Rotational stiffness and moment resistance of bolted endplate joints with hollow or CFST columns

• An extensive FE analysis was carried out for hollow and CFST columns under transverse loading.
• Empirical equations were proposed for stiffness of column face and column side wall components.
• The proposed models were incorporated into EC3 and EC4 to predict the initial stiffness of steel and composite joints.
• Obtained predictions are compared with the experimental results of 44 tests on considered joints.
• It is concluded that the proposed models are more reliable than the existing ones.

This paper deals with the prediction of the initial rotational stiffness and moment resistance of bolted endplate joints between I-beams and hollow or concrete filled steel tubular (CFST) columns. An extensive numerical analysis was carried out on a wide range of configurations of hollow and CFST columns subjected to transverse forces. Based on numerical simulation results, the stiffness models for the ‘column side walls in tension and compression’ and ‘column face in bending’ which is the most deformable component within a joint were proposed. The proposed models were then incorporated into the component method adopted in EC3 and EC4 to predict the initial rotational stiffness and moment resistance of bolted endplate joints. The obtained predictions were compared with the experimental results of 44 available tests to verify the validity of the proposed models. The comparison of results indicated that the proposed models are more reliable than the existing ones and thus could be incorporated into EC3 and EC4 guidelines for the design of bolted endplate joints with hollow or CFST sections.