Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The hypothesis postulated in this research, namely that the effectiveness of natural and constructed buffer dune systems can be assessed by a set of indicators that defines the integrity of the dune system and triggers informed management decisions, was evaluated and proved to be essentially true. Two key objectives, namely (1) the identification of key indicators that define the buffer dune integrity; and (2) the development of a scientifically defendable and practical checklist-based method of gathering qualitative information on the identified key indicators so as to guide decision-making at municipal level formed the core of the study. The six dune integrity indicators that collectively define the risk profile of a particular site along the Southern Cape coastline are (1) the degree of protection from prevailing wave energy, (2) the characteristics of the dominant winds and sand supply during the dry season, (3) the relative height of the foredune, (4) the degree of pressure on the buffer dune due to humans, (5) the vulnerability of the type of coastline to erosion, and (6) the coastline stability considering the prevailing coastal processes. The first two indicators relate to the natural (permanent) characteristics of the site and can be defined by experts and presented in the form of a risk and vulnerability atlas layer for direct use by non-experts. The third and fourth indicators relate directly to the implementation of proactive assessment and appropriate management actions to ensure a high level of buffer dune integrity. The last two indicators allow for management intervention to reduce the vulnerability but may entail costly engineering solutions and require expert input. A conceptual risk profile assessment procedure and a decision support guideline incorporating these indicators were developed and evaluated for relevance and practicality through a series of workshops with municipal officials along the south coast of South Africa. It was seen that although some initial basic training may be required, carrying out rapid assessments of the environmental status of key components of an identified human–nature system, such as a buffer dune, is practical and achievable by non-experts. / AFRIKAANSE OPSOMMING: Die hipotese wat in hierdie navorsing gepostuleer is, naamlik dat die doeltreffendheid van natuurlike en geboude bufferduinstelsels geassesseer kan word deur ’n stel aanwysers wat die integriteit van die duinstelsel bepaal en ingeligte bestuursbesluite tot gevolg het, is getoets en bewys hoofsaaklik waar te wees. Twee sleuteldoelwitte, naamlik (1) die identifisering van sleutelaanwysers wat die bufferduinintegriteit bepaal; en (2) die ontwikkeling van ’n praktiese kontrolelys-gebaseerde metode wat wetenskaplik verdedigbaar is om kwalitatiewe inligting oor die geïdentifiseerde sleutelaanwysers in te samel ten einde besluitneming op munisipale vlak te bevorder, vorm die kern van die studie. Die ses duin-integriteitsaanwysers wat gesamentlik die risikoprofiel van ’n bepaalde terrein langs die kuslyn bepaal, is (1) die graad van beskerming teen die heersende golfenergie, (2) die kenmerke van die dominante winde en sandbron gedurende die droë seisoen, (3) die relatiewe hoogte van die voorduin, (4) die graad van druk op die bufferduin as gevolg van mense, (5) die eroderingskwesbaarheid van die soort kuslyn, en (6) die kuslynstabiliteit met inagname van die kusprosesse. Die eerste twee aanwysers het betrekking op die natuurlike (permanente) eienskappe van die terrein en kan deur kundiges bepaal word en in die vorm van ’n kaart in ’n risiko-enkwesbaarheidsatlas aangebied word vir direkte gebruik deur niedeskundiges. Aanwysers 3 en 4 hou direk verband met die implementering van tydige en deurlopende proaktiewe assessering en gepaste bestuursaksies om ’n hoë vlak van bufferduinintegriteit te verseker. Aanwysers 5 en 6 bevorder bestuursaksies om kwesbaarheid te verminder, maar kan moontlik duur ingenieursoplossings inhou en kundige insette benodig. ’n Konseptuele risikoprofielassesseringsprosedure en ’n besluitondersteuningsriglyn wat die aanwysers insluit, is ontwikkel en geëvalueer vir toepaslikheid en uitvoerbaarheid deur ’n reeks werkswinkels met munisipale amptenare aan die suidkus van Suid-Afrika. Hoewel aanvanklike basiese opleiding nodig kan wees, bly dit dat vinnige assessering van die omgewingstatus van sleutelkomponente van ’n geïdentifiseerde mens–natuurstelsel, soos ‘n bufferduin, prakties en haalbaar deur niedeskundiges is.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Electric driven overhead travelling bridge cranes (EOHTC) form a vital part of industrial plants where heavy objects require moving. Overhead travelling cranes aid in production by allowing an uninterrupted work process on the ground while heavy loads are moved to their required locations. Various factors need consideration in determining the loads induced by an EOHTC on its support structure. In order to design such a support structure, the designer must understand and take into account the various loads that the support structure will be subject to during its lifetime. The procedure for determining the loads induced by the EOHTC on its support structure is laid out in the SANS 10160-6:2010 code of practice. This document was published in June 2010 and as a result very few worked examples exist to test the coherence of the procedure. This thesis presents an investigation into the procedure for determining the actions induced by overhead travelling bridge cranes adopted in the SANS 10160-6:2010 code of practice. The investigation was conducted by developing a software application to automatically determine the necessary crane actions needed for the design of the crane support structure, given certain input parameters. The motivation behind this was to have a tool that can calculate the crane induced loads automatically. And by developing such a tool the procedure given in the code of practice is better understood. The Java programming language was used to code the calculations with an object oriented programming approach (OOP). NetBeans, the integrated development environment for developing with Java was used to generate the required graphical user interface of the application. In addition, a Microsoft Excel calculation sheet was also developed for the purpose of comparison and verification. Whilst developing the software application, it was found that the model for the acceleration or deceleration of the crane was specific for four wheel cranes only. This model was then extended to accommodate eight and sixteen wheel cranes and incorporated into the algorithm architecture of the application. The application was successfully completed and verified using benchmarked examples. / AFRIKAANSE OPSOMMING: Elektriese oorhoofse brugkrane vorm ‘n belangrike deel van baie nywerheidsprosesse, waar dit gebruik word om swaar laste in die nywerheidsaanleg te verskuif. Oorhoofse brugkrane voeg waarde by die produksie lyn deur te sorg dat die werksproses op die grond onversteurd voortgaan terwyl swaar laste na hul vereiste posisies verskuif word. Verskillende faktore moet in ag geneem word om die nodige kraanlaste te bepaal. Hierdie laste word benodig om die kraan se ondersteuningstruktuur te ontwerp. Die ontwerper moet die nodige kundigheid hê en moet ook die verskeie laste in ag neem wat die ondersteuningstruktuur gedurende sy leeftyd sal dra. SANS 10160-6:2010 verskaf riglyne vir die bepaling van die laste wat deur oorhoofse brugkrane uitgeoefen word. Hierdie dokument is in Junie 2010 gepubliseer dus bestaan daar min uitgewerkte voorbeelde om die korrektheid van die riglyne te toets en toepassing te demonstreer. Hierdie