Recent developments on composite connections: behaviour of joints subjected to sagging bending moments and presentation of a free design dedicated software

In Eurocode 4, design rules are suggested for the evaluation of the mechanical properties of structural steel-concrete composite joints (rotational stiffness, resistance and ductility). These rules cover situations where the joints are subjected to moments and shear forces, but in hogging regions only. Recently, researches have been conducted on the behaviour of composite joints subjected to sagging bending moments and to combined bending moments and axial loads, types of loadings which appear in composite frame further to a column loss.
In the present paper, recent developments allowing to extend the EC4 design rules to joints in sagging regions (loading which can occur, for instance, in sway composite frames) are presented and the proposed method is validated through comparisons with experimental test results. Also, an easy-to-apply design software (which will be freely available), applying the rules recommended in Eurocode 4 in a safe and easy way, is described.