Numerical investigation of internal force transfer mechanism in push-out tests

The case of a push-out test specimen made of prefabricated slabs connected by means of grouped headed studs is investigated in this study. In order to analyse the behaviour of such a shear connection, an experimental study and a numerical analysis have been developed. This paper deals with the presentation of numerical results linked to the parametric study of several layout and loading conditions. The specific 2D nonlinear finite element model developed by two first authors has been presented in a previous paper. This specific finite element model has been developed in order to avoid convergence problems that sometimes occur with the introduction of contact-friction elements in 3D models. In addition, this simplified 2D model allows reducing considerably the time computation when the model concerns the study of a structure at real scale. This 2D nonlinear model is supposed to approach the 3D problem using a “zone-equivalence” methodology which we briefly recall the theoretical background. Material nonlinear constitutive laws, 4-noded plane elements and frictional contact finite elements were introduced in the model at the steel concrete interface between the girder flange and the concrete slab and between the studs and the filling concrete. Numerical simulations concerned by this work lead to highlight the internal force transfer mechanisms through the specimen for several layouts and loading conditions, such as the stud arrangements, the filling concrete performance, the reinforcement percentage of the slab, the restrain slab conditions and especially the combination of axial and shear loads. These results could be helpful to have a better interpretation of the push-out test measurements in accordance with the specimen arrangement and the test procedure.