Limitations on the use of partial shear connection in composite beams with steel T-sections and uniformly spaced rib shear connectors

Design codes like EC4 allow the bending resistance of composite beams with partial shear connection (PSC) to be assessed by plastic analysis procedures, based on equilibrium of forces across the composite section (equilibrium method). However, these plastic design models are limited to connectors, usually shear studs, with sufficient deformation capacity (at least 6 mm) and composite beams, where the steel sections have either equal flanges or only slightly differing areas of top and bottom flange. Beyond that, EC 4 defines a minimum degree of shear connection to be provided, that was derived for composite members with double flange steel section and stud connectors through systematic FE analysis. For composite beams with steel T-section (without top flange) and uniformly spaced rib shear connectors, limitations on the use of partial shear connection have not yet been investigated. Due to significant discrepancies in terms of steel section geometry and ductility of the connectors a simple adoption of regulations from EC4 is not possible and presumably unsafe. To resolve that problem, the paper presents the results of numerical simulations, based on which limitations on the use of partial shear connection have been derived for beams with steel T-sections and uniformly spaced connectors.