There is a lot of uncertainty in climate change developments, and therefore in its consequences. For the flood defence system of the Netherlands, an important consequence of climate change is the sea level rise. Marine locks are large, rigid, and intricate structures, with a required lifespan of at least 100 years, for which often design decisions have to be made for many decades, which is not made easy by the uncertainty of sea level rise. In this thesis, it is first analysed by means of a probabilistic model how sea level rise alters the failure probability of a marine lock, and at what degree of sea level rise the safety norm is reached. This analysis also results in knowledge on the critical lock characteristics which are required to be improved once the safety norm is reached. Once the safety norm of a lock has been reached, the lock can either be adapted, or completely replaced. Adaptation concepts were developed to improve the critical lock characteristics. To compare these adaptations to the lock replacement, an adaptive pathways map was drafted, which visualises the implementation of adaptations and replacement in regard to the sea level rise development. It was found that the application of a minor adaptation is always preferable over a replacement, but that the benefits of a drastic adaptation depends on the functional and structural state of a lock. When a lock eventually has to be replaced, because of sea level rise or any other reason, the question still remains how to implement the uncertainty of sea level rise into the design. Instead of designing for a conservative sea level rise scenario, one can create an adaptive design. This is a structure which can be adapted over time, meaning costs are saved in case of a mild sea level rise scenario, but the lock can still be made sufficient in case of a severe scenario. Again, an adaptive pathways map was drafted to compare the application of a conservative lock to several adaptive lock alternatives. Unfortunately, no general recommendation can be made for adaptive lock designs, as the advantages and disadvantages of the alternatives depend on the specifics of a lock.

An increasing awareness of sustainability problems urges the need for more sustainable practices within the infrastructure industry. Organisations actively engage sustainability in strategic missions and objectives. However, how these visions translate proactively to the tactical and operational levels of decision-making is still considered an exploratory area for the extant theoretical body of knowledge. Therefore, this research aims to support managers in tactical and operational decision-making for sustainability by means of a diagnostic research in the context of a long-term Strategic Partnership between client and contractor at Schiphol Airport. Their collaborative agreements based on Best Value aims for synergy by close cooperation between the partners and valuing professional expertise. To become highly committed to sustainability, organizations need to take responsibility over decisions regarding their organisational processes, in terms of dedication, motivation, and long-term investments to achieve effective solutions. Interventions require the direction of efforts into an organization-wide approach, meaning that both tactical and operational level management are internally aligned and stimulated to involve sustainability in their considerations. Also, a future directed mind-set and long-term investment approach are required to overcome technical and respectively cost related barriers. Fragmented decision-making can be overcome by engagement of stakeholders in sustainability ambitions. Moreover, proactivity in strategic partnering collaborations also requires extending responsibility towards supporting the partner’s responsibilities in order to achieve the best outcome for all parties involved. Therefore, it is key for both parties to allow each other to showcase their expertise within the set boundaries and ambitions of the Best Value principles. Currently, the client initiates new projects in which utility infrastructure projects play a role, whereas the contracting organization becomes involved after scope, budget, and planning are mainly determined. A mutually structured approach of formal meetings in the initiation process needs to be enhanced to collectively explore opportunities and define ambitions. Based on the gathered elements on proactive implementation of sustainability in decision-making levels, a conceptual framework is developed to test the case studies by analyzing sustainable outcomes in terms of their level of effectiveness. The analysis framework introduced by this study connects the different levels of proactivity with a chronological order of project phases, ranging on tactical and operational decision-making levels. This developed framework provides a practical solution for the collaborative setting between client and contractor, as it stimulates the development of mutual ambitions, substantive opportunities and directions for sustainable outcomes.

