Ductility of steel and composite connections - Design rules to improve the redundancy

Ductility of steel and composite connections - Design rules to improve the redundancy. The actual load bearing and deformation behaviour of beam-to-column connections in steel and composite structures might have decisive influence on the global resistance of the structural system, because the boundary conditions in the structural analyses are only idealized. Connections with smaller resistance than the adjacent beams should have sufficient deformation capacity for redistribution of internal forces, to be able to utilize the capacity of the single members best and to activate the global reserves of the structural system for exceptional situations. Designing ductile joint solutions offers not only an increase of efficiency but also an increase of redundancy for the load bearing structure. Thereof the structure is benefiting for later conversion or under exceptional loading conditions. Based on two research projects some guidelines for designing ductile joint solutions of steel and composite connections are given.