Author(s): K. Babaeyan-Koopaei; E. M. Valentine
Linked Author(s):
Keywords: Lluvial Channel; Self-formed Channel; Pier Scour; Pier Groups; Regime Channel
Abstract: An experimental investigation of scour in the bed and banks of self-formed straight channels caused by cylindrical bridge piers is presented. A unique feature of the experiments in this study is the mobility of the entire cross-section. A comparison between the data and available equations for scour depth prediction reveals that these equations mostly overpredict the scour depth. The difference is attributed to the fact that these equations are based on limited data obtained from experiments carried out in fixed wall laboratory flumes, which do not represent the real situation in the field. The effect of pier spacing on scour depth was also considered. A pier spacing coefficient has been proposed which can be used to account for the effect of pier spacing on scour depth. Scour pattern due to interactions of piers and straight channels is considered. This reveals that the main abrupt change in channel bed and banks is because of scour hole formation. An increase in channel width downstream of piers is observed, i. e. the width increases to a maximum value and then decreases. The rate of this increase is initially high and then reduces.
Year: 1999