One of the cornerstones of construction project delivery is contract management. It can be directly related to business and project performance (Muhammad et al., 2019). Nevertheless, contracts and contract management have proven to be a complex and risky undertaking. It has been named as one of the main causes of conflict in the construction sector (Jaffar et al., 2011). To mitigate these problems, information systems have been implemented in contract management. Nevertheless, these systems are not fully delivering on their promises. Evidence that overall costs were reduced or an improvement in project performance is very limited (Zhai et al., 2009), and contemporary information systems have often failed to realize their goals (Mutschler et al., 2008). These developments indicate that the implementation process needs optimization. Preliminary research identified two socio-technical theories that are useful for analyzing human-system interactions during the implementation and use of information systems. Activity theory provides the framework for the analysis of human-system interaction. At the same time, boundary objects seem to be involved when multiple specialists transfer knowledge through the use of objects. Information systems are highly involved in this process. Therefore, boundary objects are also included as a focus of this research. These two theories should provide a new perspective on the challenges concerning contract management information systems. This analysis brought a few bad practices to light: •Support for the system users was severely lacking •Wrong tactics were used to incentivize system use •Responsibilities were unclear, and accessibility of necessary knowledge was limited •Solutions were often late and ineffective or only partly effective •Turnkey solutions rarely functioned as desired •Boundary objects are often not handled correctly Generally, the implementation process was characterized as unstructured and reactive. Next, these lessons learned were applied to create a set of recommendations that should improve current practices. The first set of recommendations was aimed at creating the right information system. The creation of a development team is key in facilitating this process. By sharing responsibility over multiple specialists under the guidance of a system coordinator, the information systems can be correctly created. Next, Including feedback from users, keeping the system as simple as possible, and using proper specifications make sure the information system is fit for purpose. The second set of recommendations cover the realization of the requirements for the correct supporting infrastructure for the information system. This consists of the introduction of a few new roles under the support team and some supporting tools to align the supporting structures with the users. This supporting infrastructure requires the introduction of system ambassadors, a system developer, a system coordinator, and a trainer. The necessary supporting mechanisms are two-stage training, system meetings, clear and targeted manuals, and rules, and finally, the securing of common interpretations. Finally, to make the recommendations more usable, they were transformed into the tool-support implementation (TSI) roadmap. This roadmap transforms the recommendations into a two-phase strategy that managers can apply in their projects. The first phase ensures the right conditions to build the correct information system. Consequently, the second ensures the right conditions to create the right supporting structures. Following this roadmap should ensure the proper creation and implementation of a contract management information system. Finally, to bring these conclusions back to the starting point, the following answer to the main research question is provided. Contract management can indeed be improved with an analysis of the implementation process based on socio-technical perspectives. The application of this new perspective brought a new set of problems concerning the implementation of contract management information systems to light. By showing what went wrong, changes could be recommended in order to improve current practices. Therefore, the importance of these challenges lies in the fact they need to be addressed to gain the benefits that information systems are supposed to have. To realize this goal of the research, the recommendations, and tool-support implementation roadmap have been constructed. When these recommendations are applied by using the TSI roadmap, the presumed benefits of information systems should finally be unlocked. As a result of these benefits, current contract management practices are likely to be improved.

