Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The outdoor water consumption of residential properties is a major contributor to the seasonal fluctuation of the overall water consumption of these properties. The estimation of the relating outdoor water demand has become valuable to property developers and planners alike. This could enable designers to optimise designs of water distribution networks and assist in water resource planning and gaining legislative approvals. For the purposes of this study the outdoor water-use components were mathematically defined and combined to develop an outdoor water-demand model. In order to evaluate the results of an outdoor water demand model on a monthly temporal scale it was necessary to develop a proxy outdoor water consumption evaluation method based on the metered monthly consumption of residential properties. The method entailed verifying that the generally non-seasonal indoor water consumption as a function of the winter water consumption. This entailed analysis of the total monthly, indoor and outdoor water consumption data adopted from a noteworthy North American water end-use project. The indoor water consumption estimated in this manner could then be subtracted from the overall monthly water consumption to obtain estimated monthly outdoor water consumption data. The estimated outdoor consumption could be compared with the simulated outdoor water demand, as described by the model. The parameters that formed part of the mathematical outdoor water demand model were formulated from data available for residential estates, where conditions such as types of vegetation, irrigated area and size of pool could be prescribed in a constitution, usually instituted by a home owners association. The data was derived from one estate located in the Western Cape Province of South Africa. The mathematical model was simulated using the Monte Carlo method and the @Risk software. Three residential estates located in South Africa were subsequently modelled. Additionally, the model was employed to estimate outdoor water demand for houses located in Northern America for verification purposes. The Monte Carlo simulations of the outdoor water demand model presented in this study yielded realistic results when compared with the proxy outdoor consumption figures as well as the metered actual outdoor water consumption data analysed. The peak monthly outdoor water demand estimation results were particularly close to the consumption data. This study serves as a baseline for further research into outdoor water demand. Research into the effects of water restriction and conservation potential could follow from this work, especially in today’s environmentally conscious society. / AFRIKAANSE OPSOMMING: Die buite waterverbruik van residensiëel eiendomme dra grootliks by tot die seisoenale fluktuasie van die algehele water verbruik van hierdie eiendomme. Die beraming van die dienooreenkomstige buite wateraanvraag kan waarde toevoeg vir eiendomsontwikkelaars and beplanners, indien dit ontwerpers kan instaat stel om water verspreindingsnetwerke te optimeer en te help met water hulpbron beplanning en wetlikke goedkeurings. Vir die doeleindes van hierdie studie is die buite waterverbruik komponente wiskundig gedefinieër en gekombineer om ‘n buite wateraanvraag model te ontwikkel. Ten einde die resultate van ‘n buite water aanvraag model op ‘n maandelikse tydskaal te evalueer, was dit nodig om ‘n benaderingsmetode te ontwikkel, gebaseer of die gemeterde maandelikse water verbruike gebruik. Die metode behels dat die data, verkry van ‘n bekende Noord-Amerikaanse water eindverbruikprojek, van die algmeen nie-seisoenale binneshuise water verbruik vergelyk word met die maandelikse winter water verbruik. Derhalwe kon die binneshuise waterverbruik wat op hierdie manier beraam is afgetrek word van die algehel maandelikse waterverbruik om die maandelikse buitewater verbruik te beraam. Die beraamde buitewater verbruik kon sodoende vergelyk kan word met ‘n gesimuleerde buite wateraanvraag soos beskryf deur die gesimuleerde model. Die parameters wat deel uitgemaak het van die wiskundige buite waterverbuik model was gedefinieër uit data wat beskikbaar was vir residensiële ontwikkelings, waar voorwaardes soos plantegroei, besproeiingsarea of swembad grote dikwels voorgeskryf kan word in ‘n grondwet ingestel deur ‘n huiseienaarsvereniging. Die data wat in hierdie model gebuik word is hoofsaaklik afskomstig van ‘n landgoed geleë in die Weskaap provinsie, Suid-Afrika. Die wiskundige model was gesimuleer met behulp van die Monte Carlo metode en die @Risk sagteware. Drie residensiële landgoede geleë in Suid-Afrika was daaropvolgend gemodelleer. Daarbenewens is die model gebruik die buite watergebruik van groepe huise geleë in Noord-Amerika te beraam vir verifikasie doeleindes. Die Monte Carlo simulasies van die buite water aanvraag model van hierdie studie het realistiese resultate in vergelyking met die beraamde buite verbruike sowel as die werklike gemeterde buite water verbruiksdata opgelewer. Die piek maandelikse buite water aanvraag beramings resultate was veral vergelykbaar met die piek maandeliks waterverbruik data. Hierdie studie dien as 'n basis vir verdere navorsing in buite waterverbruik. Navorsing gefokus op die gevolge van water beperkings en bewaring potensiaal kan as aanvullende voordele van hierdie studie ontstaan, veral in vandag se omgewingsbewuste samelewing.

