Seismic response of tower-line system considering the SSI effects under translational-rotational excitations

Most existing studies usually ignore the rotational component of ground motion when a transmission tower-line system is subjected to an earthquake, leading to inaccurate results. To investigate the actual response of a transmission tower-line system under an earthquake, the rotational components of ground motion are calculated according to the surface fitting method based on the measured translational seismic data of the SMART-1 dense array. Then, a tower-line system considering soil-structure interaction is established for one tower and two span lines, and the seismic response of the tower-line system is studied. In addition, a parametric analysis is carried out to explore the influence of spans, soil conditions, and seismic incidence angles, and a comparative analysis of the seismic response of tower-line systems with and without rotational components is performed. The results show that the rotational component could amplify the seismic response of the tower-line system considering soil- structure interaction, and the influence of the rotational components increases with the deterioration of soil condition. The rotational components and soil-structure interaction should be considered simultaneously in practical engineering calculations to enhance computational accuracy.