Embedded column base rotational stiffness model based on beam-on-elastic-foundation theory and component method

This study establishes a spring‑based mechanical model for predicting the rotational stiffness of embedded column bases (ECBs). The model idealises the embedded column segment as a beam on a Winkler foundation and represents the base‑plate restraint through a rotational spring derived from the component method. An analytical solution for the rotational stiffness is then derived using the initial parameter method. The proposed model is validated against experimental data and demonstrates improved accuracy compared to existing models. Based on the validated model, the influence of key parameters is examined. The results indicate that the rotational stiffness increases notably with η (the ratio of embedded depth to column width) when η ≤ 1.5, after which the growth becomes marginal. For deeply embedded cases ( η > 2.5), the effects of the base‑plate restraint and axial compression force become negligible, and increasing the column’s flexural and shear stiffness is more effective in enhancing the overall stiffness. The influence of the inflection‑point height is also discussed, though its effect is relatively limited. The findings provide practical insights for the design of ECBs.