Thesis (MEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The South African National Standard for the structural use of cold-formed steel (SANS 10162-2) provides capacity prediction models for screwed connections. Screwed connections are designed against shear failure of the screw(s), section tear-out, net section failure and tilt-andbearing failure. Previous studies (Rogers & Hancock, 1997) showed that the capacity is typically determined by the tilt-and-bearing type failure mode. The aim of this document is to report on the reliability of single screwed connections in cold-formed steel against this critical failure mode. Predicted nominal capacities depend on the ultimate tensile strength of the steel, the thickness of the connected plates and the diameter of the screw. Design capacities are obtained by multiplying the nominal capacities by a capacity reduction factor of 0.5, according to SANS 10162-2. Reliability is assessed by means of FORM analyses, taking uncertainty in the prediction model and variability of input parameters into account. Laboratory testing of 222 single screwed connections allowed to statistically describe the model factor, i.e. the ratio of actual tested- over unbiased predicted capacity. For each connection, the steel strength, plate thickness and screw diameter were measured, with the measured values used to predict capacity. This implies that the model factor accounts for uncertainty in the prediction model and experimental setup, while the variability of input parameters is separately accounted for through appropriate statistical modelling. Variability in the input parameters was described using appropriate statistical distributions from expert literature (Holicky, 2009:199; JCSS, 2000). For steel strength, the mean value and standard deviation were obtained from tensile tests, while mean values and standard deviations of the plate thickness and screw diameter were obtained from the above mentioned measurements. The experimental work and numerical analysis resulted in a model factor with a mean just exceeding unity and a small standard deviation. This suggests that the design code under consideration is able to accurately predict the nominal capacity of screwed connections. The FORM analysis resulted in computed reliability indexes significantly higher than the corresponding target values which suggest conservative and reliable design formulations. Die eksperimentele werk en numeriese analise het gelei tot 'n model faktor met 'n gemiddeld hoër as een en 'n klein standaardafwyking. Dit dui daarop aan dat die ontwerp-kode onder oorweging in staat is om die nominale kapasitiet van skroef verbindings akkuraat te voorspel. Die betroubaarheid analise het gelei tot betroubaarheidsindekse aansienlik hoër as die ooreenstemmende teiken waardes wat daarop dui dat die ontwerp formulerings betroubaar en hoogs konserwatief is. / AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse Nasionale Standaard vir die strukturele gebruik van koud gevormde staal (SANS 10162-2) bied voorspellingsmodelle vir die kapasitiet van skroef verbindings. Skroef verbindings word ontwerp teen skroef faling, staal profiel faling, die uitskeer van skroewe en ook faling weens skroef kanteling. Vorige studies (Rogers & Hancock, 1997) het getoon dat die kapasiteit gewoonlik bepaal word deur die skroef-kantel falingsmodus. Die doel van hierdie navorsing is om verslag te doen oor die betroubaarheid van tipiese enkel skroef verbindings in koud gevormde staal strukture teen hierdie kritiese falingsmodus. Voorspelde nominale kapasiteite hang af van die treksterkte van die staal, die dikte van die verbonde profiele en die diameter van die skroef. Volgens die SANS 10162-2 word die ontwerp kapasiteit verkry deur die nominale kapasiteit met 'n kapasiteitsverminderingsfaktor van 0.5 te vermenigvuldig. Betroubaarheid word ontleed deur middel van ʼn eerste orde betroubaarheidsmetode analise, met die in ag neming van onsekerheid in die voorspellingsmodel en wisselvalligheid van die parameters. Laboratoriumtoetse van 222 enkel skroef verbindings het ʼn statistiese beskrywing van die model faktor toegelaat. Die model faktor is bereken as die verhouding tussen die getoetste kapasitiet en die voorspelde kapasitiet. Die staal sterkte, profiel dikte en skroef diameter is gemeet vir elke verbinding met die gemete waardes wat gebruik is om die kapasiteit te voorspel. Dit beteken dat die model faktor slegs onsekerhede in die voorspellingsmodel en van die eksperimentele opstelling in ag neem, terwyl die wisselvalligheid van die parameters afsonderlik in ag geneem word deur toepaslike statistiese modellering. Variasie in die parameters is beskryf met gepaste statistiese verdelings voorgestel deur verskeie literatuur (Holicky, 2009:199; JCSS, 2000). Aangaande die staal sterkte, is die gemiddelde waardes en standaardafwykings verkry deur standaard trek toetse terwyl die gemiddelde waardes en standaardafwykings van die plaat dikte en skroef diameter verkry is deur die bogenoemde metings.

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The design of the Berg River Dam bottom outlet structure with multitude draw offs was based on various hydraulic model tests on a 1:40 model that was used for original design and a 1 in 20 physical model which was used to produce the final design. These tests indicated no foreseeable malfunction and showed that the 1.8 m² air vent would provide sufficient air flow to minimize the negative pressures that would develop behind the emergency gate during its closure or opening. However, during the first trial commissioning of the dam outlet structure, air was unexpectedly expelled through the air vent at a velocity so high that the recta-grids covering the shaft were blown to a height of over 3m while the gate was closing at a rate of approximately 0.0035 m/s. The air flow velocity up the air vent was approximately 45m/s and occurred when the gate was approximately 78% closed. A brief report on the test indicated that the source of air may have been a vortex formation in the vertical intake tower upstream of the emergency gate entraining air which was drawn through the gate and released up the air vent. The purpose of this research was to utilize 3-dimensional numerical modelling employing Computational Fluid Dynamics (CFD) to carry out numerical simulations to investigate the above mentioned malfunction and thereby establishing whether the given hypotheses for the malfunction were valid. For purposes of validating the CFD modelling, a 1:14.066 physical model was constructed at the University of Stellenbosch hydraulics laboratory. The 3-dimensional CFD model was used to investigate the said incident, using steady state simulations that were run for various openings of the emergency gate. The intenetion was to establish whether there was an emergency gate opening which would reproduce the air release phenomenon. The results obtained from the numerical model showed a similar trend to those of the physical model although there were differences in values. Neither model, showed a sudden release of air through the vent. It was concluded that the unsteady air-water flow out of the air vent may have been caused by the variation of the discharge with time causing unbalanced negative pressures in the outlet structure. Therefore, it was recommended that further CFD transient simulations should be undertaken incorporating a moving emergency gate. / AFRIKAANSE OPSOMMING: Die ontwerp van die bodemuitlaat van die Bergrivierdam met multivlakuitlate is gebaseer op verskeie hidrouliese modeltoetse op a 1:40 fisiese model wat vir die oorspronklike ontwerp gebruik is, asook „n 1 tot 20 fisisiese model wat gebruik is om die finale ontwerp te lewer in 2003. Hierdie toetse het geen beduidende afwykings aangedui nie en het bewys dat die 1.8mª lugskag voldoende lugvloei sal toevoer om die negatiewe drukking wat stroomaf van die noodsluis ontstaan gedurende die sluitingsproses, sal minimaliseer. Gedurende die inlywingtoets in die veld in 2008 van die noodsluis, is lug onverwags teen 'n hoë snelheid deur die lugskag opwaarts uitgelaat, wat die rooster wat die skag beskerm teen 'n hoogte van oor 3m geblaas het terwyl die sluis teen 'n tempo van ongeveer 0.0035 m/s toegemaak het. Die lugvloeisnelheid in die lugskag was ongeveer 45m/s en het plaasgevind toe die sluis ongeveer 78% toe was. 'n Kort verslag oor die veldtoets dui aan dat die bron van die lug dalk werwelvorming in die vertikale inlaattoring stroomop van die noodsluis was, met lug wat deur die sluis getrek was en opwaarts in die lugskag vrygelaat is. Die doel van die navorsing was om drie-dimensionele numeriese modellering met rekenaar vloeidinamika (RVD) te benut om numeriese similasies uit te voer om die bogenoemde abnormale werking van die lugskag te ondersoek en daarmee vas te stel of die gegewe aannames van krag is. Vir die doel om die RVD modellering te verifieer is 'n 1:14.066 fisiese model gebou by die Universiteit van Stellenbosch se waterlaboratorium. Die 3-dimensionele RVD model is gebruik om die genoemde probleem te ondersoek, deur stasionêre simulasies wat vir verskillende openinge van die noodsluis geloop is te gebruik. Die doel was om vas te stel of daar 'n spesifieke noodsluisopening is wat die vrylating van die lug veroorsaak het. Die uitslag verkry deur die numeriese model het dieselfde windrigting soos die van die fisiese model gewys, alhoewel daar verskille in die waardes was. Nie een van die modelle het .n skielike vrystelling van lug deur die lugskag gewys nie. 'n Afleiding is gemaak dat die nie stasionêre lug-water vloei uit die lugskag moontlik veroorsaak was deur die verandering van die vloei met tyd veroorsaak deur ongebalanseerde negatiewe druk in die uitlaatstruktuur. Daarom is daar voorgestel dat verdere RVD nie stasionêre simulasies gedoen word met 'n bewegende noodsluis.