The climate is changing and industries world-wide need to transform to assure a liveable earth for future generations. Within the construction sector, this requires a different approach and perspective on the life-cycle of civil engineering assets since the construction industry and its build environment is the world’s largest consumer of raw materials and responsible for 25-40% of the CO2 emissions. To make the transit to a more sustainable system, an increasingly discussed approach is a shift from the current linear lifecycles to a circular orientated economy. This latter means the preservation of used materials rather than dispose. In this way, the lifecycle loop of the materials is closed and the energy demand and the scarcity of raw resources is reduced. This more circular way of constructing entails the integration of the assets’ end-of-life phase and its’ circular solutions into the design. The reuse of assets, flexibility and adaptability in its’ function, modular based structures and a material database are all possible ways in dealing with assets after their lifetime in a circular manner. The shift towards a circular economy provides the possibilities for reducing the use of primary materials, protection of material resources and reduce the carbon footprint. This enhances a more sustainable practise of the construction industry though asks for major changes in its current operation. Clients play a substantial part in the transition towards a circular construction industry due to their responsibility in the formulation of the scope, project ambitions and requirements in the initiation phase of a project. Rijkswaterstaat, the biggest public client in the Netherlands, has the ambition to tender all the projects climate neutral and circular together with enhancing the sustainable living environment by 2030 and be fully circular by 2050. Circular pilot projects and programs are developed to promote the use of circular principles in the initiation phase, although circularity is currently often seen as an additional feature instead of an integral design principle. This results in a late consideration of the aspect and therefore a low level of circularity. To enhance circularity in projects there is a need for a clear and integral design process that includes circularity and an increase in knowledge among all team members of a project on circularity and the possibilities for the design. The aim of this research is to unite the circularity principles with the design process of hydraulic infrastructure projects and enable circularity to become common practice and a way of thinking. This is accomplished with a framework for implementing circularity in the design process based on state-of-the-art literature and results in a flowchart that aims to guide a project team to consider circularity and its opportunities during the integral design process of an asset. The flowchart visualizes the important development steps needed for the implementation of circularity, together with a circular way of approaching de design of an asset that includes the circular design principles. Thereafter, the public clients’ current design process and practice on implementing circularity is researched in an empirical quantitative study. These findings are reflected against the approach based on literature and show the points of attention for the public client on implementing circularity in the design process. The flowchart is verified with a case study on the project Weir Grave concerning the reconditioning of a historical weir in the river Meuse in the province of North-Brabant. This case study showed that the flowchart is valuable for the implementation of circularity and includes the significant aspects to consider. Although, the flowchart is not yet an applicable chart for design teams due to the high amount of information, layout and English language. A workable version with instructions is realized to improve this. Various barriers accompany the implementation of circularity in the construction sector with the most substantial being the necessary integral character of the industry and design process along with the timing of including the aspect in this process. An integral design method benefits circularity because numerous aspects and lifecycle phases of an asset influence the level of circularity. The integral character also assist the required early consideration of circularity, which is now often considered too late in the design process. Currently, the circular guidelines for the public client are focused on their role as an acquisition party and not on their part in the design. Therefore the design steps for circular assets are not part of the clients’ procedure, although this procedure does influence the possibilities for circularity. Therefore, the public client needs to take circularity into account prior to the tender procedure, in the initiation- and design phase, as relevant decision that influence the possibilities for circularity are made in these phases. This also influences the collaboration with the market party and requires a clear and uniform ambition towards them. Additionally, support, knowledge and an organization wide approach on circularity are of significance when implementing circularity in the design process. This reduces the current risk avoidance culture on circular design and supports the decisions made. One of the most practical measures to enhance circularity in a project is the implementation of the aspect as a requirement from the start in the clients’ internal project assignment and in the tender towards the market to create a responsibility for considering the aspect.

The aim of this research was to investigate if and how the project performance of integrated construction projects can be improved by focussing on empathy during the preconstruction phase. Big infrastructural construction projects often face a poor project performance which causes the sector is aimed at searching for strategies to deal with this. Looking at what drives project success it is said the people involved and their competences are main factors of influence. These people need to integrate working processes and collaborate with each other to successfully deliver the project. Experiences from practice and a literature review resulted in a strong expectation that especially the competence empathy is important to this in construction projects. This would be important during the preconstruction phase in specific to support the alignment and integration between project team members. The research focusses hereby on the preconstruction phase of integrated construction projects and follows the Integral Project Management (IPM) structure to describe the structure of construction project teams. Empathy is defined as ‘the ability to understand and share the feelings of another’. The research adopts a difference in internal empathy ( = empathy between people within the project organization) and external empathy (= empathy with the client and/or stakeholders).

The research first investigated in interviews with experts from the industry if and where during the preconstruction phase it would be important for the involved people to be empathic. Second the empathic ability of a construction project organization has been measured to indicate how empathy is distributed across project participants. The results showed that the construction professionals on average score low on empathic competence and that in certain situations it would be important for project participants to be empathic for a good project outcome. This results in a gap in the construction sector between required empathy and actual empathic competence which demonstrates there’s room for improvement in this area.

Based on the results of the research it seems that the project performance of integrated construction projects can be improved by focussing on stimulating more empathy between client and contractor and towards stakeholders during the preconstruction phase (= external empathy). Especially in the relationship between client and contractor there’s room for improvement as there’s a gap in required empathy of the contractor. The reason that the performance of construction projects can be improved via external empathy is that when looking at what mostly causes projects to perform badly, it is said this is often related to a bad collaboration between client and contractor and/or insufficient involvement of stakeholders. The research results also showed that project performance can be improved by focussing on stimulating more empathy internally in the project organization within teams and between people from different disciplines. However, this has a lower effect on improving the performance of the project compared to stimulating external empathy. The research finally presents The Empathy Framework as a recommendation for the construction sector to be used as a strategy to improve project performance via empathy.

