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The area of the Merwedes is a transition zone between a tide-dominated area and a river-dominated area. With increasing river discharge, the influence of river flow dominates in this part of the Rhine-Meuse Delta. The composition of the river bed of the Merwedes is also a transitional area, because of the presence of both sand and mud. It is unknown how sediment transport and morphology in this area are influenced by the complex interaction of tidal flow and river flow. To be able to explain the morphological changes in the area of the Merwedes and to be able to anticipate on these changes, there is a need for better understanding of the hydraulic and mor-phological processes. This study contributes to a refinement of the system description of the Rhine-Meuse Delta by determining the influence of the tide on sediment transport and bed level in the river Merwedes. The aim of this graduation research is to gain insight into the contributions of tidal flow and river flow to sediment transport and bed level changes in the Merwedes, with a view to application of the obtained knowledge to Room for the River projects in this reach. The Room for the River project ‘floodplain excavation Avelingen’ has been chosen as case study. Three methods have been used to gain insight in the contribution of the tide to sediment transport and bed level changes in the Merwedes: (1) analysis of simulated flow, (2) analysis of simulated sediment transport, (3) analysis of simulated bed level changes. The following ranking has been determined with respect to the relevance for one-dimensional morphological modelling of the Merwedes: (1) including variations in river discharges, (2) the choice of a accurate sediment transport model, (3) including the tidal influence in the Waal and Merwedes, (4) including salt intrusion in the Rhine-Meuse Delta, (5) using a spring-neap cycle instead of a less detailed tidal cycle as sea boundary condition. These adjustments improve the simulation of the autonomous development of the bed level of the Merwedes. This ranking ap-plies to the yearly sediment transport. However, the ranking of modelling aspects varies between the Merwedes at specific river discharges. Both variations in river discharge and the tidal influence should be included in morphological studies of the Merwedes, because of interaction between river flow and tidal flow. The influence of the tide on sediment transport in the Merwedes can best be represented by a spring-neap cycle. However, a less detailed tidal cycle is a reasonable approximation of the tidal influence on sediment transport in the Merwedes.

For a proper management of rivers and river bends in particular, it is important to have good models to predict the flows through bends. It is important that those developed models are well validated with measurements to demonstrate the usefulness of the models. This research is a validation of the Delft3D-FLOW model which is a model that is often used in practice. For the validation, detailed measurements of flows through a sharp bend (radius/width < 2 a 3) flume, performed at the EPFL (Lausanne, Switzerland) and Large Eddy Simulations (LES) conducted at the TU Delft are used. The objective of this study is to analyze to what extent Delft3D-FLOW is able to predict the hydrodynamic processes in sharp open channel bends. This study contains the comparison of several important quantities of Delt3D-FLOW simulations, measurements and LES

This study extends the theoretical approach developed by JUMELET [2010] to acquire a physical description of the notional permeability coefficient applied in the VAN DER MEER stability formulae [1988]. Van der Meer introduced this coefficient to ensure that the permeability of the structure is taken into account, however due to the empirical character of Van der Meer equations and because prior to Jumelet's research there was not an available physical description of the notional permeability factor, the determination of this factor was rather vague. Because of the fact that the stability relationship includes the P-coefficient, it has to be estimated somehow and, therefore, the research carried out by JUMELET [2010] is, to some extent, the starting point to achieve the required physical description of the notional permeability coefficient. To obtain this physical description, the volume-exchange model is introduced, in which the external and internal processes that take place within a breakwater are coupled. The external process is described by a wave run-up model while the internal process is described by the „Forchheimer‟ equation for the water flow through a porous medium. According to JUMELET [2010], the notional permeability parameter P is highly related to the run-up reduction coefficient from the volume-exchange model, and thus Jumelet defines an expression for this coefficient by means of coupling the notional permeability factor with the volume-exchange model. Because of the simplicity of the notional permeability coefficient formula developed by JUMELET [2010], further research is required to analyze the actual correlation between the notional permeability factor and the so-called run-up reduction coefficient (obtained from the volume-exchange model). This study focuses on developing a general formula for the notional permeability coefficient based on JUMELET [2010] and analyzing the real influence of the hydraulic parameters and structural properties on the P-factor. As stated by JUMELET [2010], the permeability of the structure depends not only on the structural properties but also on the hydraulic parameters. In this way, a physical description of the notional permeability coefficient is given and can be applied in Van der Meer stability equations to design breakwaters. Moreover, a damage level analysis has been performed to compare the observed damage by VAN DER MEER [1988] with the estimated damage through the combined method of Jumelet's model, the generalized formula for the notional permeability coefficient and Van der Meer stability equations, which leads to introducing the combined method as a tool to determine the maintenance policies in breakwaters by taking into account the damage that waves causes on them.

