A simplified method for assessing the ductile behaviour of stud connectors in composite beams with high strength concrete slab

Abstract

Local connection shear failure in the absence of adequate connection ductility can reduce steel and concrete composite element bending resistance. For these elements, Eurocode 4 contains design rules and criteria for checking that implicitly prevent early connection rupture, by limiting the value of the parameters influencing maximum slip capacity. Such indirect ductility checks can, however, only be applied within the constraints of their formulation hypotheses, such as material strength as specified in the document for instance. The use of high strength concrete substantially changes the ratio between maximum slip requirement and connection deformation capacity and demands direct connection ductility checking. This paper identifies the magnitudes affecting maximum slip requirement and suggests a simplified assessment method. The method, having general application, enables assessing connection efficiency to bending collapse of the composite beams and is particularly useful at the initial structure design stage as no demanding sophisticated analysis is required.