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A regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in South Africa
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867614004884537344 |
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| access_status_str | Open Access |
| author | Jacques, Van Rooyen |
| author2 | Pierre Francois, Van der Spuy |
| author_browse | Jacques, Van Rooyen Pierre Francois, Van der Spuy |
| author_facet | Pierre Francois, Van der Spuy Jacques, Van Rooyen |
| author_sort | Jacques, Van Rooyen |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/127420 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:45:08.467Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/127420 A regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in South Africa Jacques, Van Rooyen Pierre Francois, Van der Spuy Gideon, Van Zijl Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Traffic load modelling, WIM, Probabilistic, Load Model. TMH7, Reliability, Normal Vehicles, Abnormal Vehicles Live loads -- South Africa Structural engineering -- South Africa Simulated annealing (Mathematics) -- South Africa Bridges -- South Africa Loading and unloading -- South Africa Thesis (MEng)--Stellenbosch University, 2023. ENGLISH ABSTRACT: The Technical Methods for Highways 7 (TMH7) is the current traffic load model used to design highway bridges in South Africa. Road traffic has changed significantly since its last revision in 1988. Van der Spuy (2020) recognised the shortcomings of the TMH7 and derived a new traffic load model based on weigh-in-motion data collected on the National Route 3 (N3) in Kwa-Zulu Natal. This study forms part of ongoing research to update the bridge design codes in South Africa. This study sets out to refine the traffic load model derived by Van der Spuy (2020) on a regional basis. Additionally, this study investigates the influence of abnormal vehicle occurrence on the magnitudes of the characteristic load effects. The goal of this study is a regionally calibrated traffic load model that makes provision for the influence of abnormal vehicle occurrence. Two primary investigations are conducted to achieve the goal of this study. The first investigation quantifies the interprovincial variation of traffic load effect magnitudes by comparing the characteristic load effects from regions throughout South Africa. It is found that considerable interprovincial variation exists. The magnitude of hogging moments in KwaZulu-Natal is 1.8 and 1.6 times that of the Eastern Cape and Northern Cape provinces, respectively, and shear forces in the Gauteng province up to 1.9 times as high as the load effects in the Northern Cape. The lowest degree of interprovincial variation is found for sagging moments. The substantial interprovincial variation motivates the derivation of load effect adjustment factors applied to the existing load model of Van der Spuy (2020) to account for this variation. The load effect adjustment factors are complimented by reliability-based partial factors, which were also determined for the respective provinces. The second set of investigations was conducted to establish the influence of normal and abnormal vehicles on the load effect magnitudes. Protocols were established to separate normal and abnormal vehicles. The protocols were primarily based on South African legislation that road traffic must adhere to, in conjunction with assumptions regarding the number of axles. These investigations were separated into two sets of investigations. Firstly, the focus was on the influence of Normal vehicles on the critical load effects. It also included implicit investigations relating to abnormal vehicles on the critical load effects. Additionally, the concept of threshold vehicles was introduced and showed the complexities involved in distinguishing between normal, permit, and illegally overloaded and abnormal vehicles. After the exclusive investigations into normal vehicles, investigations were conducted on abnormal vehicles exclusively. The first step was to separate abnormal vehicles based on the number of axles. It resulted in two primary abnormal vehicle types: eight and nine-axle abnormal vehicles. Abnormal vehicle subclasses were identified based on the modality of the static load effect histograms for eight and nine-axle abnormal vehicles, respectively. Each mode was assumed to represent a unique, abnormal vehicle type (subclass). The individual modes (each representing unique, abnormal vehicle types) were isolated and fit with normal distribution. This was done by employing Gaussian mixture modelling. Characteristic load effects were determined by evaluating the normal distributions associated with each subclass at the 95th percentile. The results of this study showed that significant interprovincial variation exists in the magnitudes of traffic load effects and motivated the use of load effect adjustment factors to account for the variation. The investigations regarding normal and abnormal vehicles suggest that if a separate load model is derived to model abnormal traffic, it should be calibrated on a case-specific basis. However, the investigations related to a separate load model for abnormal vehicles do not indicate a clear requirement for a separate load model to model abnormal vehicles when designing bridges in South Africa. AFRIKAANS OPSOMMING: Die Tegniese Metodes vir Hoofwe¨e 7 (TMH7) is die huidige verkeerslasmodel wat gebruik word om snelwegbrˆue in Suid-Afrika te ontwerp. Padverkeer het aansienlik verander sedert sy laaste hersiening in 1988. Van der Spuy (2020) het die tekortkominge van die TMH7 erken en ’n nuwe verkeerslasmodel afgelei gebaseer op weeg-in-beweging data wat op die Nasionale Roete 3 (N3), in Kwa-Zulu