Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The study of climate change and its effect on the eutrophication of surface waters is a current and critically important study for the well-being of the entire planet. Within the same emission scenario various probable climate change models outcomes are possible that affect the water quality of a body of water. Voëlvlei is an off-channel dam that supplies water to the city of Cape Town in the Western Cape Province of South Africa. Historically, it is a eutrophic dam and with climate change, its water quality is expected to worsen. Four statistically downscaled climate models are used to produce meteorological outputs that drive the hydrodynamic and water quality model. The times simulated were the present day (1971-1990), the intermediate future (2046-2065) and the distant future (2081-2100). The operating procedure was not expected to change for the dam and inflows and withdrawals were kept the same for each of the simulation periods. The water quality model CE-QUAL-W2 version 3.6 was used. The bathymetry was validated with measured data. The model was calibrated for temperature, phosphorus loading, ammonium, nitrite-nitrates and chlorophyll-a concentration. The model was used to predict a present day situation in the dam, which was the basis from which future changes would be assessed. The main driver for algal growth other than nutrients and light was water temperature, which was linked to air temperature. With climate change, the air temperature will raise and enhance algal growth. The limiting nutrient was phosphorus during the winter and the rest of the year nitrogen limits algal growth. In the present day, the dominant algal group was the green algae. With climate change an increase in the surface water temperature will increase evaporation and cause a decrease in the yield of the dam and further concentrates the algal nutrients. The surface phosphates concentration show increases in all months but especially in autumn. The total algal growth was increased annually and especially during autumn, signalling a seasonal shift and lengthening of the bloom season. The dominant algae however are still the green algae. There will be an increase in the annual concentration of diatoms. The green algae are present in the highest concentrations when compared to diatoms and cyanobacteria. The increase in its nutrients throughout the year as well as the increased water temperature allowed for unabated growth the entire year with peaks earlier in the year during autumn. Cyanobacteria are present at the surface for the entire year at significant concentrations but with intermediate and future climate change their concentrations does not change significantly. The result for cyanobacteria was inconclusive as the inter-variability between the climate models has the greatest variability for cyanobacteria, with 2 models showing an increased concentration and 2 a decreased concentration for intermediate and future time-period. For climate change, the water quality worsens especially during winter. With climate change water quality will worsen earlier in the year confirming a seasonal shift. The modelling of dissolved oxygen proved daunting as the results indicated supersaturation. The concentration of dissolved oxygen does not vary much as would be expected due to the warmer waters. / AFRIKAANSE OPSOMMING: Die studie van klimaatsverandering en die uitwerking daarvan op die eutrofiseering van die oppervlaktewater is 'n huidige en krities belangrike studie vir die welsyn van die hele planeet. Binne dieselfde emissie scenario, is verskeie moontlike uitkomste van klimaat modelle moontlik en die invloed op die kwaliteit van die oppervlakwater. Voëlvlei is 'n buite-bedding dam wat water verskaf aan die stad van Kaapstad in die Westelike Provinsie van Suid-Afrika. Histories is dit is 'n eutrofiese dam en met die verandering van die klimaat sal die kwaliteit van die water na verwagting verswak. Vier statisties afgeskaal klimaat modelle word gebruik om meterologiese toesttande te skep en hiedie word dan gebruik as invoer vir die hidrologiese and water kwaliteits model vir die huidige situasie (1971-1990), die intermediêre toekoms (2046-2065) en die verre toekoms (2081-2100). Die bedruifs-proses vir die dam was nie verwag om te verander nie en die invloei en onttrekkings was dieselfde gehou vir elk van die simulasie periodes. Die watergehalte model CE-QUAL-W2 3.6 was gebruik. Die bathymetrie was bevestig met gemete data. Die model was gekalibreer vir temperatuur, fosfor, ammonium, nitriet-nitrate en chlorofil-a konsentrasie. Die model was gebruik om 'n huidige situasie in die dam te simuleer, wat die basis vir klimaatsveranderinge sou wees. Die vernaamste aandrywer vir die alge groei anders as voedingstowwe en lig, was water temperatuur, wat met lugtemperatuur gekoppel was. Met klimaatsverandering word die lugtemperatuur verhoog en alge groei. Die beperkende voedingstof was fosfor gedurende die winter en die res van die jaar was die dam stikstof beperk. Die dominante alge-groep in die huidige situasie was die groen alge. Met klimaatsverandering stuig die temperatuur van die oppervlakwater, verhoog verdamping, veroorsaak afname in die vlak van die dam en verhoog die konsentrasie van die alge voedingstowwe. Die oppervlak fosfate konsentrasie verhoog in al die maande veral in die herfs. Die totale alge groei jaarliks en veral gedurende die herfs, 'n teken van 'n seisoenale verskuiwing en verlenging van die blom seisoen. Die dominante alge was nog steeds groen alge. Daar sal 'n toename in die jaarlikse konsentrasie van diatome wees. Die groen alge is in die hoogste konsentrasies vergelyk met diatome en sianobakterieë. Die toename in die voedingstowwe deur die loop van die jaar, sowel as die verhoogde watertemperatuur kan vir 'n onverpoos groei vir die hele jaar, veral in die herfs. Sianobakterieë is teenwoordig vir die hele jaar op beduidende konsentrasies, maar met intermediêre en toekomstige klimaat verander die konsentrasies nie veel nie. Die resultaat vir sianobakterieë was onoortuigend as gevolg van die inter-veranderlikheid tussen die klimaats modelle, met 2 modelle wat 'n toename in konsentrasie voorspel en 2 'n afname in konsentrasie voorspel. Vir klimaatsverandering, die kwaliteit van die water vererger veral in die winter. Met klimaatsverandering skyf hierdie verswakking van water kwaliteit na vroeër in die jaar, wat bevestig 'n seisoenale skui vir verergering. Die modellering van opgeloste suurstof was uitdagende en die resultate was super-versadig. Die konsentrasie van opgeloste suurstof wissel nie veel as wat verwag sou word as gevolg van die warmer water.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: In South Africa a large number of dams owned by the Department of Water Affairs (DWA) need to be rehabilitated. This study investigated the decision process involved in the prioritisation of dams for rehabilitation. DWA developed a risk analysis methodology for defining the risks associated with dam safety, expressed as the combination of the probability and consequences of dam failure. These risks are evaluated usingmultiple acceptability criteria to assess risk to human life and the economic, social, socio-economic and environmental impacts of dam failure. In this study, the criteria used in the decision process to evaluate the acceptability of life safety risks were evaluated by comparing to international best practice methods, where the acceptability of risk to human life is commonly assessed as the expected number of fatalities against life safety criteria presented as FN-criteria on an FN-diagram. Damrehabilitation should reduce the probability of dam failure, thereby reducing the risk to society in terms of the expected lives lost. However, the rehabilitation works come at a cost and the level of these investments are usually large. In addition, the rehabilitation of South African government owned dams are financed by society and these financial resources are limited. Thus investments into dam rehabilitation works should be worthwhile for society. Society’s Willingness to Pay (SWTP) for safety was applied to South African dam safety to determine the acceptable level of expenditure into life safety that is required by society. Investments into improved safety levels are not always dictated by society, but could also be driven