Most Dutch bridges were constructed around the middle of the twentieth century and considering the fact that traffic has increased exponentially since, it is important to find out if these bridges are still safe for use. Experiments on a 1:2 scale were carried out in the laboratory of the Delft University of Technology to investigate the bearing capacity of transversely prestressed concrete bridge decks subjected to concentrated wheel loads. All the tests showed failure in punching shear at loads much higher than expected from the current codes. This paper presents the results of the experimental parametric study including the effect of the transverse prestressing level (TPL), location of the load, number of loads, size of the loading area (wheel print/loading plate), and influence of previous damage to the deck slab panel, on the bearing capacity.@en

The paper investigates the effect of various geometrical and material parameters on the bearing (punching shear) capacity of transversely prestressed concrete deck slabs by numerical methods. Experiments on a 1:2 scale model of such a bridge were carried out in the laboratory and a 3D nonlinear finite element (FE) model was developed in the finite element analysis software package TNO DIANA (2012) to study the structural behavior in punching shear. A comparison of the experimental and numerical ultimate loads show that the non-linear FE models can predict the load carrying capacity quite accurately with a standard deviation of 0.1 and the coefficient of variation of only 10%. The effect of varying the transverse prestressing level, the presence and size of the ducts, size of the loading plate and the concrete class is also described as part of the parametric study. It was observed that sufficient saving in cost could be made if calibrated numerical models are employed to investigate existing structures rather than doing expensive experimental studies.@en

In the Netherlands, most of the bridges were built more than 50 years ago and it is essential for bridge authorities to find out if these bridges are still safe for modern traffic loads for which they were not designed initially. Experiments on a 1:2 scale were carried out in the laboratory of the Delft University of Technology (TU Delft) to investigate the bearing capacity of bridge decks with varying levels of transverse prestressing subjected to concentrated wheel loads. All the tests showed failure in punching shear. It was found that, as a result of compressive membrane action (CMA) by virtue of lateral restraint effects, in combination with the transverse prestressing, the punching shear resistance of the decks was much larger than predicted by most international codes that do not consider the effect of CMA. It appears to be worthwhile to regard CMA when assessing the bearing resistance of existing bridges to avoid unnecessary strengthening measures.@en