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Mechanics of local scour: supplement, methods of reducing scour

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dc.contributor.authorShen, Hsieh Wen, 1931-, author
dc.contributor.authorSchneider, V. R., author
dc.contributor.authorKaraki, Susumu, author
dc.contributor.authorCivil Engineering Department, Engineering Research Center, Colorado State University, publisher
dc.date.accessioned2019-09-17T18:28:11Z
dc.date.available2019-09-17T18:28:11Z
dc.date.issued1966-06
dc.descriptionCER66HWS36.
dc.descriptionJune 1966.
dc.descriptionPrepared for U.S. Department of Commerce, Bureau of Public Roads, Office of Research and Development, Structures and Applied Mechanics Division.
dc.descriptionIncludes bibliographical references.
dc.description.abstractThe purpose of this report is to summarize the results of tests conducted at Colorado State University on the hydraulic feasibility of reducing scour by modifying pier shapes. The following models were investigated: 1. Sharp nosed piers. 2. Rectangular pier on flat footing supported on piles. 3. Rectangular pier on a flat footing supported on piles with a vertical lip around the edge of the footing. 4. Rectangular pier with a roughened upstream face. 5. Rectangular pier with a roughened upstream face and roughened horizontal apron. 6. Rectangular pier with an additional cylinder placed upstream. 7. Cylindrical pier with a horizontal apron. 8. Split cylinder. Although limited and qualitative in nature, experimental results definitely demonstrate the feasibility of using certain pier configurations to reduce the depth of scour to a significant amount. Shape 3, mentioned above, seems to be well adapted to controlling the horseshoe vortex system. Using this shape, scour reductions of 40 percent were achieved. Tests on other shapes showed that they reduced scour lesser amounts. Further tests would be needed to establish design criteria. The economic feasibility of using any method must be determined based on local conditions for each bridge such as availability of materials, cost of labor, type of bridge, etc. An analytical study is presented which shows that maximum scour is a function of the Reynolds number based on the projected width of the pier and approach velocity. It was assumed that the pier was blunt nosed, i.e., the strong horseshoe vortex system found upstream of the pier. This analysis was verified using limited laboratory data available in the literature. Using the projected width as the length scale in the Reynolds number gives predicted scour depths that are on the safe side. No attempt was made to specify a correction coefficient to bring the scour depth in line with the actual value.
dc.description.sponsorshipUnder Contract CPR-11-8022.
dc.format.mediumtechnical reports
dc.identifier.urihttps://hdl.handle.net/10217/197930
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relationCatalog record number (MMS ID): 991012717429703361
dc.relation.ispartofCivil Engineering Reports
dc.relation.ispartofCER, 66-36
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectScour at bridges
dc.titleMechanics of local scour: supplement, methods of reducing scour
dc.title.alternativeMethods of reducing scour
dc.typeText
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