Numerical Simulations of a Concrete Bridge Deck Loaded to Shear Failure

Abstract

This paper presents numerical simulations of the shear failure of a bridge slab previously tested in full scale on an existing bridge. Using the non-linear finite element method, a model of the bridge is assembled with the purpose to simulate the test procedure and realistically capture the failure load and behaviour. This in order to conclude what type of shear failure that occurred. Furthermore, the shear capacity of the bridge is calculated according to current design codes. A parametric study is conducted on the FE model with the aim to study the influence of key variables on the outcome of the analyses. From the studied parameters, it is observed that a combined reduction of the tensile strength and fracture energy, together with a low fixed crack coefficient has the largest influence. It is also observed that the location of the failure and the ultimate load is dependent on how the loading was applied to the model, i.e. via load control or deformation control. In the final FE analysis, the model fails at a load which slightly exceeds the experimental ultimate load. The mode of failure obtained in all the analyses are the result of a large shear crack propagating from the edges of the loading plate, through the slab to the slab/girder-intersection. This indicates that the type of failure that occurred in the full scale test was primarily due to a one-way shear mechanism with a secondary punching effect. The design values calculated with current codes results in very conservative values when compared to the obtained failure load from the experiment.