ABSTRACT
Putting K2 = Q jb2d3i where ft2 is the overall width between the piers, the expression for the discharge becomes
Q = Chb2d W 2 g K + V, 2 (8.42)
This formula was developed by d’Aubuisson1 and has been widely used. Values of Cb for various shapes of bridge pier and waterway geometry are normally based on Yarnell’s 2 extensive experimental data. Usually, Cb is between 0*90 and 1*05. For a given discharge and channel characteristics, d3 (i.e. dn) may be calculated by a method previously described. The value of h& follows by simple trial and error substitution in Eq. (8.42).