by the decision maker or owner requiring an economically optimal solution for the rehabilitation. Economic optimisation accounts for considerations additional to life safety, including economic motivations, damage costs of dam failure as well as compensation costs for lives lost. Often economic optimisation would govern the decision problem. Also, the DWA current evaluation does not take the cost of rehabilitation into account in any way. Thus, FN-criteria that primarily evaluates life safety, but also incorporates a measure of economic efficiency, were suggested in this study. / AFRIKAANSE OPSOMMING: In Suid-Afrika moet ’n groot aantal dammewat deur dieDepartement vanWaterwese (DWA) besit word gerehabiliteer word. Hierdie studie het die besluitnemingsproses ondersoekwat toegepasword om damme te prioritiseer vir rehabilitasiewerke. DWA het ’n bestaande metodologie wat gebaseer is op risiko-analise. Die risikos wat verband hou met damveiligheid word deur die metode bepaal en word uitgedruk as die kombinasie van waarskynlikheid en die beraamde gevolge van damfaling. Hierdie risikosword geëvalueer teenoor verskeie kriteriawat die aanvaarbaarheid van risikos teenoor menselewens en die ekonomiese, sosiale, sosio-ekonomiese en omgewingsimpakte van damfalings assesseer. In hierdie studie word die kriteria wat gebruik word in die besluitnemingsproses om die aanvaarbaarheid van risikos teenoor menselewens te bepaal geëvalueer deur die kriteria te vergelyk met metodes wat internasionaal as beste praktyk beskou word. Internasionaal word die aanvaarbaarheid van risikos teenoor menselewens oor die algemeen as die verwagte aantal sterftes teenoor lewensveiligheidskriteria FN-kriteria op ’n FN-diagram geassesseer. Dam rehabilitasiewerke behoort die waarskynlikheid van damfaling te verminder, sodoende verminder die risiko teenoor die samelewing in terme van verwagte sterftes. Die rehabilitasiewerke vereis finansiële beleggings, en hierdie beleggings is gewoonlik groot. Verder word die rehabilitasie van Suid-Afrikaanse damme wat deur DWA besit word deur samelewing gefinansier en hierdie finasiële hulpbronne is beperk. Dus moet hierdie beleggings die moeite werd wees vir die samelewing. Die samelewing se bereidwilligheidomte betaal ("SWTP") vir veiligheid word toegepas in Suid- Afrikaanse damveiligheidomdie aanvaarbare vlak van beleggings vir ’n verbeterde veiligheid teenoor menselewens wat deur die samelewing vereis word te bepaal. Beleggings in verbeterde damveiligheidsvlakke word egter nie altyd bepaal deur die samelewing nie,maar kan ook gedryf word deur die besluitnemer of eienaar wat ’n ekonomies optimale oplossing vir die rehabilitatiesewerke vereis. Ekonomiese optimering neem oorwegings addisioneel tot lewensveiligheid in ag, insluitend ekonomiese motiverings, skade kostes as die dam faal, sowel as vergoedingskostes vir die verwagte sterftes. Ekonomiese optimering beheer dikwels die besluitnemingsprobleem. Verder neem die huidige DWA besluitnemingssproses in geen manier die kostes van rehabilitasie in ag nie. Dus word FN-kriteria wat hoofsaaklik veiligheid teenoor menselewens evalueer,maar wat ook ’n mate van ekonomiese doeltreffendheid insluit, voorgestel in hierdie studie.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This thesis is a study in the use of precast modular construction as an alternative to current methods of school construction in South Africa. Precast Modular Construction is a concept which utilises the principles of prefabrication and precast concrete. Concrete components, be they beams, columns, slabs or full volumetric modules, are manufactured either off-site in factories or in on-site facilities. These components are then assembled on-site to form the structural envelope of a building. This approach contains many inherent advantages: Time is saved due to on-site and off-site work happening concurrently and hence earlier building occupancy results which directly translates to cost reparation; quality is improved due to most of the work being carried out in a controlled factory environment; and health and safety is heightened. However, when viewed from a South African perspective, the fact that less work is done on-site indirectly implicates job loss, a serious issue in the country. Furthermore, implementing a prefabricated approach in the construction of South African schools requires a complete restructuring of the Department of Public Works’ current procurement approach. Prefabrication requires maximum integration between all parties to a project so that design and constructability issues can be addressed at an early stage. The design-build contract strategy is found to be the most integrated approach and allows for optimal collaboration between all project members. However, to only change the procurement route would not suffice as a complete solution. A broader approach is required which addresses issues prevalent in South Africa. These issues include job creation and the establishment of a sustainable and knowledgeable industry. Concepts such as standardisation and strategic partnering, in response, satisfy the need of the manufacturer - for economies of scale, and the employee - for creation of secure working environments. Verification is obtained from all of the aforementioned to propose that the optimal solution to successfully implement Precast Modular Construction for schools in South Africa would be to implement a design-build procurement approach, whereby a single design-build contractor is awarded by the Department of Public Works a contract, via competitive tendering, for the construction of a predetermined number of schools, preferably exceeding 3, over a given contract period using a standardised design and utilising customisable standardised prefabricated precast construction systems, i.e. Precast Modular Construction. This proposal will theoretically result, amongst other things, in the following: - Precast manufacturers will have a confirmed number of orders for products, and can hence be assured of a constant flow of income. This translates directly to an increase in both employment and job security at the manufacturing plant. - The economies of scale principle is satisfied and prefabricated components can therefore be manufactured or ‘mass customised’ in the most feasible way possible. - The design-build contractor will be guaranteed employment for a given period, once again providing job security for its employees, of which the number can also potentially increase. - The design-build contractor carries with it experience and lessons learned from each successfully completed project on to the next, and so becomes more proficient, resulting in better, higher quality schools delivered in shorter periods and with increased efficiency. It is recognised that the proposal is untested in practise but in a socio-economic situation such as South Africa, where large numbers of schools are required quickly, the above proposal makes sense. To additionally develop this hypothesis, further research is required in the fields of design-build procurement and strategic partnering. / AFRIKAANSE OPSOMMING: Hierdie tesis is 'n studie in die gebruik van modulêre voorafvervaardigte beton konstruksie as 'n alternatief vir die huidige metodes van skool konstruksie in Suid-Afrika. Modulêre voorafvervaardigte beton konstruksie bevat baie inherente voordele. Tyd word bespaar as gevolg van werk wat gelyktydig op en van die terrein af gebeur. Dus word die gebou vroeër betrek wat direk lei tot kostebesparings. Kwaliteit verbeter as gevolg van meeste van die werk wat in 'n beheerde fabriek omgewing uitgevoer word en as sulks lei tot beter gesondheid en veiligheid van werkers. Egter, vanuit 'n Suid-Afrikaanse perspektief impliseer die feit dat daar minder werk op die terrein gedoen word indirek werksverlies, 'n ernstige probleem in die land. Die implementering van 'n voorafvervaardigde benadering tot die bou van skole in Suid-Afrika vereis verder 'n volledige herstrukturering van die huidige verskaffing model. Voorafvervaardiging vereis maksimum integrasie tussen alle partye sodat projek ontwerp en boubaarheid op 'n vroeë stadium aangespreek kan word. Die ontwerp-bou kontrak strategie is die mees geïntegreerde benadering en laat toe vir optimale samewerking tussen alle projek lede. Om egter net die verskaffing roete te verander, sou nie voldoen as 'n enkele oplossing nie. 