Concrete is the second most used material in the world after water and recent trends show no slowing down of the concrete use around the world. Concrete is also a huge contributor to CO2 emissions as it makes up 8% of emissions. This study investigates the optimization of concrete structures to reduce environmental impact while maintaining structural integrity and cost-effectiveness, e.g. how to make a concrete structure more sustainable. A previous report where quay wall designs of different materials were compared in regard to the CO2-emissions and life cycle assessment found that a concrete quay wall had 43% more emissions than a steel quay wall. The goal of this study is to reduce the overall CO2 equivalent emissions related to a concrete structure by 50% and make the design more sustainable.
A concrete ship lock chamber as part of the Delta21 project is used as a case study. To measure the positive effect of sustainability two chambers are designed; a base case chamber designed based on what is most commonly done in practice in the structural engineering field, and an alternative chamber design with the aim of making the concrete lock chamber more sustainable. A partial life cycle assessment (LCA) is performed on both of the two design alternatives. The optimization of the alternative chamber design focused on minimizing global warming potential (GWP) by adjusting the reinforcement-to-concrete ratio and incorporating structural elements such as plated steel anchors. The two alternatives are analysed comparably as they are designed under the exact same conditions, in the same environment and with the same functionality aspects.
The base case structure is a U-basin concrete chamber with tapered walls. The alternative optimised structure enhances the structural behaviour of the chamber wall by adding anchors. This reduces the moments by 88% and the shear force by 56% compared to the base case design. By changing the structural wall type in the chamber by adding anchors, the concrete volume could be reduced by 47% between the base case design and the optimised design. This also allows for a reduction of concrete strength class, reinforcement volume, underwater concrete floor thickness and the number of tension piles for the construction pit. The LCA reveals a 55% reduction in the GWP for the alternative concrete chamber design, compared to the base case design. An optimum reinforcement ratio for the alternative concrete chamber anchored wall of 2.3% is identified, resulting in a balance between structural performance and environmental sustainability without increasing material costs. This ratio doesn’t incorporate labour cost which might affect this optimum ratio by lowering it. This demonstrates the potential for achieving environmentally responsible solutions without compromising the structural integrity of a structure or incurring additional costs.
The study highlights the potential for integrating sustainability objectives into concrete structure design, with recommendations for further research including exploring alternative materials and advanced optimization techniques. ... Read more

Het Noordzeekanaal verbindt de Haven van Amsterdam met de Noordzee via het sluizencomplex van IJmuiden. In de huidige situatie is de Noordersluis maatgevend voor de maximale diepgang van de scheepvaart op het Noordzeekanaal. Met de geplande realisatie van Zeesluis IJmuiden begin 2022, zal de Noordersluis niet langer maatgevend zijn voor de maximale diepgang. In de nieuwe situatie zal de bodemligging van het Noordzeekanaal maatgevend zijn voor de maximale diepgang van de scheepvaart. Het Centraal Nautisch Beheer en Rijkswaterstaat wensen de scheepvaart capaciteit van het Noordzeekanaal te bepalen afhankelijk van de beschikbare waterdiepte en de daarbij passende diepgang van schepen. Uit eerdere onderzoeken bleek de Velserspoortunnel maatgevend te zijn bij eventuele verdieping van het Noordzeekanaal. Daarnaast werd geconcludeerd dat de spoortunnel in de huidige situatie niet voldoet aan de eisen omtrent de minimale tunneldekking. Verder bleek de dynamische kielspeling boven meerdere Noordzeekanaal tunnels te klein te zijn. Tevens werd duidelijk dat door de optredende bodemsnelheden, veroorzaakt door schroefwerking en retourstroom, de kritische snelheid van de tunneldekking overschreden wordt. Aangezien de constructieve veiligheid van de tunnels gelegen onder het Noordzeekanaal niet in het geding mag komen dient meer inzicht te worden verkregen in de veiligheid van de tunnels bij scheepvaart calamiteiten. De rol van de dekking op de tunnels is hierbij cruciaal. In het onderzoek is daarom ingegaan op de optimalisatie van de tunneldekking bij scheepvaart calamiteiten. Aan de hand van literatuuronderzoek is inzicht verkregen in de scheepvaart calamiteiten. Vervolgens is de verkregen kennis toegepast op de casus van de Velsertunnels, door de tunnels te toetsen aan de vereiste veiligheid bij de calamiteitsbelastingen. Tot slot zijn alternatieve tunnelbeschermingen onderzocht voor de Velsertunnels waarbij het meest geschikte type bescherming verder is uitgewerkt. ... Read more

