Seismic-resilient high-strength steel column base using stiffened replaceable cover plates: experimental and numerical study

Abstract

This study focused on the research gap for seismic-resilient high-strength steel column bases. A novel configuration of exposed steel column base was proposed, where multi-strength-grade of structural steels was adopted, and bolted connection was specially designed for the energy-dissipation elements to facilitate post-earthquake quick repair. Full-scale experimental study was carried out to verify its effectiveness. Following that, design procedure of the column base was proposed and verified by the validated finite element model. Test results confirmed effectiveness of the proposed column base in providing enough stiffness and strength compared with the conventional exposed steel column bases. Plastic deformation always concentrated in the replaceable cover plates. There was no damage in the column segment, concrete foundation and anchor rods, while slightly spalling of the mortar layer may happen, which is not expected to be difficult in repairing. Only slight residual base rotation was observed in the test, which verified low residual deformation in the column base can be realized. To prevent yielding of the steel column segment, the reaction moment attributed from the column axial compression force and the four cover plates should always be less than the yielding moment of the column section, no matter under unidirectional or bidirectional loading.