Protrusions on Stepped Spillways to Improve Energy Dissipation

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dc.contributor.advisorBasson, G. R.
dc.contributor.authorWright, Henry-Johnen_ZA
dc.contributor.otherUniversity of Stellenbosch. Faculty of Engineering. Dept. of Civil Engineering.
dc.date.accessioned2008-08-11T09:42:38Zen_ZA
dc.date.accessioned2010-06-01T08:48:06Z
dc.date.available2008-08-11T09:42:38Zen_ZA
dc.date.available2010-06-01T08:48:06Z
dc.date.issued2006-12
dc.descriptionThesis (MScEng (Civil Engineering))--University of Stellenbosch, 2006.
dc.description.abstractStepped spillways constructed of roller compacted concrete (RCC) is a hydraulic and cost effective measure to dissipate energy of large water flows over the spillway of a dam. Stepped spillways, like other spillway types, have its limitations and a measure to improve the energy dissipation effectiveness is proposed. Two hydraulic models were constructed at the hydraulics laboratory of the Department of Water Affairs and Forestry (DWAF) in Pretoria, South Africa. The scales of the models were 1:20 and 1:30. The study proposes the use of triangular protrusions applied over the spillway surface. The protrusions have the same height as the steps, with the width of the protrusions varying. The triangular protrusions deflect the water sideways resulting in higher energy losses. The results indicate that the protrusions reduce scouring at the toe of the dam, thus increasing the roughness of the steps. It also indicate that aeration occur earlier than with normal stepped spillways. An optimal spacing, lateral and across the steps, are proposed. The construction of the protrusions is also discussed, as well as the cost implications. It is concluded that the protrusions are effective at a unit discharge up to 35 m3/s.m. This value is however dependent on the configuration of the apron downstream of the toe of the dam. It is proposed that protrusions be added on the downstream face of the dam on every second step, with one protrusion and then no protrusion alternating in the flow path. It is recommended that the protrusions be cast in situ.en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/2408
dc.language.isoenen_ZA
dc.publisherStellenbosch : University of Stellenbosch
dc.rights.holderUniversity of Stellenbosch
dc.subjectSpillwayen_ZA
dc.subjectHydraulic roughnessen_ZA
dc.subjectStepped spillwayen_ZA
dc.subjectProtrusionsen_ZA
dc.subjectTheses -- Civil engineeringen_ZA
dc.subjectDissertations -- Civil engineeringen_ZA
dc.subject.lcshSpillways -- Design and constructionen_ZA
dc.subject.otherCivil engineeringen_ZA
dc.titleProtrusions on Stepped Spillways to Improve Energy Dissipationen_ZA
dc.typeThesisen_ZA
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