Hydraulic structures can be prone to impulsive wave impact, which is a highly stochastic and uncertain process. This type of impact, defined by extreme pressure peaks and a very short duration, is not only caused by breaking waves, but also by non-breaking standing waves on structures with an overhang, such as culverts and steel gates. In this study, the capabilities of the Lagrangian numerical tool Smoothed Particle Hydrodynamics (SPH) are validated by means of experimental research conducted at the Hydraulics lab of the Delft university of Technology, in which two short overhang configurations were subjected to multiple non-breaking wave conditions. SPH distinguishes itself by discretizing the numerical domain in particles instead of a grid, unlike traditional computational fluid dynamics (CFD). In doing so, it excels in free surface modelling and complex wave-structure interaction. In this thesis, the theory of pressure-impulse is applied, which is defined as the integral of the pressure over the impact duration. This method is more stable than using pressure peaks and can be used to obtain the reaction forces on hydraulic structures. However, the theory is in development and subject of recent literature. This research includes the theoretical pressure-impulse model, which is based on the Laplace equation and solely includes the vertical impact by assuming a circular profile under the overhang with a constant impact velocity. Furthermore, a new conceptual model is introduced, which is based on integration by the particle velocities in both horizontal and vertical direction as described by Linear Wave Theory. The assumptions of the velocity fields of both models are assessed by the SPH method. As a result, modifications are proposed to the conceptual model and validated with the experiment. SPH shows good agreement with the experiment in terms of wave generation, pressure distribution and pressure-impulse profile. However, the lack of air in the numerical model result in overestimations of the pressure peaks. The more air is entrapped in the experimental wave impact, the higher the deviation. That said, the impact duration also becomes longer the more air is entrapped while the SPH model shows a somewhat constant and shorter duration. As a result, the pressure-impulse profiles shows corrective behavior over the vertical, mitigates the absence of air and thus greatly increases the accuracy and stability of the results. Finally, an analytical validation is performed in which the theoretical models for overhang configurations and design formulae for vertical walls are compared to SPH and the experiment.
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A ship lock scheduling model called LOSCO was developed in order to decrease passage times at locks with two parallel chambers. Three locks were chosen to model, as they are some of the busiest locks of the Netherlands. The Krammersluizen, the Sluizen Hansweert and the Kreekraksluizen. Passage times are not collected at the locks, therefore the model was compared to SIVAK. SIVAK is the standard model for research on locks at Rijkswaterstaat. To schedule vessels in locks three types of choices can be made. Every vessel needs to be assigned to a chamber, the initiation time of locking should be decided and the order of sailing in a chamber should bedefined. By optimising these choices, passage times can be decreased. Optimising is however not straightforward, as the problem is an instance of the job shop scheduling problem. No exact algorithm has been found to solve these problems in a practical amount of time. Therefore the challange is to find a balance in solution quality and the speed of the model when creating a lock scheduling model. In this thesis, four ideas to improve the lock scheduling model by Verstichel were researched. The first idea is to change the resolution of the timesteps. The gain in performance was however not found to weight up against the loss in solution quality for resolution to be useful. The second idea is to drop the first come, first serve constraint that Verstichel created. This idea was also not found to be effective. The third idea is to divide the scheduling problem up into chunks. This is called cut separation. Chunks of around 25 vessels were found to be effective. The fourth and last idea is that of a maximum waiting time. The maximum waiting time makes the performance of the model better and also makes the scheduling model fairer. Data from the year 2016 was used to schedule all lockings. The LOSCO model is effective for reducing the average assage time per vessel with about 3.9 ± 0.12 SE minutes for the Krammersluizen and 2.0 ± 0.14 SE minutes for the Sluizen Hansweert compared to the SIVAK model. At the Kreekraksluizen, the model could not find a solution, as the Kreekraksluizen are a lot busier than the other locks that were tested. At the Kreekraksluizen on average every 7.8 minutes a vessel arrives, whereas at the Krammersluizen and the Sluizen Hansweert respectively every 14.0 and 13.0 minutes a vessel arrives throughout the year. The LOSCO model is only better than SIVAK if the lock is relatively quiet. At the busiest time of the day, typically in the afternoon, SIVAK performs better. The models perform equal at inter arrival times of around 8
to 10 minutes. Optimisation on economical value of the vessels was found to be less effective than optimisation on time. Optimisation on time was also found to be fairer. The LOSCO model is a step ahead towards a practical lock scheduling model. In order to achieve a fully practical model, some simplifications need to be expanded. It is recommended to first improve the model before it is applied in practice, as the model is able to outperform SIVAK in some cases, but not in the busiest cases. After this some extra features can be implemented, such as the model dealing with vessel delays and locks with 3 chambers. ... Read more