In many coastal engineering problems the application of coastal structures to resolve these problems seems to be a proper solution. In a lot of cases, however, the implementation of coastal structures does not lead to the expected situation. Erosion management operations may have unwanted impacts on a coastal system. Decisions on the most appropriate management approach at a given site should be driven in part by the desire to minimise these impacts so as to preserve the natural characteristics of the coast. It is important to bear in mind that erosion of beach and dune areas is a natural and dynamical process and normally should not be regarded as a problem. Problems only arise when erosion threatens human activities or assets, or when the erosion is the result of human interference with coastal processes along an adjacent frontage. A profound study of the actual processes causing the problem should always precede the design of the structure itself. This report intends to provide some clear guidelines to facilitate the design process of coastal structures by discussing several cases and relevant design aspects that seem to be obvious but could easily be overlooked. Especially the recognition of the mechanisms that cause the occurring problem takes a central part in the design process of coastal engineering measures and thus the main emphasis of this report is to awaken consciousness of the mechanisms involved. The cases as discussed in this report are all examples of actual problems. Every solution has its impact on the morphological balance of the coastal zone; this report describes these impacts. It becomes clear after studying all cases that measures to resolve coastal engineering problems are very complicated and adverse effects can be expected in many cases. The main purpose of this report is to make decision-makers in coastal engineering matters aware of the complications that are involved.

This thesis studies cost estimation and investment decisions under cost uncertainty of large construction projects. The combination of these two topics intends to satisfy the Master’s theses of Civil Engineering at the Delft University of Technology and Quantitative Finance (Econometrics) at the Erasmus University Rotterdam. The first part relates to the Delft University of Technology, the second to the Erasmus University Rotterdam. Both parts are interrelated but can be read separately. Part A develops a model for APM Terminals to estimate costs of new terminals investments. Present-day estimates of APM Terminals insufficiently incorporate risk. Therefore, the study formulates and analyses six (new) estimation models. Differences in the model include the use of error distribution function or the incorporation of interdependency. The analysis subjects the models to various constraints and selects the most appropriate model for APM Terminals. The selected model requires little input information, uses normally distributed error distributions and accounts for shocks. Moreover, the study points out shocks are of great importance in the estimation of costs. Shocks increase expected costs and mainly determine cost uncertainty. The change of estimation model and occurrence of shocks implies that APM Terminals changes its estimation process. The new approach requires an estimate of both expected cost and uncertainty to estimate construction costs. Part B studies investments of projects subjected to cost uncertainty. Prior to construction investors have an idea of the value but not of the costs. Academic research assumes that cost uncertainty is composed of technical and input uncertainty (Pindyck (1993)). Technical uncertainty covers the physical difficulty to complete the project and is only known after completion. Input uncertainty relates to the pricing uncertainty of the required commodities to complete the project and is known beforehand. This study adds shocks to uncertainty because of the significant contribution to uncertainty (Part A). The research argues that shocks are a special form of technical uncertainty. Shocks occur after investing and complicate physical completion. But where technical uncertainty can accelerate construction, shocks solely delay progress. The study uses option theory to examine investments subjected to the different types of uncertainty. The analysis defines optimal investments and shows shocks increase the aversion to invest.

Multilayered Safety (MLS) is seen as the next step in Dutch flood risk management. In the last decades the idea that only flood defenses can prevent floods gave way to the realization prevention can also be implemented along other lines, e.g. giving the rivers more space. The next thought was that next to preventing floods it should be possible to reduce the loss due to flooding. Therefore, MLS is meant to introduce comprehensive flood risk management by implementing three layers, or put differently safety nets: 1. Prevention (dikes, space for rivers, etc.), 2. Spatial Solutions (flood-proofing houses, elevating houses, re-locating etc.), 3. Crisis Management (evacuation, warning, etc.). Before this study, there was no academic interpretation of MLS and it had never been tested comprehensively. Consequently, a theoretical framework is being developed in this thesis to be able to model MLS. This is followed by a hypothetical case study and additional one for the City of Dordrecht to examine the actual effect of MLS on the flood risk and its cost-efficiency. It was found that theoretically MLS is indeed an alternative to only Prevention. Furthermore, it introduces the option to better customize flood risk management to local circumstances. By doing so, flood risk management becomes more cost-efficient. As the cost-efficiency is found to be dependent on the initial safety level, it is concluded that in the Netherlands MLS only has the potential to supplement the existing flood protection. In areas with a heavy implementation of flood defenses like in Dordrecht, MLS is fit to complement flood risk management rather than replacing the prevailing Prevention approach. However, to do so (local) authorities need to be able to base their flood management policies on flood risk, e.g. by benchmarking a certain Individual Risk.

