PROGRAMME

ABSTRACT Climate impacts are expected to intensify weather related flooding events that are the most common and damaging natural disaster. Riverine bridges are particularly prone to failure during floods and their disruption may impair significantly flood evacuation plans. Thus, in the design of bridges, it is especially important to consider the impact of flooding and more specifically to determine the flow characteristics around bridges for a range of discharges including flood conditions. Typically, we perform such calculations using 1D approaches. In the present work we demonstrate that 1D approaches are not adequate as follows. Firstly, we apply the conventional approach using the hydrodynamic model HECRAS-1D in the Historical Bridge of Arta and determine the hydrodynamic characteristics and forces. Secondly, we apply the 3D CFD model FLOW3D and repeat the calculations. Thirdly, we compare the results of both approaches and draw the following conclusions: (1) Under normal flow conditions, the two approaches give similar results for the hydrodynamic forces on the bridge piers that range from 12 to 18 KN/m2, and (2) Under flood conditions calculated forces using FLOW3D increase dramatically ranging from 34 to 37 KN/m2, while these using HECRAS-1D remain at the same levels as for normal flow conditions.