For the design of a steel sheet pile, verification checks should be done on multiple failure mechanisms. One of the failure mechanisms which should be checked is the check on global buckling. This is a mechanism in which the deformation of the pile is enlarged due to the normal or vertical force. With the enlargement of the sheet pile, the soil must be displaced as well, which results in extra resistance against global buckling. However, the check to this mechanism stated by the Eurocode is based on the so called critical global buckling load, which is currently based on the stiffness of the sheet pile. The resistance delivered by the soil is fully neglected in the check on global buckling, which gives that it is thought that this check is too conservative. It is studied how the influence of the soil can be taken into account to the global buckling mechanism. This is done by describing the background of the current check, followed by stating possible methods to determine the influence of the soil. By the use of calculation program’s D-sheet pilling and Plaxis 2D, some examples are calculated in which the proposed methods are compared with the current method. From those examples, it was found that the check on global buckling might be significant lower if the influence of the soil is taken into account. ... Read more

The weirs in the river Meuse reach their theoretical lifespan. The weirs were built in the early 1930s and now one is faced with a replacement task. Various studies have been carried out in recent years on the future of the weirs in the river Meuse. This concerns research into the entire weir system, different types of weirs and the way in which the current weirs should be replaced. This study does not focus on one specific task, but focuses on various aspects that are important for the replacement task, both “soft” and “hard” technical aspects. The first aspect is to find a suitable assessment framework that a new weir must meet. This assessment framework has been developed by means of literature research and interviews with specialists from Rijkswaterstaat, resulting in a risk and opportunity plan especially for weir structures. The assessment framework thus forms the basis for finding both a suitable weir type and a suitable solution for construction. A variant study has been carried out into different weir types. The considered weir types are delineated into a conventional variant, the flap weir, and three innovative variants, namely variants with inflatable technology. The steel-rubber gate, also known as the Obermeyer weir, scores best. This weir type consists of air-filled bellows that inflates and deflates the flaps. It is distinctive in terms of discharge capacity, nuisance and ease of maintenance.
The next phase is to make a conceptual design. A new weir regime has been developed on the basis of several considered weir configurations. A weir configuration with two weir spans of 50 m weir, each with 5 separate flap-bellow components has been designed. Furthermore, the weir sill has been designed with a length of 34 m. Based on the design loads on the bottom, a soil protection has been designed. A block mattress with a geotextile as a filter proves to be a suitable soil protection. The downstream length of the bottom protection is designed as a total of 50 m. Thereafter the forces in the membrane are determined, after which a suitable type of membrane is designed.
The last phase of this research focuses on finding a suitable solution for construction for the new weir in Linne. Three different construction methods have been developed, in-situ, side channel and prefab. For each method, the (global) weir dimensions are verified for the governing load situations. Ultimately, a suitable construction method is selected on the basis of an overall cost indication and assessment criteria, derived from the assessment framework that has been compiled in the first phase. Construction variant C, the prefab solution, scores best. It is an innovative solution in which the entire weir, including flap and bellow elements, is built in a construction dock upstream of the current weir and then transported using pontoons with winches. The major challenges of this construction method are the floating transport where the enormous weir construction must not be damaged, the coupling of the air supply pipes to the compressors in the abutment underwater by divers and the guarantee of a good transfer of forces from the weir sill to the bottom. On the other hand, there is considered to be a great advantage over the other variants in terms of, among other things, costs and construction time. The solution is therefore proposed as the implementation solution for the Obermeyer weir to replace the current weir in Linne.
In addition to this study, a strategy has been developed to deal with uncertainty in design as a depth study. The case of the bottom protection for the new weir has been used to apply this strategy. Different stability relations have been compared that come to the required nominal stone diameter. Based on a consideration of the impact in costs, impact on failure and risk mitigation measures included in this strategy, a broadly-based choice can be made for the design of the soil protection. ... Read more