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Strain hardening cement‐based composites (SHCC) are fibre‐reinforced composites designed to form multiple fine cracks under tensile and flexural load. The cracks are controlled to small widths, whereby significant toughness, or energy dissipation, is realised on the one hand, and high resistance to gas and liquid ingress is maintained on the other hand. These two physical phenomena define application fields of SHCC, i.e. for instance elements of buildings and infrastructure for enhanced earthquake resistance, and protection of steel bars under service loads which lead to crack formation. Also exploiting the potential protection offered by SHCC to existing structures, thin overlays have been applied to existing dam faces, reinforced concrete retaining walls, water channels and RC road pavements. The layers vary between 20 and 40 mm in thickness. Considering the fibre length, usually 8 or 12 mm, as well as the application method, such thin layers may have dominantly two dimensional fibre orientation, with little or no component in the layer thickness direction. While several research groups have performed uniaxial tensile tests and flexural tests on SHCC specimens, little or no information is available on SHCC response to biaxial loading, as is to be expected in road pavement repair layers, or other repair layers. This paper reports the results of biaxial testing of 20 mm thick SHCC specimens produced in such a way to have dominantly two‐dimensional fibre orientation, and another group of specimens produced by cutting from larger specimens, whereby three‐dimensional fibre orientation was preserved in the resulting 20 mm thick specimens. Biaxial tests were performed in three quadrants, i.e. compressioncompression, compression‐tension, and tension‐tension. A clear fibre orientation‐related difference in the failure patterns involves out‐of‐plane splitting under biaxial compression of specimens with twodimensional fibre orientation, at significantly lower load, as opposed to in‐plane tensile splitting of specimens containing three‐dimensional fibre orientation. / AFRIKAANSE OPSOMMING: Vervormingsverhardende sement‐gebaseerde saamgestelde materiale (SHCC) is veselversterke saamgestelde materiale wat ontwerp is om verskeie fyn krakies te vorm onder trekspanning en buig spanning. Die kraakbreedtes word beheer, waardeur betekenisvolle taaiheid verkry, of energie verlies beheer word aan die een kant, en die hoë weerstand teen die gas en die vloeistof penetrasie aan die ander kant gehandhaaf word. Hierdie twee fisiese verskynsels definieer die toepassingsvelde van SHCC, d.w.s vir byvoorbeeld elemente van geboue en infrastruktuur vir verbeterde aardbewing weerstand, en die beskerming van staal stawe onder die dienslaste wat lei vorming te kraak. By eksploitasie van die potensiële beskerming aangebied deur SHCC aan bestaande strukture, is dun oorlae op bestaande dam walle, versterkte beton keermure, water kanale en staal‐versterkte beton paaie gebruik. Die SHCC lae wissel tussen 20 en 40 mm in dikte. Met inagneming van die vesel lengte, gewoonlik 8 of 12 mm, sowel as die toepassingsmetode, kan so 'n dun lag ‘n oorheersend tweedimensionele vesel oriëntasie hê, met min of geen komponent in die rigting van die laag dikte nie. Terwyl verskeie navorsingsgroepe eenassige trektoetse en buigtoetse op SHCC monsters gedoen het; is daar min of geen inligting beskikbaar op SHCC se reaksie op biaksiale belasting, soos verwag kan word in die pad herstel lae, of ander herstel lae. Hierdie verslag rapporteer die resultate van die biaksiale toetsing van 20 mm dik SHCC monsters wat op so 'n manier gemaak word om dominante twee‐dimensionele vesel oriëntasie te hê, en 'n ander groep monsters wat deur die sny van groter monsters, waarvolgens die drie‐dimensionele vesel oriëntasie verseker is. Biaksiale toetse is uitgevoer in drie kwadrante, d.w.s druk‐druk, druk‐trek en trek‐trek. 'n Duidelike verskil in die falingspatrone, aan die hand van vesel oriëntasie, behels uit‐vlak splyting onder biaksiale toetsing van monsters met twee‐dimensionele vesel oriëntasie, op 'n aansienlik laer lading, in teenstelling met die in‐vlak trek splyting van monsters wat ‘n drie‐dimensionele vesel oriëntasie het.

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The design of railway station environments in South Africa and to a certain extent internationally, is based on rules of thumb. These rules, using general macroscopic principles for determining peak passenger loads are inadequate and misleading for detailed design purposes. The principles advocated in local design guideline documents are erroneous and ignore the highly variable flow nature or “micro-peaking” effects that typically occur within railway station environments. Furthermore, there are no procedures proposed in these guideline documents, which leads to ambiguous assessment techniques used by practitioners in the determination of pedestrian spatial areas. It is evident that the knowledge in the area of pedestrian movement contained within the design guidance is far from comprehensive. Without a reliable method for estimating pedestrian levels-of-service and capacities, design of new facilities does not follow a uniform process, resulting in high levels of uncertainty in determining if the time, money and resources invested in upgrading facilities will actually cater to the demand. The situation is further exacerbated by current industry thinking towards pedestrian modelling in South Africa, where it is perceived by both clients and practitioners to be more cost effective to use macroscopic techniques and designing infrastructure according to a “one-level-up” level-of-service method. Working with architects confirmed that the area of circulation design was lacking in data and guidance and that associated quantified assessments of pedestrian movement was rarely, if ever, carried out. Towards addressing these issues, the development of a Spatial Parameter (SP)-model spreadsheet application became the main objective of the study. The model contributes towards addressing the needs of individual station users based on the trade-off between level-of-service and infrastructure costs. The output of the model allows the designer to avoid the under-provision (detrimental to operations) and oversizing of railway station infrastructure (with obvious financial implications). The author recognised the lack of pedestrian movement data in South Africa and addressed this by conducting extensive video-based pedestrian observations aimed at exploring the macroscopic fundamental relationships and the ways in which these relationships might be influenced by the various personal, situational and environmental factors that characterise the context in which pedestrians move. The movement trajectories of 24,410 pedestrians were investigated over three infrastructure environments at Maitland and Bonteheuwel stations in Cape Town, carefully selected to incorporate