The Netherlands is facing a housing crisis, with a growing shortage due to urbanization and limited available land. An alternative for constructing new buildings is adding levels to existing buildings, but this poses challenges in ensuring structural stability, particularly as existing buildings were designed with older design codes, while new levels must comply with the latest Eurocode. However, an overview of the exact changes in wind loads and what kind of influence this has on adding new levels to an existing building is missing. Additionally, it is unknown what the exact gap is between the building or location specific wind load and the wind load according to the design codes. This research aims to clarify how changes in wind load design codes affect adding levels to existing buildings.
The study analyses the development of design codes from TGB 1955 to the Eurocode, focusing on wind loads. Wind pressure and pressure coefficients are examined through KNMI data and computational fluid dynamics (CFD) simulations. Findings suggest that while overall wind speeds align with design codes, certain coastal locations like Hoek van Holland and Vlissingen show deviations, indicating a need to revise the wind area map. Additionally, pressure coefficients are not constant over building surfaces. Especially the width seems to have an influence and this parameter not considered in the current Eurocode.
Adding levels to an existing building influences the wind load in a twofold manner: extra surface subjected to wind load and a difference in design codes for wind load between the now and past. The structure of the existing building must be used optimally to support the added levels. A case study on the SCYE010 building demonstrates that optimizing the top level's design and geometry can reduce wind pressure and loads, emphasizing the importance of code evolution in such projects. These findings offer critical insights for designing additional levels on existing structures.

Wind turbine blades have a service life of around 20 to 25 years and are then decommissioned while generally still having excellent structural performance and high-value material properties. Currently, the recycling options for the fibre-reinforced polymer (FRP) composite components that make up the blade are limited, so most blades are either landfilled or incinerated at the End-of-Life, essentially wasting these qualities. By repurposing the blades instead, the qualities can be preserved while also lowering the environmental impact of the new structure. This research focusses on repurposing decommissioned wind turbine blades as main structural elements in traffic bridges, where the focus is on the structural design and feasibility.

The possibilities for repurposing largely depend on the type, size and condition of the specific batch of blades. Based on literature research regarding the common features of blades that are soon to be decommissioned, a custom 38-meter-long blade model is developed. Next, a variety of design options including multi-membered bridge structures have been created and arranged in an overview. By combining these options with the findings from the literature study, several designs for ‘blade bridges’ are proposed, most of which have the potential to already be realised in the upcoming years. Some of these designs are only intended for pedestrians and cyclists, while others are intended for regular road traffic. The maximum allowable spans for these bridge designs are all between 15 and 20 meters, thus confirming the large potential for repurposing blades in bridges.

Based on the structural analysis of the blade bridge designs, it can be concluded that for blade bridges as pedestrian and bicycle bridges, the natural frequency is governing. A prerequisite is that the blade-to-support connections at the aerofoil parts are designed to prevent stress concentrations, but this should be easily achievable. For road traffic bridges, it is found that the deflections are of greater importance than the natural frequencies. Also, the blades in a road traffic bridge will be highly stressed, especially locally near the supports of the aerofoil parts. These local stresses are likely to be governing, making the connection design at these supports crucial. A thorough investigation of these local stresses is therefore recommended in a real-life blade bridge project.

Many countries such as Brazil, have a low percentage of recycled container glass due to multiple factors, such as inadequate waste collection and recycling infrastructure, low public awareness about recycling’s significance, and insufficient laws to promote it. In addition, the country faces high levels of homelessness and inadequate housing. As a result, an increasing number of builders are exploring repurposing glass bottles as a construction material for walls, occasionally incorporating them into traditional earthen building techniques. Therefore, this thesis investigates the potential of repurposing glass container bottles for the construction of load-bearing walls for affordable housing in Brazil while at the same time reducing pollution, enhancing aesthetics, and promoting environmental friendliness.

The main research question is formulated as follows:
How can the structural feasibility of re-purposing beer bottles in Glass Bottle Earth Bricks (GBEB) for wall constructions be ensured?

The report consists of four parts, which are created for each research area: state of the art, experimental investigations, numerical investigations, and finally the discussion, conclusion and recommendations section.