proefskrif ondersoek die riglyne vir die bepaling van oorhoofse brugkraan aksies soos uiteengesit in die SANS 10160-6:2010. Die navorsing is uitgevoer deur middel van die ontwikkeling van ‘n sagteware toepassing wat die nodige oorhoofse brugkraanlaste automaties bepaal, gegee sekere invoer waardes. Die rede hiervoor was om ‘n hulpmiddel te ontwikkel vir die outomatiese bepaling van oorhoofse brugkraan. Deur die bogenoemde hulpmiddel te ontwikkel word die riglyne, soos gegee in die kode beter verstaan. Java is gebruik as programmeringstaal waar die objek geörienteerde programeringstyl toegepas was. Die geintegreerde ontwikkelingsomgewing vir ontwikkeling met Java, naamlik NetBeans is gebruik om die nodige gebruikers koppelvlak op te bou. ‘n Microsoft Excel sigblad is ook ontwikkel vir kontrolerings doeleindes. Gedurende die ontwikkeling van die sagtewarepakket is dit bevind dat die lasmodel vir die versnelling of vertraging van die oorhoofse brugkraan slegs op vierwiel krane van toepasing is. Hierdie lasmodel is dus uitgebrei om agt- en sestienwiel krane ook te bevat. Die lasmodel aanpassing is dan ook in die program se algoritme-argitektuur ingebou. Die sagteware toepassing is suksesvol ontwikkel en gekontroleer met ‘n maatstaf voorbeeld.

Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The southbound screener lane of the Heidelberg Traffic Control Centre received structural improvements by means of an ultra thin continuously reinforced concrete pavement (UTCRCP) overlay. This experimental overlay forms part of the South African National Roads Agency Limited’s innovative highway repair strategy on existing pavements that have exceeded design life. The primary objective of this study was to characterize the UTCRCP overlay with regard to crack spacing formation under accelerated pavement testing (APT). Characterization comprised of empirical modelling techniques, statistical analysis, non destructive testing and software simulations. Pavement deflection responses were empirically and linear elastically converted to input parameters. These parameters were used in the mean crack spacing prediction model of the Mechanistic-Empirical Pavement Design Guide (M-E PDG). Observed cracking under APT was recorded and analyzed by means of descriptive statistics. The outcome of the M-E PDG’s mean crack spacing and the statistics of the observed cracking were evaluated against cncPave simulations. Initial shrinkage crack formations ranged from 500 mm to 900 mm, with a mean spacing of 695 mm. Subsequent secondary cracking reduced the segments, delineated by initial cracking, to intervals consisting of 100 mm to 350 mm. A statistical analysis of the observed cracking indicated that traffic had little effect on the transverse crack spacing formation. The observed cracks yielded a mean spacing of 296 mm, compared to the 186 mm of the M-E PDG mean crack spacing calculation. cncPave simulations indicated that the expected range of cracking would fall between 237 mm and 350 mm with a probability of 50% that crack spacing would exceed 265 mm. The 50th percentile of the observed cracks resulted in a spacing of 233 mm. The APT project was limited to a single test section. No pavement failures occurred during the APT project. A total of 2.8 million 80 kN load repetitions were applied to the UTCRCP. However circular crack formations regarded as a punchout development have formed on the UTCRCP test section. Circular cracks formed around weaknesses in the pavement system. The prediction of these punchout formations incorporates the mean crack spacing result. Occurrence of mean crack spacing forms part of a crack spacing distribution defined by a range. Therefore designing a punchout prediction model for UTCRCP should include the characteristics and range of the crack pattern and not merely the mean crack spacing value. Key Words: UTCRCP, APT, Mean Crack Spacing, Punchout, Descriptive Statistics, cncPave, M-E PDG, Transverse Cracks, Dense Liquid Foundation, Elastic Solid Foundation. / AFRIKAANSE OPSOMMING: Die suidwaartse moniteerings laan van die Heidelberg Verkeersbeheer Sentrum, het strukturele verbetering ondergaan deur die konstruksie van ‘n ultradun aaneen-gewapende betonplaveisel (UDAGBP) wat dien as ‘n deklaag. Hierdie eksperimentele deklaag is deel van die Suid-Afrikaanse Nasionale Paaie Aggentskap Beperk (SANRAL) se vernuftige deurpadherstelstrategie vir bestaande deurpaaie waarvan die ontwerplewe verstryk het. Die primêre doel van hierdie studie is om die UDAGBP te karakteriseer, met betrekking tot kraakspasiëring, deur middel van Versnelde Plaveisel Toetsing (VPT). Die karakteriseringsproses het bestaan uit empiriese moduleringstegnieke, statistiese ontleding, nie-destruktiewe toetsmetodologieë en sagtewaresimulasies. Die plaveiseldefleksiegedrag is empiries en linieêr elasties ontleed en omgeskakel na invoerparameters. Hierdie parameters is gebruik in die peilingsmodel vir gemiddelde kraakspasiëring van die Meganisties-Empiries Plaveisel Ontwerpsgids (M-E POG). Waargenome kraakspasiëring na die afloop van VPT is opgeteken en deur middel van beskrywende statistiek ontleed. Die resultate van die M-E POG se gemiddelde kraakspasiëring en die statistiese ontleding van die waargenome krake is geëvalueer teenoor cncPave simulasies. Aanvanklike krimpingskrake het gevorm met wisselende kraakspasiëring tussen 500 mm en 900 mm met ‘n gemiddelde spasiëring van 695 mm. Daaropvolgende krake het die aanvanklike segmente, wat gevorm het tydens die aanvanklike krimpingskrake, verkort na intervalle van 100 mm tot 350 mm. ‘n Statistiese ontleding van die waargeneemde krake het aangedui dat verkeer weinig ‘n aandeel het in die dwarskraak-vormingsproses. Die waargenome krake het ‘n gemiddelde spasiëring van 296 mm in vergelyking met 186 mm van die M-E POG se gemiddelde kraakspasiëring berekening. cncPave simulasies het aangedui dat die verwagte kraakspasiëringsgrense tussen 237 mm en 350 mm is en ‘n 50% waarskynlikheid dat die kraakspasiëring meer as 265 mm is. Die VPT projek is beperk tot ‘n enkele toetsseksie. Geen plaveiselfalings is waargeneem gedurende die VPT projek nie. In totaal was 2.8 miljoen as-lasherhalings aangewend op die UDAGBP. Daar het egeter sirkelvormige kraakformasies, wat beskou word as ponsswigting, ontwikkel op die UDAGBP toetsseksie. Sirkelvormige kraakpatrone het gevorm rondom swak plekke in die plaveisel. Die peilingsmodelle van hierdie ponsswigting maak gebruik van die gimiddelde kraakspasiëringsresultaat. Die verskynsel van gemiddelde kraakspasiëring in hierdie studie is deel van ‘n kraakspasiëringsverdeling, gedefinieerd deur ‘n spasiëringsgrens. Daarom moet die kraakspasiëringskarakteristieke en spasiëringsgrense in ag geneem word in die ontwerpsproses van ‘n UDAGBP ponsswigting-peilings-model, nie slegs die waarde van die gemiddelde kraakspasiëring nie. Sleutel woorde: UDAGBP, VPT, Gemiddelde Kraakspasiëring, Ponsswigting, Beskrywende Statistiek, cncPave, M-E POG, Transversale Krake, Digte Vloeistof Fondasie, Elasties- Soliede Fondasie.