Reuse is highly appraised in the theories about circularity and sustainability. However, overpass girders in the main road network of Rijkswaterstaat are never reused for the same function. There are barriers present which hampers the reusing elements in comparison with the traditional way of handling infrastructure projects. Most of the main reasons why girders are never reused in the main road network of Rijkswaterstaat according to the interviewed authorities can be diminished with the designed process model. The process model creates insight in the process and results are gained in the SBIR project. Insight is necessary in the total process, environmental impact, financial impact, supply and demand, and dismantling the structural components. Next to the process steps there are essential boundary conditions for reusing structural components in large scale. External boundary conditions are clear laws & regulations and the improvement of environmental impact both in calculation tools and in environmental gains for tender contracts. The laws and regulations must explicitly state what rules should be followed. Rijkswaterstaat can provide this necessary clarity. Also, the calculation tools must be adjusted so that all reuse advantages and disadvantages are included in the calculation and a fair comparison can be made. The process steps consist of evaluation of the structure, impact calculation and supply & demand. When the process steps are followed the highest potential of reusing elements can be reached. After the process steps are ran through, the knowledge must be shared with all market parties and clients. This will create new insights in the sector which can result in new ambitions and new eco-innovations. With the newly gained insight, the process model of reusing structural components can be followed again to improve the circularity and sustainability of the sector at each new process cycle.

Infrastructure mega-projects are highly important for economic and societal growth, but they are also extremely susceptible to a high degree of risks leading to massive delays. These delays affect not only the project schedule but also the cost and the quality. The delay events are present throughout the project life cycle but, according to the researcher’s observation, most of the delays were found to occur in the design-construction interface. In general, the problem of delay has been studied a lot by previous researchers; however, being one of the critical phases, delays in the design-construction interface have still not been investigated. Therefore, this research conducts a detailed study for developing mitigation measures for delays within the design-construction interface in the infrastructure mega-project. To achieve the above goal, the research investigates critical events in an infrastructure megaproject to develop measures with the help of the critical incident technique (CIT). CIT was used for the research because it helped in evaluating the success or failure of the adopted and recommended measures. Based on the evaluation the research proposed a preventive and corrective measure framework to minimize the delay's effect on the project schedule.

