Local Scour at Complex Pier Geometries

This paper follow a conceptual paper on the same topic presented by the authors at the 1998 Water Resources Engineering Conference held in Memphis TN. That paper described the hypothesis that local scour depth predictions for the individual components of a complex structure (pier pile cap and pile group exposed in the flow field) can be combined to obtain a reasonable prediction for the composite structure. At that time there was very little reliable data to back up the hypothesis. Since that time the authors have conducted a systematic series of experiments in three separate laboratories to produce a preliminary set of design curves and a proposed procedure which are presented in this paper. The procedure has been tested on several physical models of complex piers and the computed values are compared to the measured values.