A theoretical model for predicting the rotational capacity of steel base joints

• A method for predicting the rotational capacity of base plate joints is presented.
• Ductility supply of main sources of deformability of base joint is characterized.
• A procedure for evaluating the overall base plate rotational capacity is proposed.
• Three experimental tests performed at the University of Salerno are presented.
• A comparison between experimental and predicted joint ductility is performed.

The last version of Eurocode 8 has opened the door to the design of Moment Resisting steel Frames (MRFs) promoting the dissipation of the seismic input energy in the joints. Within this framework, in order to provide the basic tools for the prediction of the main parameters characterizing the monotonic and cyclic behaviour of joints, in the last two decades, many experimental and theoretical studies have been carried out. As a result of this effort, in EC3 the formulations for predicting stiffness and resistance of common joint typologies have been codified. Despite this, dealing with the rotation capacity of base joints, there is still a lack of knowledge. In order to overcome the knowledge gap surrounding the evaluation of the plastic rotation capacity of base joints, in this paper the development of a mathematical model able to evaluate the ductility supply of exposed base plate joints is presented. Within the framework of the component method, a mechanical approach for predicting the rotational capacity of base plate joints is set up starting from the definition of the ductility supply of the single joint components. Furthermore, the proposed mechanical model is validated by means of the comparison with three full scale experimental tests carried out at the University of Salerno.