Design procedure for steel column bases with stiffeners

Abstract

The procedure of calculation of steel column bases with stiffeners including plastic distribution of stresses in concrete has been shown. The strain model from section analysis, similar to model used in calculations of reinforced concrete columns has been used in this purpose. The assumption of linear strain of base plate under stiffeners and column has been made, according to Bernoulli-Euler Theory. The displacements of compressed part of columns bases have been associated with deformations of concrete foundation. Limitations of dimensions of compression zone have been defined based on results of FEM analysis. Ultimate compressive strain in the concrete under compression and bending, according to Eurocode 2 has been taken into consideration in the procedure. Deformation of base plate based on stiffness coefficients used in determining of rotational stiffness of steel joints has been assumed in the tensioned part. Incomplete utilisation of bolts resistance due to insufficient deformation has been also included. All the mentioned assumptions results in universal procedure that allows calculation of resistance of column bases under any combination of axial force and bending moment. Finally design example with an entire proceeding has been presented.