Evolution of Four Formulae Derived Over Five Decades to Predict Temporal Scour at Circular Pier

Ever since man discovered how to build the bridge elements to cross broad rivers, scour in stream beds has continued to be a significant factor in bridge failures involving the release of sediment from the stream bed and banks. Because both scour and flooding are time-dependent phenomena, understanding how they evolve is crucial in streambed flooding. Over the decades, several researchers have proposed approaches to predict temporal local scour at circular piers. It is very important to examine the progress of such formulae as these formulae can be useful for designing bridge piers. In this study, therefore, four formulae are analyzed using previous literature data where, the parameters that influence temporal scour are Reynolds number, Froude number, constriction ratio, pier slenderness ratio, sediment coarseness ratio, flow intensity, geometric standard deviation and time. Reviewing and analyzing all four formulae under cohesionless and clear water scour conditions, the performances corresponding to observed and computed scour depths are assessed by applying useful statistical factors. The best performing formula is identified for the given experimental range.