Seismic Response Analyses of Transmission Towers under Multidimensional Ground Motions with Rocking and Torsion Components

Most current studies on the seismic responses of transmission towers are performed using two or three translational components of ground motion as earthquake inputs. In this study, a novel surface fitting method (SFM) for extracting rotational components from a dense array is presented based on which two sets of rotational components are derived from the translational earthquake recordings on the SMART-1 array. The seismic response of the transmission tower under multidimensional ground motions that included rocking and torsion components are calculated and analyzed. The results show that three rotational components can largely contribute to the seismic responses with respect to the displacements and accelerations at nodes, as well as the element internal force distribution and base reactions. (c) 2020 American Society of Civil Engineers.