De provincie Zuid-Holland wil de bereikbaarheid van de regio waarborgen en daarom het goederenvervoer over water stimuleren. Dit afstudeeronderzoek bevat een netwerkanalyse om de knelpunten bloot te leggen. Het aanbod van de infrastructuur heeft beperkingen. Vernauwingen, krappe bruggen, scherpe bochten en spitsuursluitingen zorgen er voor dat de gemiddelde reistijd van een schip laag is. Voor een betere benutting van de vaarweg dient ook de vraag naar vervoer over water te steigen. Naast korte en betrouwbare reistijden is het belangrijk dat bedrijven zich dicht bij de vaarweg vestigen en een losvoorziening hebben aan het water. Qua oplossing voor een snellere en betrouwbaardere reistijd kunnen knelpunten opgelost worden door de vaarweg en bruggen te laten voldoen aan een bepaald profiel. Daarnaast hebben sommige gemeenten het plan om de industrielocaties te verplaatsen. Ook het opheffen van de spitsuursluiting zorgt voor een vlottere reistijd. Echter een spitsuursluiting is ingesteld om de wachttijd van kruisend verkeer te voorkomen. Voor de vaarweg van Rotterdam naar Den Haag is een model-studie gemaakt, waarbij diverse scenario’s zijn door-gerekend. De gemiddelde reistijd, afwijking van de reistijden en de wachttijden voor het kruisend wegverkeer vormen de belangrijkste uitvoer. Uit deze modelstudie bleek dat de beoogde reistijdverkorting (circa 10%) alleen gehaald kan worden als er gesleuteld wordt aan de spitsuursluiting. Echter de wachttijden voor het kruisend verkeer neemt toe. Om de wachttijd te beperken dient voor enkele stroomwegen de spitsuursluiting gehandhaafd te blijven. Daarnaast dient men een maximale openingsduur van 5 minuten te hanteren. Echter door deze maatregelen moet men ook een aantal fysieke knelpunten, zoals vernauwingen en een scherpe bocht, oplossen om zo de gewenste reistijd te halen.

De Maas kent een aantal waterbouwkundige kunstwerken die het einde van hun ontwerp levensduur van 50 tot 100 jaar naderen. Het is daardoor van belang te bepalen wat de huidige conditie van de kunstwerken is om de betrouwbaarheid van de Maascorridor te waarborgen. Om de huidige conditie van de kunstwerken te bepalen, dienen de constructieve elementen conform de voorschriften getoetst te worden. De uitkomst van de toetsing van een elementen geeft aan of het element wel of niet voldoet aan de voorschriften. Het resultaat zegt niks over de betrouwbaarheid van een element. Het doel van het onderzoek is: Het komen tot een algemene relatie tussen de “Unity Check” van onderdelen van natte kunstwerken en de faalkansen, dat uiteindelijk voor elk onderdeel toegepast kan worden, om zo tot een nauwkeurige faalkans voor de corridor te komen die op een snelle manier toegepast kan worden. In dit onderzoek wordt uiteindelijk gewerkt vanuit de basis van de relatie naar de relatie voor een aantal case studies. Voor het modelleren van de case studies moeten de kansverdelingen met bijbehorende verdelingsparameters voor de stochastische variabelen bepaald worden. Voor en deel van de stochastische variabelen is in het verleden al onderzoek naar gedaan. De sterkte van materiaal en afwijkingen in de dimensies zijn variabelen waarvoor al onderzoek is gedaan, maar belastingen zijn erg situatie afhankelijk, waardoor hiervoor in dit onderzoek extra aandacht aan besteed is. In dit onderzoek zijn voor twee stuwen in de Maas een aantal stalen en op druk belaste betonnen elementen als case studies genomen. De uitkomsten van de probabilistische berekeningen (uitgedrukt in betrouwbaarheidindices) zijn vergeleken met de unity checks van de elementen. De resultaten zijn gecategoriseerd om uiteindelijk de betrouwbaarheidsindex voor de unity check te kunnen bepalen.

