Research Pays Off: Uncovering the Past: Maine DOT Rediscovers the Benefits of Culvert Outlet Diffusers
A novel method for increasing culvert capacity has been rediscovered at the Maine Department of Transportation (DOT). During a literature search on the use of outlet diffusers in highway culverts, Maine DOT researchers came across extensive laboratory testing of diffusers by David Yarnell in the 1920s. Both Yarnell’s work and Maine DOT research indicate that adding a diffuser reduces outlet losses, markedly increasing the culvert’s efficiency. This article discusses Maine DOT's research of diffuser systems including publishing design details, protocol, and method of calculation in the research report, "Outlet Diffusers to Increase Culvert Capacity". Diffusers have been built, installed, and tested in Thorndike and Mattawamkeag, Maine. The performance of these culverts was analyzed using the culvert analysis program (HY-8) created by the Federal Highway Administration. The slip lined culvert had a notable decrease in capacity relative to the original corrugated metal pipe (CMP) culvert because of the reduction in diameter from 24 inches to 20.5 inches. In the drawdown tests, the addition of the diffuser outlet and bell inlet significantly increased the capacity of the slip lined pipe and markedly exceeded the calculated values for the original 24-inch CMP. The increase in performance achieved by adding the diffuser was comparable to that found in Yarnell’s testing of diffusers. The article concludes with a list of benefits associated with effective diffuser installation.
- Record URL:
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/07386826
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Authors:
- Mann, Alexander W
- Publication Date: 2020-9
Language
- English
Media Info
- Media Type: Digital/other
- Features: Figures; Photos; References;
- Pagination: pp 53-55
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Serial:
- TR News
- Issue Number: 329
- Publisher: Transportation Research Board
- ISSN: 0738-6826
Subject/Index Terms
- TRT Terms: Benefits; Culvert outlets; Design; Diffusers; Field tests; Performance; Research projects
- Identifier Terms: Maine Department of Transportation
- Subject Areas: Bridges and other structures; Design; Highways; Research;
Filing Info
- Accession Number: 01759379
- Record Type: Publication
- Files: TRIS, TRB, ATRI
- Created Date: Nov 30 2020 5:27PM