The literature review underscores a rising trend of incorporating glass bottles into earth-based constructions, driven by their shared advantages of environmental friendliness and affordability. Nevertheless, challenges emerge in connecting glass bottles when constructing walls with mortar due to their irregular shapes. To enhance construction efficiency and quality, innovative methods entail pouring mortar between the bottles rather than applying it manually. This approach is complemented by creating bricks while using molds where the bottles are placed inside, facilitating easier stacking and faster execution. The
direct integration of glass bottles into bricks further expedites the process. Prefabricating these blocks with pre-placed glass bottles in controlled environments further optimizes efficiency.

During experimental investigations, a self-compacting earth-based mortar mixture is formulated using local Dutch soil from Emmen. Five different mixture designs are explored, utilizing both artificial and natural soil. The mechanical properties of the earth-based mortar mixtures are evaluated through compressive and flexural strength tests, as well as a mini slump flow test to assess workability. The selected earth mixture is anticipated to achieve an average compressive strength of 12.1 MPa after 28 days, an average flexural strength of 3.67 MPa after 7 days, and a flow diameter of 23.05 mm.

Subsequently, a prototype glass bottle earth brick containing a horizontally aligned longneck beer bottle is produced, revealing a compressive strength ranging between 8.21 and 11.40 MPa after 28 days of casting. Upon failure, a fracture analysis indicated that the origin of failure lies at the bottom of the bottle, with breaking stresses at failure measuring 608 kg/cm² and 431 kg/cm² for two samples.

Results from SEM-EDS analyses reveal iron and aluminum residue at the fracture origin in the glass bottle. The earth mortar cast around the bottle showcases a similar composition, suggesting that scratches were likely introduced during brick manufacturing by the earth mixture. Additionally, an initial evaluation of the thermal behavior of the Glass Bottle Earth Brick (GBEB) indicates that the mortar acts as a heat sink, suggesting that the GBEB could contribute to thermal comfort.

Through numerical investigations employing Finite Element Methods (FEM), a comprehensive understanding of stress propagation and behavior within a Glass Bottle Earth Brick is achieved. Modeling the brick with the bottle from laboratory experiments aligns with expected peak stresses. However, the Finite Element Method (FEM) model's simplification disregards knurls, the ribbed patterns commonly present on the outer bottom surface of the bottle. Simplifying the model by removing the knurls lowers the computational complexity but potentially overestimates the strength of the GBEB. This underscores the importance of considering knurls to accurately predict peak stresses.

Based on these findings, it is inferred that repurposing glass bottles for constructing walls capable of supporting small-scale structures is feasible. However, since this represents a novel building approach, it demonstrates potential while also highlighting the need for further investigation and clarification. Increasing the number of samples tested and expanding the range of factors examined can enhance confidence and provide insights into the material results and assumptions made.

In the more than sixty years of experience in forensic structural engineering of Adviesbureau Hageman, damages in underground concrete parking structures repeatedly passed by. In a master study, mainly based on the comprehensive archive of Adviesbureau Hageman, an overview of the various damages that can be distinguished, is made and causes for the occurrence and measures to prevent them, are addressed. Furthermore, one category of damages, that is not limited to only parking structures, but generally occurring in concrete structures, is damage to concrete corbels. In order to investigate the behaviour of such corbels, finite element analyses are performed with the FE Code ATENA. Its behaviour in case of a corbel and support according to the Codes is investigated, but also in case of a support close to the edge and applied horizontal loading due to imposed deformations in the elements that are supported by the corbel. In the thesis the overview of damages in concrete parking structures and the study into the behaviour of corbels will be presented.