'n Breër benadering word vereis wat kwessies algemeen in Suid-Afrika aanspreek. Hierdie kwessies sluit in werkskepping en die vestiging van 'n volhoubare en kundige industrie. Konsepte soos standaardisering en strategiese vennootskap, as oplossings, voldoen aan die behoeftes van die vervaardiger - vir 'n ekonomieë van skaal, en die werknemer - vir die skepping van 'n versekerde werksomgewing. Die voorafgaande bevestig dat die optimale oplossing vir suksesvolle implementering van Beton Modulêre Konstruksie vir skole in Suid-Afrika sou wees om 'n ontwerp-bou verskaffingsprosedure te volg. Hierdeur kan 'n kontrak aan 'n enkele ontwerp-bou kontrakteur deur die Departement van Openbare Werke toegeken word, deur middel van ‘n mededingende tender proses. Daar word voorgestel dat die projek, vir die konstruksie van 'n voorafbepaalde aantal skole behoort te wees, verkieslik meer as 3, oor 'n bepaalde kontrak tydperk met behulp van 'n gestandaardiseerde ontwerp. Voorts word daar voorgestel om gebruik te maak van aanpasbare gestandaardiseerde voorafvervaardigde beton konstruksie stelsels, dws Beton Modulêre Konstruksie. Hierdie voorstel sal teoreties, onder andere, die volgende gevolge hê: - Beton vervaardigers sal 'n bevestigde aantal bestellings vir produkte hê, en kan dus verseker wees van 'n konstante vloei van inkomste. Dit lei direk tot 'n toename in indiensneming en werksekerheid by die fabriek. - Die ekonomieë van skaal beginsel is bevredig en voorafvervaardigde komponente kan dus vervaardig word in die mees haalbare manier moontlik. - Die ontwerp-bou kontrakteur is gewaarborg van indiensneming vir 'n gegewe tydperk, as sulks ook die verskaffing van werksekerheid vir sy werknemers, waarvan die aantal moontlik ook kan vermeerder. - Die ontwerp-bou kontrakteur neem ondervinding en lesse wat geleer is uit elke suksesvolle voltooide projek saam na die volgende een, en raak dus meer bedrewe, wat lei tot beter, hoër gehalte skole gelewer in korter tydperke en met toenemende doeltreffendheid. Die voorstel is egter ongetoets in die praktyk, maar in 'n sosio-ekonomiese situasie soos die van Suid-Afrika, waar 'n groot aantal skole vinnig benodig word, maak die bogenoemde voorstel sin. Om hierdie hipotese te ontwikkel, is verdere navorsing nodig in die gebied van ontwerp-bou verskaffing en strategiese vennootskappe.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Road traffic accidents have been a global concern facing all countries. Approximately 1.2 million people are killed annually as a result of traffic accidents and 50 million are injured. More than 90 percent of road fatalities occur in the developing world which has only 48 percent of the world’s registered vehicles. Beyond the problem of road fatalities, road traffic accidents result in disability and long term injury. They also cause considerable economic losses to victims and their families and damage properties and infrastructures. In South Africa, pedestrian fatalities account for about 40 percent of all road traffic accidents. Behaviour patterns of both pedestrians and motorists at pedestrian crossings are the main influential factors of pedestrian accidents. This study investigates behaviour patterns of pedestrians negotiating different types of crossing facilities in the town of Stellenbosch, in South Africa. A total number of 17 pedestrian crossings were selected for the study on the basis of their geometric and operational characteristics. Video-based observations together with on-street interviews were used to understand crossing behaviour patterns, namely pedestrian walking speed, pedestrian delay, gaze behaviour, pedestrian-vehicle conflicts, pedestrian compliance with road traffic rules and gap-acceptance behaviour. Results of the study showed that male pedestrians walk more than female pedestrians. The 15th percentile crossing speed for all pedestrians observed while crossing was found to be 1.13 m/s whereas the mean crossing speed was found to be 1.48 m/s. Demographic variables appeared to significantly influence pedestrian walking speed. Male and younger pedestrians exhibited higher walking speeds than female and older pedestrians. Pedestrian walking speed was also found to be affected by group size, encumbrance, type of pedestrian facility and distraction while walking. However, no effects of conflicts and the presence of a pedestrian refuge on pedestrian walking speed were found in this study. A mean total delay of 5.10 seconds was found in this study. Male and younger pedestrians experienced shorter delay compared to female and older pedestrians. The type of pedestrian facility and traffic signals during which pedestrians arrived at the kerb and crossed appeared to be other influential factors of pedestrian delay. With regard to gaze behaviour, an average number of head movements ranged from 2 to 5 at the kerb and from 3 to 5 while crossing. Conflicts with motorists peaked where crossing distances were longer and traffic volume was heavy. A red light violation ranging from 82 to 87 percent was observed in this study and on-street surveys indicated that beliefs and attitudes towards traffic control devices and traffic environment significantly explained pedestrians’ unsafe crossing behaviour. The calculated critical gap and critical lag ranged from 2.19 to 3.90 seconds and the effect of crossing distance on gap-acceptance emerged in this study. Possible interventions are finally suggested. / AFRIKAANSE OPSOMMING: Padongelukke is 'n wêreldwye probleem wat al die lande in die gesig staar. Ongeveer 1,2 miljoen mense sterf jaarliks as 'n gevolg van verkeersongelukke en 50 miljoen word beseer. Meer as 90 persent van padsterftes kom voor in die ontwikkelende wêreld met slegs 48 persent van die wêreld se geregistreerde voertuie. Bo en behalwe die probleem van padsterftes, het padongelukke gestremdheid en lang termyn beserings tot gevolg. Dit veroorsaak ook aansienlike ekonomiese verliese vir die slagoffers en hul gesinne en skade aan eiendomme en infrastruktuur. In Suid-Afrika is voetgangersterftes verantwoordelik vir sowat 40% van alle padongelukke. Gedragspatrone van beide voetgangers en motoriste by voetoorgange is die belangrikste bepalende faktore van voetganger-ongelukke. Hierdie studie ondersoek gedragspatrone van voetgangers by verskillende tipes kruisings in die dorp van Stellenbosch Suid-Afrika. ʼn Totale aantal van 17 voetoorgange is gekies vir die studie op die basis van hul geometriese en operasionele eienskappe. Video-gebaseerde waarnemings saam met op-straat onderhoude is gebruik om kruising-gedragspatrone, naamlik voetganger stapspoed, voetganger vertraging, kyk gedrag, voetganger-voertuig konflikte, voetganger nakoming van padverkeersreëls en gaping-aanvaarding gedrag te verstaan. Resultate van die studie het getoon dat manlike voetgangers vinniger loop as vroulike voetgangers. Die 15de persentiel kruising spoed vir alle voetgangers waargeneem binne kruisings was 1,13 m/s, terwyl die gemiddelde kruising spoed 1,48 m/s is. Demografiese veranderlikes beïnvloed voetgangers loop-spoed. Manlik en jonger voetgangers loop vinniger as vroulike en ouer voetgangers. Voetgangers loop-spoed word ook geraak deur die grootte van die groep, die dra van items, die tipe voetganger-fasiliteit en afleiding terwyl geloop word. Daar is egter geen gevolge van konflikte op voetgangers loop-spoed in hierdie studie gevind nie. 'n Gemiddelde totale vertraging van 5,10 sekondes is in hierdie studie gevind. Manlik en jonger voetgangers ervaar korter vertraging in vergelyking met die vroulike en ouer voetgangers. Die tipe voetgangerfasiliteit en verkeerseine was ander invloedryke faktore van voetganger vertraging. Vir waarneming van die verkeer is gevind dat die gemiddelde aantal kopbewegings gewissel het van 2 tot 5 teen die randsteen en van 3 tot 5, tydens die kruising. Konflikte met motoriste het ʼn hoogtepunt bereik waar kruising afstande langer en verkeersvolume hoër was. Rooi lig oortredings wat wissel van 82 tot 87 persent is in hierdie studie waargeneem en op-straat opnames het aangedui dat houdings teenoor verkeer-beheer toestelle en die verkeersomgewing die voetgangers se onveilige kruising-gedrag verduidelik. Die berekende kritiese gaping het gewissel van 2,19 tot 3,90 sekondes en die effek van die kruisinglengte op gaping-aanvaarding het in hierdie studie na vore gekom. Moontlike intervensies word voorgestel.

