Investigations on the system reliability of composite beams by transferring brittle and ductile Daniels systems to the shear connection

In the design of a composite beam, the load‐bearing capacity of a shear connector is assumed to have its design value P_Rd. But a shear connection consists of dozens to hundreds of connectors whose individual capacities are scattered and randomly distributed. Thus, the load‐bearing capacity of the shear connection is usually higher than the capacity assumed in design n · P_Rd.

In 1945, H. G. Daniels described the system reliability of ideal elastic‐brittle fibre bundles with force redistributions after failure of individual fibres. In many cases the system reliability increases for few elements. And it increases continuously for ductile elements.

This article shows a reliability analysis of ideal Daniels systems with brittle and ductile elements. For the shear connection, the ideal Daniels system is extended to unequal load distributions in the shear connection of a composite beam. In parameter studies, the influence of the number of connectors on the system reliability of the composite beam is investigated for different boundary conditions. Again, an increase in reliability can usually be observed with only a few shear connectors. Conversely, if the reliability should remain the same, the design level of the shear connection could be raised by adjusting the partial safety factor γ_V.