Thesis (Masters Diploma (Engineering))--Cape Technikon, 1997 / The idea for this study occurred when movement of the caisson extension to the breakwater was observed. The major concern was, what would happen if the caisson breakwater extension failed? What would the financial implications be to the port? The CSIR have carried out a number of studies with regards to the safety of the structure. The consequences of caisson failure and the possible effects on the port were however not investigated. When it was determined that settlement was taking place, information concerning the condition of the caisson structure and factors influencing the structure were gathered. Investigations on the following were done: (a) Extent of caisson settlement. (b) Sediment movement around the structure. (c) Foundation condition. (d) Wave impacts of long and short period waves on the Ben Schoeman Dock in the event of caisson failure. (Refraction and diffraction). (e) Financial implications due to possible container operation downtime at Ben Schoeman Dock in the event of caisson failure. (f) The tourist potential of the structure. The conclusion reached in this study was that the Ben Schoeman Dock would not be adversely effected if partial or complete failure of the main breakwater should take place. One could even question the length of the extension and whether it was actually required. The recommendations of this study would be as follows follows: Maintain the caisson extension in good condition as it will be important for possible future extensions to the port. Develop the breakwater as it is an asset which has potential for tourism to Cape Town.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Rigoberto Omar Romero. / M.S.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: For the safekeeping or harbouring of small craft, whether for leisure or commercial use, a tranquil basin is the principle requirement in designing a functional harbour facility. Waves transmitted through the perimeter structures of a marina result in agitation of the basin and thereby a reduction in tranquillity. Similarly, waves reflected off the perimeter structures that line entrance channels could result in difficulty when manoeuvring through the entrance channel water areas. An alternative to the conventional breakwater becomes a necessity when the conventional mass-filled or caisson breakwaters are not feasible in technical or financial terms. One of the alternative options could be to consider a piled row breakwater. In broad terms, this consists of closely spaced piles that attenuate wave energy whilst not forming an impermeable barrier, allowing for currents and sediment to pass through. When comparing the different options for creating a piled row breakwater the quantity of material used to achieve a desired level of wave dissipation could be the most important aspect in considering possible alternatives, as this would relate directly to construction costs and time when considering implementation. A literature review revealed multiple references to theories that predicted the transmitted and reflected waves for various breakwater porosities and wave conditions. However, there is limited coverage in literature enabling prospective designers. For example, literature describing the applicable ranges of shape configurations that one should start off with when developing concepts is not readily available. This thesis study used physical modelling to compare the wave transmission properties of breakwaters comprised of three different piled element shapes, namely round, square and diagonal square piles. The pile element shapes are compared for varying porosity values over a range of input wave parameters. A comparison of the transmission incurred by these configurations with previous work is presented and it was found that the physical model experiment closely simulated the predicted values. The tests were scaled from actual conditions in possible marina locations and therefore the performance criteria measured could be applied in reverse to potential site locations. From analysis of the physical model results, it was clear that the highest energy loss was found, in general, to occur with low porosities (below 10%), as could be expected. For a fixed screen configuration in terms of pile element shape and porosity, the performance is heavily dependent on wave steepness, the steeper waves incurring a lower transmission coefficient than the less steep waves. For a given porosity, circular piles performed the best (transmit the least) followed by square piles and then diagonal square. When comparing the material used, diagonal square piles yielded better performing breakwaters due to the expanded cross section gained in elevation. The work has provided useful insight into the performance of piled row breakwaters in restricting transmission of wave energy. Design guidance has been provided when considering the parameters for deriving conceptual layouts for piled row breakwater structures. Recommendations were put forward for further work in this field, including potential study areas, data gathering, and study methods, as well as more applied uses of piles, for example in combination with other elements in a marina. / AFRIKAANSE OPSOMMING: die veilige bewaring van klein vaartuie, hetsy vir ontspanning of kommersiële gebruik, is die hoofvereiste in die ontwerp van 'n funksionele hawe fasiliteit dat die beskermde hawegebied ‘n rustende