Analysis of shear connection distributions in continuous steel-concrete composite beams

Continuous beams are widely adopted in steel-concrete composite construction for both building floors and bridge decks, owing to the many advantages arising from combining the two materials. Many aspects related to the service state and ultimate state behaviour of continuous composite beams have thoroughly been investigated in the past, by using both experimental tests and numerical simulation. Some other aspects deserve more attention since reduced information is available. Among them is the evaluation of the effects of different distributions of shear connectors on the global and local response of composite beams. In this work the behaviour of continuous steel-concrete composite beams with different shear connection distributions is analyzed. For this purpose a finite element code [1] specifically developed by the authors for the nonlinear analysis of steel-concrete composite beams and validated by comparisons with experimental tests [2] is adopted. This finite element model includes material nonlinearity of concrete, beam steel and reinforcement steel as well as slab-beam nonlinear partial interaction due to the deformable shear connection. The inclusion of the partial interaction in the composite beam model provides information not only on the slab-beam interface slip and shear force but also enables to model the failure of shear connectors. In this way it is possible to analyze and quantify the effect of shear connector distributions on the global and local response of continuous steel-concrete composite beams, both under service load levels and at collapse. Particular attention is focused on the ductility requirements on the shear connectors when varying the connection design approach and distribution.