A large number of offshore wind turbines have been installed in recent years, and even
more are being erected in current and future projects. The majority of these turbines
have been or are being built of monopile foundations. Eventually, both the turbine and
the foundation have to be decommissioned. However, decommissioning options for
monopile foundations are limited, especially for complete removal of the foundation.
This thesis aims to study a new removal method patented by the company Iv-Consult,
which could potentially make entire monopile removal possible. The method uses
deformation of the monopile wall by a clamping tool to generate a vertical force. Since
the thesis served as a preliminary study into the removal method, it was chosen to limit
the scope of this study to the monopiles that are expected to be decommissioned in the
near future. With this information, a single case of monopile with dimensions that are
representative for these monopiles was presented. To analyse the removal method on the
case monopile the finite element method was used. In order to ensure results obtained
using the finite element method are accurate and representative, a convergence study was
carried out. To determine the element type and the mesh size that was the most suitable,
two different models were used: a ring model and a small cylinder model. Each was
studied using different combinations of inputs. After the results from the convergence
were obtained, these results were used on the models with which the removal method
was studied. Different configurations of the removal method were analysed with the
aim of maximizing the force that can be generated by the method to overcome resistance
forces. As a final step, the resistance forces that need to be overcome were calculated
for different soil types and compared to the results obtained from the removal method
models to verify the feasibility of the method.
From the results of the convergence study, it was shown that it is possible to model
the removal method using the finite element method and obtain representative results.
The final results of this thesis showed that clamping the monopile multiple times
does not have a positive influence on the vertical force that can be generated. This is
because clamping the monopile only once caused the highest vertical force. However, the
forces generated using the different setups of the clamping method were not sufficient
to overcome the resistance forces. This shows that the removal method in the current
configurations is not feasible, without applying any soil resistance reducing methods.

Vertical greening systems (VGS), i.e. vegetated building facades, can harness the benefits of nature to contribute to resilient and healthy cities. A lack of guidelines for the early selection and design of VGS currently limits implementation. Based on a literature study and expert interviews, this thesis proposes a multi-criteria framework and tool to assist architects and engineers in the holistic selection of multi-purpose VGS. The research compares the performance of different system types on 18 impact criteria, ranging from urban noise reduction to installation costs. Depending on project-specific input about environmental conditions and building project objectives, the framework provides a ranking of the most suitable VGS. Design recommendations ensure a VGS that is fit for purpose. Subsequently,
sensitivity analyses, a case study and testing on sample projects validate the usability and results of the tool. The thesis extends current perspectives on evaluating the impact of VGS on the built environment. The tool enables users to make holistic and justified decisions on the application of a VGS.

Traditional approaches to noise barrier design often rely on outdated techniques and resource-intensive materials like concrete and steel. However, with sustainability gaining prominence, aligning noise barrier design with green construction principles becomes crucial. Structural optimization, aimed at minimizing material usage, emerges as a promising strategy to mitigate environmental impact. This study focuses on determining the optimal geometry of a noise barrier composed of low-tensile strength material, under the influence of self-weight and uniformly distributed lateral load.

The methodology employed addresses this question through a series of key steps. Beginning with a two-dimensional analytical form-finding process, optimal cross-sections are derived for the noise barrier. The application of uniform strength theory, known for its efficiency in generating material-effective structures, results in constant stress shapes. These solutions are validated using Finite Element Analysis (FEA) to ensure conformity with predefined stress criteria. Subsequently, numerical structural optimization is conducted to achieve minimum weight geometries that adhere to stress constraints, utilizing a penalty function. The validation process involves comparing numerically optimized geometries with analytical solutions, confirming their reliability and mutual consistency. This validated optimization approach is then extended to three dimensions, exploring the optimal combination of longitudinal profiles and varying cross-sections along the barrier.

Analytical solutions for 2D uniform strength cross-sections of the noise barrier differ based on load conditions. For self-weight, an exponential function describes constant stress, ensuring uniform compressive stress across the structure. Conversely, under uniformly distributed lateral load, a linear function depicts constant maximum bending stress along the height. The interaction between self-weight and lateral load results in symmetric geometries defined by specified constant tensile stress. A square root geometry guarantees constant zero tensile stress, offering advantages like reduced need for additional structural elements and practicality in real-world scenarios.

A significant distinction arises between 2D cross-section and 3D structural optimization regarding bending capacity. In three dimensions, the entire structure contributes to bending resistance by shaping itself. Releasing the rotational degree of freedom at the bottom support enables the generation of a corrugated longitudinal profile, enhancing bending stiffness. This corrugation distributes bending moments over longer spans, reducing stress and material requirements. Notably, the optimized corrugated profile exhibits enhanced bending stiffness, minimizing the impact of practical constraints.

In summary, this research provides insights into optimal geometries for free-standing structures, highlighting the efficiency of analytical and numerical approaches. The numerical optimization framework proves highly effective and efficient, contributing valuable insights to noise barrier design within a sustainable framework.

The current understanding of auxetic metamaterials in structural engineering applications is limited. Auxetic materials exhibit lateral contraction under compressive loads, possessing a negative Poisson's ratio. The research addresses this gap, focusing on the use of auxetics for steel reinforcement in structural concrete elements to enhance sustainability by reducing material usage without compromising safety.