Worldwide, more and more actors have started to speak out their belief in a future with three-dimensional mobility as one of the solutions for congesting and polluted cities. Electric Vertical Take-Off and Landing vehicles – more popularly referred to as drones – are supposed to relieve the current infrastructure network, mainly roads, and quickly transport cargo and people through the sky to their desired location. This new mode of transportation is also called Urban Air Mobility (UAM). To make UAM a reality, three main components are required: the aircraft and aircrew, the management of the airspace and the integration in the community. Over the last years, the industry has made major steps in the first two aspects. However, the community integration of UAM – which is about infrastructure, social acceptance and regulations, among others – has fallen behind, as cities are barely preparing themselves for this new transportation mode. Still, UAM may become a reality much earlier than those cities may expect. When that happens, cities will have to be prepared for this. It is therefore important to explore what it means and takes when UAM is integrated into a community. It is the latter which forms the fundament for this research. Where the literature extensively discusses the aircraft and airspace integration, a knowledge gap can be identified on the community integration of UAM. For this reason, the main goal for the research was to analyze the required changes in the urban mobility regime, which challenges this will cause and what actions communities can take in preparation for UAM. To contribute to the understanding of the subject and analyze the practical elaboration of UAM Community Integration, the research tried to answer the question how the transition of Urban Air Mobility can be realised in communities, which formed the main research question. To answer the research question, a qualitative approach was chosen, recommended to be used when the investigated phenomenon is new and when the investigator seeks to answer “why” and “how” questions. A combination of different qualitative data gathering methods was adopted: literature reviews and semi-structured interviews. This thesis shows that there is a lot involved in the transition from two-dimensional to three-dimensional urban transport, or Urban Air Mobility. The transition is driven by large-scale developments such as urbanization, mobility growth and climate change, putting pressure on the mobility regime. Besides, there are technological innovations in development, such as battery and communication technologies and automation, which the development of UAM as a new mode of transportation will depend on. In addition, there are internal frictions in the existing mobility system, such as congestion, which require new, sustainable mobility solutions. The comparison between the existing and future mobility regime – the latter including UAM – makes clear that the community integration of UAM requires changes in every single dimension in the mobility regime. This is accompanied by various challenges and requires actions from cities. Major challenges are mainly found within the dimensions of sectoral policy, infrastructure and culture or symbolic meaning. The most important actions that cities can take therefore also address these challenges. For example, there are currently a patchwork of rules that restrict or prohibit the use of drones and thus make UAM virtually impossible. This requires standardization of rules, which above all allow the use of drones, while respecting the social impact that drones can have. Furthermore, there is usually a lack of existing infrastructure, which means that new infrastructure must be developed. However, the limited space, suitability of existing buildings, financial feasibility and social value of UAM are some important factors that make infrastructure development within urban centers a challenging task. Cities will have to identify suitable locations for vertiports, taking these types of factors into account. Existing energy capacity can also be an obstacle. Whereas typical passenger vehicle DC fast charging typically ranges from 50kW-350kW, UAM requires charging capacities of up to 600 kW. To provide this, cities may have to make adjustments to their existing energy network. Finally, UAM will likely have a significant social impact in terms of noise, horizon pollution, privacy, safety and price,. The risk of social resistance is therefore high. It is important that cities anticipate this by, among other things, informing and educating the community about UAM, carrying out pilot projects and drawing up social guidelines. Other actions that cities can take to prepare for UAM include the exploration of potential user practices and the definition and division of stakeholder roles, among others. To conclude, the realization of UAM in communities is only in its infancy and involves an extensive process of (interdependent) developments and actions. Once the variety of niche-innovations have developed into a more mature state – which can still take several years –, UAM will be able to start its breakthrough into the urban mobility regime. This transition requires changes in all regime dimensions. The integration in the community will have impact in different ways, of which it is assumed that the spatial, energy and social domains will be impacted most. Challenges rise, mainly with regard to the sectoral policy, infrastructure and culture or symbolic meaning within the mobility regime. In order to realise the transition of UAM in communities, these must be addressed. This thesis proposed some of the more important actions that communities can take for the community integration of UAM. These are outlined in the final roadmap, which should give the final answer on how the transition of UAM can be realized in communities. The research recommends cities to take up the identified actions for UAM community integration. They provide an insight into what needs to be done to enable the community integration of UAM. This research has taken a first, exploratory step in the right direction, but the identified actions - logically - have no outcome yet. Further research into these actions is therefore required. Cities are therefore recommended to continue with this, so that they can find an answer to the implicit research questions that lie hidden in these actions.

The city of Venice has been prone to flooding throughout its history. However, flooding has recently been occurring more often than before. As a result, engineers have collaborated to come up with a potential solution to the flooding. This solution, a mobile barrier known as the Experimental Electromechanical Module (Modulo Sperimentale Elettromeccanico, or Mo.S.E.) has been in progress for quite some time now and is therefore still not functional. On 12 November 2019, an extreme high water level event occurredwith the second highest recorded water level in history. The flooding event should have been prevented by the construction by a flap gate storm surge barrier, a project started after the 1966 historical high water event, which takes the name of Mo.S.E. project. In this paper, the 2019 event is analyzed, investigating the causes of the event and the design criteria of the Mo.S.E. barrier project in terms of its structure, construction process and completion state at the time of the event.The meteorological and hydrological causes of the 12 November 2019 is studied to better understand what caused the event. If the causes of an event are understood, a solution to similar future events can be more easily determined. Historic waterlevel data is used to better understand the hydraulic conditions within the Venice Lagoon. Existing research projects that utilized similar data are studied to estimate the return periods considered in the design of the Mo.S.E. barrier. The return period for the 12 November event (187 cm) was found to be about 130 –140 years. The return period for the water level at which the Mo.S.E. barrier is designed to be fully closed (110 cm) is 5 –7 years. The effects of climate change and subsequent eustacy are also analyzed to determine how this would affect the return periods of both the 12 November 2019 event and the barrier closure level. Analysis of estimated future return period data predicted thatthe return period range for the 12 November event would decrease from 130 –140 years to50 –100 years while the return period range for the Mo.S.E. barrier closure would decrease from 5 –7 years to 2 –5 years. An estimation of the flooded buildings and roads is made. Surface elevation data is compared with the water level of the November 2019 flood event. In this way information is gained about what areas were flooded. By using downloaded from Open Street Maps, information about all buildings and roads, including their location, are obtained. Analyzing this data results in information about what buildings and roads are flooded. These results, together with numbers of damage per flooded object, are used to make an estimation of the total direct damage due to the flood event. The estimated total direct damage amounts to €870 million.The estimated damage to cultural heritage amounts to €244 million. Also, the case was investigated in which the Mo.S.E. barrier would have been operational during the November 2019 flood event. If the barrier had closed, the total direct damage would have been€257 million.Conclusively, an analysis of the management system of the Riequilibrio E Ambiente (REA, Lit. Rebalance and Environment) mega-project and the Mo.S.E. project is conducted to visualize the main failures and delay causes which lead to the circumstances of incompletion of the barrier at the time of the 2019 flood event. Through a careful analysis of the main events and technical problems encountered throughout the planning and construction of the barrier, the leading cause of delay is found to be political corruption, along with uncareful definition of project objectives and extreme levels of project complexity. Currently, the completion of the storm surge barrier is scheduled to be at the end of 2021. In 2019, the construction of the barrier wasfound to be completed at its 94%, signifying an 8-year delay past the original completion date of 2012, which was determined at the begging of the construction works in 2005. The Mo.S.E. barrier project is merely one part of a much larger mega-project designed for the safeguard of Venice which was meant to be completed in 1985. While the Mo.S.E. barrier is delayed almost 8 years, the entire project is delayed by a total of 26 years.It is recommended to direct further researches to future impact, considering climate change, and the amount of damage for certain return periods and the impact of the Mo.S.E. barrier on this last. Hence data collection making damage estimations more accurate, internal corruption prevention and management within large infrastructure works and feasible optimizations solutions to apply to the Mo.S.E. barrier in order to face sea level ris

