Improving hydraulic capacity with inlet modifications to box and circular culverts

dc.contributor.advisorLoots, Ione
dc.contributor.coadvisorVan Dijk, Marco
dc.contributor.emailu20424028@tuks.co.zaen_US
dc.contributor.postgraduateGiliomee, Maria Dorothea
dc.date.accessioned2025-02-14T12:49:05Z
dc.date.available2025-02-14T12:49:05Z
dc.date.created2025-04
dc.date.issued2025-02
dc.descriptionDissertation (MEng (Water Resources Engineering))--University of Pretoria, 2025.en_US
dc.description.abstractCulverts convey water underneath roads or through embankments. Culverts can become inadequate over time due to increasing flood peaks caused by higher-intensity rainfall events and urban development. When roads are upgraded, the culverts on these roads might also require upgrades to comply with new road standards. Modifying the culvert inlet to increase discharge capacity can negate the need to rebuild the entire structure, providing a cost-effective solution with minimal disruption to traffic. This study used physical modelling to evaluate different inlet modifications for box and circular culverts under inlet control. The tested modifications included adjustments to wingwall and headwall angles, rounded or tapered inlet edges and the addition of an air vent. Different angles for the wingwall and headwall, when combined, significantly improved the discharge capacity. For box culverts, a 15º headwall with a 30º wingwall increased the flow capacity by up to 34% at a headwater depth of twice the culvert opening (2D). Headwalls and wingwalls had a smaller influence on circular culverts than on box culverts. However, rounded edges that smoothly direct water into the circular barrel shape improved flow by up to 34% at a headwater depth of 2D. The installation of an air vent had an insignificant influence on the discharge capacity under inlet control. A flow improvement coefficient, CTG, in the form of a set of equations, has been developed to quantify the improvement for each type of inlet. This coefficient can be used in South Africa and globally with existing equations to calculate the improved discharge capacity for specific inlet modifications. This practical solution enhances culvert performance and, if applied in practice, will reduce flood risks, especially within South Africa’s expanding road network. It is envisaged that implementing inlet improvements for both new and existing culverts will contribute to a sustainable drainage infrastructure for the country.en_US
dc.description.availabilityUnrestricteden_US
dc.description.degreeMEng (Water Resources Engineering)en_US
dc.description.departmentCivil Engineeringen_US
dc.description.facultyFaculty of Engineering, Built Environment and Information Technologyen_US
dc.description.sdgSDG-09: Industry, innovation and infrastructureen_US
dc.description.sdgSDG-11: Sustainable cities and communitiesen_US
dc.description.sdgSDG-13: Climate actionen_US
dc.description.sponsorshipSouth African National Roads Agency SOC Limited (SANRAL)en_US
dc.description.sponsorshipWater Research Commission (WRC)en_US
dc.identifier.citation*en_US
dc.identifier.doihttps://doi.org/10.25403/UPresearchdata.28417010en_US
dc.identifier.otherA2025en_US
dc.identifier.urihttp://hdl.handle.net/2263/100931
dc.language.isoenen_US
dc.publisherUniversity of Pretoria
dc.rights© 2023 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria.
dc.subjectUCTDen_US
dc.subjectSustainable Development Goals (SDGs)en_US
dc.subjectCulvert inleten_US
dc.subjectHeadwallen_US
dc.subjectWingwallen_US
dc.subjectUrbanisationen_US
dc.subjectClimate adaptationen_US
dc.subjectClimate changeen_US
dc.titleImproving hydraulic capacity with inlet modifications to box and circular culvertsen_US
dc.typeDissertationen_US

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