The research goals include:

Describing the state of the art in auxetic materials for concrete structural elements.
Investigating auxetic behavior under different loading conditions (compression, tension, shear, and bending).
Developing a geometrical design for auxetic steel reinforcement, considering practical aspects like manufacturability and mortar flow.
Performing numerical analyses on proposed beams under various loading conditions, comparing Young's modulus and Poisson's ratio.
Exploring upscaling solutions for architected metamaterials.

The research follows a systematic approach:

Literature Study:
Examines the use of auxetics in concrete structural elements.
Selects a bow-tie architecture for its adaptability and manufacturability using Laser Powder Bed Fusion (LPBF).

Geometrical Study:
Focuses on a cantilever beam subjected to rotation, ensuring pure bending with a linear geometry.
Chooses a range of unit cell angles for desired structural behavior.
Designs unit cells and beams, considering compatibility, continuous lattice, and manufacturability.

Numerical Study:
Utilizes FEM software (ABAQUS) to analyze effective Young's modulus and Poisson's ratio.
Validates models against literature using Euler-Bernoulli beam theory.
Studies the influence of boundary conditions on results.

Upscaling Technologies:
Explores technologies for upscaling auxetic lattices beyond current LBPF methods.
Proposes multi-robotic fabrication for automated assembly using conventional rebar.

Findings and conclusions include:

Selected Architecture:
Chooses bow-tie architecture for its modifiability and manufacturability.
Proposes "single cells" and "three angle" units for different loading conditions.

Design Expansion:
Develops a stacking sequence for a 3D lattice, considering dimensions and relative density.
Creates beams with auxetic, cubic, non-auxetic, combined, and gradual behaviors.

Numerical Model Conclusions:
Affirms constant moment and zero shear in designed beams.
Emphasizes the dominance of effective modulus in lattice geometry.
Validates Poisson's ratio behavior in different beams under pure bending.

Upscaling Proposal:
Recommends multi-robotic fabrication for full-scale lattice construction.
Uses software like Rhinoceros 7 and COMPAS FAB for design and control.

In summary, the research contributes to understanding auxetics in structural applications, providing insights into their behavior under various loads, proposing practical designs, and exploring upscaling possibilities. The proposed approach and findings aim to advance the use of auxetics in steel reinforcement for sustainable and safe construction practices.

