Lab report for the Acosta Bridge scour study

The purpose of this study is to investigate the relative effects that a proposed commuter bridge spanning the St. Johns River in Jacksonville, Florida, will have on scour at two existing bridges. This was accomplished through physical modeling of the study area performed at the Federal Highway Administration's Hydraulics Laboratory. Wooden scale models of bridge piers were placed in a sand-filled sump within a flume. Many different configurations of bridge piers were placed in the flume, and the resulting scour holes were measured and compared. Other, nonsite-specific scour issues were also investigated. Experiments were run which tested the influence that pile spacings have on scour. Scour resulting from equivalent width piers versus pile groups was also investigated. Finally, riprap tests were performed for comparison with empirical formulas for establishing stability (A).