Abstract:In order to accurately predict the rotational stiffness of embedded steel column bases, shallowly embedded, in particular, this paper proposes a stiffness model that collectively allows for the effects of the embedded depth, shear deformation of the embedded column, axial force applied to the column and restraint from the base plate. For developing the model, the embedded segment of the column is simplified as a beam on the Winkler foundation, and its deformation is computed using the Timoshenko beam theory on Winkler foundation, considering the influence of axial force applied to the column and solved by initial parameter method. To investigate the influence of the above-mentioned factors and verify the proposed model, finite element (FE) models are developed and validated against existing experimental results. Comparisons between the FE results and model predictions show that the proposed model exhibits higher accuracy than the theoretical models reported, especially for shallowly embedded column bases. The model prediction and FE results indicate that the rotational stiffness of the column base depends on the embedded depth in a nonlinear fashion-the stiffness increases rapidly for small embedded depth but remains almost constant when embedded depth is larger than a certain value; the axial compression load applied to the steel column is a beneficial factor to the stiffness; the restraint from the base plate shows a significant effect on the rotational stiffness of embedded column bases with the embedded depth ratio less than 1.5, being negligible when the embedded depth ratio increases up to 2.5.