamic equation considering the coupling of the ground motion translational acceleration,the rocking acceleration and the rocking displacement,and performing time-history analysis to the effect of the rocking component of ground motion.The seismic effect of the transmission tower line structure model is discussed.The results show that considering the rocking displacement of ground motion term and its additional P-? effect,the seismic response of the structure is obviously higher than that of the unconsidered,and the asymmetric displacement effect is obvious;(4)Establish a three-dimensional finite element model of the transmission tower-line.The difference in dynamic characteristics between the single tower and the tower-line model can be seen from the different effects of the transmission line on the seismic effect of the structure.The effect of the quality of the transmission line on the seismic effect of the transmission tower structure has also been studied.The results show that the different transmission quality of line has different effects on the seismic displacement response of the tower-line model.And under different earthquakes,the influence of the transmission line on the response of the tower-line model is also different,and when the quality is uncertain,the impact may be increased or decreased.The rocking component of ground motion has no significant effect on the response of different quality lines of the transmission line. |
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