'Analyze This!' Taking the Guesswork out of Broken-Back Culvert Analysis

摘要

For many years, highway designers at the Nebraska Department of Roads (NDOR) have faced the difficult task of building culverts at locations that have an inlet substantially higher than the outlet. This requires the construction of "broken-back" culverts, which have either one or two breaks in the vertical alignment (Figure 1). The hydraulic performance of these culverts, however, has been unpredictable. Field inspections of broken-back culvert installations did not reveal many clues about performance. Some locations experienced scour-the loss of sediment-at the outlets; in others, silt had plugged the entire outlet section; and yet other locations had neither scour nor sedimentation.