The Mekong Delta in Vietnam is facing several challenges as a result of climate change. Among others, the effects include an increase in river discharge during the wet season, leading to river floods, and a decrease in river discharge during the dry season. The decrease in discharge results in a shortage of fresh water required for irrigation and drinking water. Besides that, the combination of sea-level rise, land subsidence, and decreased river discharge during the dry season results in saltwater intrusion. This threatens freshwater supply even more. Furthermore, there is an increasing risk of floods from the sea due to low land elevation and the rising sea level in combination with the occurrence of storm surges. The scope of this research is the area around the Ham Luong estuary, which is a branch of the Mekong River. The partial closure of this river branch is considered by the Vietnamese government as a measure to reduce the effect of the above-mentioned effects of climate change. However, not enough research has been conducted yet on the impact of a partial closure on the Ham Luong estuary. This has lead to the following research question: “What is the impact of various closure scenarios on the hydraulic characteristics and social activities in the Ham Luong estuary, considering a 75-year forecast?” The region of the Ham Luong estuary is characterised by its intensive agri- and aquaculture. More than 60% of the inhabitants is directly active within the agri- or aquaculture. As these activities are strongly dependent on the salinity of the estuary, they are highly affected by the effects of climate change. The region is densely populated with more than 125,000 inhabitants living near the Ham Luong estuary. It is clear that the effects of climate change are threatening the region in hydraulic aspects, as well as socio-economic aspects. A partial closure could reduce these effects, but will influence the region in several ways. In order to estimate the impact, a combination of hydraulic and socio-economic aspects is assessed based on a criteria set. This criteria set contains the criteria of freshwater supply, agricultural and aquaculture adaptation, biodiversity, stable riverbanks, and navigability. These criteria will be tested on a total of four alternative interventions in the Ham Luong estuary. Three alternatives with a storm surge barrier and one alternative without a storm surge barrier. All alternatives include heightening of the existing dyke system, as this seems to be inevitable when aiming for long-term development in the region. The extend of dyke heightening is subject to the choice of alternative. As a part of the impact analysis, a Delft3D model was built to analyse the hydrodynamic and morphodynamic processes in the Ham Luong estuary. The model was restricted to the chosen spatial scope, which only covers the Ham Luong estuary, without any upstream bifurcations. The model gave insights in processes like salt intrusion, sedimentation rates, and water levels. However, due to model simplifications and assumptions, the outcomes of the model where not useful for quantitative assessments. Still, the results are used to compare the impact of the different alternatives to each other. As expected, the alternatives that include a storm surge barrier will provide more possibilities to retain fresh water than the alternative without a barrier. From the results, it followed that the limited spatial scope excludes the redistribution of upstream discharge. It is recommended to look at a larger scale of the Mekong Delta when assessing hydro- and morphodynamic processes. Forming a flood protection system, the structural design of such a storm surge barrier, together with a quick estimation of a dyke system. The dyke system is different for each alternative, depending on the presence and the location of a barrier. The barrier design includes a thorough analysis on feasibility of gate types, technical requirements, load combinations, design of dimensions, and the operation. The load combinations take hydrostatic, hydrodynamic, wind, and soil loads into account. The design of the dimensions is done for the gates, sill, lifting structure, pier, foundation, and the bed protection. By assessing the above-mentioned criteria, a preferred solution is identified. This preference is based on a Multi-Criteria Analysis, which includes weighted scores for all alternatives. The outcome of the Multi-Criteria Analysis appears to be very sensitive to the rating and weights of the criteria, which makes it difficult to identify one of the alternatives as the preferred solution based on only the score on the different criteria. For this reason more research is needed. However, when including a cost estimation of the four alternatives, it can be stated that the alternative of no storm surge barrier and only the corresponding extensive dyke heightening could be considered as most cost-beneficial alternative and therefore as the preferred solution. It is expected that with or without closure of the Ham Luong estuary the system will change. The availability of fresh water will be improved by the presence of a closure, although more research is needed to specify this further. The increasing salt intrusion, as a result of Relative Sea-Level Rise (RSLR) will lead to agricultural and aquaculture adaptation in all alternatives. Either due to the construction of the barrier, or due to the gradual RSLR. A closure also has effect on the biodiversity, stability of the river banks, and navigability in the river. When implementing a closure these effects should be further investigated to assess the effect quantitatively.

Waste generation is one of the main environmental problems and is a result of the current linear economy. Materials/elements are used whereafter they are wasted which is a problem considering the finite material supply on earth. Therefore, the current linear economy needs to move towards a circular one in which materials are reused and thus kept in the circle. However, reuse is still not a common practise. This is due to the fact that there are no insights in the structural feasibility, potential savings on environmental impact, and costs related to reuse. Besides the lacking knowledge about the different aspects there is no clear image where the potentials for reuse are located within the sector.
The goal of this research is to give insights in the reuse potentials and to find opportunities within the sector. This research started with a material flow analysis to find promising material flows in the sector. In this material flow analysis it was found that the demolition of office buildings is responsible for a big portion of the outgoing material flow and the majority of the ingoing material flow is related to the new construction of serial houses. In the analysis it was found that the elements with the highest ECI and mass are floor elements. Next the available floor elements coming from office buildings and the floor elements needed for the construction of serial houses were examined to check possible matches. It was found that new plank- and hollow core slab floors used in serial houses can potentially be substituted for reused monolithic- and hollow core slab floors out of office buildings.
Thereafter, two different tools were developed. One related to the reuse of monolithic floors and one related to the reuse of hollow core slab floors. These tools are means to give insights in the reuse potentials considering the structural feasibility, potential savings on environmental impact, and costs. Different cases were checked using the tools and the following results were found:
-In all cases it was structurally feasible to use reused floors coming from office buildings in the new construction of serial houses.
-When reused floor elements are used it is possible to save 40-90% on environmental impact.
-Reused floor elements can be cheaper or more expensive as new floor elements.
These results are promising and hopefully contribute to an acceleration of reuse in practise. The research states where the potentials for reuse are located in the sector and presents two tools which check the reuse potentials considering structural feasibility, environmental impact, and costs.