Immersed tunnels, located in waterways, could be a limiting factor in the dredging in waterways. This dredging is required since cargo vessels draught increased the past decades. In this thesis a new method is defined for temporarily, effectively, re-floating immersed tunnels. With this method extra risks arise, for these risks’ measures are given. The validity of this method is proven by applying the method a relevant case study. This case tunnel is the Wijkertunnel, consisting of six elements and a total immersed length of 600 meters. It showed that the maximum deepening available is 6.60 meters. It is concluded that the impact of the risk measures is limited. Finally other immersed tunnels are compared to the Wijkertunnel. For these tunnels the different types are described, and the impact of these differences are discussed. It showed that for all the immersed tunnels the method is viable, except for immersed tunnels with a very few elements.

In infrastructure construction projects, stakeholder alignment is an important factor that contributes to project success and prevents excessive delays. Literature shows that it is known how to align stakeholders and what to do, however, when to carry out those actions, it not yet clear. This research contributes to that knowledge gap by analysing the Landside Infrastructure project of Schiphol as a single case study. Interviews with project stakeholders, project documents and field observations were used to collect data in order to develop a model.

Wind energy from the North Sea is one of the solutions to achieve the climate goals of the Paris agreement. The Dogger Bank, a North Sea sandbank, has a lot of potential for wind energy due to the relatively shallow location and good wind conditions. An artificial island creates even more opportunities, because alternating energy can be converted here into direct current. An island will also make the construction and maintenance of the windmills cost-effective. The Dogger Bank, however, is part of Natura2000 area, for which strict legislation applies. To design a stable island coastal defence, which contributes to the North Sea ecology, it is researched how natural value could be added to make the island licensable.

The flat oyster (Ostrea edulis) has been chosen as an umbrella species, a species that creates an environment in which a large group of other species can benefit. The disappearance of the present ecology by building an island can be counteracted by restoring an oyster habitat. To obtain the boundary conditions for a successful oyster bed, research was done into the relationship between the bed shear stress and the historic presence of oyster beds. The shear stress boundary condition for the highest significant waves was 119.8 N/m2 while the shear stress due to the average significant wave climate must stay between 2.5 and 10.3 N/m2. The orientation of the coastal protection, the depth, the profiles (as the presence of a reef or foreshore) and the chosen material are decisive factors for success of oyster beds. Concluded is that opportunities are available in the coastal defence. In typical cross-section are only few areas suitable. For the most exposed side (330-360ºN), it is opportune for oyster beds to grow around the toe and foreshore when located in water deeper than -25.0 m MSL. At the least exposed side (120-150ºN) this is -18.0 m MSL. Reefs and prolonged foreshores are expected to be efficient for creating larger nature enhancing surfaces.

