Seismic Performance Analysis Of 500kV Cat-Head Transmission Tower

A large number of earthquakes show that the intense earthquake often results in serious harm to people’s life. In recent years, performance-based seismic design attracts extensive attention, which is economical and reliable to ensure that the function of building structures in the earthquake will not be lost and even affected. At present, with the growing of voltage, transmission capacity, tower height and volume, the seismic vulnerability of transmission lines is increasing. The method of performance-based seismic design is used in the seismic performance analysis of transmission tower under the strong shock, which can provide good referential supporting to transmission tower.This paper takes 500kV cat-head tower structure used in practical engineering as an example, and creates the finite element analysis model. Through analysis of the model, we find two methods to improve its dynamic characteristics, namely to increase the rigidity of poles and the area of diaphragms. We choose three kinds of site, each site records for the model after increasing the area of diaphragms to carry out the nonlinear time-history analysis. Based on the results of nonlinear time-history analysis and five performance levels, the seismic performance analysis of transmission tower will be finished.Through comparison and analysis, both methods increase the rigidity of poles.The area of diaphragms can effectively reduce the node displacement response, and increase the stability of structure. The integrity has also been greatly improved, and the effect of diaphragms becomes better. The peak accelerations of transmission tower can be experienced in three kinds of site that are all greater than lg. It is indicated that the seismic performance of cat-head transmission tower is very good. In the same seismic wave, with the increasing of peak acceleration, the seismic response of transmission tower is also increasing, which shows the significant nonlinear characteristics. Through the seismic performance analysis of transmission tower, we obtain 12 performance objectives matrixes in 12 earthquake accelerations of record, as well as the performance objective matrixes for three kinds of site by composing the dates of 12 performance objective matrixes.The research of this paper can guide transmission tower design in the practical earthquake motion, and establish foundation for further study.