water oppervlak sal moet handhaaf. Golwe wat oorgedra word deur die omtrek golfbrekers van ‘n hawe deur middel van transmissie veroorsaak oppervlak versteurings in die hawe bak en dus ook ongewensde versteurings in die vasmeer kondisies. Op ‘n soortgelyke wyse, veroorsaak golwe wat gereflekteer word vanaf die toegangs kanaal golfbrekers problematiese kondisies vir die navigeer van bote deur die kanaal. Die behoefte aan 'n golfbreker alternatief vir die konvensionele oplossing word genoodsaak wanneer die konvensionele stortrots of caisson golfbrekers nie haalbaar is nie as gevolg van tegniese of finansiële aspekte (Park et al. 2000). Een van die opsies wat oorweeg kan word as 'n alternatief is ‘n heipaal-ry tipe breekwater. In breë terme, bestaan dit uit naby gespasieërde heipale om golf energie te breek, sonder om ‘n ondeurdringbare versperring te vorm. Wanneer die verskillende opsies vir die skep van 'n heipaal-ry tipe breekwater vergelyk word, kan die hoeveelheid konstruksie materiaal benodig per opsie die belangrikste vergelykende parameter word. Die rede hiervoor is die direkte verwantskap aan konstruksie kostes sowel as tyd aspekte wat gepaardgaan met die konstruksie materiaal hoeveelhede. Vanuit die literatuurstudie is verskeie verwysings geïdentifiseer waarin vorige teorieë oor oordrag en refleksie van golwe evalueer word vir wisselende porositeit waardes en intree golf waardes. Daar is egter 'n beperkte dekking in die literatuur wat ontwerps-riglyne betref. Byvoorbeeld, die toepaslike omvang van die vorm konfigurasies wat oorweeg moet word wanneer konsep ontwerp gedoen word, is nie geredelik beskikbaar nie. Hierdie tesis vergelyk, deur middel van fisiese skaal model toetse, drie heipaal-ry element vorms, naamlik ronde, vierkantige en diagonal geroteerde vierkante vir verskillende porositeit waardes oor 'n verskeidenheid van golf inset parameters. 'n Vergelyking is getref tussen die toetsdata en vorige werk en daar is bevind dat die fisiese model eksperiment die voorspelde waades uit die literatuur redelik akkuraat kon naboots. Die toets kondisies is geskaal vanaf werklike moontlike marina terreine en dus kon die toets resultate toegepas word in die ontwerp van potensiële terreine. Vanuit die data-analise, is waargeneem dat die hoogste energie verliese oor die algemeen plaasvind by laer porosititeit waardes (onder 10%) soos wat verwag kon word. Vir 'n gegewe golfbreker opset, in terme van die heipaal element vorm en porositeit, is die verrigting hoogs afhanklik van die golf steilheid, met hoër verrigting by steiler golwe. Vir 'n gegewe porositeit, sal ronde heipaal elemente die beste verrigting gee, gevolg deur vierkante heipale en laastens diagonal geroteerde vierkante. Vir soortgelyke hoeveelheid heipale, sal diagonal geroteerde vierkante beter verrigting lewer moontlik as gevolg van die verlengde deursnit dimensie in vooraansig. Hierdie navorsing het goeie insig verskaf oor golfdeurlaatbaarheid en weerkaatsing van heipaalry breekwaters. Ontwerp riglyne word ook verskaf wat betref die parameters wat gebruik kan word vir die konsep ontwikkelings fase vir heipaal-ry breekwaters. Aanbevelings word gemaak vir verdere navorsingswerk in hierdie veld, insluitend moontlike studie-areas, data insameling, studie metodes, sowel as vir meer toegepasde situasies, byvoorbeeld waar die heipaal elemente in kombinasie met ander marina komponente ontwerp moet word.

L’objectif de cette thèse était de proposer une contribution dans le domaine de la modélisation du comportement de digues flottantes permettant d’optimiser le positionnement et le dimensionnement de ces structures. La finalité étant de participer à la définition d’outils d’aide à la décision pour l’aménagement portuaire destiné à la protection des installations. Nous avons proposé un nouveau modèle de comportement de digues flottantes. Ce modèle de comportement simple et efficace combine deux modèles. Le premier est un modèle de Berkhoff étendu et amélioré qui prend en compte les effets de frottement au fond, de bathymétrie fortement variable et de déferlement. Il permet d’évaluer dans le plan horizontal du port la propagation de la houle. Le second est un modèle décrivant le comportement hydrodynamique d’une digue flottante dans le plan vertical de sa section transversale. Une étude paramétrique a permis de valider globalement ce nouveau modèle. Nous avons proposé ensuite une démarche d’optimisation spécifique basée sur une formulation multicritère du problème d’optimisation et utilisant des techniques de méta modélisation et un algorithme stochastique pour accélérer les calculs. Le front de Pareto obtenu permet pour un port donné, de déterminer la capacité maximale d’absorption de la houle et les dimensions de la plus petite digue / The objective of this thesis is to add a contribution in the field of modeling of the behavior of floating breakwaters, in order to optimize the positioning and sizing of these structures. It is aimed to participate in the definition of the decision making techniques in harbor development intended to the protection of installations. A new model for the behavior of floating breakwaters is proposed. This simple and efficient behavior model combines two models: The first is an extended and improved Berkhoff model that takes into account the effects of bed friction, highly variable bathymetry and wave breaking so that the propagation of waves in the horizontal plane of harbor is evaluated. The second model describes the hydrodynamic behavior of a floating breakwater in the vertical plane of its cross section. A parametric study is used to globally validate the new model, after which a specific optimization approach based on a multi criteria formulation of the optimization problem is proposed. Meta-modeling techniques and stochastic algorithm are together employed to speed up the calculations. The obtained Pareto front allows, for a given harbor, to determine the maximum absorption capacity of waves and the dimensions of the smallest breakwater