the cultural diversity common in South Africa. Tracking of pedestrians was achieved via the use of an in-house developed “video annotator” software tool. Boarding and alighting rates of 7,426 passengers were also observed at these stations incorporating contributory attributes such as age, gender, body size, encumbrance, group size, time of day, and location. The research makes a number of significant advances in the understanding of pedestrian flow behaviour within railway station environments and provides recommendations to industry of what issues to consider. The empirical study has provided comprehensive pedestrian movement characteristics incorporating the relationships between density, speed and flow including the effect of culture and other context factors unique to the local South African environment. New methods for determining spatial requirements are proposed, together with new and unique empirical data for use by the local industry. A calibrated spreadsheet SP-model for assessing the design of concourse type railway stations is developed and presented in the study. The advance in local pedestrian flow knowledge, together with the SP-model, is shown to be practical through application to two real railway station case study projects. The results of this study constitute an important contribution to local pedestrian flow knowledge and is considered a valuable resource for those developing pedestrian models in practice. It is expected that the results will be useful in the planning and design of pedestrian environments in South African railway stations and can be applied to other African metro railway stations with similar pedestrian characteristics. Overall, this research has succeeded in advancing the approach to railway station design, empirical data, knowledge and methods held within the local engineering industry. However, the contribution of this study and associated conference papers is an early step in changing the perceptions in this country towards ensuring fully informed and appropriate performance-based spatial designs. / AFRIKAANSE OPSOMMING: Die ontwerp van areas binne Suid-Afrikaanse spoorweg stasies en ook tot ‘n sekere mate internasionaal, is gebaseer op historiese ondervindings asook riglyne wat tans in die praktyk gebruik word. Die riglyne gebruik algemene makroskopiese beginsels om die spits passasiersvrag te bepaal vir gedetaileerde ontwerp doeleindes. Hierdie riglyne is egter ongeskik en misleidend aangesien dit nie die hoogs wispelturige natuur van vloei en mikrospits effekte wat binne die stasies plaasvind, in ag nie. Die riglyne ontbreek ook van prosedures wat gevolg moet word vir die bepaling van ruimtelike areas vir voetgangers wat die gevolg het dat dubbelsinnige beramingstegnieke deur praktisyne gebruik word. Die kennis oor voetganger bewegings in die ontwerp riglyne is nie omvattend genoeg nie. Sonder ‘n betroubare beramings metode vir die bepaling van voetganger diensvlak en kapasiteit kan daar nie bepaal word of die tyd, geld en hulpbronne wat in die fasilitieit geinvesteer word, aan die behoeftes gaan voldoen nie. Die situasie word verder vererger deur die huidige persepsie oor voetganger modellering in Suid-Afrika, waar dit deur beide kliënte en praktisyne, as ‘n meer koste effektiewe oplossing gesien word om makroskopiese tegnieke te gebruik en om infrastruktuur te ontwerp volgens ‘n metode waar ‘n hoër diensvlak as die teiken diensvlak gebruik word. In samewerking met argitekte is dit bevestig dat die area van sirkulasie ontwerp ‘n tekort het aan data en riglyne en dat die kwantitatiewe skattings verbonde aan voetganger beweging selde, indien ooit, uitgevoer word. Die ontwikkeling van ‘n Spatial Parameters (SP)-model om die bogenoemde problem te oorkom, is die hoofdoel van hierdie tesis. Die model poog om die behoeftes van individuele stasie gebruikers aan te spreek gebaseer op die wisselwerking tussen diensvlak en infrastruktuur kostes. Die uitsette van die model stel die ontwerper in staat om ondervoorsiening en oorvoorsiening van spoorweg stasie infrastruktuur te voorkom wat nadelige vir die bedryf is en ook ooglopende finansiële implikasies tot gevolg het. Die skrywer het die tekort aan data aangaande voetganger bewegings in Suid-Afrika geidentifiseer en dit aangespreek deur omvattende video gebaseerde voetganger waarnemings te maak met die doel om die basiese makroskopiese verhoudings te ondersoek asook in hoe ‘n mate hierdie verhoudings beinvloed word deur verskeie persoonlike, liggings- en omgewingsfaktore wat die konteks waarin voetgangers beweeg, karakteriseer. Die bewegingsprofiel van 24,410 voetgangers is ondersoek by drie infrastruktuur omgewings by Maitland en Bonteheuwel stasies in Kaapstad. Die stasies is noukeurig uitgesoek om Suid-Afrika se kulturele diversiteit te verteenwoordig. Die voetgangers is nagevolg deur gebruik te maak van ‘n selfontwikkelde video-annoteerder sagteware. Waarneming van die opklim- en afklimspoed van 7,426 passasiers is gemaak by hierdie stasies en faktore soos ouderdom, geslag, liggaamsgrootte, mobiliteit, grootte van groepe, tyd van die dag en ligging was ingesluit by die waarnemings. Hierdie navorsing maak belangrike bydraes tot die begrip van die vloei van voetgangers binne spoorweg stasies en aanbevellings word aan die industrie gemaak oor die faktore wat in ag geneem moet word by ontwerp van fasilitieite. Die empiriese studie het omvattende voetganger beweging karakteristieke uitgewys wat die verhoudings tussen digtheid, spoed en vloei inkorporeer asook die effek van kultuur en ander faktore wat verband hou met die unieke konteks van die plaaslike Suid-Afrikaanse omgewing. Nuwe metodes om ruimtelike-vereistes te bepaal word voorgestel, saam met nuwe en unieke empiriese data vir gebruik deur die plaaslike industrie. ‘n Gekalibreerde en gevalideerde SP-model is ontwikkel om die ontwerp van spoorweg stasies te assesseer en word in hierdie tesis beskyf en aangebied. Die studie toon dat akkurate data en kennis oor plaaslike voetganger vloei met die SP-model verkry kan word, soos bewys uit twee spoorweg stasie studiegevalle. Die resultate van hierdie tesis dien as ‘n belangrike bydrae tot die kennis van plaaslike voetganger vloei en word geag as ‘n waardevolle hulpbron vir die ontwikkeling van voetganger modelle in die praktyk. Hierdie resultate mag nuttig wees gedurende die beplanning en ontwerp van voetganger-areas in Suid-Afrikaanse spoorweg stasies. Dit kan ook toegepas word vir spoorweg stasies in die res van Afrika wat soortgelyke voetganger karaktereienskappe het. Die navorsing het daarin geslaag om die benadering tot spoorweg stasie ontwerp te verbeter, asook om empiriese data, kennis en die metodes wat binne die plaaslike ingenieurs industrie voorgehou word, te verbeter. Let egter daarop dat die bydrae wat hierdie tesis maak, asook bydraes deur relevante konferensie verhandelinge, ‘n vroeë stap is in die verandering van persepsies in Suid-Afrika om geskikte prestasie-gebaseerde ruimte ontwerpe te verseker.