Thesis (MScEng (Civil Engineering))- -University of Stellenbosch, 2011 / ENGLISH ABSTRACT: The limited water supply and an increasing water demand means that the effective management of water resources becomes much more important than in the past. The implementation of water demand management / water conservation (WDM/WC) projects are usually used as a crisis management tool to reduce immediate water shortage and to allow time for the planning and construction of infrastructure to increase water supply. It is however possible to incorporate WDM/WC into integrated water resource management and to use WDM/WC as an economic viable option for the upgrade of infrastructure to balance supply and demand. Existing economic evaluation methods to compare different options with each other were used to evaluate WDM/WC measures. Literature showed that to perform an economic evaluation of WDM/WC measures, the costs associated with the implementation of the WDM/WC measures, as well as the expected water saving from the implementation of the WDM/WC measure, must be known. Models were developed to estimate the expected water savings from different WDM/WC measures. The economic impacts of specific WDM/WC measures were investigated by using these models. Different economic models were developed to perform an economic evaluation of WDM/WC measures. WDM/WC measures were evaluated in terms of its economic feasibility. Economical evaluations of WDM/WC measures were also done as an alternative to the upgrading of infrastructure. In the last evaluation, the financing of WDM/WC measures through the deferral of capital cost, was investigated. Case studies from literature, where costs as well as water savings were available, were used to evaluate these WDM/WC measures by using the developed economic models. Cost estimates for the upgrading of infrastructure, to supply an equal amount of water as the water saving achieved in each case study, were done. These estimates were used to compare WDM/WC measure with the upgrading of infrastructure. / AFRIKAANSE OPSOMMING: Daar word al hoe meer druk op bestaande hulpbronne geplaas om voldoende water te lewer. Die fokus skuif na effektiewe bestuur van hierdie hulpbronne. Wateraanvraagbestuur/ Waterbewaring (WAB/WB) projekte word geïmplementeer om krisisse van water tekorte aan te spreek en tyd te wen om nuwe hulpbronne te ontwikkel. Dit is wel moontlik om WAB/WB in geïntegreerde waterbron bestuur in te sluit en WAB/WB as ʼn ekonomiese alternatief tot kapitale investering aan te wend. Om die ekonomiese aspekte van WAB/WB te ondersoek, is daar op bestaande ekonomiese evaluerings metodes gefokus om verskillende opsies met mekaar te vergelyk. Uit die literatuur is gevind dat die belangrikste aspekte vir die ontleding van WAB/WB alternatiewe i.t.v. hul ekonomiese waarde, die koste van implementering van die WAB/WB alternatief is en die waterbesparing wat deur die implementering van die WAB/WB alternatief verkry word. WAB/WB modelle is ontwikkel om die verwagte water besparing van bepaalde WAB/WB alternatiewe te beraam. Die moontlike ekonomiese impak van bepaalde WAB/WB alternatiewe is deur die gebruik van hierdie modelle ondersoek. Ekonomiese evaluerings modelle is opgestel om WAB/WB alternatiewe te ontleed. WAB/WB alternatiewe kan as ʼn ekonomiese haalbare projek geïmplementeer word waar die kostes van die waterbesparings meer as die kapitale koste van die projek is. WAB/WB alternatiewe kan ook meer ekonomies as die ontwikkeling van nuwe bronne of opgradering van ʼn bestaande netwerk wees. Laastens is die moontlikheid om WAB/WB as ʼn alternatief te finansier deur die besparing wat bereik kan word deur ʼn kapitale projek uit te stel, ondersoek. Gevalle studies uit die literatuur, waar die kostes en waterbesparings bekend is, is ontleed deur van hierdie ekonomiese evaluerings modelle gebruik te maak. Vir elk van die gevalle studies is ʼn koste vir die opgradering van die infrastruktuur beraam om die ekwivalente hoeveelheid water te voorsien as wat deur die WAB/WB alternatief bespaar is.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: South African municipalities are under pressure to improve the current state of the water andwastewater service delivery industry. Knowing that there exists a need for improvement within the municipal water and wastewater industry, the Department of Water Affairs (DWA) launched a municipal strategic self-assessment (MuSSA) initiative to evaluate the business health of the industry. MuSSA asks high level technical management staff five key questions about sixteen key business attribute areas. This study seeks to determine if theMuSSA data can be used to aid municipal decision making, by way of drawing correlations between key performance indicators contained in the MuSSA questions. The correlations are to bring forth areas thatmust be focussed on to improve selected attribute areas requiring attention within municipalities. Three areas have been chosen from theMuSSA data to be investigated in this research project namely; (i)staff skill levels and capacity, (ii)non-revenue water and (iii)the execution of planned water services activities. In the MuSSA questionnaire there are questions addressing each of (i), (ii) and (iii) to determine the municipality’s performance in each of the three areas. Non-parametric statistics are used to determine with which of the MuSSA questions’ answers the relevant questions’ answers significantly correlate for (i), (ii) and (iii). Engineering judgement and expert opinion are used to determine if the questions correlating with the relevant questions for (i), (ii) and (iii) either affect, are affected by or have no relation with the question. These results are then organized using a flow diagram and are discussed in detail by way of a bivariate histogramof each correlation. The investigation revealed that municipalities not having sufficient technical management capacity are not performing well on at least one of the five questions asked on eleven of the sixteen MuSSA business attributes. The skill level of water and wastewater treatment works staff were found to be strongly affected by technical management capacity and skill, water services planning and financial sustainability of the organization. Municipalities training technical management and operational staff showed a high percentage of skilled operational staff employed at treatment works. Water and wastewater treatment works staff capacity are very dependent of the level of skill and capacity of technical management employed by the municipality. Municipalities having appropriate budgets and funding to appoint and train staff showed a tendency to be better at operational staff capacity building than those lacking funding. The reduction of non-revenue water (NRW) showed strong correlations with technical management and network operational repair staff skills and development. Municipalities employing staff with correct skills and experience combined, with commitment from management to reduce NRW by way of monitoring and practicing of pressuremanagement programs, significantly reduced NRW percentages. Equally crucial to the reduction of NRW, as revealed from the investigation, is the practicing of infrastructure asset management within the municipality. It was concluded that municipalities should strive to reach a NRW percentage of 30% or less to become financially stable, due to correlation between funding of routine operations and building up of cash reserve versus NRW percentages. Municipalities wanting to improve the execution rate of planned water services activities are recommended to address, among other factors, technical management skill levels and capacity. Municipalities lacking technical management skill and capacity reported a low percentages of planned activities being executed. Also of high significance, is the technical operational staff skill levels and capacity, due to their involvement in the execution of planned activates. The involvement of council members in water and wastewater planning and the reporting of data and issues to council greatly enhancesmunicipalities’ abilities to execute planned activities. This can mainly be contributed to increased funding in situations where council members support planned projects. The lack of funding was found to be a major inhibitor of the execution of planned activities. Even though a great deal of municipalities indicated that they are effectively spending allocated budgets, this