The design and three-dimensional consequences of the suggested measures are recommended to study into detail. In addition, the biotic factors and the method of initiation of oyster beds will have to be further investigated to obtain more information about successfully creating oyster beds around an island on the Dogger Bank.

The Dutch Ministry of Infrastructure and Water Management (Rijkswaterstaat) currently manages 137 navigation locks. Most of them have been constructed during the 20st century and were considered as unique projects. This led to a great variety in their designs and characteristics. Currently, 52 locks are reaching the end of their technical life span and require significant renovation and renewal.

Almost all locks are different and this variety complicates their management and maintenance. These complications cause several problems concerning sub-optimal availability, unpredictable reliability and high life cycle costs. Rijkswaterstaat performed several studies, indicating that the standardization of lock gates could potentially solve these problems. However, how to standardize these lock gates is still unclear. This research investigates the standardization possibilities with the aim of reducing the variety found in lock gates, focusing on the mitre gates present in 37 of the 52 locks requiring large renovation and renewal. Focus is put on mitre gates as these are the most common gate type used in Dutch navigation locks.

The approach of reducing the variety in the lock gates is based on the creation of clusters, in which one standardized gate is applied. The clustering of the mitre gates is based on the widths and required door heights of the considered locks.

To tackle the problem of standardizing gates in locks with different widths, it has been decided to vary their angle of closure. The degree to which the angle of closure can vary is dictated by physical boundaries, indicating the limit with respect to stability requirements.

Consequently it was chosen to modularize the doors so that they can be scaled up or down to the desired height, solving the problem of applying a standard door in locks with different retention heights.

To grasp the effects of standardization, the over-dimensioning is approximated by using estimates for the amount of material required for the gates. To determine the optimum cluster configurations, a clustering program has been developed, taking into account both over-dimensioning and physical boundaries.

The clustering program encompasses the study of 37 locks. This study shows that the gates of these locks can be grouped into a minimum of five clusters. Due to a modular gate design and fewer spare components, excessive over-dimensioning is prevented. A conceptual design and a comparative analysis indicated that the gates can best be grouped into eight clusters, potentially leading to improved management and a € 7.100.000 cost reduction.

This research included several assumptions and starting points. The following steps should be taken in order to deepen and enhance the current research:

• Assess the influence of the determining aspects on the costs of a lock gate instead of the material required.
• Better approximation of over-dimensioning by using a more complex and accurate model for the estimation of the required material.
• Perform a study on the amount of spare components required for each separate gate cluster.

More than 50 locks owned by Rijkswaterstaat need replacement or renovation in the coming 40 years. Due to this fact an opportunity for changing the traditional way of building and maintaining navigational locks has arisen. Because of the replacement/renovation of locks in the coming time, implementing a new owning and building strategy is relatively easy. Rijkswaterstaat is interested in how standardization could be applied to (some) lock components to save costs, and increase reliability and availability.
The lock gates are the lock components with the highest potential for standardization. A parametric model for several lock gates is made in order to compare these gate types for a range of boundary conditions. The comparison of several gate types which can be made by the parametric model, could lead to a prescription of a standard gate type for specific boundary conditions. With this prescription, standardization could be implemented in the design process for navigational lock gates. The parametric model can also be used to assess the impact of design choices on the standard design. A parametric model is made to assess rolling gates and mitre gates (with and without clearance at the pivots) made in steel. The model has led to a way of optimising one design (in terms of steel volume used) per gate type for these gates for a range of boundary conditions. The model is able to prescribe a gate type for the case study used, the Prinses Marijkesluizen. The model is unable to prescribe a gate type for bilateral retaining gates, since the results of the design are too close to each other to prescribe one variant as the best variant. It is recommended to record more data, since costs can be added as optimisation criteria (instead of material volume) when this data is known.

