Analyses of the rotational capacity of composite connections for plastic design

The demand for economic and eco-efficient solutions in construction industry is particularly enforcing efficient design and construction methods. The design of composite construction according to the plastic hinge theory in combination with semi-rigid joints provides one contemporary promising answer to these demands. This combination enables to mobilize almost all cross section and system reserves. However, the capability for redistribution of the bending moment from internal support to mid-span, to activate these system reserves requires sufficient rotation capacity of the composite beam and, especially, the connections. This paper presents design guidance on plastic and robust design of composite beams with semi-rigid composite conenctions with special focus on the influence of the reinforcement (ratio, diameter and type). With the provision of an engineering logic, new opportunities to design elegant and slender structures are given to engineers in a simple way.