In this research an effort is made to contribute to the goals of the Betonakkoord. This is done by optimising the design of big and bulky structures consisting out of a lot of concrete, namely lock heads. Lock heads are part of the navigation lock. The main research question answered in this thesis is phrased as follows: How can the design of lock heads be optimised to increase the sustainability?
Different alternatives have been generated to try to increase the sustainability. Each alternative has been compared to the lock head in Empel to test their feasibility. The following alternatives are considered: Inhomogeneous cross section, Prestressing and Hollow sections. From the alternative study it becomes clear that none of the alternatives are effective. The alternatives show no significant decrease in cost and MKI. Therefore, the alternatives are neglected in the remainder of the research. Based on this conclusion the following question arises: Is it possible to increase the sustainability of a lock head design based on commonly used design rules? In the next step of the research a parametric model is developed in order to answer this question. The parametric model design is based on the rules prescribed by the 'Handboek voor het ontwerpen van Schutsluizen' and the 'Richtlijnen Vaarwegen 2017'. The parametric model takes into account two types of gates, being a single leaf gate and a mitre gate. Again, the lock head in Empel has been used to validate the parametric model. From the parametric model it follows that in general a mitre gate is more cost effective and sustainable than a single leaf gate. This is because a mitre gate is generally shorter than a single leaf gate, so less materials are used and the construction pit can be smaller. Furthermore, the parametric model shows that the global stability check horizontal bearing capacity is a key parameter in the design of a lock head. To account for the horizontal bearing capacity the length and the weight of the lock head are important factors. The next step is to compare the lock head designs from the parametric model with the lock head design in Empel. The lock head design in Empel deviates from the rules prescribed by the 'Handboek voor het ontwerpen van Schutsluizen'. By deviating from the rules a more cost effective and sustainable design is acquired than both the designs from the parametric model. The lock head in Empel is shorter and lighter than the lock head designs from the parametric model. This is due to the fact that the lock head in Empel derives its horizontal bearing capacity from the lock chamber. In order to design a more cost effective and sustainable lock head it is advised to incorporate the lock chamber in the stability calculations. Hereby a shorter lock head can be achieved. ... Read more

Currently, there is no infrastructure between the two Indonesian islands Flores and Adonara. The islands are separated by the Larantuka Strait, which has a width varying between 600 and 1000 meters. The local government would like a bridge between the two islands. However, as the water in the 18 meter deep strait is heavily subjected to tidal forces - creating a tidal amplitude of about 1.5 m and tidal flow velocities ranging up to 4.5 m/s - structural design is challenging. As traditional bridges were deemed too expensive, a new type of bridge was introduced: the `Tidal Bridge'. The pendulum founded floating bridge, which is proposed to span the deepest 400 meters of the cross-section, is designed with tidal turbines attached to the bottom of the structure. The energy production mitigates the financial burden that the 225 million US dollar Palmerah Tidal Bridge will bring. At the time of writing, a pre-feasibility study has been performed by Antea, proposing initial structural dimensions. BAM took over the design process, which lead to questions regarding the dynamic stability of the design. The objective of this report is to answer the following two research questions: 1. How can the dynamic response due to two-dimensional forcing of a Tidal Bridge be determined? 2. What design choices can further optimise the dynamic behaviour of a Tidal Bridge? A numeric tool has been created to predict the dynamics of the proposed design as function of an input of wind, waves, and current. Based on (experimental) literature, hydrodynamic coefficients determining the fluid-structure interaction were determined. The complex shape of the floaters did not allow appropriate validation of the accompanying added mass and radiation damping coefficients. Comparison with a model constructed in Ansys Aqwa showed values of similar magnitude, but precise magnitudes could not be determined. In order to find these important coefficients, a set of experiments has been performed to determine the added mass (moment of inertia) and radiation damping (moment of inertia) for heave and roll motion. The experiments showed that the added mass equations for heave were well defined, while the added mass moment of inertia equations for roll motion deviated up to 250 per cent. The acquired data was used to find better relations between the added mass (moment of inertia) and the floater dimensions. Please note, the empirical relations are based on limited data and with little mathematical background. Hence, the relations should be used with care. The radiation damping coefficients that were also extracted from the experiments showed no clear trend, but did confirm that the hand-calculations were of correct magnitude. Using the constructed model, forcing characteristics of the Tidal Bridges are investigated. In these computations, the Palmerah Tidal Bridge dimensions are used as a case study. It was noted that the extreme non-linearity of different elements of the problem (changing pendulum angle, hydrodynamic pressure field, and particle velocity/acceleration field) do not allow for linear approximation. While a linear mass-spring system predicts that the natural period is about 6.7 seconds, the maximum dynamic amplitude is found for wave periods of 9 seconds. This coincides with the largest expected waves for the Palmerah Tidal Bridge location. Reducing the natural period of the design is recommended. Additionally, research was done into the contribution of the various types of forcing, where it was found that traffic weight has negligible effect on the dynamics. Wind forces add only a few percent to the pendulum forces, but do have a significant contribution to the displacements. Furthermore, research into the impact of an approaching wave field showed that accelerations during first impact may overshoot the maximum steady state acceleration by more than 200 per cent. A parametric study on the dynamics of Tidal Bridges was performed, which did research into the the forcing combinations that lead to most amplification of the dynamics. It shows that different loading combinations are governing for accelerations in the three different degrees of freedom present in a two-dimensional system. In here, difference was found for the dynamic behaviour induced by waves from the two different wave directions, leading to two sets of three forcing combinations. This data was used to investigate the effect of three design parameters: the angle of the pendulum, the hinge location of the pendulum and the depth of the strait. Moreover, a sensitivity study is performed on a set of parameters defining the Tidal Bridge. It shows that the mass of the segment, the added mass, the floater length, the design turbine force, and the pendulum angle are most important if it comes to design optimisation. Based on the parametric study and the forcing characteristics, conclusions and recommendations are made for improvements of Tidal Bridge designs in general and more specifically: the Palmerah Tidal Bridge. ... Read more