Thesis (PhDEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The interaction between moving water and the physical attributes of a river, as displayed by the channel morphology, determines the availability of physical habitat for aquatic species and thus also the condition of the ecosystem. As such, the environmental flow assessment process requires knowledge on how changes in the flow regime will affect both the morphological and hydraulic conditions within a river channel. With the increasing development of water-related infrastructure in mountain regions, knowledge of the morphological and hydraulic characteristics of rivers in the upper catchment areas is very important. Cobble and boulder bed rivers in the Western Cape are typical examples. They are characterized by steep gradients, great variability in sediment size and relatively low flow depths. The bed configuration contains a series of pools, steps, rapids, riffles and plane beds, while energy losses are high as a result of turbulence and hydraulic jumps. Due to their wideranging morphological and associated hydraulic attributes, the physical habitats within these rivers are extremely diverse, both on a spatial and temporal scale. This study addresses the interaction between moving water and the physical attributes of cobble and boulder bed rivers. Empirical, semi-empirical and theoretically based models are developed which define the hydraulic and morphological related characteristics of environmental flow components in cobble and boulder bed rivers. They cover macro scale channel deformation, the scouring of sand from the interstitial spaces between the cobbles as well as velocity-depth relationships, which prove to be key components in the assessment of environmental flow requirements in cobble and boulder bed rivers. / AFRIKAANSE OPSOMMING: Die wisselwerking tussen die vloeiende water en die fisiese eienskappe van 'n rivier, soos beskryf deur die morfologie, bepaal die beskikbaarheid van habitat vir akwatiese spesies en gevolglik ook die welstand van die ekosisteem. Kennis omtrent die impak van 'n veranderde vloei regime op beide die morfologiese en die hidrouliese toestande in 'n rivierloop is dus nodig vir die bepaling van omgewingsvloeibehoeftes. Met die toenemende ontwikkeling van water-verwante infrastruktuur in bergagtige gebiede is 'n grondige kennis van die morfologiese en hidrouliese eienskappe van riviere in hierdie bo-opvanggebiede gebiededend noodsaaklik. Spoelklip riviere in die Wes-Kaap is tipiese voorbeelde van sulke riviere. Hierdie riviere word gekenmerk deur steil hellings, 'n wye verskeidenheid sedimentgroottes, relatiewe lae vloeidieptes en hoë energieverliese as gevolg van turbulensie. Verder bevat die ri vierbed afwisselend poele en stroomversnellings en gevolglik word 'n wye verskeidenheid habitat tipes in hierdie riviere aangetref. Hierdie studie fokus op die interaksie tussen bewegende water en die fisiese eienskappe van spoelklip riviere. Met behulp van empiriese, semi-empiriese en teoretiese modelle word die morfologiese en hidrouliese eienskappe van omgewingsvloeibehoeftes in spoelklip riviere aangespreek. Dit sluit makroskaal kanaal vervorming, die uitskuur van sand tusen die spoelklippe asook die verwantskap tussen vloeisnelheid en vloeidiepte in. Hierdie aspekte kan beskou word as van die sleutel elemente vir die bepaling van omgewingsvloeibehoeftes in spoelklip riviere.

Thesis (PhD)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Suburbanisation is a world-wide phenomenon and is characterised by the decline of central business districts and accelerated growth of commercial activities in the suburbs. The impact of suburbanisation is wide-spread and multi-dimensional, affecting the whole urban system in terms of its structure, activity and transport patterns. In South Africa, suburbanisation, together with the impact of the former group areas policy, has made suburban developments less accessible to the low-income groups living on the edges of the metropolitan area. Planners have proposed various urban densification strategies for the rather unique problems of the spatially inefficient South African cities, including corridor development along main public transport routes and the development of activity nodes. In order to implement these urban densification strategies successfully, it is important to understand the locational choice behaviour of business managers, and the factors that will attract them to locate in a certain area. This will enable metropolitan authorities to evaluate and implement the best policies to promote development of priority corridors and nodes The research for this dissertation was motivated by the extensive problems of suburbanisation, the lack of knowledge on the relative impact of land-use transport factors on the locational choices of businesses, and the apparent limited application of stated preference (SP) survey techniques and discrete choice models to spatial choices of businesses for urban planning purposes. The main objectives of the research were to determine the locational choice behaviour of retail businesses in strategic spatial terms, and how this knowledge can best be used to manage suburbanisation. The dissertation reviews intemational and South African studies on the planning and policies of the main role players in the urban system relating to retail suburbanisation, i.e. the planning authority, retail firms and consumers. The dissertation discusses the results of the market research that was done among Cape Town retailers located in the CSO, and in low- and high-income suburbs. The survey collected quantitative information regarding the locational choice factors of retail managers, importance ratings of choice factors as well as stated preferences for CSO and suburban locations. The calibration results of various discrete locational choice models are discussed, including elasticities of choice factors obtained from model applications to the SP data. The development of a spreadsheet locational choice model based on typical characteristics of CSO and suburban locations is subsequently discussed. Elasticities of choice factors from the application of the spreadsheet model were determined and the model was also used to test a decentralisation trend scenario and a managed suburbanisation scenario. The dissertation makes conclusions and recommendations regarding the most important locational choice factors of retail managers, and the most effective policies and strategies for metropolitan authorities to manage suburbanisation and promote urban densification. The performance of SP models applied to spatial choices are also evaluated and recommendations are made regarding their application and further research needs. / AFRIKAANSE OPSOMMING: Stedelike desentralisasie is 'n wêreldwye verskynsel wat gekenmerk word deur die verval van sentrale sakegebiede (SSG) en die snelle groei van handelsbedrywighede in voorstede. Die impak van desentralisasie is verreikend en multi-dimensioneel en beïnvloed die hele stadstelsel in terme van sy struktuur, aktiwiteite and reispatrone. In Suid Afrika het desentralisasie saam met die impak van die voormalige groepsgebiedebeleid voorstedelike ontwikkelings minder toeganklik gemaak vir die lae-inkomstegroepe wat op die rand van die metropolitaanse gebiede woon. Beplanners het verskeie stadsverdigtingstrategieë, insluitende korridorontwikkeling langs hoofvervoerroetes en die ontwikkeling van aktiwiteitsnodusse voorgestelom die unieke probleme van die ruimtelik ondoeltreffende Suid-Afrikaanse stede die hoof te bied. Om hierdie stadsverdigtingstrategieë suksesvol te implementeer, is dit egter belangrik om die liggingskeusegedrag van besigheidsbestuurders, sowel as die faktore wat