During the design of the new Danube Bridge (‘Lužný most’) in Bratislava, Slovakia, the scouring processes on a movable bed were assessed using a hybrid physical and numerical methodology and applied to sharp-nosed complex piers. The objectives included analyzing changes in riverbed topography, calculating the scour depth and affected area, assessing the stability of scour countermeasures, and gaining a better understanding of the spatial distribution of fluvial circulation around the bridge piers. The study began with the theoretical scour depth values calculated with the HEC-18 methodology. Due to its limitations, a physical model was built to test the storm events of Q20 and Q100 return periods using real data, for different geometries of the piers. Physical test results validated the hydro-morphodynamical modelling of sharp nose piers using Delft3D. A correlation and a more accurate approach for assessing scouring for simple and complex sharp-nose piers was made after comparing the hybrid methodology with HEC-18 formulation.

physical model,Numerical simulation,movable bed,Danube,Local Scour,Complex pier,Rip Rap,HEC-18