It is common practice to protect subsea pipelines by embedding them into the soil. Trenches can be made before or after the pipelines have been laid. In the latter case, the excavation process is called post-trenching. The essence of post-trenching, as handled in this thesis, is erosion of sand by a water-jet. The literature study focused on the processes of jets and erosion. A lot of research has been done in the field of water jets and useful information is widely available. Nevertheless the available information on the subject of impinging jets is rather limited and the validity remains questionable. Water jets used for post-trenching create high flow velocities for which the traditional erosion equations are not valid. Therefore use is made of a special set of equations for high speed erosion. With the information provided by the literature study a description of jetting in sand was made. The known processes were arranged resulting in a set of equations. Following the rules for scaling the set of equations was converted into a properly scaled model. Preliminary model tests were conducted to observe the jet-process and narrow down the possible jet angles. These preliminary tests were followed by scale model tests to determine the erosion depth for different nozzle angles, flow velocities etcetera. A numerical model was developed to simulate jet-induced erosion. Since the erosion equations, making use of the average flow velocity, could not model the erosion behaviour of a jet, a turbulence term was introduced. The results of the simulations were compared with the model tests. Though the numerical erosion model showed promising results, it could not be validated due to a lack of data. The most important conclusions are that soil can be eroded to the desired depth, a data-set has been created and much insight is gained with respect to the post-trenching process. Last but not least, a numerical model was made that can prove to be useful after better validation.

Richards Bay Port, located in the East Coast of South Africa, was built during the 1970s. Two rubble mound breakwaters were constructed to protect the deep-water entrance channel and create a sheltered area for the vessels. Since the completion of these breakwaters in 1976, they have withstood several major storms, including cyclones that have caused significant damage to the dolos armour layers. To restore their functionality, two major reparations were carried out in 1976 and 1996, respectively. In addition, a severe storm that occurred in March 2007 caused relevant damages to the breakwaters of Richards Bay Port. Their damage level was established after the survey conducted in May 2007. This survey concluded that most of the breakwaters sections had an intermediate damage, except from the South Breakwater’s roundhead, which was in failure and it required urgent repairs. Since then provisional measures have been adopted to avoid the spread of damage along the breakwater while new repair works are designed. The main objective of this thesis was to determine the most suitable design for the repair works that should be applied in the roundhead of the South breakwater at Richards Bay Port through a Quasi Three-Dimensional (3D) model testing. This was achieved by reproducing the observed damage at the structure’s roundhead in one of CSIR’s hydraulic laboratory flumes and testing three repair alternatives. These repair alternatives consisted of covering the damaged structure with new armour units. Dolos, Core-Loc and antifer cubes were the armour units used in this research. The wave basin used to conduct this research had a length of 32m, a width of 4m and an available height of 1m. A transitional slope of 1:15 that extends about 4.5m long was built inside the basin to connect the deep water with the shallower water close to Richards Bay Port. Thereafter, the seabed profile corresponding to the South East direction was constructed along the next 20m of the basin. The structure was placed at a distance of 26m from the wavemaker. Graded gravel was used to construct the core, underlayer and toe protection of the roundhead, with a nominal size of 4.2g, 4.8g and 12.2g, respectively. The existing armour layer was built using dolos of 68g and gravel that represented the broken pieces. Above this damaged armour layer, the new armour units were placed with a nominal size of 82g for the dolos, 102g for the Core-Loc and 100g for the antifer cubes. The new armour units were placed trying to replicate the placement conditions at the roundhead. A total of 8 to 9 tests were conducted per armour unit. Five wave conditions were tested with increasing significant wave heights varying from 7cm to 18cm. Two water levels were set up per wave condition (High Water and Low Water). The tested wave conditions were generated with a JONSWAP spectrum and a duration that corresponded to a 1000 waves approaching the structure. Prior to and after each test, pictures were taken from three fixed positions perpendicular to the roundhead. These images were visually compared with the Armour Track software developed by CSIR to identify and quantify the movement of the armour units. This software is based on the superposition technique and it is useful to determine the stability of the structure. For each test, the stability number and the measured damage within the reference area were estimated. Generally the movements of the units occurred along the water line. However for higher wave heights (return periods of 20, 50 and 100 years), the waves overtopped and the damage started to concentrate in an area located between the angles 120 and 150 degrees from the direction of the incident wave, until failing with the overload condition. From these experiments it followed that the Core-Loc repair alternative does not perform as good as the other two options. Although all the repair options have difficulties to achieve the placement requirements at the roundhead, this phenomenon has a larger impact in the Core-Loc armour layer because it consisted of a single layer and any unit displacement resulted in failure of the structure. Therefore repairs should be undertaken more frequently, which leads to larger maintenance costs. The remaining repair options had a similar performance, even though the resistance mechanism of dolos and antifer cubes is different. The first one resists by the interlocking between the units, whereas the antifer cubes resist by their mass. Both are placed as double armour layers and thus some damage is allowed before carrying new repair works. The main difference between them is the actual feasibility to construct the units. The antifer cubes do not have any size restriction. Therefore heavier units can be manufactured without changing the stability of the unit. However, dolos have a size limitation because of its slenderness, and right now dolos heavier than 30-tonne cannot be built. Overall it could be concluded that the repair alternative consisting of antifer cubes is the one that should be applied at this particular location due to its performance and its construction feasibility.