Due to global warming, in the construction sector there is aimed for a transition towards the circular economy. The past years, many utility buildings were demolished, consisting of a concrete structure. This results in concrete rubble which is often down- or recycled. For new construction projects, new concrete elements will be produced. However, instead of producing new concrete structural elements, potentially concrete structural elements can be reused. Therefore, this research focuses on the reuse potential of in-situ concrete elements whose can be dismantled from demolition projects of utility buildings. In order to stimulate structural engineers to reuse concrete structural elements in practice, this research presents the Reusability Tool. This tool assesses the reuse potential of in-situ concrete structural elements based on structural safety, environmental impact, and economic impact.

Based on an extensive desk research, interviews with experts from the field, and a case study, the processes of three circular strategies are analysed: reusing, upcycling, and downcycling. These processes are made operational in the Reusability Tool. Based on input information about the analysed structural element, the Reusability Tool assesses the element on structural safety, environmental impact, and economic impact. This assessment result in an advised circular strategy for the element: reuse, upcycling, or downcycling.

The Reusability Tool is validated by a case study and feedback sessions with structural engineers. The Reusability Tool is a user friendly tool which can be used to assess the reuse potential of in-situ concrete structural elements from utility buildings, and will prevent valuable elements to get lost. The tool can give insight in the reuse potential in an early design stage of a future project, and can form the basis for further investigations.

Due to global warming and the subsequent rise of the sea level, scarcity of land to build on, the continues increase of the world’s population and a shift in population from rural areas to the city, there is a need for innovative projects to tackle or deal with the increase of needed liveable area. One of the solutions is floating cities. A component of a modern city is high-rise buildings. High-rise is an advantageous option to deal with the limited availability of ground surface on the floating platforms. The question is whether it is possible to realise these floating high-rise structures.
This research investigates whether it is possible to realise high-rise buildings on floating platforms with limited dimensions on the sea or ocean regarding stability. And if it is feasible, what the requirements are for the general dimensions of both the platform and the high-rise building. For this purpose, conditions were used from three representative locations. At these three locations, the floating high-rise is tested for four different wave situations: Tsunami, Growing waves, most extreme wave. And an Irregular wave field. The platform and building are tested whether the structure could meet the various requirements and regulations. These are divided into three forms of stability: Buoyancy, static stability and dynamic stability.
In this study, for both the platform and the building a square cross-section is used and both are prismatic in the direction of the height. The platform and the core of the building are made of concrete. Apart from the four parameters: height of the building and width, height and depth of the platform all other parameters are based on these four parameters. No stability systems in the building were used (except the core), nor methods to keep the platform in place, such as mooring systems.
For the buoyancy, mainly the relation between the mass and the depth of the platform is determined. This is a relationship that has been used extensively in static and dynamic stability. The mass of the building and platform pose few problems for staying afloat. In fact, extra ballast water can easily be used to make the platform heavier in order to achieve the desired mass or depth.
For the static stability a combination of hand calculations based on the GM-method and a model that can include deformations in the calculations as well is used. A linear relationship was found between the height of the building and the width of the platform for which the floating high-rise is stable.
The model is used to determine the minimum platform depth and height, as well as the rotation for different building heights and platform widths. It follows that there are platform widths for which the vertical force is minimal. This is when the width of the platform is equal to the wavelength of the wave or a multiple of it. In addition, there are platform widths for which the moment due to the wave force on the platform is minimal. These values are called "zero moment widths" because for these widths the wave moment, regardless of position or time, is approximately equal to 0 kNm. Therefore the rotation is minimal when these zero moment widths are used for the platform width. These widths are only optimal for the specific wavelength for which they are calculated. If the wavelength is different, the zero moment widths will be different.
For the dynamic stability, a model consisting of three point masses distributed over the height connected with a beam was used. The three point masses each have three degrees of freedom: vertical and horizontal translation and rotation. With this model the accelerations of the three possible motions for different heights of the building, platform widths and platform masses (this can be adjusted by including ballast water) are calculated. It follows that: The tsunami and the growing wave are not a problem and the most extreme wave or the irregular wave field is normative; The vertical acceleration is minimal when the width of the platform is equal to the wavelength or a multiple of it; The vertical acceleration is only normative for small building heights and platform widths, whereas it is the biggest cause of seasickness; The horizontal acceleration at the top of the building due to both the horizontal motion and the rotation is almost always normative. It is largely caused by the rotation of the platform; If the zero moment widths are used for the width of the platform, the rotation and thus the horizontal acceleration is minimal. This does not mean that the accelerations are below the limit.
In order to avoid resonance in the motion, and thus extreme accelerations, of the floating high-rise with an irregular wave field, graphs are made were the combination of the height of the building and the width of the platform that result in resonance are shaded.
Using the results of the static and dynamic analysis and a few case studies, it can be concluded that with the design choices and simplifications used, it is not possible to realise floating high-rise buildings on platforms with limited dimension at the North Sea and the North of the Atlantic ocean due to too extreme condition causing too high accelerations, especially in the horizontal motion. The static stability and the buoyancy are less of a problem. If one of these locations is chosen, platforms over 600 m wide are required that are so stable that the rotation of the platform is minimal and no resonance occurs in the rotation motion. In this case, the conditions are similar to those on land and the wind force becomes the governing factor. In those cases, the same approach and measures should be used as for high-rise buildings on land. Even with these sizes, it is advised to use the zero moment widths to limit the rotation as much as possible.
The location on the Atlantic Ocean around the equator is the only location that is promising. The results show that several building heights are possible on different platform dimensions for the highest wave, as long as the platforms have the zero moment widths dimensions. However, it appears that the accelerations become too high when these sizes for the building and platform are tested with different wave frequencies with lower wave heights. Therefore, this option might not be suitable either, but it is not excluded in this research. One option is found that meets the regulations for all possible wave frequencies is a 50 m building on a platform 223 m wide (a zero moment width) and 22.7 m deep for the location around the equator. This proves that it is possible to construct high-rise buildings on platforms of limited size with the design choices used, but that it is very difficult and the options are limited.
Despite the conclusion that it is almost impossible with the design choices, floating high-rise buildings on limited platforms are still expected to be possible as the design can be improved. The first next steps to investigate are other, better shapes for the platform and building to increase stability and reduce overall forces. In addition, it is recommended that other methods of increasing stability and reducing motion, such as building stabilisation systems and tuned mass dampers, are investigated. With these improvements floating high-rise is more feasible than found in this research.