hulle beweeg om hulle in 'n spesifieke gebied te vestig, te verstaan. Hierdie kennnis sal metropolitaanse owerhede in staat stelom beleid te evalueer en die beste beleidsopsies te implementeer om die ontwikkeling van voorkeurkorridors en nodusse te bevorder. Die navorsing vir hierdie verhandeling is gemotiveer deur die omvattende probleme wat deur stedelike desentralisasie veroorsaak word, die gebrek aan kennis oor die relatiewe impak van grondgebruik-vervoerfaktore op die liggingskeuse van besighede, en die klaarblyklik beperkte toepassing van verklaardevoorkeuropnametegnieke (V V) en diskrete-keusemodelle op die liggingskeuses van besighede vir stadsbeplanningsdoeleindes. Die hoofdoelstellings van die navorsing was om die liggingskeusegedrag van kleinhandelbesighede in strategiese ruimtelike terme te bepaal en vas te stel hoe hierdie kennis gebruik kan word om stedelike desentralisasie te bestuur. In hierdie verhandeling word 'n oorsig gegee van die internasionale en Suid- Afrikaanse studies oor die beplanning en beleid van die belangrikste rolspelers in the stadstelsel wat desentralisasie van kleinhandel betref, naamlik die beplanningsowerheid, kleinhandelfirmas en verbruikers. Die resultate van marknavorsing onder kleinhandelaars vanuit Kaapstad se SSG en lae- en hoë-inkomstevoorstede, word bespreek. Die opname het kwantitatiewe inligting oor die liggingskeusefaktore van kleinhandelaars, die belangrikheid wat hulle aan keusefaktore heg, en hulle verklaarde voorkeure ten opsigte van vestiging in die SSG of die voorstede, ingesamel. Die kalibrasieresultate van verskeie diskretekeusemodelle word bespreek, insluitende die elastisiteite van keusefaktore wat deur die toepassing van die modelop V V-data verkry is. Vervolgens word die ontwikkeling van 'n liggingskeusemodel in 'n spreitabel wat op tipiese kenmerke van SSG- en voorstedelike liggings gebaseer is, bespreek. Elastisteite van die liggingsfaktore is bepaal deur die toepassing van die spreitabelmodel, en die model is ook gebruik om 'n desentraliasietendensscenario en 'n bestuurdedesentralisasiescenario te toets. Ten slotte word daar gevolgtrekkings en aanbevelings gemaak oor die belangrikste liggingskeusefaktore van kleinhandelaars, en die mees effektiewe beleidsopsies en strategieë wat metropolitaanse owerhede kan volg om stedelike desentralisasie te bestuur en stadsverdigting te bevorder. Die werkverrigting van V V-modelle wanneer dit op die liggingskeuse van besighede toegepas word, word ook geëvalueer en aanbevelings word gemaak oor die toepassing daarvan en verdere navorsing wat nodig is

Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: South Africa‟s hydrological and geographical characteristics, coupled with the location of a large part of its mineral endowment, required the development of the complex Vaal River Supply System, including inter-basin water transfer (IBT) projects which have been in operation for over twenty-five years. This research compares the actual water transfers of two such IBTs with their original, appraisal stage, predictions. Transfers are shown to be significantly less and also more variable than predicted. Further research reveals that the state of the receiving system has a large bearing on year-to-year decisions regarding transfers. Past appraisals, following what is called the Incremental Approach, do not adequately consider the likely future inter-basin transfer operating regime. Examination of six case studies, four South African, one Chinese and one Australian, shows that the Incremental Approach is still in general use – despite tools available for an improved approach. A new approach is proposed to upgrade estimations of variable costs associated with water transfers – often substantial life-cycle cost components of IBTs. The generally used unit reference value (URV) measure for appraising and ranking water resource projects in South Africa is also rooted in the economic theory of cost-effectiveness. This shows that the current approach is conceptually flawed; it fails to distinguish between water transfers and effectiveness outputs. The determination of the URV equation is expanded and improved. The upgraded appraisal approach, inclusive of the improved URV methodology, is named the Comprehensive Approach. A step-wise demonstration of the Comprehensive Approach is provided. Uncertainty regarding future water transfers and associated variable costs are provided for by stochastic simulation modelling. Decision analysis theory is applied to obtain the appropriate input value of variable costs. It is shown that the Comprehensive Approach can lead to an outcome significantly different from the Incremental Approach. The research provides new insights, placing water resource planning practitioners in a better position to recommend appropriate IBTs in future. These insights can also be transferred to the design of institutional and financial models related to IBTs, as well as the configuration and operation of supply systems including sea-water desalination projects. / AFRIKAANSE OPSOMMING: Suid-Afrika se hidrologiese en geografiese eienskappe, gekoppel aan die ligging van 'n groot deel van sy minerale bates, het gelei tot die ontwikkeling van die komplekse Vaalrivier Voorsieningstelsel, insluitend tussen-bekken oordragskemas waarvan sommige al vir meer as vyf-en-twintig jaar in werking is. Hierdie navorsing vergelyk die werklike wateroordragte van twee sulke oordragskemas met die oorspronklike vooruitskattings tydens die beplanning-stadium. Daar word getoon dat oordragte noemenswaardig minder en ook meer onreëlmatig was as wat voorspel is. Verdere ondersoek toon dat die stand van die stelsel, aan die ontvangskant, die besluitneming rakende die jaar-tot-jaar oordrag beïnvloed het. Historiese evaluerings het 'n “Inkrementele Benadering” (soos hier genoem) gevolg, wat nie voldoende die toekomstige bedryfsomgewing ten opsigte van tussen-bekken oordragte inagneem nie. Ondersoek van ses gevalstudies, vier Suid-Afrikaans, een Sjinees en een Australies, toon dat die Inkrementele Benadering nog algemeen in gebruik is, ten spyte daarvan dat hulpmiddels vir 'n verbeterde benadering beskikbaar is. 'n Nuwe benadering word voorgestel vir die verbetering van vooruitskattings van veranderlike koste wat met wateroordragte geassosieer word – dikwels 'n aansienlike gedeelte van die lewenssiklus-koste van sodanige skemas. Die Eenheidverwysingswaarde (EVW) maatstaf, wat algemeen in Suid-Afrika gebruik word om waterbronprojekte te beoordeel en in rangorde te plaas, word ook geanker in die ekonomiese teorie van koste-effektiwiteit. Daarmee word getoon dat die huidige gebruik van die EVW konsepsioneel gebrekkig is; dit tref nie 'n onderskeid tussen wateroordragte en effektiwiteitsuitsette nie. Die bepaling van die EVW vergelyking is verbreed en verbeter. Die opgegradeerde benadering, met insluiting van die verbeterde EVW metodiek, word die Omvattende Benadering genoem. 'n Stapsgewyse uiteensetting van die Omvattende Benadering word voorsien. Onsekerhede ten opsigte van wateroordragte en geassosieerde veranderlike koste word deur middel van stogastiese modellering aangespreek. Besluitnemingontledingsteorie word ingespan om die toepaslike insetwaarde van die veranderlike koste te bepaal. Daar word getoon dat die Omvattende Benadering tot 'n resultaat kan lei wat aansienlik verskil van wat met die Inkrementele Benadering verkry word. Die navorsing verskaf nuwe insigte wat die waterbronbeplanner in 'n beter posisie sal plaas om gepaste tussen-bekken oordragskemas voor te stel. Hierdie insigte kan ook oorgedra word na die ontwerp van institusionele en finansiële modelle rakende oordragskemas, asook die uitleg en bedryf van voorsieningstelsels, insluitend seewater-ontsoutingsaanlegte.

