Computation Of Abutment Scour Depth For Open Channel Flow

For conditions of open channel flow at a bridge, the net scour depth for open channel flow is:

 ysa = y2a - (yo)adj
where
ysa = net depth of abutment scour before adjustment
y2a = depth of open channel flow at the bridge after abutment scour has occurred (see details here) and
(y0)adj = adjusted initial depth of flow at the immediate downstream end of the bridge sections prior to the occurrence of scour. Click here for the depth adjustment.

The above scour depth shall be adjusted for the abutment shape, the embankment angle and factor of safety,

 (ysa)adj =FS*Kt*Ke*ysa 
Where:
FS= factor of safety
Kt=abutment shape factor
Ke=embankment angle factor