*Civil Engineering Department, College of Engineering, Osmania UniversityHyderabad
**Hydraulic Section, College of Engineering, Osmania University, Hyderabad.
***College of Engineering, Osmania UniversityHyderabad.
On the basis of the concept of ‘equilibrium depth of scour’, a simple equation for the depth of scour at the pier has been obtained by using the specific energy equation. The depths calculated using this equation compare well with the experimental data.
Tests were also run for the comparative study of the depths of scour for the commonly used shapes of piers, that is, semi-circular, triangular (90° and 60° nose) and parabolic. Among these, the parabolic shape gives the least scour and 90° nose triangular shape gives the maximum scour.
The maximum depth of scour in all the tests was observed at the nose of the pier, where the stream-lines are deflected most, rather than in the contracted section where the velocity is maximum. It appears, therefore, that the deflection of the stream-lines around any obstruction (pier) is one of the main causes of the scour. These studies, as such, confirm the previous studies of TISON in this connection.
