Shaking table test on a low-damage controlled multiple-rocking-column steel frame

Abstract

Ancient timber structures represented by the Shaka Pagoda can remain intact after strong seismic actions. Inspired by the rocking and energy dissipation mechanisms of ancient timber structures, a multiple-rocking-column steel frame (MRCSF) system was proposed in this study. The proposed system consists of continuous beams, segmented columns and self-centering friction connections. Friction joints are employed at the beam-column and column base connections to dissipate energy, and the self-centering capacity is mainly provided by the gravity load and additional springs at the connections. A 1/3-scale model of a three-story MRCSF was designed, fabricated and tested on a shaking table at Tongji University. Test results showed that the columns started to rock when subjected to excitations beyond the frequent earthquake level, as expected. The tested frame successfully underwent a series of strong excitations and exhibited excellent low-damage characteristics. Negligible residual drifts and structural damage were measured after the tests. Finally, a feasible design process for the newly proposed MRCSF system was proposed.