Study on hysteretic characteristics and restoring force model of an earthquake resilient rocking column

To achieve rapid performance restoration of moment-resisting frame structures after major earthquakes, an earthquake resilient rocking (ERR) column was proposed. Refined finite element model of the ERR column was established and parameter studies were carried out after model validation based on the existing test results. Finally, a theoretical restoring force model was then proposed for the ERR column. The results show that the axial compressive ratio is a main factor affecting hysteretic characteristics of the ERR column. With the increase of axial compressive ratio of ERR columns, the load-resisting capacity increases, the residual deformation decreases rapidly, and the hysteretic hoop gradually switches from pinched "shuttle" shape to "flag" shape, showing better resilient capacity of the column. The design of bolt groups is also an important issue to guarantee good hysteretic performance of ERR columns. The relative slippage between the connecting plate at the column bottom and the steel slit damper will cause pinching of the hysteretic loop and decrease the energy dissipation capacity of the specimen. It is recommended that high-strength friction bolts should be used in the ERR column and designed according to the "strong connection-weak damper" principle. The calculated hysteretic loops agrees well with both the test and FEM results. © 2022 Central South University of Technology. All rights reserved.