positive indication is not seen in the percentage municipalities executing planned activities and leads to the conclusion that there is a lack of funding. Municipalities taking actions in other areas of their business such as infrastructure assetmanagement and planning were more effective at executing planned activities. In all, it was concluded that technicalmanagement and operational staff skill levels and capacity need to be present for amunicipality to function properly. Municipalities also are in need of funding to execute planned activities and need to become financially self sustainable. One way of working towards the goal of financial self sustainability is the reduction of NRW percentages. The data from this investigation shows great similarity with the literature consulted on the current state and functioning of South African municipalities. The statistical analysis of the MuSSA data accurately revealed correlations among key performance indicators in municipalities. The conclusion can be drawn that investigation of correlations amongMuSSA questions can be used to help aid municipal decision making. / AFRIKAANSE OPSOMMING: Suid-Afrikaanse munisipaliteite is onder druk om die huidige toestand van die water en afvalwater dienslewering te verbeter. Met die wete dat daar ’n behoefte vir verbetering in die munisipale water en afvalwater bedryf is het dieDepartement vanWaterwese ’n munisipale strategiese self-assessering (MuSSA) projekte geïnisieer omdie welstand van die bedryf te evalueer. MuSSA vra hoë vlak tegniese bestuurs personeel vyf kern vrae oor sestien sleutel besigheids aspekte. Hierdie studie poogomvas te stel of dieMuSSA data gebruik kan word om munisipale besluitneming te help verbeter, deur middel van die evaluering van korrelasies tussen die sleutel prestasie aanwysers soos vervat in MuSSA vrae. Die korrelasies bring na vore gebiede waar op gefokus moet word om geselekteerde kenmerk areas binne munisipaliteite, wat aandag vereis, te verbeter. Drie areas uit die MuSSA-data is ondersoek in hierdie navorsings projek naamlik; (i) personeel vaardigheidsvlakke en kapasiteit, (ii) nie-inkomste water en (iii) die uitvoering van die beplande waterdienste aktiwiteite. In die MuSSA vraelys is daar vrae wat elk van (i), (ii) en (iii) aanspreek om die munisipaliteit se prestasie op die drie gebiede te monitor. Nie-parametriese statistiek word gebruik om die oorblywendeMuSSA vrae wat se antwoorde met die relevante vrae se antwoorde korreleer vir (i), (ii) en (iii) vas te stel. Kundigheid en oordeel van ingenieurs word gebruik om te bepaal of die vrae wat korreleer met die relevante vrae vir (i), (ii) en (iii) die relevante vraag beïnvloed, beïnvloed word deur die relevante vraag of geen verhouding het met die relevante vraag nie. Hierdie resultate word dan georganiseer met behulp van ’n vloeidiagram en word in detail bespreek deur middel van ’n tweeveranderlike histogram van elke korrelasie. Die ondersoek het aan die lig gebring dat munisipaliteite wat nie genoegsame tegniese bestuurs kapasiteit het nie swak presteer op ten minste een van die vyf vrae van elf van die sestienMuSSA besigheid eienskappe. Die personeel vaardigheidsvlakke van water en afvalwater behandelings werke word sterk beïnvloed deur die tegniese bestuurskapasiteit en -vaardigheid, waterdienste beplanning en die finansiële volhoubaarheid van die organisasie. Munisipaliteite wat opleiding van tegniese bestuur en operasionele personeel uitvoer het ’n hoë persentasie van opgeleide operasionele personeel werksaam by suiweringswerke. Water en afvalwater behandelingswerke se personeelkapasiteit is baie afhanklik van die vlak van vaardigheid en kapasiteit van tegniese bestuur in diens van die munisipaliteit. Munisipaliteite met toepaslike begrotings en befondsing om personeel aan te stel en op te lei het ’n neiging om beter te presteer met kapasiteitsbou van operasionele personeel as die wat aan ’n gebrek ly van befondsing. Die vermindering van nie-inkomste water (NRW) het sterk korrelasies met tegniese bestuur en netwerkherstel personeelvaardighede en ontwikkeling. Munisipaliteite wat personeel met die korrekte vaardighede en ervaring in diens het, gekombineer met bestuur wat dit nastreef om NRW te verminder by wyse van monitering en uitvoering van druk beheer in water netwerke het aansienlik kleiner NRWpersentasies. Ewe noodsaaklik vir die vermindering van NRW, soos geopenbaar deur die ondersoek is die beoefening van interne infrastruktuur batebestuur deur diemunisipaliteit. Daar is tot die gevolgtrekking gekom dat munisipaliteite daarna moet streef om ’n NRW persentasie van 30% of minder te bereik om finansieel stabiel te word, as gevolg van die korrelasie tussen befondsing van roetine bedrywighede en die opbou van kontant reserwe teenoor NRWpersentasies. Munisipaliteitewat die uitvoeringskoers van beplande waterdienste aktiwiteitewil verbeter, word aanbeveel om onder andere, tegniese bestuurs vaardigheids vlakke en kapasiteit aan te spreek. Munisipaliteite wat nie tegniese bestuursvaardigheid en -kapasiteit het nie, berig dat ’n lae persentasie van beplande aktiwiteite uitgevoer word. Die tegniese operasionele personeel vaardigheidsvlakke en kapasiteit, as gevolg van hul betrokkenheid in die uitvoering van beplande aktiwiteite is ook van groot belang. Die betrokkenheid van lede van die raad by water en afvalwater beplanning en die rapportering van data en kwessies aan die raad verhoog baiemunisipaliteite se vermoëns om beplande aktiwiteite uit te voer. Dit kan hoofsaaklik toegeskryf word aan verhoogde befondsing in situasies waar raadslede beplande projekte ondersteun. Dit is gevind dat die gebrek aan befondsing ’n groot inhibeerder van die uitvoering van beplande aktiwiteite is. Alhoewel ’n meerderheid van die munisipaliteite aangedui het dat hulle begrotings effektief spandeer, word dit egter nie weerspieël in die persentasie munisipaliteite wat beplande aktiwiteite uivoer nie en lei dit tot die gevolgtrekking dat daar n gebrek aan befondsing is. Munisipaliteite wat klem lê op ander gebiede van hul besigheid soos, infrastruktuur batebestuur en beplanning was meer effektief met die uitvoering van die beplande aktiwiteite. Daar is tot die gevolgtrekking gekom dat tegniese bestuur en operasionele personeel vaardigheidsvlakke en kapasiteit noodsaaklik is vir ’n munisipaliteit om behoorlik te funksioneer. Daar is ook ’n behoefte aan befondsing by munisipaliteite om beplande aktiwiteite uit te voer en munisipaliteite moet finansieel onafhanklik en lewensvatbaar word. Een manier om te werk te gaan om finansiële self volhoubaarheid te bereik, is die vermindering van NRW persentasies. Die data van hierdie ondersoek toon groot ooreenkomste met die literatuur wat geraadpleeg is oor die huidige stand en funksionering van Suid-Afrikaanse munisipaliteite. Die statistiese analise van die MuSSA data het akkurate korrelasies geopenbaar tussen die sleutel prestasie-aanwysers inmunisipaliteite. Die gevolgtrekking kan gemaak word dat die ondersoek in terme van die korrelasie tussen MuSSA vrae gebruik kan word om munisipale besluitneming te help verbeter.