Scaling Analysis of Pier-Scouring Processes.

This study presents a scaling analysis of the time development of clear-water scour depth at bridge piers. It shows that the widely-used exponential formula can be theoretically derived with scaling arguments. The derivation provides connections between the physical pier-scouring process and two empirical constants used in the formula. The dependence of the two constants on sediment coarseness is calibrated using published laboratory data with scour duration ranging from 49 to 1094 h. The analysis presented is restricted to conditions, including steady flow, clear-water scour, narrow circular cylindrical pier, and uniform sediment with low coarseness. [ABSTRACT FROM AUTHOR]