Thesis (MEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The suitability of local construction materials for construction purposes is governed by several rock mechanical properties. Strength, durability, performance and petrography of aggregates all influence the decisions engineers make in deciding if the aggregate is suitable and sustainable throughout the lifetime of a structure. This thesis investigates these properties by combining engineering, chemistry and geological disciplines to make informed decisions. The pertaining project for which the research was conducted is the construction of the gravimeter vault at the Matjiesfontein Geodesy and Earth Observation Observatory (MGO) although the research acquired can be used for other projects of a similar nature and other outbuildings at the MGO. Material at and around the site were tested for strength and durability according to certain South African National Standards (SANS). Slake durability was tested as certain rock types tend to slake when exposed to the atmosphere such as tillite of the Dwyka formation and shale of the Karoo Supergroup. Concrete cube strength was determined on cubes containing crushed rock from Matjiesfontein as well as river sand. Cube strength was conducted to analyse performance and to establish a mix design that would be sustainable throughout the lifetime of the project. Petrographic examination using Powder X-ray diffraction (PXRD), X-ray fluorescence (XRF), Scanning Electron Microscopy (SEM) and inspection under a petrographic microscope were conducted. These methods were used to determine if a risk exists for alkali-silica reactivity (ASR) in concrete when the rock types are used as aggregate, particularly if high quartz-bearing rock types such as quartzite of the Table Mountain group were to be used as coarse aggregate. Inspection of thin sections for strained quartz under a petrographic microscope and SEM imaging were important in determining if ASR may occur. The gravimeter vault was constructed using materials sourced mainly from Laingsburg. Tillite satisfied all tests and analyses conducted during the research, making it more suitable for construction than the other materials from Matjiesfontein. The slake durability test indicates that tillite is nearly as durable as quartzite, which is considered the most durable rock type at Matjiesfontein. This is due to atmospheric conditions in the Karoo being very dry with low humidity in comparison to the coast where slaking is known to occur. Slaking properties were most prominent for shale at Matjiesfontein and if excavated, it is recommended to cover the exposed shale with a layer of asphalt or cement to prevent slaking. The 10% fines aggregate crushing test (10%FACT) value for tillite was over the 210 kN prerequisite and the wet-to-dry ratio over 75% making it suitable for road construction according to the 10%FACT. All cube tests reached the desired 40 MPa prerequisite although the mixtures containing local river sand were unworkable. Unlike quartzite and quartzitic sandstone from Matjiesfontein, tillite is low in quartz and has minimal strained quartz. Therefore, no risk exists for ASR if tillite were to be used as aggregate in concrete. / AFRIKAANSE OPSOMMING: Die geskiktheid van plaaslike konstruksiemateriale vir konstruksiedoeleindes word deur sekere rots meganiese eienskappe beïnvloed. Sterkte, duursaamheid, volhoubaarheid en petrografie van aggregaat beïnvloed die besluite wat ingenieurs moet neem sodat die aggregaat aan standaarde voldoen en gedurende die leeftyd van ‘n struktuur volhoubaar is. Hierdie tesis ondersoek die genoemde eienskappe deur ingenieurs-, chemiese- en geologiese dissiplines te kombineer. Die voorgenome projek, waarvoor die navorsing ter sprake is, is vir die konstruksie van die gravimeterkluis by die “Matjiesfontein Geodesy and Earth Observation Observatory (MGO)”, alhoewel die navorsing ook gebruik kan word vir soortgelyke projekte, sowel as die konstruksie van die res van die geboue by die MGO. Materiale van die terrein en die omgewing is volgens sekere Suid-Afrikaanse kodes vir sterkte en duursaamheid getoets. Die blusbaarheid van materiale is getoets omdat sekere materiale, soos tilliet van die Dwyka-formasie en skalie van die Karoo Supergroep blus wanneer dit aan die atmosfeer blootgestel word. Die betonsterkte van kubusse, waarin plaaslike gesteentes en riviersand van Matjiesfontein vir aggregaat gebruik is, is bepaal. Die kubusse is getoets om die sterkte daarvan te analiseer en om ‘n betonmengsel, wat tydens die leeftyd van die projek volhoubaar is, daar te stel. Petrografiese eksaminering deur X-straal difraksie (XRD), X-straal fluoressensie (XRF), Skandeerelektronmikroskopie (SEM) en inspeksie onder ‘n petrografiese mikroskoop is gedoen. Met die doel om die petrografiese samestelling van materiale van Matjiesfontein te bepaal, is hierdie metodes gevolg om te uit te vind of daar ‘n risiko vir alkalie-silikaat reaksies (ASR) bestaan, as die gesteentes in beton gebruik word. Veral gesteentes met ‘n hoë hoeveelheid kwarts, soos kwartsiet van die Tafelberg-groep, is hier ter sprake. Inspeksie van dunsnitte vir gespanne kwarts onder ‘n petrografiese mikroskoop en SEM was belangrik om die risiko vir ASR te bepaal. Die gravimeterkluis is hoofsaaklik met materiale afkomstig van Laingsburg gebou. In vergelyking met die ander gesteentes by Matjiesfontein is tilliet, volgens alle toetsparameters, die mees geskikte gesteente vir konstruksiedoeleindes. Die blusbaarheid van tilliet vergelyk goed met kwartsiet, wat as die sterkste en duursaamste gesteente by Matjiesfontein, beskou word. Die rede hiervoor is die atmosferiese toestande wat baie droër is, asook die laer humiditeit in die Karoo, in vergelyking met gebiede nader aan die kus waar blusting meer algemeen voorkom. Die blusbaarheid van skalie by Matjiesfontein kom algemeen voor. As daar dus uitgrawing in hierdie gebied plaasvind, word dit aanbeveel dat ‘n laag sement of asfalt oorgegooi word om die blusting te verhoed. Die 10%FACT waarde vir tilliet was bo die vereiste 210 kN, asook bo die 75% nat-teenoor-droog-verhouding en daarom is dit volgens die 10%FACT-toets as padboumateriaal geskik. Alhoewel mengsels, wat plaaslike riviersand bevat het, onwerkbaar was, het alle toetsmonsters (kubusse) die vereiste 40 MPa- sterkte bereik. In vergelyking met kwartsiet en kwarsitiese sandsteen, bevat tilliet min kwarts en ook minimale gespanne kwarts. Daar bestaan dus geen risiko vir ASR indien tilliet van Matjiesfontien in die beton gebruik word nie.