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Chip and spray surfacing seals has been widely used in South Africa as the preferred surface treatment for rural roads. The design of these seals has also experienced renewed interest and continuous development in several other countries over the past two decades. In South Africa seals are continually used as increasing attention is given to the periodic maintenance of existing surfaced roads. There is also a significant increase in the use of surfacing seals in North America as the need to develop more energy and resource efficient surfacing options becomes a priority. Despite this growing use of surface seals, the seal design and especially the selection of binder type and grade does not always follow scientific processes. Seals are often designed based on client preference, previous experience, material availability and industry trends. With an ageing road network and limited funding to ensure timeous maintenance, the focus in South Africa is moving towards more stringent and scientific design processes. The USA and Europe, forced by increasing traffic volumes and heightened performance demands, are moving towards performance- based specification to account for deficiencies in their current surface seal design methods. One of the major failure mechanisms of surface seals is ravelling which takes place when the binder and the aggregate bond becomes weak and are broken by the forces generated by traffic. This leads to loose aggregate on the road which in turns leads to bare surface patches and broken windscreens. To prevent and address this as part of the development of performance-based specifications, the need for a simple and inexpensive technique for evaluating bitumen and bitumen emulsion bond strength development over time, as well as binder-aggregate compatibility, was identified. Although various tests exist for investigating adhesion between bituminous emulsions and aggregate chips most of the tests does not deliver the level of information required by the performance-based specifications. The Bitumen Bond Strength (BBS) test method was therefore developed with the aim to address some of the limitations encountered in evaluating bond strength between binders and aggregates. The BBS test (AASHTO TP-91, 2011) was developed by the University of Wisconsin – Madison (UWM) in partnership with the University of Ancona – Italy (UAI) and the University of Stellenbosch – South Africa (US) specifically for evaluating bond strength between aggregates and hot applied binders and emulsions, respectively. US became involved in BBS test efforts in 2008 to assist in the development and practical evaluation of the BBS test method. UAI contributed significantly to the development of the test apparatus through their work in conjunction with UWM. Due to time and resources available, the involvement of the US was limited to various discussion sessions, a study tour, the evaluation of the BBS test, and conducting a series of control tests. By using the Bitumen Bond Strength test it was possible to evaluate the practicality and repeatability of the developed procedure and the results measured was successfully used to evaluate the bond strength development of modified and unmodified bitumen emulsions on tillite and granite aggregates. It was also possible to correlate the results achieved at the University of Stellenbosch with results from the University of Wisconsin-Madison due to the fact that testing took place at both institutions. The development of the test and the inter-laboratory test results in essence reinforced the hypothesis that the BBS test protocol can be used to effectively evaluate bond strength of different emulsion types and aggregate types. Except for the loading rate which is a known critical influence, the emulsion type and curing intervals are both identified as the most significant other factors contributing to bond strength development. Aggregate type is also identified as a significant factor that will influence the bond strength development. Interactions between emulsion type and curing interval are identified as the most significant interaction. A lot of further validation test on the BBS test method is still required for the test to be integrated into a performance-based specification system for surface seals. / AFRIKAANSE OPSOMMING: “Chip and Spray” oppervlak seëls is die verkose seël tipe vir gebruik op Suid Afrikaanse plattelandse paaie. Die ontwerp van hierdie tipe seëls is ook tans besig om hernude aandag te trek in heelwat lande. In Suid Afrika word die tipe seël al meer gebruik soos die behoefte na herseël projeke op die verouderde pad netwerk groei . Daar is ook heelwat groei in die gebruik van “Chip en Spray” seëls in Noord Amerika aangesien daar n behoefte is om n meer energie en materiaal effektiewe seëls te gebruik. Ten spyte van die groeiende gebruik van hierdie seëls het daar min wetenskaplike ontwikkeling plaasgevind in the ontwerp daarvan. Seëls word meestal ontwerp gebaseer op klient voorkeur , ondervinding, materiaal beskikbaarheid en ook industrie norms. ‘n Verouderde pad netwerk dwing die Suid Afrikaanse industrie om meer deeglike en wetenskaplike ontwerp prosedures te volg. Die VSA en Europa word deur vinnig groeiende verkeersvolumes en verhoogte kwaliteits behoeftes gedwing om prestasie gebaseerde spesifikasies te ontwikkel. Een van die hoof defekte op seëls is klipverlies wat plaasvind as die verbinding tussen die bitumen en aggregaat verswak en gebreek word deur die kragte wat deur verkeer oorgedra word. Dit lei tot los klip op die pad wat weer tot skade aan voertuie lei. Om dit te voorkom en aan te spreek het die behoefte laat ontwikkel vir n maklike en goedkoop tegniek om te meet hoe sterk die verbinding is wat ontwikkel tussen verskillende bitumen, bitumen emulsies en aggregaat monsters. Alhoewel daar alreeds toetse bestaan wat kan toets hoe sterk die verbinding is , gee die meeste van die toetse nie die informasie wat benodig word deur die voorgestelde prestasie gedrewe spesfikasies nie. Die “Bitumen Bond Strength” (BBS) toets metode is daarom ontwikkel om die tekortkoming in die toets van die bitumen en aggregaat verdindinge aan te spreek. Die BBS toets (AASHTO TP-91, 2011) is ontwikkel by die Universiteit van Wisconsin – Madison (UWM) in vennootskap met die Universiteit van Ancona – Italy (UAI) en die Universiteit van Stellenbosch (US) , spesifiek om die die sterkte van die verbinding wat vorm tussen aggregaat en bitumen te meet. Die US het in 2008 betrokke geraak by die BBS toets studie om hulp te verleen met die ontwikkeling en praktiese evalueering van die BBS toets metode. As gevolg van tyd en personeel tekorte is die betrokkendheid by die US beperk tot verskeie besprekings sessies, n studie toer, die evalueering van die BBS toets sowel as die voltooing van n uitgebreide stel toetse. Deur die voltooing van eksperimente met die BBS toets was dit moontlik om die uitvoerbaarheid en herhaalbaarheid van die ontwikkelde prosedure te toets. Die resultate van die toetse is suksesvol gebruik om die ontwikkeling van die verbinding sterkte tussen gemodifiseerde en ongemodifiseerde bitumen emulsies en tilliet en graniet te definïeer en te evalueer. Dit was ook moontlik om die resultate van die Universiteit Stellenbosch en die Universiteit of Wisconsin-Madison suksesvol met mekaar te vergelyk aangesien toetse by beide die instansies voltooi is. Die ontwikkeling van die toets en die inter laboratorium toets resultate het dit moontlik gemaak om die hipotese te bevestig dat die BBS toets prosedure effektief gebruik kan word om die bitumen en aggregaat verdindinge te toets en te evalueer. Behalwe vir die tempo van die lading waarteen die aftrek sterkte getoets word , is die emulsie tipe en die nabehandeling tydperk beide geidentifiseer as die mees beduidende invloede wat bydrae tot die ontwikkeling van die verbinding sterkte. Die aggregaat tipe is ook geidentifiseer as n belangrike faktor wat die verbinding sterkte ontwikkeling sal beïnvloed. Die interaksie tussen die emulsie tipe en nabehandeling tydperk was geïdentifiseer as die mees beduidende interaksie. Daar sal wel nog heelwat eksperimente voltooi moet word met die BBS toets prosedure voordat dit volkome geïntegreer kan word as deel van n prestasie gebaseerde spesifikasie stelsel vir die ontwerp van seëls.