In the vicinity of locks and bridge piers, guide works are placed in order to steer inland navigation vessels through a narrowed passage. The design of these structures is generally done in a static way, thus without consideration of time-dependent phenomena. By treating the contact force during a brush collision as a static force, several phenomena are overlooked. First of all, it is possible that, in case of a brush collision, a second impact occurs due to the yawing motion of the vessel that is generated during the first impact. Considering the time domain in the analysis of brush collisions also enables the investigation of the length that is required for a guide work to fulfill its function. Within this thesis the time aspect is considered for brush collisions between inland navigation vessels and guide works with steel hollow tubular cross-sections.Objective of this research is to quantify the second impact and to provide a recommendation for the length of guide works, in order to answer the question: “In what ways is the design of guide works affected by taking into account the time domain?. A parametric tool that simulates brush collisions is created in Python. By variation of one parameter at a time, the influence of this parameter on the magnitude of the second impact and the required length for a guide work is visualised. 
Eventually, the model created in Python is translated to SCIA Engineer. By using the automatic post-processing environment of the Finite Element Software, this translation can be used to speed up the design guide works in future projects. On top of that, the influence of torsion on the mechanical behaviour of the structure is taken into account. For the investigated parameters a second impact always occurs within the 90 seconds of performed analysis, except for vessels with a large mass or length, or a small initial velocity. On top of that, the contact force during the second impact generally appears to be 30 to 40 percent larger than the first impact, while guide works are commonly designed for the first impact. Only for initial contact angles larger than 13 degrees or vessels with draught of more than 7 meters, the first impact is governing. The required length of a guide work to facilitate a brush collision itself is very well obtainable by using the created model. Nonetheless, due to the spread of the location of the first contact, a large uncertainty still remains in determining the total length of a guide work. For the translation to SCIA Engineer it holds that it is possible translate the Python model into a model involving SCIA Engineer. The long computation time of this translation, however, make this tool rather impractical.
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The concept of shear loading and the shear resistance is well known for ‘regular’ sized beams, meaning beams that can be characterized as a slender beam. However, once the beam increases in size such that it is characterized as a deep beam or even falls outside the range of the typical deep beam, less knowledge is available. A case study of the Itaipu lock walls is used to compare three different calculation methods for shear loading (sectional method, strut & tie method, and a linear and nonlinear finite element model) to each other. The calculation methods are applied to the large concrete lock walls in order to determine which of these methods can best be used for shear calculations on structural elements that fall out of the range of these so-called ‘regular’ sized beams.  The effect of increasing thickness is studied and it can be concluded that the combination of a certain crack width and the aggregate interlock mechanism, and thus the grain size of the concrete mixture, play an important role in the shear capacity of beams.  The existing norms and guidelines, such as the Eurocode and the American Concrete Institute codes, have been proven to be inadequate for shear calculations on structural elements that surpass the definition of a deep beam in size, such as the Itaipu lock walls. The sectional calculation, which is based on these norms and guidelines is however still used as a rough reference calculation in this research. The first calculation, which is the sectional calculation, resulted in two alternative designs next to the original lock wall design by Witteveen+Bos: total wall thickness original design: 33m, total wall thickness alternative design 1 (i): 17m and total wall thickness alternative design 2 (ii): 29m. The Strut & Tie calculation is then performed for the original Witteveen+Bos design, resulting in a reinforcement plan based on the normal forces in the ties. The third calculation type consisted of three linear models (of the original design and the two alternative designs) and one nonlinear model of the original Witteveen+Bos design. The stress trajectories of the linear models illustrated that the wall is predominantly stressed in compression, as a result of the large self-weight of the wall. Only the lower part of the wall and the lock floor connected to this wall are stressed in tension. The nonlinear model was therefore reinforced only in the lock floor and the lower part of the wall connected to the lock floor.  Because the linear finite element approach does not include material behavior beyond the elastic stage, this approach is not sufficient and does not provide the necessary required insight for a shear resistance calculation. The nonlinear finite element model has proven to be the most accurate and adequate calculation method. The downside is that this method will take longer and requires more background information about the materials used, the connection between structural elements and the type of subsoil. The Strut & Tie approach, is a good first design step. However, for a thorough tradeoff between wall thickness, the complex connection between the floor and the wall, and the amount of reinforcement necessary to prevent cracking, the nonlinear finite element method gives the most accurate estimate.  From the calculation results, the conclusion is drawn that the current wall design by Witteveen+Bos is an overly conservative design. Decreasing the current total wall thickness and increasing the amount of reinforcement in the lock floor and the lower part of the wall connected to the lock floor, will also result in a design that is able to resist the shear loading. ... Read more