Guidance structures are built in the vicinity of a sluice complex to serve as berth for ships waiting for the sluice to be available. The structure is loaded by the ship and should stop the ship without being damaged. The design of a guidance structure did not significantly change over the last decades. Therefore one could talk about a traditional structure. The structure consists of vertical supports with horizontal beams covered with timber. A new solution is found by mr. Ros who proposes to use pre-tensioned cables to stop the ship. The high tension capacity will make it possible to significantly reduce the use of material. The load on a guidance structure is formed by the ships kinetic energy. The interaction between ship, water, structure and soil will determine the reaction force by which the ship is slowed down. The influence of the water is formed by added water mass and damping through wave radiation. A cable structure has relatively low stiffness which leads to a larger stopping length, which implies more kinetic energy to absorb through the water influence. The guidance structures should be able to serve the entire fleet. The stiffness needs to be low enough for an empty ship which hits all the cables and high enough for a loaded ship which only hits the lower cables. To guaranty safety, the ship should not be able to sail underneath any cable. The solution is found in the use of an integral pre-tensioning system. By a balancing bar the cables are connected and able to interact. A lever beam with counter weight is used for pre-tensioning. With this system the vulnerability for stretch, creep, relaxation, deformation or temperature is minimal. Skirts are providing vertical stiffness, so all cables will deform together. Cables are connected to vertical supports. Those supports are relatively stiff compared to the stiffness halfway the span. Calculations showed the stiffness of the guidance structures increases gradually as the ship approaches the support. To get the ship safely past the support a support glider is invented. The support gliders are also used to prevent crushing of the cable between support and ship. The determent factor for the design of a cable guidance structure is the cable span. For a first design the situation at Krammersluizen (Netherlands) is used. The span is 57,6 meter and the total length is 288 meter. With the use of a maximum allowable stopping length, the needed pretension force is calculated. Only elastic deformation of the supports is allowed. This limits the maximum stopping length to 1,0 meter in the case of 57,6 meter cable span. Optimizing the design is done through varying the amount of support and thereby changing the cable span. Even the extreme case of 1 span of 288 meter has a solution that satisfies all demands. The steel cables have a design factor of 2,3. Reducing the amount of supports leads to a net profit. Extra costs for cables and the pre-tensioning system are not as big as the savings by reduction of the amount of steel. The cheapest possibility is a cable guidance structure with 1 support. Due to placement of bollards and ladders a minimum of 4 supports are needed. The cost reduction for this design is 32% and the reduction on environmental impact 44%. The cable guidance structure is technical and economic feasible. Further research should focus on the proposed issues to reduce costs and environmental impact even further.

Research into hydraulic loads by a bow thruster. The hydraulic loads on the slope at an open quay construction on piles is investigated. The propeller (bow thruster) jet induces hydraulic loads on the bed, which could result in scour holes and damage to the quay construction. Performed scale model tests provide details about the hydraulic loads in this specific situation with an inclining slope and piles. Measurements are compared to the current engineering guidelines, to include in the design of open quay constructions on piles.