Thesis (MEng)–Stellenbosch University, 2014. / ENGLISH ABSTRACT: The Port of Durban is forecasted to reach its capacity in terms of container handling soon, which necessitates the investigation of an alternative port in the vicinity. The old Durban Airport site has been identified as a potential location to develop a new deep water container harbour. This is driven by a demand for deep water berth capacity as a result of shipping liners preferring the benefits of scale in their operations, leading to the use of larger ships with deeper drafts. To protect the new port from wave energy penetrating inside the basin as well as from sedimentation from the adjacent beaches, the design and construction of breakwaters are required. The proposed main breakwater for this dig-out port is expected to extend 1 200m into the sea, up to depths of 30m at the seaward roundhead. The deeper parts of the breakwater face wave onslaught in a different manner than a conventional breakwater in shallower waters. At these larger depths, the breakwater has to dissipate the energy of non-breaking waves. In this thesis, the wave climate nearshore, adjacent to the proposed breakwater is studied and extreme wave events are simulated with a SWAN numerical model. The results for a range of wave conditions, corresponding to selected events up to a return period of one in 100 years, are presented. A study of deep water breakwaters was undertaken to investigate other examples of similar structures. This indicated a clear distinction between vertical wall type breakwaters and the more traditional rubble-mound type breakwaters. For this thesis, a rubble-mound breakwater was chosen as the breakwater type for testing under conditions of the Durban Dig-Out Port (DDOP). Focussing on a deep water trunk section of the proposed main breakwater, a concept cross-section was designed using deterministic design methods. The formulae incorporated in this method did however not take into account the packing density of the armour layer and only assumed the recommended values. The hypothesis is thus put forward that the breakwater will still be hydraulically stable for packing densities below the recommended values. This would decrease material consumption and save on cost over the entire breakwater. A physical model was designed to experiment with different armour layer configurations of single- and double layer Cubipod arrangements. The unit was chosen for its massive shape and structural integrity even during impact. A physical model study was performed at the facilities of the CSIR in Stellenbosch. It entailed setting up a fixed-bed two-dimensional physical model in a glass wave flume. Measuring wave heights, wave reflection, overtopping, wave transmission and armour damage, the hydraulic stability and operational performance were analysed for several tests. Based on the results of the first few test series, alterations were made to the breakwater geometry and armouring. The results confirmed the hypothesis that lower packing densities were still hydraulically stable under 1 in 100 year return period wave conditions without inhibiting operational performance. A final cross-section is presented as concept design for the deep section of the proposed DDOP main breakwater. / AFRIKAANSE OPSOMMING: Volgens vooruitsigte gaan Durban hawe binnekort sy kapasiteit bereik wat die hantering van skeepshouers betref. Hierdie verwikkeling noodsaak die ondersoek na ‘n alternatiewe hawe in die nabye omgewing. Die voormalige Durban lughawe is intussen geïdentifiseer as ‘n potensiële perseel waar ‘n diep water houervrag hawe ontwikkel kan word. Dit word gedryf deur die aanvraag na diep water kaai kapasiteit as gevolg van skip operateurs wat skaalvoordele verkies, sodat groter skepe met diep rompe meer populêr word. Die ontwerp en konstruksie van breekwaters word dus benodig, om te verhoed dat beide golwe, sowel as sediment van aangrensende strande, die hawe binnedring. Die voorgestelde hoof breekwater vir hierdie hawe sal na verwagting tot 1200m in die see in strek, waar dit tot 30m diep is naby die seewaartse hoof van dié breekwater. Die dieper gedeeltes van só ‘n breekwater sal blootgestel word aan ‘n ander soort golf aanslag as ‘n soortgelyke konvensionele breekwater in vlakker water. In hierdie waterdiepte is die breekwater verantwoordelik vir die energie verbreking van ongebreekte golwe. In hierdie tesis word die golfklimaat langs die kus, naby aan die voorgestelde breekwater bestudeer. Die uiterste golf gebeurtenisse word gesimuleer met ‘n SWAN numeriese model. Die resultate van ‘n reeks golf kondisies, ooreenstemmend met bepaalde gebeurtenissemet herhaal periodes van tot 100 jaar, word aangebied. ‘n Studie van diep water breekwaters is onderneem om voorbeelde van soortgelyke strukture te ondersoek. Die studie toon ‘n definitiewe onderskeid tussen vertikale muur breekwaters en die meer tradisionele “rubble-mound” breekwater