In the Meuse seven weirs are located in the Dutch reaches, controlling the water level to enable inland navigation through the river. The weirs are being scheduled for replacement, where weir Grave is the first one in 2028. They are reaching their end-of-life time. One of the main issues that became of more importance in the recent years is ship collision. In the past 20 years two major ship collisions happened on two different existing weirs in the Meuse, one at Grave and one at Linne. The place of impact at the weirs was significantly damaged after those collisions. As a consequence, the water level dropped and inland navigation was not possible for one month. In this study an inflatable weir is proposed as replacement of the existing steel weirs in the Meuse. A conceptual inflatable weir design is made for location Grave, for replacement of the existing weir. The design is based on existing literature, such as the inflatable storm surge barrier Ramspol. The design for Grave is considered to be scalable to the overflow (Poirée) parts of the Meuse weirs. One of the aspects that has not yet been considered for those inflatable weirs is ship collision. The theory and formulas found for the existing collision analysis are not fully applicable to the inflatable weir, mainly due to large elastic deformation of the inflatable weir. In literature a standard expression has been found to quantify the ship force on the colliding structure. This expression forms the basis of the analytical model. The inflatable weir in the analytical model is schematized by a two-dimensional plate sheet. An effort was made to validate the strain found in the analytical model by a numerical model in Ansys. However numerical instabilities were found that lead in considerable modification of the desired model and so the results indicated no representative outcomes.
To see what happens during the ship collision a physical scale model was made, with scale 1:25 for accurate representation of the physical phenomena.
Sixteen experiments were done with four different draughts and four different velocities of the ship. For the experiment with the scaled maximum draught (0.14m) and velocity (1.1m/s). The full video experiments are uploaded to the 4TU-datacentrum (https://data.4tu.nl/portal). The two aspects uplift of the ship and gliding over the weir observed in the experiments are not yet included in the analytical model, therefore the analytical model is extended. The extended analytical model showed a 25% deviation with the uplift of the ship and a 15% deviation with the displacement of the weir from the experiments. With the extended model it was calculated that the limit strain is not exceeded and that the strain is maximum 5% on top of the static strain of 1.9%. Concluding, the first steps have been taken into research of ship collision on inflatable weirs. Further investigation on the ship with V-bow, the propeller of the ship and a more extensive numerical model is recommended for ship collision on inflatable weirs. ... Read more

Vertical sliding valves that are part of a filling and emptying system of a lock are often subjected to an underflow of water during emptying and filling. The flow induces time varying forces on the structure which leads to dynamic behaviour of the valve. Whether the structure is in the range of resonance and what the amplitude of the vibrations will be depends on the mass, damping, stiffness and forcing quantities of the system. This thesis focussed on gaining insight in the behaviour of such a cylinder and its various components in terms of stiffness and damping of the total system including the vertical sliding valve. The research questions focussed on whether it is possible to influence the dynamic characteristics of a system (natural frequency and dynamic amplification) by adjusting the geometry of the hydraulic cylinder. Furthermore it is investigated which components are influencing the dynamic characteristics of the system and which damping and stiffness components are found to be subordinate to the dominant sources. Results were based on a Python script that included all relevant sources of damping and stiffness of a hydraulic cylinder, as well as the fluid structure interaction components such as added mass, damping and stiffness. The added damping components included the self-excitation suction damping. The sensitivity of different components to the natural frequency and dynamic amplification was explored. This was done for different cases, where in each case one variable varied while the others were kept constant. The results from the sensitivity analysis were used to find an optimal parameter that would lead to an optimal design in terms of natural frequency increase or decrease, reduction of the dynamic amplification and a minimal influence on the mass of the system. Besides these two studies, a third study was adopted to find the relative influence of different damping and stiffness components of the hydraulic cylinder for varying boundary conditions such as water level difference and gate opening. The study showed four components of a hydraulic cylinder that influenced the dynamic characteristics the most when varying their dimensions in a realistic range. These where the diameter of the hydraulic cylinder, the cylinder length, the thickness of the rod and the length of the tube that transport fluid into the cylinder. From these, the tube length and the cylinder diameters turned out to be the most effective design variables for tuning the stiffness, damping and correspondingly the natural frequency and the dynamic amplification of the system. Furthermore it was found that under all conditions (varying water level, gate opening height, pressure and stiffness), the stiffness was mostly determined by the axial stiffness of the rod and piston as well as the stiffness due to compaction of the cylinder fluid. For damping it was found that the cylinder only had limited influence and that most damping resulted from friction between the valve and the guiding rails. ... Read more