Jetties are designed by the guidance of the deterministic standards. These standards are based on the standardized values of safety factors (semi-probabilistic) and use the load and the capacity of every element as a standard value. The interaction of every separate element as a part of a whole is not taken in to account. The use of deterministic standards can result in a design that is not economically optimal. A probabilistic approach gives a better insight in the occurrence of an unwanted events and leads to more insight of the optimizing of the structure. The “Lyondell jetty” in the Europort in Rotterdam is used as reference structure. This jetty is constructed in 1997 and is in use by a manufacturer of chemical derivatives for all kinds of synthetic products. It concerns a continues berthing structure founded on piles and is covered with fender wood, with a double deck jetty, that offers space to berth two large sea vessel and two smaller barges. The failure of the berthing structure is a conditional chance for functioning of the jetty. The berthing structure is submitted to further examination by means of a Monte Carlo simulation. Using the Monte Carlo simulation a measure of failure of an event is expressed in strength and resistance. In this study this event consists of reaching the yielding stress in the structure or the exceeding of a determined boundary of deformation during the berthing of a vessel. The energy loading is introduced with the equation of Saurin. The soil is modelled as a spring and meets the requirements of the Winkler model. In analysing the deformations of the structure the soil needs to have elasto-plastic characteristics (p-y curves that were developed by Reese). The actual structure that was designed with the Blum method, the design was recalculated, using help of p-y curves. This becomes the Kool model that is used for comparison with the results of the Monte Carlo simulation. In this thesis only the berthing of the mooring point 2 (large sea vessel) is considered. First the question if the developed 3 dimensional simulation technique is applicable answered and second whether the application of the model leads to differences in capacity. The soil model developed in Scia-engineer has the same behavior as in M-pile and the structure shows the expected behavior according the rules of mechanics. In the model relating to the energy load the variables of length, width, depth, mass, angle of berthing and the coordinates of impact are described as a stochastic. In the resistance of the structure the volume weight, internal angle of friction, cohesion, yielding stress and wall thickness of the tubular segments are described as a stochastic. From the results it appears that the loads occurs only very locally. Consequently there appears an over capacity in the reference design relating to the length of all the piles and the diameter of the piles. The five most loaded piles in the structure are checked due to the energy loading of the bow at Mooring Point 2. It appeared that the diameter of these piles can have a smaller fitted diameter. In length a reduction of 9% is found. A trend can be distinguished that indicates a large reduction of capacity in length over the whole structure. The critical variable in the design is the velocity of the vessel. The critical element in the structure is the berthing beam self. The sensitivity analysis of strength indicates that the chance of failure in strength can be diminished by the strengthening of the berthing beam and reducing the thickest wall thickness’s of the piles.

Zoals uit de eerste deelstudie naar voren kwam, blijven er na een uitvoerige afweging van een aantal verschillende typen afmeervoorzieningen (kademuurkonstrukties) verscheidene varianten over, die in aanmerking komen om nader te worden uitgewerkt. In dit deel is een kademuurkonstruktie op palen met een ontlastvloer ontworpen, die in plaats van een stalen damwand een betonnen diepwand als grondkerende wand heeft. In dit afstudeerwerk ligt de nadruk op de onderbouwkonstruktie (= diepwand + palen). De betonnen diepwand (hfst4 en 5) is doorgerekend met verschillende komputerprogramma' s (methode Blum, methode DAMWAND/3 en PLAXIS). Uit de resultaten blijkt dat een diepwand kan worden berekend naar analogie van een stalen damwand, waarbij wel rekening dient te worden gehouden met het feit dat een diepwand veel stijver dan een stalen damwand reageert. Hierdoor komen de aktieve en passieve korreldrukken niet overal volledig tot ontwikkeling, zodat volledige inklemming niet mogelijk is (a- 0.70). De resultaten van de eindige elementenprogramma's (methode DAMWAND/3 en PLAXIS) komen goed overeen. Bij de berekening van de inheidiepte van de palen en het palenplan (hfst 6) blijkt dat door variatie in positie en schoorstand van de palen de krachtsverdeling in de funderingselementen positief kan worden beïnvloed. Hierdoor is het mogelijk het ontwerp te optimaliseren. De bovenbouwkonstruktie (hfst 7) is globaal gedimensioneerd. De belangrijkste maten en dikten van de ontlastvloer en de koker zijn bepaald. Uit de berekening van de veiliqheidsfaktor van de konstruktie (SF) (hfst 8) m.b.v. PLAXIS blijkt dat deze voldoende hoog ligt. De veiligheidsfaktor is zowel met methode Bishop als met de eindige elementenmethode bepaald. Tenslotte wordt opgemerkt dat het toepassen van een betonnen diepwand een interessante variant is op een stalen damwand, maar wel een uitvoeringsrisiko in zich heeft (hfst 9) . De kontrole op grotere diepten blijft een gevoelig punt.