tipes. Vir hierdie tesis is die “rubble-mound” breekwater tipe gekies vir toetsing, onderhewig aan die kondisies van die “Durban Dig-Out Port” (DDOP). ‘n Konsep deursnit is ontwerp vir ‘n diep water romp gedeelte van die voorgestelde hoof breekwater, deur van deterministiese metodes gebruik te maak. Die formules soos vervat in hierdie proses maak egter nie voorsiening vir die pakdigtheid van die bewapeningslaag nie, maar aanvaar slegs die voorgestelde waardes. Die hipotese word dus aangevoer dat die breekwater steeds hidrolies stabiel sal wees vir pakdigthede wat laer as die voorgestelde waardes is. Dit sal die verbruik van materiale verlaag en lei tot koste besparings vir die breekwater. ‘n Fisiese model is ontwerp om te eksperimenteer met verskillende opstellings van die bewapeningslaag. Dit sluit enkel- en dubbel laag bewapening met Cubipod eenhede in. Hierdie eenheid is gekies vir sy massiewe vorm en strukturele integriteit, selfs tydens impak. ‘n Fisiese model studie is uitgevoer by die fasiliteite van die WNNR in Stellenbosch. Dit het die opstel van ‘n vaste-bodem, twee-dimensionele fisiese model in ‘n glas golftenk (“wave flume”) behels. Hidroliese stabiliteit en operasionele werksverrigting is geanaliseer deur golf hoogtes, -weerkaatsing, -oorslag, -deurlating, en skade aan die bewapening te meet vir verskeie toetse. Gebasseer op die resultate van die eerste paar toetsreekse, is veranderinge gemaak aan die breekwater se geometrie en bewapening. Die resultate het die hipotese bevestig dat laer pakdigthede steeds hidrolies stabiel is tydens golf kondisies met ‘n 1 in 100 jaar herhaal periode, sonder om die werksverrigting van die breekwater te belemmer. ‘n Finale deursnit word voorgestel as ‘n konsepontwerp vir die diep water deursnit van die DDOP se hoof breekwater.

Computer based simulation models have often been used to study the multimodal freight transportation system. But these studies have not been able to dynamically couple the various modes into one model; therefore, they are limited in their ability to inform on dynamic system level interactions. This research thesis is motivated by the need to dynamically couple the multimodal freight transportation system to operate at multiple spatial and temporal scales. It is part of a larger research program to develop a systems modeling framework applicable to freight transportation. This larger research program attempts to dynamically couple railroad, seaport, and highway freight transportation models. The focus of this thesis is the development of the coupled railroad and seaport models. A separate volume (Wall 2010) on the development of the highway model has been completed. The model railroad and seaport was developed using Arena® simulation software and it comprises of the Ports of Savannah, GA, Charleston, NC, Jacksonville, FL, their adjacent CSX rail terminal, and connecting CSX railroads in the southeastern U.S. However, only the simulation outputs for the Port of Savannah are discussed in this paper. It should be mentioned that the modeled port layout is only conceptual; therefore, any inferences drawn from the model's outputs do not represent actual port performance. The model was run for 26 continuous simulation days, generating 141 containership calls, 147 highway truck deliveries of containers, 900 trains, and a throughput of 28,738 containers at the Port of Savannah, GA. An analysis of each train's trajectory from origin to destination shows that trains spend between 24 - 67 percent of their travel time idle on the tracks waiting for permission to move. Train parking demand analysis on the adjacent shunting area at the multimodal terminal seems to indicate that there aren't enough containers coming from the port because the demand is due to only trains waiting to load. The simulation also shows that on average it takes containerships calling at the Port of Savannah about 3.2 days to find an available dock to berth and unload containers. The observed mean turnaround time for containerships was 4.5 days. This experiment also shows that container residence time within the port and adjacent multimodal rail terminal varies widely. Residence times within the port range from about 0.2 hours to 9 hours with a mean of 1 hour. The average residence time inside the rail terminal is about 20 minutes but observations varied from as little as 2 minutes to a high of 2.5 hours. In addition, about 85 percent of container residence time in the port is spent idle. This research thesis demonstrates that it is possible to dynamically couple the different sub-models of the multimodal freight transportation system. However, there are challenges that need to be addressed by future research. The principal challenge is the development of a more efficient train movement algorithm that can incorporate the actual Direct Traffic Control (DTC) and / or Automatic Block Signal (ABS) track segmentation. Such an algorithm would likely improve the capacity estimates of the railroad network. In addition, future research should seek to reduce the high computational cost imposed by a discrete process modeling methodology and the adoption of single container resolution level for terminal operations. A methodology combining both discrete and continuous process modeling as proposed in this study could lessen computational costs and lower computer system requirements at a cost of some of the feedback capabilities of the model This tradeoff must be carefully examined.