Natal, ingesamel is. Hierdie studie vorm deel van deurlopende navorsing om die brugontwerpkodes in Suid-Afrika by te werk. Die doel van hierdie studie is om die verkeerslasmodel wat deur Van der Spuy (2020) afgelei is, op ’n streekbasis te verfyn. Daarbenewens ondersoek hierdie studie ook die invloed van abnormale voertuie op die groottes van die karakteristieke laseffekte. Die doel van hierdie studie is ’n streeksgekalibreerde verkeersladingmodel wat voorsiening maak vir die invloed van abnormale voertuie. Twee primˆere ondersoeke is uitgevoer om die doel van hierdie studie te bereik. Die eerste ondersoek kwantifiseer die interprovinsiale variasie van verkeer laseffek-groottes deur die karakteristieke laseffekte van streke regoor Suid-Afrika te vergelyk. Daar word bevind dat aansienlike interprovinsiale variasie bestaan. Die omvang van steunpuntmomente in KwaZulu-Natal was 1.8 en 1.6 keer so hoog soos die laseffekte in onderskeidelik die Oos-Kaap en Noord-Kaap provinsies, en skuifkragte in die Gauteng provinsie tot 1.9 keer so hoog soos die laseffekte in die Noord-Kaap. Die laagste graad van interprovinsiale variasie word gevind vir middelspan momente. Die aansienlike interprovinsiale variasie motiveer die afleiding van laseffek-aanpassingsfaktore wat toegepas word op die bestaande lasmodel van Van der Spuy (2020) om met hierdie variasie rekening te hou. Die laseffekaanpassingsfaktore word aangevul deur betroubaarheidsgebaseerde gedeeltelike faktore, wat ook vir die onderskeie provinsies bepaal word. Die tweede stel ondersoeke word uitgevoer om die invloed van normale en abnormale voertuie op die laseffek-groottes vas te stel. Protokolle word ingestel om normale en abnormale voertuie te onderskei. Die protokolle word hoofsaaklik gebaseer op Suid-Afrikaanse wetgewing waaraan padverkeer moet voldoen, in samehang met aannames oor die aantal asse. Hierdie ondersoeke word in twee stelle ondersoeke geskei. Eerstens is die fokus op die invloed van Normale voertuie op die kritieke laseffekte. Dit sluit ook implisiete ondersoeke in wat verband hou met die invloed van abnormale voertuie op die kritieke laseffekte. Daarna word die konsep van drempelvoertuie bekendgestel en het die ompleksiteite getoon wat betrokke is by die onderskeid tussen normale, permit- en onwettig oorlaaide en abnormale voertuie. Na die eksklusiewe ondersoeke na normale voertuie word ondersoeke uitsluitlik op abnormale voertuie gedoen. Die eerste stap is om abnormale voertuie te onderskei op grond van die aantal asse. Dit het twee primˆere abnormale voertuigtipes tot gevolg: agt- en nege-as abnormale voertuie. Abnormale voertuig subklasse word ge¨ıdentifiseer op grondvan die modaliteit van die statiese laseffek histogramme vir onderskeidelik agt en nege-as abnormale voertuie. Daar word aanvaar dat elke modus ’n unieke, abnormale voertuigtipe (subklas) verteenwoordig. Die individuele modusse (wat elkeen unieke, abnormale voertuigtipes verteenwoordig) word ge¨ısoleer en pas by normale verspreiding. Dit word gedoen deur gebruik te maak van Gaussiese mengselmodellering. Kenmerkende laseffekte word bepaal deur die normale verdelings wat met elke subklas geassosieer word by die 95ste persentiel te evalueer. Die resultate van hierdie studie toon dat daar noemenswaardige interprovinsiale variasie bestaan in die groottes van verkeer laseffekte en motiveer die gebruik van laseffekaanpassingsfaktore om die variasie te verantwoord. Die ondersoeke rakende normale en abnormale voertuie dui daarop dat indien ’n aparte vragmodel afgelei word om abnormale verkeer te modelleer, dit op ’n gevalspesifieke basis gekalibreer moet word. Die ondersoeke wat verband hou met ’n aparte lasmodel vir abnormale voertuie dui egter nie op ’n duidelike vereiste vir ’n aparte lasmodel om abnormale voertuie te modelleer wanneer brˆue in Suid-Afrika ontwerp word nie. Masters 2023-03-07T09:39:46Z 2023-05-18T07:21:21Z 2023-03-07T09:39:46Z 2023-05-18T07:21:21Z 2023-03 Thesis http://hdl.handle.net/10019.1/127420 en_ZA en_ZA Stellenbosch University xxi, 147 : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Traffic load modelling, WIM, Probabilistic, Load Model. TMH7, Reliability, Normal Vehicles, Abnormal Vehicles Live loads -- South Africa Structural engineering -- South Africa Simulated annealing (Mathematics) -- South Africa Bridges -- South Africa Loading and unloading -- South Africa Jacques, Van Rooyen A regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in South Africa |
| title | A regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in South Africa |
| title_full | A regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in South Africa |
| title_fullStr | A regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in South Africa |
| title_full_unstemmed | A regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in South Africa |
| title_short | A regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in South Africa |
| title_sort | regional characterisation and calibration of load effects for normal and abnormal vehicles for the structural design of highway bridges in south africa |
| topic | Traffic load modelling, WIM, Probabilistic, Load Model. TMH7, Reliability, Normal Vehicles, Abnormal Vehicles Live loads -- South Africa Structural engineering -- South Africa Simulated annealing (Mathematics) -- South Africa Bridges -- South Africa Loading and unloading -- South Africa |
| url | http://hdl.handle.net/10019.1/127420 |
| work_keys_str_mv | AT jacquesvanrooyen aregionalcharacterisationandcalibrationofloadeffectsfornormalandabnormalvehiclesforthestructuraldesignofhighwaybridgesinsouthafrica AT jacquesvanrooyen regionalcharacterisationandcalibrationofloadeffectsfornormalandabnormalvehiclesforthestructuraldesignofhighwaybridgesinsouthafrica |