Siltation of harbour basins and navigation channels is a serious problem in the port of Rotterdam as well in many other harbours all over the world. Due to siltation, basins and channels require frequent maintenance dredging to guarantee safe navigational depths. The costs associated with these dredging activities are quite high. To keep the channels and harbours in Rotterdam navigable, Rijkswaterstaat and the Port of Rotterdam are dredging approximately 15 million m3 of sediment a year. The dredging cost of the Botlek Harbour only is already about 3 million Euros a year. It is a task to keep the costs in the Port of Rotterdam as low as possible to compete with other ports. Reducing maintenance dredging costs is in line with the goal of the Port of Rotterdam to be the most competitive, innovative and sustainable port in the world. Most sedimentation within the maintenance area of the Port of Rotterdam occurs in the Botlek. According data, between 1.5 and 3 million m3/year is dredged in the Botlek Harbour. Although the current dredging philosophy more or less works, the question arises whether there are solutions that are more cost-effective. However, the problem is so complex that it narrowed down for the sake of research quality. The main causes of siltation in general and specifically in the Botlek Area form an important part of the study. Hydrodymical models (SIMONA & Delft3D), were used to gain insight in the sedimentation problem. The focus in this thesis was more on the hydrodynamics. The exchange mechanisms between the river and Botlek Harbour were investigated, which were needed to examine the effectiveness of certain solutions. In practice a lot of solutions are proposed in literature, however in this study only a couple of ‘hard’ measures are investigated. The first possible solution that was examined was the use of a Current Deflecting Wall. It turned out that the hydrodynamics were very sensitive to the configuration of the CDW. While sometimes it would lower the exchange flow, at other cases it would even make the problem worse. The second solution was to make a gap in the Geulhaven dam. However this was not a good solution as high exchange flows occurred. The last proposed solution, the filling of the underwater dam, seemed more feasible as it would decrease the exchange flow according the numerical models. The research has first order results which can be used in further studies. According to this results, certain solutions will decrease the exchange flows. On turn it would very likely result in lower sedimentation rates in the Botlek Area. It is expected that some CDW configurations and the filling of the underwater dam would have a positive effect when it comes to sedimentation. However, this research is the first step of an extensive study that must made to deal with the problem. First of all many things can be done to improve the models, for example by using a higher spatial resolution. Secondly, other sets of conditions must be modelled to see what kind of effect this has on exchange flows. In addition, sediment must be included in the models to have more insight on the sedimentation itself. The next step would be a feasibility study, including a cost benefit analysis. It would be wise to improve the models further and to make a scale model for the most feasible solution. In the ideal case, were all steps are positive and hard conclusion can be made, it would be a good idea for the Port of Rotterdam to start a pilot.

Container traffic has grown exponentially since 1980 and has become a reliable and efficient means of transportation of goods. In addition, world wide containerization and the availability of cheap and frequent container transport to all corners of the world have had a profound influence on industrial production, transport and the environment. All these aspects result in increasing the pressure on container terminals to provide good service to shipping companies. The Royal Haskoning Maritime Division (hereafter, RHMD) deals internationally with development of different types of terminals such as container, liquid and dry bulk. Due to involvement of numerous stockholders in a port planning project, different design concepts may be considered to satisfy interests of different stockholder; therefore, various scenarios should be studied quantitatively. As an international maritime consultant, it is of crucial importance to own a simple and cheap tool to estimate the dimension of a container terminal. The goal of this study is to develop a tool for engineers to prepare concepts of terminal layout, and estimate the required areas of those concepts, for sake of comparison, for design of a new container terminal. Container terminal design is divided into “waterside” and “landside” areas. Waterside consists of a quay for serving vessels. Landside consists of a storage yard for stacking containers and a hinterland area for serving truck and trains. The developed package, in two consecutive steps, first, accepts the waterside, landside and cost estimation information, such as terminal throughput, downtime, stack occupancy, and second, requires the possible equipment concepts, such as ship to shore cranes and reach stackers etc. Based on the above input data, the performance of the terminal concepts is quantitatively evaluated. Eventually, the dimensions of the container terminal yard are presented. The container terminal design tool is verified against two formerly performed projects (in India and Guatemala) that have been successfully designed at RHMD. The validation showed good performance of the tool, with justified differences compared to actual designed values. As a case study, the package is also applied on design of a container terminal for a port in Angola. In this case study, four different scenarios and their impacts on layout dimensions are considered and analyzed.

