Abutment Scour Equation - Vertical Wall Abutments
The adjustment factors presented above are combined with Laursen's contraction scour equation to develop the equation for abutment scour:
y2a/y1 = kp*kf*(kv*q2/q1)k2
where:
y2a = total depth of flow at the bridge abutment after scour has occurred
y1 = initial depth of flow at the approach section prior to the occurrence of scour.
q2 = unit width discharge at the bridge section
q1 = unit width discharge at the approach section
kp = pressure flow adjustment factor
kf = spiral flow adjustment factor
kv = velocity adjustment factor
k2= sediment transport experimental constant