Steel-fibre reinforced concrete in compo-site structures as a mean to increase re-sistance and ductility

Steel-fibre reinforced concrete is a well-known material used for decades for industrial floorings, shot-crete, or other specific applications. Its use is now spreading in structural applications as a complement or a substitute for conventional bar-reinforced concrete since the normative framework is ready to provide design approaches for several concrete applications. Nevertheless, some adaptations are needed for implementing steel-fibre reinforced concrete in the design approach for steel-concrete composite struc-tures whereby complementary aspects need to be considered. In this field, besides the increase of tensile properties and durability of the concrete member, a very important contribution may be given by the in-crease of the concrete ductility in compression. This property is conferred by the steel fibres which pro-vide a confinement effect increasing the plastic damage that the concrete matrix can absorb. If this prop-erty is widely accepted, its benefits are limited for the design of conventional concrete sections. Con-versely, for composite sections, the possibility to reach higher strains in compression means ensuring full exploitation of the strength capacity of structural steel. Besides reaching an optimization of already in-use cross-sections, this new material combination enhances the use of higher structural steel strengths in composite structures.