Steel-HSC composite beams with partial shear connection and miniaturized limited-slip-capacity connectors

The flexural strength of steel-concrete composite members depends on both the shear capacity and the ductility of the shear connectors between steel beam and concrete slab. Plastic design strategies of composite beams (equilibrium method) allow the shear strength of the connectors to be easily considered. However, these models do not take into account the deformation behaviour of the connectors nor their limited slip capacity. Several design codes only allow ductile shear connectors with a deformation capacity delta(ult) of at least 6 mm to be used, while composite beams with non-ductile connectors (delta(ult) < 6 mm) are excluded from plastic design. Consequently, promising innovative shear connectors with non-ductile deformation behaviour cannot be used economically. Using the example of the miniaturized pin connector, this paper illustrates how finite element models of composite beams - considering both the shear and slip capacities of the connectors - can be used to derive the minimum degree of partial shear connection for beams with limited slip capacity. The proposed modelling strategy and the methodology for deducing the minimum degree of partial shear connection can be transferred and assigned to other types of shear connector with either a ductile or non-ductile deformation behaviour.