In the Netherlands, a new assessment method for the required safety level of primary flood defences is introduced in the Water Act. It is estimated that currently roughly 1900 kilometres of flood protection does not meet the safety requirements for the future (Jonkman, Jorissen, Schweckendieck & Van den Bos, 2017). Past flood defence projects show that integrating reinforcement measures is a difficult assignment. It is specifically focused on dike reinforcement projects in this thesis. A deficiency in the design process is identified in the role that the influence on the existing situation has on the evaluation and selection of design alternatives that are input for the Environmental Impact Assessment. The difficulty for improving the importance of the existing situation in the surroundings, in the design process is that the subject experts on these themes are typically assessing the consequences of proposed interventions (Aalberts, 2018). The research objective is set to develop a method that allows to include the influence on the existing situation within the evaluation and selection of design alternatives in dike reinforcement projects. This method aims for providing information to compare the spatial integration of reinforcement designs in early stages of reinforcement projects. Subject experts should assess the provided information, and determine whether a reinforcement design provides a satisfying influence on the project area. It is focused on dike reinforcement projects in rural area. A research through design study is used to develop the method to compare design alternatives. The study included the identification of technical design measures to increase the strength of dikes in rural area, and the decomposition of rural areas in functional characteristics that can be valued. A conceptual evaluation model is developed to express the relation between functional characteristics and design alternatives for dike reinforcements. It is studied how a method can be provided to compare the outcome of the conceptual evaluation model for a large variety of design alternatives. The value of the developed method is assessed in a case study, which is the dike reinforcement project “Wolferen-Sprok”. The resulting method is able to compare design alternatives on the influence on the existing situation by following seven steps. It is providing design measures for the identified safety problem of the dike in a certain project area. Simultaneously, the characteristics of the project area should be identified and visualized on maps. This provides the required information to apply the conceptual evaluation model that identifies effects of design alternatives on the existing situation. The retrieved data is visualized to compare design alternatives. It is concluded that the developed method focusses mainly on natural, cultural, and social economic functions in rural project areas. This means that influence of design alternatives on costs, maintainability, and landscape values should be addressed separately, in the evaluation and selection of design alternatives. It is recommended to study how the influence on these topics can evaluated in a similar method. The developed method can be applied to include the existing situation in the project area in the evaluation and selection of design alternatives in dike reinforcement projects in rural areas. It is expected that application of the method in design teams provides new input for further improvement of the method.

A new trend to found offshore wind turbines at larger depths or on harder soils is to apply gravity based foundations (GBFs). These foundations are caissons with a set of properties which are different with respect to other caisson types. The number of constructed caissons is large and the timeframe for construction and transportation from land into water is small when these foundations are applied on commercially scaled offshore windfarms. In general, an offshore wind farm is constructed within two years and all GBFs must be constructed and transported into the water in a tight time schedule.

To accomplish the construction and installation of a large number GBFs in a tight timeframe, a new design method is developed. A realistic case study is composed and the target is to construct and install 64 GBFs in front of the Belgium coast in a timeframe of 2 years.
Two designs are considered, a materialefficient design and a design which is optimized regarding the constructability.

When the GBF-design is known, the transportation method from land into water is considered. According to the decision matrix, developed in the literature study, the only feasible method is to apply a semi-submersible vessel. However this solution is quite expensive, whether the storage location is at the construction area or in the sea. Due to the large costs a new alternative method could be feasible. Several new ideas are created and the most promising solution is ‘The immersion structure’.

Because time is the most important factor, the construction planning and construction area layout are considered. Three options are considered and the most optimal construction planning is chosen. On four locations the construction activities are optimized and with the use of a production line it is possible to construct the 64 GBFs in time with minimal use of area and equipment. Because of the small area left, the storage location cannot be designed on the construction area.

The design of the immersion structure consists of a platform which consists of H-beams and two concrete hollow legs. The immersion structure is innovative because it is placed directly on sand and no foundation works are needed. Due to the large capacity the main part of the caisson types can be transported. Because the structure is able to float it can be easily transported.

At last the construction and operational costs of the immersion structure are compared with the cost of renting a semi-submersible vessel. The semi-submersible vessel seems to be the best solution but when the immersion structure is applied at multiple projects it could be a profitable solution. The depreciation and interest costs for the immersion structure are calculated and the immersion structure is profitable when a minimal utilization rate of 22% is achieved during a service lifetime of 20 years. Depending on the market development and the amount of applicable caisson construction projects the immersion structure could be profitable. Comparing with the case study the immersion structure is profitable if three comparable projects are executed in the service lifetime.