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: South Africa is currently experiencing a time in which existing infrastructure is reaching its design life end. With a growing economy and the increased level of social development, existing infrastructure is under extreme pressure. South Africa is also facing a challenge in which a need exists for engineering capabilities. These capabilities include engineering skills to maintain and manage existing infrastructure, plan for new infrastructure and construct new needed infrastructure. This study looks at a possible solution towards the above mentioned challenges. As a solution, the study proposes a professional development program to prepare engineers to work in the environment of infrastructure development. More specifically the program prepares civil engineers to work in public sector organisations responsible for basic service infrastructure. The research for the proposed professional development program is done by comparing literature with feedback received from various industry professionals. By doing this, the components for the proposed program were researched and identified. The components for the proposed program are professional work experience, professional training and structured mentorship. A further deliverable of the proposed program is to assist candidates taking part in the program to register as professional engineers on completion of the program. The study further showed the proposed program should be structured in such a way that all the components mentioned above work together interactively and should be centrally managed to ensure all the goals for the program are being reached. It is further stated that if the proposed program could successfully be implemented and if all the stakeholders commit towards the goal of the proposed program, the program could have a significant positive impact towards the challenges mentioned above. / AFRIKAANSE OPSOMMING: Suid-Afrika beleef tans 'n tyd waarin bestaande infrastruktuur besig is om hul ontwerp tydperk te bereik. Met 'n groeiende ekonomie en die verhoogde vlak van maatskaplike ontwikkeling is bestaande infrastruktuur onder geweldige druk. Suid- Afrika staar ook tans `n uitdaging in die gesig in verband met onvoldoende getalle professionele ingenieurs, veral in die omgewing van die instandhouding van bestaande infrastruktuur, die konstruksie van nuwe infrastruktuur, en die beplanning van verdere nodige infrastruktuur. Hierdie studie ondersoek dus 'n moontlike oplossing tot bogenoemde uitdagings. As 'n moonlike oplossing stel die studie voor dat `n professionele ontwikkelingsprogram vir ingenieurs saamgestel word. So `n program sal dus ingenieurs oplei en voorberei vir werk binne die openbare sektor wat verantwoordelik is vir die ontwikkeling en bestuur van basiese dienste infrastruktuur. Die navorsing vir die voorgestelde professionele ontwikkeling program is gedoen deur bestaande literatuur te vergelyk met inligting ontvang vanaf verskeie professionele ingenieurs in die praktyk. Deur dit te doen, is die komponente vir die voorgestelde program nagevors en geïdentifiseer. Die geïdentifiseerde komponente vir die voorgestelde program is dus soos volg: professionele werkservaring, opleiding en gestruktureerde mentorskap. 'n Verdere aflewering van die voorgestelde program is om kandidate te registreer as professionele ingenieurs teen voltooiing van die program. Die studie toon ook verder aan dat al die komponente, soos wat hierbo genoem is, geïntegreerd moet plaasvind en dat die program gestruktureerd bestuur moet word vanaf `n sentrale punt of organisasie. Dit word dan verder genoem dat indien die voorgestelde program suksesvol geïmplementeer kan word, en indien die verskeie belanghebbendes tot die program hulle self tot die program kan verbind, die program 'n beduidende positiewe impak op die uitdagings hierbo kan maak.

Thesis (MScEng)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: Most of the parameters involved in the design and analysis of structures are of stochastic nature. This is, therefore, of paramount importance to be able to perform a fully stochastic analysis of structures both in component and system level to take into account the uncertainties involved in structural analysis and design. To the contrary, in practice, the (computerised) analysis of structures is based on a deterministic analysis which fails to address the randomness of design and analysis parameters. This means that an investigation on the algorithmic methodologies for a component and system reliability analysis can help pave the way towards the implementation of fully stochastic analysis of structures in a computer environment. This study is focused on algorithm development for component and system reliability analysis based on the various proposed methodologies. Truss structures were selected for this purpose due to their simplicity as well as their wide use in the industry. Nevertheless, the algorithms developed in this study can be used for other types of structures such as moment-resisting frames with some simple modi cations. For a component level reliability analysis of structures different methods such as First Order Reliability Methods (FORM) and simulation methods are proposed. However, implementation of these methods for the statistically indeterminate structures is complex due to the implicit relation between the response of the structural system and the load effect. As a result, the algorithm developed for the purpose of component reliability analysis should be based on the concepts of Stochastic Finite Element Methods (SFEM) where a proper link between the finite element analysis of the structure and the reliability analysis methodology is ensured. In this study various algorithms are developed based on the FORM method, Monte Carlo simulation, and the Response Surface Method (RSM). Using the FORM method, two methodologies are considered: one is based on the development of a finite element code where required alterations are made to the FEM code and the other is based on the usage of a commercial FEM package. Different simulation methods are also implemented: Direct Monte Carlo Simulation (DMCS), Latin Hypercube Sampling Monte Carlo (LHCSMC), and Updated Latin Hypercube Sampling Monte Carlo (ULHCSMC). Moreover, RSM is used together with simulation methods. Throughout the thesis, the effciency of these methods was investigated. A Fully Stochastic Finite Element Method (FSFEM) with alterations to the finite element code seems the fastest approach since the linking between the FEM package and reliability analysis is avoided. Simulation methods can also be effectively used for the reliability evaluation where ULHCSMC seemed to be the most efficient method followed by LHCSMC and DMCS. The response surface method is the least straight forward method for an algorithmic component reliability