The building industry consumes a lot of material, which causes depletion of material stocks, toxic emissions, and waste. Circular building design can help to reduce this impact, by moving from a linear to a circular design approach.
To reach a circular build environment, all disciplines should be involved, including fire safety design. However, there is a contradiction between the objectives of circular and fire safety design, either affecting the aim of protection of material sources, or protection against fire risk.

Timber is a material that has high potential in contributing to a circular building industry, as it is renewable, recyclable and can store CO2. However, timber is combustible, which increases the risk of fire. Therefore, mass timber building design has traditionally been restricted by building regulations. To enhance mass timber building design research on timber buildings has increased, to allow understanding of the risks. However, yet general guidelines or understanding on the fire behaviour and risk in timber buildings is lacking. This is a problem for the fire safety design and the potentials of timber contributing to a circular building industry.

Until now, there was no specific method available that quantifies this relation between material use and fire risk in mass timber buildings. This limits the possibility of fire safety design and mass timber design to contribute to a more circular building industry. By creating a method that allows comparison between the economic and environmental impact of material use and fire risk, a well-founded choice of building materials is easier to make.

The design tool created in this research quantifies the impact on material use for fire safety measures relating to CLT, encapsulation and sprinkler availability and their effect on the fire risk in mass timber buildings. This way insight is provided between the balance of material use and fire risk. By the sum of the impact on material use and fire risk, the total “circular fire safety impact” value is calculated. This value represents the total economic and environmental impact of the design based on the choice of building materials. By changing the fire safety design, the most optimal design variant can be determined. This is the variant with the lowest total impact value.

This way, a circular design approach is used to steer fire safety design in mass timber buildings towards a design solution that does not only provide sufficient safety for people, but also provides maximum economic and environmental safety from a material point of view.