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The devastating effects floods have on both social and economic level make effective flood risk management an essential part of rural and urban development. A major part of effective flood risk management is the application of reliable design flood estimation methods. Research over the years has illustrated that current design flood estimation methods as a norm show large discrepancies which can mainly be attributed to the fact that these methods are outdated (Smithers, 2007). The research presented focused on the evaluation and updating of the Midgley and Pitman (MIPI) and the Catchment Parameter (CAPA or McPherson) empirical design flood estimation methods. The evaluation was done by means of comparing design floods estimated by each method with more reliable probabilistic design floods derived from historical flow records. Flow gauging stations were selected as drainage data points based on the availability of flow data and available catchment characteristics. A selection criterion was developed resulting in 53 gauging stations. The Log Normal (LN) and Log Pearson Type III (LP III) distributions were used to derive the probabilistic floods for each gauging station. The flow gauging stations were used to delineate catchments and to quantify catchment characteristics using Geographic Information Systems (GIS) software and their associated applications. The two methods were approximated by means derived formulas instead of evaluating and updating the two methods from first principles. This was done as a result of the constraints brought about by both time and the attainment of the relevant literature. The formulae were derived by means of plotting method inputs and resulted in graphs, fitting a trendline through the points and deriving a formula best describing the trendline. The derived formulae and the catchment characteristics were used to estimate the design floods for each method. A comparison was then done between the design flood results of the two methods and the probabilistic design floods. The results of these comparisons were used to derive correction factors which could potentially increase the reliability of the two methods used to estimate design floods. The effectiveness of any updating would be the degree (or level) in which the reliability of a method could be increased. It was proven that the correction factors did decrease the difference between the „assumed and more reliable probabilistic design floods‟ and the methods‟ estimates. However, the increase in reliability of the methods through the use of the recommended correction factors is questionable due to factors such as the reliability of the flow data as well as the methods which had to be used to derive the correction factors. / AFRIKAANSE OPSOMMING: Die verwoestende gevolge van vloede op beide ekonomiese en sosiale gebiede beklemtoon die belangrikheid van effektiewe vloed risiko bestuur vir ontwikellings doeleindes. „n Baie belangrikke gedeelte van effektiewe vloed risiko bestuur is die gebruik van betroubare ontwerp vloed metodes. Navorsing oor die laaste paar jaar het die tekortkominge van die metodes beklemtoon, wat meestal toegeskryf kan word aan die metodes wat verouderd is. Die navorsing het gefokus op die evaluering en moontlike opdatering van die Midley en Pitman (MIPI) en die “Catchment Parameter” (CAPA of McPherson) empiriese ontwerp vloed metodes. Die evaluering het geskied deur middel van die vergelyking van die ontwerp vloed soos bereken deur die twee metodes en die aanvaarde, meer betroubare probabilistiese ontwerp vloede, bepaal deur middel van statistiese ontledings. Vloei meetstasies is gekies as data-punte omrede die beskikbaarheid van vloei data en beskikbare opvanggebied eienskappe. „n Seleksie kriteruim is ontwikkel waaruit 53 meetstasies gekies is. Die Log Normale (LN) en Log Pearson Tipe III (LP III) verspreidings is verder gebruik om die probabilistiese ontwerp vloede te bereken vir elke meetstasie. Die posisie van die meetstasies is ook verder gebruik om opvanggebiede te definieer en opvanggebied eienskappe te bereken. Geografiese inligtingstelsels (GIS) is vir die doel gebruik inplaas van die oorspronlik hand metodes. Die twee metodes is benader deur die gebruik van afgeleide formules inplaas van „n eerste beginsel benadering. Dit is gedoen as gevolg van die beperkings wat teweeggebring is deur beide tyd en die beskikbaarheid van die relevante litratuur wat handel oor die ontwikkeling van die twee metodes. Die formules is verkry deur middel van die plot van beide insette en resultate in grafieke, die passing van tendenslyne en die afleiding van formules wat die tendenslyne die beste beskryf. Die afgeleide formules saam met die opvanggebied eienskappe is toe verder gebruik om die ontwerp vloede van elke meet stasie te bepaal, vir beide metodes. The resultate van die twee metodes is toe vergelyk met die probabilistiese ontwerp vloede. Die resultate van hierdie vergelyking is verder gebruik om korreksie faktore af te lei wat moontlik die betroubaarheid van die twee metodes kon verhoog. Die doeltreffendheid van enige opdatering sal die mate wees waarin die betroubaarheid van n metode verhoog kan word. Gedurende die verhandeling is dit bewys dat die korreksie faktore wel n vermindering teweebring in die verskil tussen die ontwerp vloede van die aanvaarde meer betroubare probabilistiese ontwerp vloede van beide metodes. Die toename in betroubaarheid van die metodes deur die gebruik van die voorgestelde korreksie faktore is egter bevraagteken as gevolg van faktore soos die betroubaarheid van die vloei data self asook die metodologie wat gevolg is om die korreksie faktore af te lei.

Thesis (MEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Sedimentation and the effects it has on turbine blades was the primary problem identified in run-of-river (RoR) hydropower schemes. Sedimentation in RoR hydropower schemes also increases trash rack blockage and reduces energy output in the long-term. Damage occurs to all underwater parts that come into contact with sediment. The main concern is sediment passing through the hydropower intake and causing turbine damage. The reason for the abrasion and cavitation of turbine blades is increased sediment loads in river channels. This problem can be overcome in two ways. The first is the use of existing lakes or reservoir storage upstream as natural sand traps, and the second is by investigating the three features associated with river bend diversion, which are: the optimum diversion location in a river bend to minimise the abstraction of sediment, the optimum diversion structure angle to limit coarse sediment diversion, and the sediment load diverted through the intake. The first objective of the research was investigated by construction of a physical model of a curved river channel to determine the location of the deepest scour forming on the outside of the bend. The second objective was to test the diversion orientation to maximize the local scour and thereby limiting sediment diversion at the intake. A third objective was to compare mathematical 2D model simulated scour results with the findings of the laboratory tests to evaluate the reliability of the numerical model predictions. Finally different diverted discharge ratios were tested with different intake setups in the physical model, to evaluate the sediment load diverted. . The first experiment in the curved laboratory channel was to predict where the deepest scour takes place without a diversion structure. This was then followed by placing a diversion structure at the maximum scour position, retrieved from experiment one, and by angling the structure with reference to the flow direction. The flow direction vector was placed as a tangent to the bend