Low-damage Performance of Rocking Column Bases With Belleville Springs for Enhanced Seismic Resilience

This paper investigates the low-damage performance of strong axis-aligned asymmetric friction connection (SAFC) column bases, with a focus on enhancing seismic resilience through the incorporation of Belleville Springs (BeSs). Cyclic loading tests were performed along the strong axis of the column, considering three cases: INITIAL (as-built), AFTERSHOCK (post-testing without repair), and REPAIR (restored condition via bolt re-tightening or replacement), with a maximum drift of 3 %. In the absence of BeSs, the column base exhibited a 22.9 % reduction in initial rotational stiffness and a 13.6 % decrease in ultimate moment resistance in the AFTERSHOCK case. However, the use of BeSs maintained the bolts within the elastic range, resulting in near-identical hysteretic behavior across all cases, with losses in stiffness and strength remaining within 7 %. Both column base configurations, with and without BeSs, exhibited satisfactory performance restoration in the REPAIR case. A finite element analysis (FEA) model was developed to quantitatively evaluate the low-damage performance, sliding behavior, bolt pre-tension loss, and energy dissipation of the column base. The findings showed that BeSs improved seismic resilience by mitigating bolt pre-tension loss and minimizing plastic deformation. Finally, a simplified flag-shaped hysteretic model was proposed and validated through test results.