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The increased use of reclaimed asphalt (RA) in Bitumen Stabilised Materials (BSMs), shortcomings in the existing design guidelines and manuals and ongoing developments in the concepts and understanding of these materials require further research into the fundamental properties and behaviour of BSMs. The state-of-the-art of foamed bitumen techniques is reviewed in the literature study. Current best practices in the design of BSMs and pavements incorporating such materials are also included in this literature study. Shortcomings and areas for further improvement of the design practice have been identified. With new environmental legislation, the importance of BSM technology including RA as an environmentally-friendlier and more sustainable construction technique is set to increase in the coming years. Changes in the behaviour of materials and failure mechanisms of BSM mixes are long-term phenomena. This implies that the study of the physico-chemical and mechanical properties of the mixes with increasing amount of RA is vital. Therefore, fundamental understandings of moisture damage and thermo-physical characteristics, which are related to material properties, are required. The main objective of this study is to advance BSM technology by assessing the influence of the selected materials on durability behaviour, temperature distribution and long-term performance in all phases of application (i.e. mix design, construction, and in-service condition). This study begins with a comprehensive literature review of research dealing with the interactions between RA and mineral aggregates. The properties of RA and mineral aggregates were reviewed. This was followed by a review into the mechanical properties of BSM-foam mixes with high percentage of RA and its durability performance. Factors influencing the temperature gradient of BSMs were then identified. Achieving a better understanding of the fundamental performance properties and temperature influence on the behaviour of BSMs with high percentage of RA is one of the key factors of this research, with a view to using the extended knowledge for improvements to current mix design and structural design practices. Finally, the fundamental theories on thermo-conductivity and the mechanical properties of the BSM were used to create a relationship between temperature and mechanical properties in a pavement section. A laboratory testing programme was set up to study the properties and behaviour of BSMs and to establish links with the compositional factors, i.e. the type of binder used, the percentage of RA in the mix and the addition of a small amount of cement as active filler. BSMs were blended in three different proportions of RA and good quality crushed stone materials: 100% RA (with 2 % bitumen content), 50% RA and 50% G2 Hornfels crushed stone (with 2.1% bitumen content) and 100% G2 (with 2.3 % bitumen content). Tri-axial testing was carried out to determine shear parameters, resilient modulus and permanent deformation behaviour, while brushing testing was carried out to determine the possible durability performance of the BSMs. The mixture durability in terms of moisture damage was investigated. Temperature data were collected and a model to accurately simulate the temperature distribution in the BSMs was identified and proposed for further investigation and validation. It was found from the laboratory temperature data collected in this study that the temperature gradient varied according to the depth of the BSMs. A considerable part of the efforts of this study were dedicated to characterise and model the temperature distribution in a pavement section, taking into account the mechanical properties and performance of the BSMs at different temperature layers. The study provides an insight into fundamental mechanical performance, material durability properties, and the thermal capacity and conductivity of the BSM-foam mixes with high percentage of RA. This will assist in improving the current procedure for selection, combining and formulation of the mix matrices for BSMs. In addition, the study provides guidelines that will enable practitioners to confidently understand the relationship between temperature gradient and mechanical behaviours of BSM-foam pavement section. The specific durability-related issues addressed in this study are substance for future research. / AFRIKAANSE OPSOMMING: Die toenemende gebruik van herwonne asfalt (Engels: reclaimed asphalt (RA)) in bitumen gestabiliseerde materiaal (Engels: Bitumen Stabilised Materials (BSMs)), tekortkominge in die bestaande ontwerpriglyne- en handleidings en deurlopende verbeteringe in die konsepte en begrip van hierdie material vereis verdere navorsing oor die fundamentele eienskappe en gedrag van BSM. In die literatuurstudie word die huidige stand van kennis van die ontwerp van skuimbitumentegnieke ondersoek. Die literatuurstudie dek ook die huidige beste praktyke in die ontwerp van BSM en plaveisels wat hierdie materiale insluit. Tekortkominge en areas van verdere verbetering in die ontwerppraktyke is geïdentifiseer. Onlangse omgewingswetgewing verhoog die belangrikheid van BSM tegnologie, insluitend RA, as ‘n meer omgewingsvriendelike en volhoubare konstruksie-tegniek. Hierdie faktor sal in die toekoms al hoe belangriker word. Die verandering in die gedrag van materiaal en die falingsmeganismes van BSM mengsels is langtermynverskynsels. Dit impliseer dat die studie van die fisio-chemiese en meganiese eienskappe van mengsels met toenemende verhoudings van RA van kardinale belang is’n Fundamentele begrip van die vogskade en temo-fisiese eienskappe, wat verwant is aan die materiale se eienskappe, word vereis. Die primêre doelwit van die studie is die bevordering van BSM tegnologie deur die invloed van die geselekteerde materiale op duursaamheid, temperatuurverspreiding en langtermyn gedrag in al die fases van toepassing (mengselontwerp, konstruksie en in-dienstoestand) te bepaal. Die verhandeling begin met ‘n omvattende literatuuroorsig van navorsing oor die interaksie tussen RA en mineraalaggregate. Die eienskappe van RA en die mineraalaggregate word bespreek. Dit word gevolg deur ‘n oorsig van die meganiese eienskappe van die BSM-skuimbitumenmengsels met ‘n hoë persentasie RA en die duursaamheidgedrag daarvan. Faktore wat die temperatuurgradient van BSM beïnvloed word dan aangetoon. ‘n Beter begrip van die fundamentele gedragseienskappe en die invloed van temperatuur op die gedrag van BSM met ‘n hoë persentasie RA is een van die sleutelfaktore van hierdie navorsing. Dit het ten doel om die uitgebreide kennis te gebruik om huidige mengselontwerp en strukturele ontwerppraktyke te verbeter. Laastens is die fundamentele teorie van termogeleiding en die meganiese eienskappe van BSM gebruik om ‘n verhouding tussen temperature en meganiese eienskappe in ‘n plaveiselsnit te ontwikkel. ‘n Laboratoriumtoetsprogram is opgestel om die eienskappe en gedrag van BSM te bestudeer en om verwantskappe tussen samestellende faktore soos die tipe bindmiddel gebruik, die persentasie RA in die mengsel en die toediening van klein hoeveelhede sement as aktiewe vuller te bepaal. BSM is in drie verskillende verhoudings van RA en goeie gehalte gebreekte klipmateriaal vermeng: 100% RA met 2 % bitumen, 50% RA en 50 % G2 Hornfels gebreekte klip met 2.1 % bitumen en 100% G2 met 2.3 % bitumen. Drie-assige druktoetse is gebruik om skuifsterkteparameters, elastiese modulus en permanente vervormingsgedrag te bepaal. Borseltoetse is gebruik om die duursaamheidgedrag van BSM te bepaal. Die mengsels se duursaamheid is ook in terme van vogskade ondersoek.

Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: When a sailing ship passes a moored ship the moored ship experiences forces and moments. These forces and moments cause the moored ship to move. The resulting ship motions due to the passing ship can sometimes be more severe than the ship motions due to ocean waves and can cause serious accidents at moorings such as the failing of mooring lines or even the total break away of the ship from the berth. Since bulk carriers and tankers were traditionally the largest seafaring ships, passing ship studies have focused mainly on these vessels, but recently container ships have grown to a comparable size. In this study an existing numerical model “Passcat” is validated with physical model measurements for a Post Panamax container ship passing a Panamax bulk carrier. Other existing mathematical formulae are also evaluated by comparison with these model tests. In the physical model tests the passing speed (V), passing distance (G), depth draft ratio (d/D) and the presence of walls and channels were varied. It was found that the passing ship forces are proportional to the passing speed to the power of 2.32. This is slightly higher than the generally accepted quadratic relationship for passing ship induced forces. Similar relationships were found for the other variables. The numerical model results were compared to the physical model measurements by determining agreement ratios. A perfect agreement between the numerical and physical models would result in an agreement ratio of 1. Agreement ratio boundaries, wherein agreement would be regarded as good, were drawn between 0.7 and 1.3. The numerical model, Passcat, was found to under predict the passing ship forces. It was found that Passcat is valid for a wide range of sensitivities and remains within the agreement ratio limits as long as passing speed is limited to 10 knots (kt), depth draft ratio to more than 1.164, passing distance to less than four times the moored ship beam (Bm) for surge and sway estimation and passing distance to less than three times the moored ship beam for yaw estimations. These limits are true for no structures in the water. For structures in the water only the passing speed limits are different. When quay walls are present, the surge and sway forces will only provide acceptable answers at passing speeds below 9kt. When 9Bm or 12Bm channels are present, the sway force will only provide acceptable answers at passing speeds below 7kt. When a 6Bm channel is present, the yaw moments will only provide acceptable answers at passing speeds below 6kt. From the mathematical model evaluation study it was found that empirical or semi empirical methods can not provide answers with good agreement to the physical model when walls or channels are present. For the open water case, it is only the Flory method that can provide answers with good agreement to the physical model for surge, sway and yaw forces. The Flory method can provide answers with acceptable agreement within narrow boundaries of passing distance (1 to 2 times the beam of the moored ship), passing speed (4 kt to 14 kt) and depth draft ratio (less than 1.7). The numerical model, Passcat can be used with little effort to provide answers with better agreement to the physical model for a larger range of variables. / AFRIKAANSE OPSOMMING: Wanneer ’n skip verby ‘n vasgemeerde skip vaar, ondervind die vasgemeerde skip kragte en momente. Hierdie kragte induseer beweging van die vasgemeerde skip. Die beweging kan soms groter wees as die effek van wind of golwe. Indien die bewegings groot genoeg is kan dit van die vasmeer lyne van die skip laat breek, of al die lyne laat breek sodat die skip vry in die hawe ronddryf. Aangesien erts skepe en tenk skepe vir jare die grootste skepe in the wêreld was, het die meeste van die skip interaksie studies op daardie skepe gefokus. Die grootte van behouering skepe het egter in die onlangse tye gegroei om dimensies soortgelyk aan die van erts en tenk skepe te hê. In hierdie studie word ’n bestaande numeriese model “Passcat” gestaaf met fisiese model metings op ’n Post Panamax behoueringskip wat verby ‘n Panamax erts skip vaar. Bestaande wiskundige formules is ook getoets deur dit met dieselfde fisiese model metings te vergelyk. In die fisiese model studie is die spoed van die skip (V), tussenafstand (G), diepte diepgang verhouding (d/D) en die teenwoordigheid van kaai mure en kanale in die water getoets. Daar is gevind dat die kragte op die vasgemeerde skip direk eweredig is aan die spoed van die skip tot die mag 2.32. Dit is effens meer as die algemeen aanvaarde kwadratiese verhouding tussen vloeistof sleurkrag en vloeisnelheid asook tussen skip interaksie kragte en vaar snelheid. Soortgelyke verhoudings is vir al die veranderlikes bereken. Numeriese model resultate is vergelyk met die fisiese model om die verhouding van ooreenstemming te bepaal. ’n Perfekte ooreenstemming word voorgestel deur ’n verhouding van ooreenstemming van 1. Grense waarbinne die verhouding van ooreenstemming as goed beskou word is getrek tussen 0.7 en 1.3. Daar is gevind dat die numeriese model, Passcat, kragte oor die algemeen onderskat. Passcat is geldig vir 'n breë reeks van veranderlikes en sal geldig bly solank die skip spoed tot 10 knope, diepte diepgang verhouding tot meer as 1.164, tussenafstand tot minder as vier skipwydtes (Bm) vir 'surge' en 'sway' kragte en tot minder as drie skipwydtes vir 'yaw' momente beperk word. Hierdie grense is opgestel vir geen strukture in die water. Vir strukture in die water word slegs die skip spoed aangepas. Wanneer daar mure in die water is sal 'surge' en 'sway' slegs geskikte antwoorde gee as die skip spoed tot 9 knope beperk word. Vir 9Bm of 12Bm kanale sal geskikte antwoorde vir 'sway' kragte slegs voorkom met 'n skip spoed minder as 7 knope. Vir 6Bm kanale sal geskikte antwoorde vir 'yaw' momente slegs voorkom met 'n skip spoed van minder as 6 knope. Van die wiskundige model evaluasie studie is gevind dat empiriese of semi empiriese metodes nie resultate met goeie ooreenstemming tot the fisiese model metings kan gee, wanneer daar kaai of kanaal mure in die water is nie. Vir die oopwater geval is dit slegs die Flory metode wat antwoorde kan voorsien wat goed ooreenstem met die fisiese model vir 'surge', 'sway', en 'yaw' kragte. Die Flory metode voorsien hierdie resultate binne noue grense vir tussenafstand (1 tot 2 wydtes van die vasgemeerde skip), verbyvaar spoed (4 knope tot 14 knope) en diepte diepgang verhouding (minder as 1.7). Die numeriese model, Passcat, kan met min moeite antwoorde bereken wat beter ooreenstemming vir 'n groter reeks veranderlikes gee.