After the storm surge of 1953, the Dutch Delta project was initiated in order to protect the southwestern part of The Netherlands. A storm surge barrier in front of the Oosterschelde and various dams at the back of the estuary were constructed. These interventions led to a large change of the hydrodynamics of the Oosterschelde: a large decrease in tidal volume and flow velocities. This decrease in flow velocities caused a decrease in sediment transport from the channels with about 75%. It is estimated that an amount of 400-600 million m3 of sediment is necessary to increase the flow velocities, restore the sediment transport from the channels and to obtain a new dynamic equilibrium (Kohsiek, 1987). This need for sand is called the ‘sand demand’. At present, the shoal height inside the estuary decreases by wave erosion. This decrease in shoal height mainly has a negative influence on the protected nature in the Oosterschelde. The Oosterschelde was ebb dominant and exporting sediment for centuries. All the events and interventions from 1530 up to the construction of Volkerakdam and Grevelingendam in 1969, caused an increase in tidal prism and export of sediment towards the ebb tidal delta. By the construction of the storm surge barrier, Philipsdam and Oesterdam in 1986, the situation changed, the tidal prism decreased and the ‘sand demand’ started. This research is aimed at finding a structural solution for the ‘sand demand’ by opening the storm surge barrier. The present situation of the Oosterschelde and a future situation with a new inlet channel at Neeltje Jans are analyzed in order to determine if a new inlet channel could influence the hydrodynamics and sediment transport in order to structurally solve the ‘sand demand’. A process based hydrodynamic and morphological model (Delft3D) is used to analyze the present and possible future situations with a new inlet channel. The new model and the methods of Van de Kreeke (1993) and Groen (1967) applied to the present situation of the basin, show that the Oosterschelde is still ebb dominant and would be exporting fine and coarse sediment if the inlet would not block the sediment transport. This ebb dominance follows from the large intertidal area and deep channels. Notwithstanding the ebb dominance, there is no sediment export possible through the inlet. The inlet blocks the sediment transport in both directions mainly because of a ‘tidal jet’, caused by the small inlet and large tidal prism. The tidal prism increases with a new inlet channel and thus increases the flow velocities in the channels. The increase in tidal prism and thus flow velocities brings the Oosterschelde closer to the old situation. The higher flow velocities increase the sediment transport from the channels and thus increase the shoal building. It is not known how much the shoal building is exactly restored. Some channels have such an increase in flow velocities that shoal building occurs again. However, parts of the basin are still not in equilibrium, which can be seen from comparing the old with the new flow velocities and by comparing the tidal prism and the cross-sectional areas of the channels with the empirical relations of Louters (1998) and Haring (1976). An important disadvantage of an increase in tidal prism is the enhancement of the ebb dominance that causes more sediment transport in ebb direction. However there is no export possible through the new inlet channel, because also the new inlet channel has a ‘tidal jet’ that blocks all sediment transport through the inlet. The large-scale effects of the Oosterschelde, like the ebb dominance and ‘sand demand’ cannot be structurally changed a new inlet channel. However the shoal degradation rate will probably be slowed down with an increase in tidal prism.

Civil structures, especially hydraulic structures, are subject to influences from the environment around the structure. As a result of these influences the structure degrades, which lowers the strength of the structure. Several actions are available to lower the speed of degradation and/or restore the structure to a certain condition. Within the operations and maintenance of a structure, the question is whether regularly small reparations or once a large replacement needs to be performed. In order to make a founded decision a quantification is needed. One of these is using risks as part of the decision making process. Risk is defined as the probability of occurrence times the consequences. Since this can be expressed as costs, it can be compared with the costs of the reparations or replacement to find the value of this action. In this thesis, a framework is presented to aid in the development of a one replacement-multiple reparations-strategy. The method describes the steps needed to find all information to make a stochastic based deterioration model. Also the steps to calculate the costs for each strategy, where the moment of replacement and reparation interval are variable, are shown. The framework ends with an optimisation, resulting in the most optimal strategy within the set boundaries and assumptions. Testing of the framework has been performed with a case study of a fictional lock. After collecting all needed information about the degradation models, distribution and parameters, several calculations have been performed. With both a level II as a level III method these calculations have been made. The framework proved to be a good guideline for the determination of sought-after strategy. Since degradation models can have a more complex (than adding and multiplying parameters) shape, the level II method became significantly more complex than what it is used for (an indicative calculation). Even though level III method (the Monte Carlo method was used) requires more processing time (on a commercial laptop) than the level II method, the time it took to program was equal. A level II method is therefor only of use when a comparison with an analytical method is wanted.