Prediction of time-dependent local scour around bridge piers

摘要

Most formulas for predicting the scour depth around bridge piers result in over-predictions. This is partly due to ignoring the fact that the local scour is a time-dependent process. Formulas that take into account time-dependent local scour around bridge piers have been developed in the past. However, these formulas predict the scour process well, but only when applied to datasets from which they were constructed. Motivated by this, the present study proposes a relationship for time-dependent local scour using dimensional analysis and nonlinear regression. Similarly, another relationship for the time to equilibrium is also developed. The findings indicate that the proposed relationship predicts time-dependent local scour better than existing formulas. The proposed relationships are applicable to local scour around cylindrical bridge piers. It is assumed that the bed sediment is uniform and the bedform effect is minor and can be ignored.