and orientated at angles of 0⁰, 30⁰, 45⁰ and 60⁰ into the bend direction. The optimum diversion location was found to be positioned on the outside of the bend, approximately 60⁰ into the channel bend. The final position of maximum scour in a 90⁰ bend corresponds with the Sediment Committee and the Chinese Hydraulic Engineering Societies (1992) prediction of 60⁰ into the bend. The optimal diversion had a 30⁰ angle to the flow direction, as this presented the most efficient and effective scouring in front of the model intake. Numerical simulations were performed with the CCHE 2D (hydrodynamics and sediment dynamics) modelling program. The numerical results were compared to the physical results to validate CCHE as a beneficial simulation tool. It was found that the numerical model predicted the scour depths at the intakes tested with an accuracy of 43.8%, which is within the accuracy range of the sediment transport equation used by the numerical model. The final experiment was the diversion of sediment with different intake level heights and discharges. It was evident from the results that low sediment diversion ratios were achieved with a diverted discharge ratio of 50% or less. The intake elevation highest above the channel bed diverted the least sediment. The interrelationship between Diverted Discharge Ratio (DDR), Diverted Froude number Ratio (DFrR) and Diverted Sediment load Ratio (SDR) was established in the study. It is recommended that RoR schemes have sand traps downstream of the diversion structures and that turbines are coated with HVOF to overcome the power loss arising due to the excessive erosion of hydro turbines. / AFRIKAANSE OPSOMMING: Sedimentasie en die invloed wat dit het op turbines was die primêre probleem geïdentifiseer in “run-of-river” (RoR) hidrokrag-skemas. Die sediment wat saam met die water uit ‟n rivier uitgekeer word beskadig die inlaatrooster en verlaag kragopwekking in die langtermyn. Skade word aangerig aan alle onderwatertoerusting en masjinerie wat aan sediment blootgestel word. Die grootste probleem tydens die uitkering van water is die growwe sediment wat daarmee deur die onttrekking inlaat gaan en turbineskade veroorsaak. Soos wat die sedimentlading in die rivier drasties toeneem, sal afslyting en kavitasie van turbinelemme meer gereeld voorkom. Dié probleem kan op twee maniere beperk word. Die een is die gebruik van bestaande opgaardamme stroomop, en die tweede is deur die ondersoek van drie kenmerke van rivierdraaie en uitkeringstrukture, bv. die optimale uitskurings posisie in 'n rivierdraai (sonder ʼn struktuur) om die diepste uitskuringposisie op die buitekant van die draai te bepaal, die optimale uitkeringsstruktuuroriëntasie wat maksimum uitskuring verseker en die sediment uitkering beperk, en die lading van sedimentonttrekking deur die inlaat. Die eerste doelwit van die navorsing is ondersoek deur ʼn fisiese model te bou van ʼn kronkelkanaal en te bepaal waar die diepste uitskring plaasvind op die buitekant van die draai. Die tweede doelwit van die studie was om die optimale uitkeringshoek te bepaal vir 'n uitkeringstruktuur sodat die uitskuring by die inlaat ʼn maksimum is om die uitkering van sediment te beperk. ʼn Derde doelwit was om die akkuraatheid van ʼn wiskundige model se uitskuring voorspelling te toets teen die waargenome laboratorium resultate. Die finale doelwit was om vir verskillende inlaatontwerpe, rivier- en uitkeervloeie die sedimentladings wat uitgekeer word te ondersoek. Die eerste eksperiment in die kronkelende kanaal was voorberei om die optimale uitskuring in die draai te bepaal. Dit is gevolg deur toetse met uitkeerstrukture by die maksimum uitskurings posisie te plaas en die hoek van die struktuur dan te verander met verwysing na die vloeirigting. Die vloeirigting vektor was as 'n raaklyn geplaas op die kanaal draai en georiënteer met hoeke: 0⁰, 30⁰, 45⁰ en 60⁰, in die rigting van die draai. Die optimale uitskurings posisie was aan die buiterand van die kanaal draai gevind, ongeveer 60⁰ in die draai in. Die maksimum uitskuur posisie van 'n 90⁰ kanaal draai stem ooreen met SC en CHES (1992) se resultaat van 60⁰ in die draai in. Daar was ook genoegsame bewyse dat 'n optimale uitkeerwerke oriëntasie van 30⁰ die doeltreffendste en effektiefste uitskuring sal gee. Numeriese simulasies is deur middel van 'n twee dimensionele wiskundige model CCHE 2D (hidro- en sedimentdinamika) uitgevoer. Die numeriese resultate was vergelyk met die laboratoriumresultate om die CCHE program te verifieer as 'n voordelige simulasie program. Daar is gevind dat die wiskundige model die uitskuurdieptes by die inlate met ʼn akkuraatheid van 43.8 % voorspel, wat binne die akkuraatheid is van die sedimentvervoervergelyking wat deur die numeriese model gebruik word. Die finale eksperiment was die uitkering van sediment met verskillende inlaathoogtes en uitkerings sedimentladings. Uit die toetse was dit duidelik dat 'n lae sediment uitkeerverhouding behaal kan word met 'n uitkeerverhouding van 50% en minder. Verdere waarnemings het ook gewys dat die inlaathoogte van die uitkeerstruktuur met die optimale resultate die hoogste bokant die rivierbedding was. Die verwantskap tussen die uitgekeerde deurstromingverhouding, die uitgekeerde Froude getal verhouding en die uitgekeerde sedimentlading is bepaal in die navorsing. Dit word aanbeveel dat sandvangkanale stroomaf van uitkeerwerke geplaas word en dat turbines met HVOF as bedekkingsmateriaal beskerm word om kragverliese as gevolg van buitensporige erosie van die turbines te voorkom.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The Western Cape has been subject to extreme rainfall storms in the last decade, which has been responsible for millions of Rands worth of damage to public infrastructure and human settlements. Current climate model projections under climate change suggest that the Western Cape can expect greater rainfall intensities, with magnitude of rainfall events increasing, but the frequency of occurrence of events decreasing. The aim of this research is to assess if historical short duration rainfall data provides any evidence to support increasing intensities in rainfall in the Western Cape. Short duration rainfall data (< 24 hours), consisting of digitised autographic- and automatic weather station data (AWS), was selected from the South African Weather Services’ database for the Western Cape and wider South African region, in order to combine the data for an extension of the effective record length. Numerous difficulties were encountered with the data that required the application of editing and quality control procedures. The digitised autographic data contained many errors and generally compared poorly to standard gauge daily rainfall totals of the same period. After the application of editing and quality control procedures, seven stations were selected and their autographic and AWS data was combined for further detailed analysis. Analysis was divided into two sections, one for the analysis of the magnitude of the rainfall, the other for the frequency of occurrence of rainfall events. For the magnitude analysis, nonstationary extreme value theory was applied by implementing a parametric and non-parametric non-stationary approach to both the generalised extreme value distribution (GEV) with an annual maximum series, and a generalised Pareto distribution with a peaks over threshold series. The parametric approach entailed fitting linear models to the parameters of the extreme value distributions, and the non-parametric approach tested if return levels of the distributions remained constant over a moving window period. The frequency analysis entailed the recording of the annual number of rainfall events exceeding predetermined threshold values. For