analysis; however, it is useful for the system reliability evaluation. For a system level reliability analysis two methods were considered: the ß-unzipping method and the branch and bound method. The ß-unzipping method is based on a level-wise system reliability evaluation where the structure is modelled at different damaged levels according to its degree of redundancy. In each level, the so-called unzipping intervals are defined for the identification of the critical elements. The branch and bound method is based on the identification of different failure paths of the structure by the expansion of the structural failure tree. The evaluation of the damaged states for both of the methods is the same. Furthermore, both of the methods lead to the development of a parallel-series model for the structural system. The only difference between the two methods is in the search approach used for the failure sequence identification. It was shown that the ß-unzipping method provides a better algorithmic approach for evaluating the system reliability compared to the branch and bound method. Nevertheless, the branch and bound method is a more robust method in the identification of structural failure sequences. One possible way to increase the efficiency of the ß-unzipping method is to define bigger unzipping intervals in each level which can be possible through a computerised analysis. For such an analysis four major modules are required: a general intact structure module, a damaged structure module, a reliability analysis module, and a system reliability module. In this thesis different computer programs were developed for both system and component reliability analysis based on the developed algorithms. The computer programs are presented in the appendices of the thesis. / AFRIKAANSE OPSOMMING: Meeste van die veranderlikes betrokke by die ontwerp en analise van strukture is stogasties in hul aard. Om die onsekerhede betrokke in ontwerp en analise in ag te neem is dit dus van groot belang om 'n ten volle stogastiese analise te kan uitvoer op beide komponent asook stelsel vlak. In teenstelling hiermee is die gerekenariseerde analise van strukture in praktyk gebaseer op deterministiese analise wat nie suksesvol is om die stogastiese aard van ontwerp veranderlikes in ag te neem nie. Dit beteken dat die ondersoek na die algoritmiese metodiek vir komponent en stelsel betroubaarheid analise kan help om die weg te baan na die implementering van ten volle rekenaarmatige stogastiese analise van strukture. Di e studie se fokus is op die ontwikkeling van algoritmes vir komponent en stelsel betroubaarheid analise soos gegrond op verskeie voorgestelde metodes. Vakwerk strukture is gekies vir die doeleinde as gevolg van hulle eenvoud asook hulle wydverspreide gebruik in industrie. Die algoritmes wat in die studie ontwikkel is kan nietemin ook vir ander tipes strukture soos moment-vaste raamwerke gebruik word, gegewe eenvoudige aanpassings. Vir 'n komponent vlak betroubaarheid analise van strukture word verskeie metodes soos die "First Order Reliability Methods" (FORM) en simulasie metodes voorgestel. Die implementering van die metodes vir staties onbepaalbare strukture is ingewikkeld as gevolg van die implisiete verband tussen die gedrag van die struktuur stelsel en die las effek. As 'n gevolg, moet die algoritme wat ontwikkel word vir die doel van komponent betroubaarheid analise gebaseer word op die konsepte van stogastiese eindige element metodes ("SFEM") waar 'n duidelike verband tussen die eindige element analise van die struktuur en die betroubaarheid analise verseker is. In hierdie studie word verskeie algoritmes ontwikkel wat gebaseer is op die FORM metode, Monte Carlo simulasie, en die sogenaamde "Response Surface Method" (RSM). Vir die gebruik van die FORM metode word twee verdere metodologieë ondersoek: een gebaseer op die ontwikkeling van 'n eindige element kode waar nodige verandering aan die eindige element kode self gemaak word en die ander waar 'n kommersiële eindige element pakket gebruik word. Verskillende simulasie metodes word ook geïmplimenteer naamlik Direkte Monte Carlo Simulasie (DMCS), "Latin Hypercube Sampling Monte Carlo" (LHCSMC) en sogenaamde "Updated Latin Hypercube Sampling Monte Carlo" (ULHCSMC). Verder, word RSM tesame met die simulasie metodes gebruik. In die tesis word die doeltreffendheid van die bostaande metodes deurgaans ondersoek. 'n Ten volle stogastiese eindige element metode ("FSFEM") met verandering aan die eindige element kode blyk die vinnigste benadering te wees omdat die koppeling tussen die eindige element metode pakket en die betroubaarheid analise verhoed word. Simulasie metodes kan ook effektief aangewend word vir die betroubaarheid evaluasie waar ULHCSMC as die mees doeltre end voorgekom het, gevolg deur LHCSMC en DMCS. The RSM metode is die mees komplekse metode vir algoritmiese komponent betroubaarheid analise. Die metode is egter nuttig vir sisteem betroubaarheid analise. Vir sisteem-vlak betroubaarheid analise is twee metodes oorweeg naamlik die "ß-unzipping" metode and die "branch-and-bound" metode. Die "ß-unzipping" metode is gebaseer op 'n sisteem-vlak betroubaarheid ontleding waar die struktuur op verskillende skade vlakke gemodelleer word soos toepaslik vir die hoeveelheid addisionele las paaie. In elke vlak word die sogenaamde "unzipping" intervalle gedefinieer vir die identifikasie van die kritiese elemente. Die "branch-and-bound" metode is gebaseer op die identifikasie van verskillende faling roetes van die struktuur deur uitbreiding van die falingsboom. The ondersoek van die skade toestande vir beide metodes is dieselfde. Verder kan beide metodes lei tot die ontwikkeling van 'n parallelserie model van die strukturele stelsel. Die enigste verskil tussen die twee metodes is in die soek-benadering vir die uitkenning van falingsmodus volgorde. Dit word getoon dat die "ß-unzipping" metode 'n beter algoritmiese benadering is vir die ontleding van sisteem betroubaarheid vergeleke met die "branch-and-bound" metode. Die "branch-and- bound" metode word nietemin as 'n meer robuuste metode vir die uitkenning van die falings volgorde beskou. Een moontlike manier om die doeltre endheid van die "ß-unzipping" metode te verhoog is om groter "unzipping" intervalle te gebruik, wat moontlik is vir rekenaarmatige analise. Vir so 'n analise word vier hoof modules benodig naamlik 'n algemene heel-struktuur module, 'n beskadigde-struktuur module, 'n betroubaarheid analise module en 'n sisteem betroubaarheid analise module. In die tesis word verskillende rekenaar programme ontwikkel vir beide sisteem en komponent betroubaarheid analise. Die rekenaar programme word in die aanhangsels van die tesis aangebied.

