Scour evaluation on The Little Beaver Creek Crossing on Goshen Road, Mahoning County,Ohio.

Abstract

Design of bridges over major waterways takes into consideration the effects of scour, or long term lowering of the river channel from an assumed datum. The effects of scour on a structure can be devastating, and many bridge failures have been attributed to this cause. A bridge over a small Northeastern Ohio stream, the North Fork of Little Beaver Creek, was studied to analyze and predict scour effects during 100 and 500 year flood events. The Federal Highway Administration (FHWA) methodology was used for this analysis. Scour estimates reveal that the bridge will most likely fail under both 100 year and 500 year events. This is primarily due to the undermining of the south abutment due to erosion. Had the structure not been subject to this cumulative damage, these flood events may not cause failure. Another conclusion found by this study is that a thorough understanding of the accepted scour analysis equations is required to produce accurate results. It is suggested that scour countermeasures be immediately incorporated to ensure the safety of motorists using this bridge. Potential countermeasures include abutment strengthening through backfill and foundation construction, channel restoration to the original design configuration, tributary relocation and installation of riprap. In the absence of the onset of a major flood event, the bridge requires some of these improvements to offset the effect of the creek flowing partially under the south abutment.