the magnitude analysis, the parametric approach only produced two stations with significant non-stationarity and only for the GEV, whilst the non-stationary approach produced results that can indicate non-parametric behaviour, but this was most likely because of the combination of autographic and AWS data. The frequency analysis produced results that indicated no observable results for some stations, while others produced trends that are consistent with a change from the autographic to AWS data. This lead to the conclusion that with the available data, no clear or significant evidence supporting increasing intensities or any other change in short duration rainfall was found regarding the magnitude and frequency of occurrence of rainfall events. / AFRIKAANSE OPSOMMING: The Wes-Kaap het die afgelope dekade deur uiterse storms deurgeloop wat miljone Rande se skade aan publieke infrastruktuur en nedersettings veroorsaak het. Huidige klimaatsmodel resultate wat klimaatsverandering inkorporeer, beraam dat die Wes-Kaap hoër reënvalintensiteite kan verwag, waar die grootte van die en reënvalgebeurtenisse toeneem, maar die frekwensie van die reënvalgebeurtenisse afneem. Die doel van hierdie navorsing is om te bepaal of historiese kortduurtereënvaldata in die Wes-Kaap enige toenemende reënvalintensiteite aandui. Kortduurtereënvaldata (< 24 uur) wat uit versyferde autografiese- en automatiese weerstasie (AWS) data bestaan, was uit die Suid Afrikaanse Weerdienste se databasis gekies vir stasies in dieWes-Kaap en die wyer Suid Afrikaanse gebied, sodoende om die effektiewe rekordlengte te verleng. Redigering- en kwaliteitsbeheerprosudures moes toegepas word na ’n aantal probleme met die data ontdek was. Die versyferde autografiese data het baie foute bevat en oor die algemeen swak vergelyk met die standaard daaglikse totaalmetings van dieselfde periode. Na die redigering- en kwaliteitsbeheerprosudures toegepas was, was sewe stasies gekies en hul autografiese en AWS data was saamgestel vir verdere analise. Die analise het uit twee afdelings bestaan: die analise van die grootte van die reënvalgebeurtenisse, en die frekwensie van die reënvalgebeurtenisse. Nie-stasionêre ekstreemwaardeteorie was toegepas op die grootte van die reënvalgebeurtenisse deur gebruik te maak van parametriese en nie-parametriese nie-stasionêre metodiek. Die veralgemeende ekstreemwaardeverdeling (AEW) met ’n jaarlikse maksimum reeks, en die veralgemeende Paretoverdeling met ’n pieke bo drempelwaarde reeks was gebruik. Die parametriese metode het bestaan uit die passing van lineêre modelle aan die parameters van die estreemwaardeverdelings. Die nie-parametriese metode het getoets of die terugkeervlakke van die verdelings konstant gebly het oor ’n bewegende vensterperiode. The frekwensie analise het bestaan uit die aantekening van die jaarlikse reënvalgebeurtenisse wat bepaalde drempelwaardes oorskry. Die parametriese metode het net twee beduidende nie-stasionêre staties opgelewer, uitsluitlik vir die AEW. Die nie-parametriese metode het resultate gegenereer wat moontlike niestasionarieit aandui, maar dit is heel moontlik as gevolg van die samestelling van die autografiesen AWS data. Die frekwensie analise het óf geen sigbare neiging vir die resultate vir ván stasies gegenereer nie, óf het resultate gegenereer wat aandui op die samestelling van die autografiesen AWS data. Dit het tot die gevolgtrekking gelei dat daar geen aanduiding in die kortduurtereënvaldata bestaan wat toenemende reënvalintensiteite ondersteun nie vir beide die grootte en frekwensie van reënvalgebeurtenisse.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Different types of live loading due to traffic may act on bridges. The focus of this study is on normal traffic loading according to the South African specification of TMH7. Heavy vehicles are not included in normal traffic loading. TMH7 represents the code of practice for the design of highway bridges and culverts in South Africa. The aim of the study is to provide an insight into the flexural analysis of skew bridges, under the effects of normal traffic loading. The need for the study arose since the specification of TMH7 does not explicitly specify application patterns for normal traffic loading. Only the intensity of normal traffic loading is specified and it should be applied to yield the most adverse effects. For these reasons, a set of so-called standard application patterns are investigated and developed through the course of this study. The envelope of the values from the standard application patterns are compared to the most adverse application pattern for flexural effects in certain design regions of the bridge deck. Flexure, as in the context of this study, translates into the bending and twisting of the bridge deck under loads. A number of numerical experiments are performed for typical single span and multi-span continuous carriageways, where the standard application patterns are compared to the most adverse application patterns. The results from the numerical experiments are documented and compared as the angle of skew of the bridge deck increases in plan-view. For this purpose, the development of effective and specialized software was necessary. It was found that the set of standard application patterns can be used as a preliminary approximation for the most adverse effects of normal traffic loading, for specific flexural resultants in certain design regions of a bridge deck. However, for a large number of secondary flexural effects, the set of standard application patterns did not represent a good approximation for the most adverse values. / AFRIKAANSE OPSOMMING: Verskillende tipes lewendige belasting, as gevolg van verkeer, kan op brûe inwerk. Die fokus van die studie is op normale verkeers-belasting volgens die Suid-Afrikaanse spesifikasie van TMH7. Swaar-voertuie word nie ingesluit by normale verkeers-belasting nie. TMH7 verteenwoordig die kode vir die ontwerp van padbrûe en duikers in Suid-Afrika. Die doel van die studie is om insig te verskaf in die buig-analise van skewe brûe, as gevolg van die werking van normale verkeers-belasting. Die rede vir hierdie studie ontstaan aangesien die spesifikasie van TMH7 nie eksplisiet aanwendingspatrone vir normale verkeers-belasting voorskryf nie. Slegs die intensiteit van normale verkeersbelasting word voorgeskryf en dit moet aangewend word om die negatiefste effekte te verkry. Vir hierdie redes word 'n versameling van sogenaamde standaard aanwendings-patrone deur die loop van die studie ondersoek en ontwikkel. Die omhullings-kurwe van die waardes wat deur die standaard patrone gelewer word, word vergelyk met die waarde van die aanwendings-patroon wat die negatiefste buig-effek in sekere ontwerp-areas van die brugdek veroorsaak. Buig-effekte, soos van toepassing op hierdie studie, verwys na buig en wring van die brugdek as gevolg van belastings. 'n Aantal numeriese eksperimente, vir enkel-span sowel as multi-span deurlopende brugdekke, word uitgevoer en die standaard aanwendings-patrone word vergelyk met die aanwendings-patrone wat die negatiefste waardes lewer. Die resultate van die numeriese eksperimente word gedokumenteer en vergelyk soos die hoek van skeefheid van die brugdek in plan-aansig toeneem. Vir hierdie doel is die ontwikkeling van effektiewe en gespesialiseerde sagteware dus nodig. Daar is gevind dat die standaard aanwendings-patrone, vir spesifieke buig-resultante in sekere ontwerp-areas van die brugdek, as 'n voorlopige benadering vir die negatiefste effekte van normale verkeers-belasting gebruik kan word. Dit was egter verder gevind dat vir 'n groot aantal sekondêre buig-effkte, die versameling standaard aanwendings-patrone nie as 'n goeie benadering vir die negatiefste waardes dien nie.