Thesis (MEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The Touw River estuary and Wilderness coastal lakes is a sensitive system from a flooding and ecological viewpoint and, therefore, careful consideration is placed on the hydrodynamics and salinity levels within the system. The estuary consists of a “temporary open/closed” estuary, where during closed mouth conditions, the sand bar at the estuary mouth is artificially managed in an attempt to reduce flood water levels in the system. The reason behind this management strategy is the construction of residential property along the flood plains of the estuary and coastal lakes, which in the past, had been exposed to regular cycles of inundation during flood events. In an attempt to reduce flood water levels in all water bodies and hence reduce the risk of inundation, a management policy was formulated. The past and present management plan is to maintain the sand bar at Touw estuary mouth, during closed mouth conditions, at an elevation of between +2.1m to +2.4m MSL, based on proposals made by the CSIR in 1981. Recent flood events, after the implementation of the management policy, still occasionally result in significant inundation of residential property, which has raised concern for some interested parties over the effectiveness of the management strategy. Furthermore, a growing concern was also evident over the long term wellbeing of the system from an ecological viewpoint. Historical data shows significant changes in salinity levels since the implementation of the management strategy which could impose negative long term effects on the system. In this study, numerical models were consequently constructed and applied in order to analyse the effectiveness of the current management policy and recalculate flood water levels under a number of proposed scenarios. Long term salinity changes were also analysed in an attempt to better understand salinity propagation throughout the system, using extreme hypothetical cases. Through the analysis of the simulation results, it was concluded that flood water levels in the Touw estuary were almost completely dependent on the size of the Touw River flood and the initial height of the sand bar at the estuary mouth. Whereas, water levels in the coastal lakes are almost entirely dependent on the quantity of runoff into the lakes and their initial water levels. The current management plan, involving only artificial manipulation of the sand bar at the estuary mouth, therefore has a fairly insignificant effect on flood water levels achieved in the coastal lakes. Furthermore, it was concluded that the construction of the preparatory channel is a vitally important aspect of the current management plan and that skimming of the sand bar alone is ineffective to completely mitigate the risk of residential inundation along the banks of the Touw River. The salinity modelling study provided a first indication of the salinity characteristics within the system. It was found that the penetration of seawater into the system was less prominent as the water bodies became further removed from the ocean and that a direct relationship was evident between the volume of direct freshwater inflow to a water body and the degree of salinity variation in that specific water body. In water bodies with high volumes of direct freshwater inflow such as the Touw estuary, a large degree of salinity variation is evident. However, in water bodies with no freshwater inflow, such as Rondevlei, salinity levels remain more stable and are less likely to fluctuate. / AFRIKAANSE OPSOMMING: Uit ‘n vloed- en ekologiese oogpunt is die Touwsriviermonding en Wilderniskusmere ‘n uiters sensitiewe stelsel en daar is dus deeglike oorweging gegee aan die hidrodinamika en soutvlakke in die stelsel. Die monding bestaan uit 'n "tydelike oop / geslote" monding, en tydens geslote mondtoestande word die sandbank by die riviermond kunsmatig beheer in 'n poging om vloedwatervlakke binne die stelsel te verminder. Die rede vir hierdie strategie is omdat baie residensiële eiendomme langs die vloedvlaktes van die monding en kusmere gebou is, wat in die verlede aan 'n gereelde siklus van oorstromings blootgestel is tydens vloede. In 'n poging om vloedwatervlakke in al die watermassas te verminder, en sodoende die risiko van oorstroming te verminder, is 'n bestuursbeleid geformuleer. In beide die vorige en die huidige bestuursplanne is die sandbank in die Touwsriviermond tydens geslote mondtoestande in stand gehou op 'n hoogte van tussen 2,1 m en 2,4 m MSL, gebaseer op die voorstelle wat deur die WNNR in 1981 gemaak is. Onlangse vloede wat plaasgevind het na die implementering van die beleid, het steeds van tyd tot tyd gelei tot noemenswaardige oorstromings van residensiële eiendomme, en kommer is uitgespreek deur 'n paar belanghebbende partye oor die doeltreffendheid van die strategie vir die bestuur. Daar is verder kommer uitgespreek oor die langtermyn welstand van die stelsel uit 'n ekologiese oogpunt. Historiese data toon 'n beduidende verandering in soutvlakke sedert die implementering van die bestuurstrategie met ‘n negatiewe langtermyn uitwerking op die stelsel. In hierdie studie is daar derhalwe numeriese modelle opgestel en toegepas ten einde die doeltreffendheid van die huidige bestuur van die beleid te bepaal, asook om die vloedvlakke te herbereken en te analiseer na aanleiding van 'n aantal voorgestelde scenario's. Langtermyn soutgehalte veranderinge is ook ontleed in 'n poging om die soutgehalte verspreiding deur die hele stelsel beter te verstaan, deur gebruik te maak van uiterste hipotetiese gevalle. Deur die ontleding van die simulasie resultate, is daar tot die gevolgtrekking gekom dat vloedwatervlakke in die Touwsrivier-monding byna heeltemal afhanklik was van die grootte van die Touwsrivier vloed en die aanvanklike hoogte van die sandbank by die riviermond. Watervlakke in die kusmere is egter byna heeltemal afhanklik van die hoeveelheid afloop na die mere en die aanvanklike watervlakke. Die huidige bestuursplan, wat slegs ‘n kunsmatige manipulasie van die sandbank by die riviermond behels, het dus 'n redelik onbeduidend invloed op die vloedwatervlakke wat in die kusmere bereik is. Daar is verder tot die gevolgtrekking gekom dat die konstruksie van die voorbereidende kanaal 'n uiters belangrike aspek van die huidige bestuursplan is, en dat die afskraping van die sandbank alleen oneffektief sou wees om die risiko van residensiële oorstroming langs die oewer van die Touwsrivier uit te skakel. Die soutgehalte modelleringstudie verskaf 'n eerste aanduiding van die soutgehalte eienskappe binne die stelsel. Daar is gevind dat die penetrasie van seewater in die stelsel minder prominent was as in die watermassas verder van die see af, en dat daar 'n duidelike direkte verband is tussen die volume van die varswater wat direk invloei na 'n watermassa en die mate van soutgehalte variasie in daardie spesifieke watermassa. In watermassas waar hoë volumes varswater direk invloei soos die Touwsrivier-monding, is 'n groot mate van soutgehalte variasie sigbaar. In die watermassas waar geen varswater invloei nie, soos die Rondevlei, bly soutvlakke meer stabiel en is minder geneig om te wissel.

Thesis (MScEng)-- Stellenbosch University, 2013. / ENGLISH ABSTRACT: Concrete is used in most of the modern day infrastructure. It is a building material for which there exist various design codes and guidelines for its use and construction. It is strong in compression, but lacks tensile strength in its fresh and hardened states and, when unreinforced, fails in a brittle manner. The structural use of synthetic fibres in concrete is investigated in this study to determine its effect on enhancing the mechanical properties of concrete. Slabs on grade are used as the application for which the concrete is tested. The material behaviour is investigated in parallel with two floor design theories. These are the Westegaard theory and the Yield-Line theory. The Westegaard theory uses elastic theory to calculate floor thicknesses while the Yield-Line theory includes plastic behaviour. Conceptual designs are performed with the two theories and material parameters are determined from flexural tests conducted on synthetic fibre reinforced concrete (SynFRC) specimens. Large scale slab tests are performed to verify design values from the two theories. Higher loads till first-crack were measured during tests with concrete slabs reinforced with polypropylene fibres than for unreinforced concrete. It is found that the use of synthetic fibres in concrete increases the post-crack ductility of the material. The Westegaard theory is conservative in its design approach by over-estimating design thicknesses. This was concluded as unreinforced slabs reached higher failure loads than predicted by this theory. The Yield-Line theory predicts design thicknesses more accurately while still accounting