When designing a construction pit adjacent to a navigation channel, the event of a ship colliding with the structure is something to take into account in the design of the pit. However, several aspects regarding ship collisions, i.e. the probability of occurrence of a collision, the magnitude of the collision force and the influence on the safety of the pit, are uncertain. The goal of this research is to develop a method to determine the safety of a temporary construction pit. The Blankenburg Connection, which is being built by BAAK, is used as a case study in this thesis. The construction pit in this project is located in the Scheur and has to deal with a busy navigation channel. The end-wall of the pit is a temporary wall, as it has to be removed in order to to be able to float a tunnel element to the middle of the channel.A Bayesian Network is used as a method to take into account all the different parameters influencing the probability of collision. When comparing the outcome of the model with values based on historical data for the Scheur, it can be concluded that the model predicts the probability quite well. A small difference can be noticed, which is probably explained by the fact of under-reporting. To determine the magnitude of the force, a Monte Carlo simulation is used. In this way a probability density function of the magnitude of the force is generated, giving insight in the occurrence of forces on the structure. The resistance of the structure is determined and mitigation measures to increase the safety of the construction pit are examined. ... Read more

This thesis introduces a fragility-based framework in order to perform a custom assessment of the complex Eastern Scheldt storm surge barrier. By applying a conditional approach to loading parameters, the statistical dependency between failure mechanisms and structure elements can be described separately for the strength and loading part of the assessment, allowing for a reduction of the conservatism. This report applies this fragility-based assessment to assess the barrier on the failure mechanisms ‘height’ and ‘failure due to failing closure’. ... Read more

This research is about the effects by climate change on the inland shipping sector of low discharges in the River Waal. Two different situations are investigated, one without any measure and one with canalization of the river. These two situations are compared with a zero variant where no navigation restrictions occur and therefore a so- called reference situation is also investigated. The focus is on the direct costs for the inland shipping sector due to navigation restrictions caused by insufficient water depth and canalization. Besides, the more integral picture is taken into account by the total costs due to canalization, which consist of the shipping costs due to canalization and the weir- and lock complex costs. For studying the effects of the different developments on the inland shipping sector an effect model is developed, validated and used.
The consequences in case of several scenarios for this canalization option are investigated to get insight in the range of possible outcomes. The scenario analysis shows that the shipping costs for all scenario combinations are lower in case of canalization than in case without any measure. Looking to the more integral picture, the total costs due to canalization are only in case of the most extreme climate scenario lower than the shipping costs in case without any measure. For all other scenarios, the total costs due to canalization are much higher. During the sensitivity analysis, the total costs due to canalization for various weir- and lock complex costs are investigated. The result is shown in the figure alongside to here. For total weir- and lock complex costs below 400 million Euro the feasibility of Waal canalization is quite high, which means that for many scenario combinations the costs due to canalization are lower than the costs in case without measure. However, for WLC costs between 400 million Euro and 900 million Euro the feasibility decreases to 20%. It is expected that 1000 million Euro is quite large for one complex and therefore it is assumed that a feasibility of at least 20% is reached. ... Read more

Over the past years Fibre Reinforced Polymers, or FRP, have started making more of an appearance in civil engineering structures. They have the advantages that they are light-weight, do not corrode and theoretically require little maintenance during their lifespan. Originally they were used to construct reinforcement, cables and small bridges but more and more they are finding uses for larger scale structures. One of these newer applications is in lock gates.

Locks are structures which are responsible for enabling water based transport while also retaining high water where necessary and are critical links in the water defence system of a region. Their gates also have a relatively large risk of collision due to the amount of moving vessels passing through them. In order to safely construct these lock gates from FRP laminates it is important that their response to such collision loads is well understood. This is the focus of this study with the aim to construct a model to help better understand the collision scenario.

