Abstract
Bridges with a protected river bed under the structure suffer a combination of different types of erosion during flood events.
Local scour develops upstream piles and abutments. Contraction scour is present due to the narrowing of the cross
section. And finally, erosion downstream the protected zone may occur as a result of a change in the riverbed rigidity.
These phenomena cannot be separately studied, as their total effect does not equal a simple addition of the single effects.
In this paper, an experimental campaign is conducted in order to evaluate how the factors involved in this phenomenon
affect total scour and its dimensions. Furthermore, one of the experiments is simulated by means of a hydraulic
mathematical model, which incorporates sediment transport equations. Agreement between numerical and experimental
results is discussed, alongside the proposal of future model improvements.