for the requirements set by the ultimate- and serviceability limit states. By using SynFRC in combination with the Yield-Line theory as design method, thinner floor slabs can be obtained than with the Westegaard theory. / AFRIKAANSE OPSOMMING: Beton word gebruik as boumateriaal in meeste hedendaagse infrastruktuur. Daar bestaan verskeie ontwerp kodes en riglyne vir die gebruik en oprig van beton strukture. Alhoewel beton sterk in kompressie is, het beton ‘n swak treksterkte in beide die vars- en harde fases en faal dit in ‘n bros manier indien onbewapen. Die gebruik van sintetiese vesels in beton word in hierdie projek ondersoek om die invloed daarvan op die eienskappe van die meganiesegedrag van beton te bepaal. Grond geondersteunde vloere word as toepassing gebruik. Parallel met die materiaalgedrag wat ondersoek word, word twee ontwerpsteorieë ook ondersoek. Dit is die teorie van Westegaard en die Swig-Lyn teorie. Die teorie van Westegaard gebruik elastiese teorie in ontwerpsberekeninge terwyl die Swig-Lyn teorie ‘n plastiese analise gebruik. ‘n Konseptuele vloerontwerp is gedoen deur beide die ontwerpsmetodes te gebruik. Materiaalparameters is bepaal deur buig-toetse uit te voer op sintetiesevesel-bewapende beton. Grootskaalse betonblaaie is gegiet en getoets om die akkuraatheid van die twee metodes te verifieer. Die betonblaaie wat bewapen was met polipropileen vesels het groter laste gedra tot by faling as die blaaie wat nie bewapen was nie. Die vesels verbeter die gedrag van beton in die plastiese gebied van materiaalgedrag deurdat laste ondersteun word nadat die beton alreeds gekraak het. Die Westegaard teorie kan as konserwatief beskou word deurdat dit vloerdiktes oorskat. Hierdie stelling is gegrond op eksperimentele data wat bewys dat onbewapende betonblaaie groter laste kan dra as wat voorspel word deur die Westegaard teorie. Die Swig-Lyn teorie voorspel ontwerpsdiktes meer akkuraat terwyl daar steeds aan die vereistes van swigting en diensbaarheid voldoen word. Deur gebruik te maak van sintetiese vesels en die Swig-Lyn teorie kan dunner betonblaaie ontwerp word as met die Westegaard teorie.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Currently maritime ports, including the Port of Cape Town, experience congestion, pollution and other logistics-related problems due to increasing levels of container traffic. The presence of these problems has caused port planners, port operators and logistics firms to look for new solutions in this transport sector. The dry port concept, whereby offloaded containers are stored outside the maritime port in a dedicated logistics area, is recognized as a means for solving some of these major problems, thereby promoting economic development and logistics integration as well as reducing the demand on limited capacity (land and access) at the maritime port. Therefore, the core objective of this study is to demonstrate that the implementation of the dry port concept is a feasible alternative for expanding the throughput capacity of the Cape Town Container Terminal. The Port of Cape Town is strategically one of the best placed ports in South Africa as it is positioned at the South Western extremity of the continent of Africa, thereby linking America and Europe with Asia, the Far East and Australia. Furthermore, the Port of Cape Town also forms a direct link between international trade and about three (3) million consumers in the Western Cape. The recent expansion of the Cape Town Container Terminal was a major investment which included the upgrading of equipment and the expansion of workable surface area, thereby increasing the container terminal yard capacity to 1.4million TEU (TEU = Twenty foot Equivalent Unit) per annum. However, this report showed that the abovementioned increase in volumes as well as the resulting congestion continues to be a challenge at the Port of Cape Town. Firstly, the predicted future container volumes show that the demand in the Port of Cape Town could reach between 1.9 million and 3.2 million TEU per annum by 2039. Secondly, the evaluation of the operational and infrastructural characteristics of the existing Cape Town Container Terminal demonstrated that container terminal yard (CY) area is the capacity limiting characteristic of the terminal and that the operational and infrastructural limits could be reached between 2018 and 2026. The two main functions of a dry port in the Western Cape transportation network would be international trade processing and congestion relief, which are achieved through the duplication and supplementation of the Cape Town Container Terminal facilities at an inland location. The dry port would allow the Western Cape supply chain to absorb any future container volume demands that exceed the CY capacity of the Port of Cape Town and could potentially attract an annual throughput of 0.7 million TEU by 2039. Furthermore, the facility could address the problem of congestion in and around the greater Cape Town metropolitan, resulting in an improved transportation network that will have a positive effect on passenger traffic, productivity of trucks, competitiveness of the Port of Cape Town as well as the environmental sustainability of the transportation system. The dry port concept would therefore be appealing to Transnet Port Authority / Transnet Port Terminals, Shippers and Logistics Managers and the Western Cape Regional Community. The site selection analysis performed in this study evaluated three possible dry port locations, namely: Kraaifontein Area, Ysterplaat Air Force Base and Bellville Precinct. Although the analysis identified that all three of the sites have the potential to be developed into a successful dry port; however, that the Bellville Precinct is the preferred location due to the presence of the Belcon freight rail facility. The success of such a facility will greatly depend on the project’s ability to ensure that the resources needed for the initial investment is kept to a minimum, and ultimately the most viable dry port solution in the Western Cape region would be the phased development of Bellville Precinct. From this it is clear that a dry port could be a feasible alternative for expanding the throughput capacity of the Port of Cape Town, as well as improving the transport infrastructure in the Cape Town area. / AFRIKAANSE OPSOMMING: Maritieme hawens, insluitende die Kaapstadse hawe, ondervinding tans opeenhoping, besoedeling en ander logistieke probleme as gevolg van toenemende vlakke van die houer verkeer. Die teenwoordigheid van hierdie probleme het veroorsaak dat hawe beplanners, hawe-operateurs en logistiek maatskappye op soek is vir nuwe oplossings in die vervoer sektor. Die droë hawe konsep word erken as 'n middel vir die oplossing van sommige van hierdie probleme, en sodoende ekonomiese ontwikkeling en logistieke integrasie te bevorder, sowel as die verlaging van aanvraag op beperkte kapasiteit (grond en toegang) by die maritieme hawe. Daarom is die kern doel van hierdie studie om aan te toon dat die implementering van die droë hawe konsep 'n haalbare alternatief is vir die uitbreiding van die deurset kapasiteit van die Kaapstadse Houerterminaal. Die Kaapstadse hawe is strategies een van die bes geplaaste hawens in Suid-Afrika, want dit is geleë aan die suid-westerlikste punt van Afrika en verbind Amerika en Europa met Asië, die Verre Ooste en Australië. Verder vorm die Kaapstadse hawe ook 'n direkte skakel tussen die buitelandse markte en die drie (3) miljoen verbruikers in die Wes-Kaap. Die onlangse uitbreiding van die Kaapstadse Houerterminaal het die stoorkapasiteit van die terminaal aansienlik verbeter an 1.4 miljoen TEU per jaar, deur middel van die opgradering van toerusting en die uitbreiding van werkbare oppervlak. Hierdie verslag bewys egter dat die bogenoemde toename in volumes sowel as die gevolglike opeenhoping steeds teenwoordig is in die Kaapstadse hawe. Eerstens, die voorspelde toekomstige houervolumes toon dat die aanvraag in die Kaapstadse hawe tussen 1.9 miljoen en 3.2 miljoen TEU's per jaar kan bereik teen 2039. Tweedens, die evaluering van die operasionele en infrastrukturele kenmerke van die bestaande Kaapstadse Houerterminaal het getoon dat die houer stoorarea die kapasiteit beperkende kenmerk van die terminaal is en dat die operasionele en infrastrukturele perke moontlik tussen 2018 en 2026 bereik kan word. Die twee hoof funksies van 'n droë hawe in die Wes-Kaap vervoer netwerk sal internasionale handel verwerking en opeenhoping verligting wees. Hierdie funksies sal bereik word deur die duplisering en aanvulling van die Kaapstadse Houerterminaal fasiliteite by 'n binnelandse perseel. Die droë hawe sal toelaat dat die Wes-Kaap verskaffersiklus enige toekomstige houervolumes, wat meer is as die houer stoorarea kapasiteit van die Kaapstadse hawe, te kan hanteer en kan potensieel 'n jaarlikse deurset van 0.7 miljoen TEU hanteer. Verder kan die