To make the theory concrete a case study is done on the lock gates of Sluis III which is situated in the Wilhelminakanaal in Tilburg. These gates are, at the time of writing, the largest FRP lock gates in the world. With the down stream gates being 13.9 by 6.3 meters. The event in which a Class III vessel collides with these gates will be examined in detail.

The collision is schematised as a one dimensional collision using a series of springs and dampers to obtain understanding of the general collision behaviour. From this model it is concluded that the application of a load from the ship’s engine or taking elastic deformations of the ships bow into account has negligible influence of the results (in the order of 2%), simplifying the calculations considerably. This simple model is later advanced in three ways: Two numerical finite element models are used to determine the structural response of the gate elements on a global and local scale and a more advanced analytical model is made to account for non-elastic deformation in the ship’s bow. The gate’s structure consists of multiple overlapping laminates which together form the skins of the gate. The numerical model is set up in two ways, one of which is used to determine the overall response of the gate element and the other to focus on the interlaminar resin layer in the skins. The results show that it is of importance to apply the load in a realistic manner as the results may vary widely depending on bow shape and point of impact. The approximation suggested in the Dutch codes in which the load is applied as a distributed load of a 0.5m2 areas proved to be inaccurate. For this reason a dynamic LS-Dyna calculation is run using a rigid model of the ships bow to apply the load. The outcome of this analysis shows minor damage to the gate over a large area around to point of impact, but the stresses remain under the failure limit of the laminates except for the internal flanges directly under the impact. These flanges will fail, but this will not threaten the water retention of the gate. The stresses in the resin layer also remain under their critical limit. It can be concluded that the gate satisfies the requirements but significant repairs will be necessary to restore it to a fully operational state.

The expanded analytical model is based on the fact that the force between the bow and the gate is larger than the failure load of the bow itself. The failure which will then take place will dissipate large portions of energy (in the order of 50%) making the current approach, in which this does not take place, highly conservative. The model suggested here is a segmented failure model in which parts of the ship bow fail completely once their failure load in reached. The results of this model are dependent on a series of inputs based on the ships structure and the damping during collision, but for all input values within their expected regions it shows a significant reduction in the amount of the energy that must be retained by the gate as well as a decreased sensitivity to the, hard to predict, damping factor. This model shows potential to reduce material usage for lock gates in which collision
are considered governing. With further refinement this model could be used during the design of future lock gates to come to a cheaper design. Experimental data would serve an important purpose during this refinement. ... Read more

Hydraulic structures that are surrounded by flowing water can experience undesirable Flow-Induced Vibrations. These vibrations have a record of negative consequences. The most important cause of vibrations is self-excitation. This is a mechanism in which the forces acting on the hydraulic gate are amplified by the movement of the hydraulic gate itself which then further increases the vibration intensity. This mechanism potentially results in structural failure of hydraulic gates. Therefore, prevention of this type of excitations should be priority number one in the design stage of hydraulic gates One of the vertical self-excitation mechanisms is the galloping-type vibration and is addressed in this thesis. In this research the possible occurrence of galloping-type vibrations of a dynamic one degree of freedom system is simulated.

CFD computations were used to obtain a force matrix that served as an input for the simulation of vertical vibrations of the one degree of freedom system. This research has shown that the force matrix, obtained using CFD software, can used to derive the hydrodynamic damping coefficients due to flow and hydrodynamic stiffness coefficients due to flow and buoyancy for a range of combinations of opening heights and accompanying vertical velocities of the hydraulic gate.

The damping coefficient that was required to obtain a fully stable situation for all initial opening heights complied with the results found by determining the negative hydrodynamic damping coefficients due to flow. Therefore, this research has shown that the stability to galloping-type vibrations and the required external damping coefficient can be derived from the force matrix obtained using CFD.

The research performed has shown that the hydraulic gate, designed as an FRP laminate experienced roughly twice as high negative hydrodynamic damping values than a typical steel hydraulic gate consisting of a plate stiffened with ribs. This means that the FRP laminate requires twice as much external damping to neutralise the significantly higher negative hydrodynamic damping due to flow. The steel hydraulic gate experiences a larger range of negative hydrodynamic damping albeit with much lower negative hydrodynamic damping coefficients than the FRP laminate hydraulic gate.

Concluding this research, results show that FRP hydraulic gates are more susceptible to galloping-type vibrations than traditional steel hydraulic gates, meaning that either the design of the hydraulic gate has to be altered or much more external damping, in this case twice as much, is required to compensate for the negative hydrodynamic damping due to flow, with respect to steel hydraulic gates.
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