Politicians, scientific researchers and companies all know; the transition to a Circular Economy [CE] should start now, or actually should have started yesterday. The CE is an economic system that replaces the current take-make-waste linear system and replaces this with the reduction, reuse and recovering of resources. The challenge is to build with limited emissions, depletion and pollution of the living environment. Looking more specifically to a building, the load-bearing structure is responsible for a significant part of the material related environmental impact. In order to reduce the environmental impact of a building, more guidance is needed as the implementation of the CE principles requires a new approach for designing. The principles of the CE are safeguarded in various circular design strategies. Which circular design strategy is most beneficial for the project depends on the requirements and ambition of the project. The resulting difference in environmental impact caused by the design choices should be illustrated. Unfortunately, the current determination methods for the environmental impact do not include the design principles of the circular design strategies. Besides, the environmental impact is assessed at the end of the design process. Once the design is final, adjustment to improve the environmental impact are too difficult or costly.
In this research a design tool is developed that makes the practitioners in the building sector aware of the environmental impact of the design choices. Three circular design strategies are presented in the tool that can be followed to stimulate the development of a circular building project. The design tool can be used in the preliminary design phase to create and explore varying structural design variants in line with the chosen circular design strategy. The structural design variants can be compared on their environmental impact expressed in five indicators: the MPG, the environmental performance value (in Dutch: Milieu Prestatie Gebouwen [MPG]), the produced amount of CO2 emission, material usage, expected service life and building costs.
The research shows that based on literature review, expert judgement and open databases a design tool can be built, which gives insight in the environmental impact and more design parameters to support the implementation of circular solutions in the preliminary design phase. To meet the unique project specifications different solutions are required. Therefore, the design tool supports the design process with a uniform approach. The outcome of this research highlights three main influential aspects for the determination of the environmental impact; (1) the expected lifespan of the design assumed in the calculation method, (2) the quality of the environmental database of materials and (3) the total applied materials in the load-bearing structure. For the practitioners of the design process it is extremely important to be aware of the effect of changing the expected lifespan and thus the determination method for the environmental impact and the quality of the environmental database used.

According to the European Commission, buildings are responsible for approximately 40% of the EU energy consumption and 36% of the CO2 emissions, resulting in the largest energy consumer in Europe. Especially, the reduction of energy consumption for heating of residential dwellings has gained more and more interest in the last decades. Although some reduction has been achieved by implementing passive or active strategies and improving the thermal performance of new or renovated dwellings, the decrease is found to be lower than predicted by the energy performance models. One possible reason is that the existing thermal comfort models, the PMV and the adaptive thermal comfort model, are not appropriate for all different types of buildings and climates, resulting in inaccurate predictions of thermal comfort and leading to amounts of energy use different than the actual ones. In addition, the occupants’ behaviour, which is determined by their thermal comfort preferences might play a significant role on the energy use which needs to be explored. Therefore, the main topic of the current thesis is to explore the relationship that different parameters such as dwelling and installation characteristics, indoor and outdoor climate parameters, household and physiological characteristics as well as occupants’ behaviour have with thermal comfort and energy use.

A measurement campaign took place within the context of the OPSCHALER project and data related to thermal comfort perception, indoor climate and energy consumption was collected for 96 dwellings in the Netherlands during periods ranging from two to twelve months over a one-year period (2017-2018). The gathered data included both quantitative and subjective data. The quantitative data included the indoor climate data (air temperature, relative humidity, CO2, presence), the gas use and the electricity use collected through smart meters and sensors. The subjective data related to comfort was gathered by a comfort mobile application where users recorded their thermal sensation and other comfort related parameters (thermal preference, clothing, metabolic activities, actions), while questionnaires and inspections did also take place. This data was analysed using different types of graphical representation (bar charts, pie charts, stacked bar plots, scatterplots) as well as statistical tests such as chi-square tests, regression analysis, Kruskal-Wallis and correlation tests. Due to limited or unavailable data only 78 dwellings were included in the analysis, while the reliability and generalisation of the results entails some uncertainty due to the number of dwellings and data points available.

All in all, it was found that the thermal sensation is correlated with the four comfort related factors (thermal preference, clothing, metabolic activity, action), the indoor air temperature as well as the energy labels and the ventilation types, while only age was resulted in not being associated with thermal sensation. Indoor air temperature was found to be related with the energy label of the dwellings, but not with their ventilation type. In addition, the results indicated that the heating energy use is related with the outdoor air temperature as well as with the indoor-outdoor air temperature difference, but not with the indoor air temperature. Energy labels and ventilation types were found to be related with the heating energy use, while thermal sensation, actions and income did not show any correlation with it.

Based on the findings it is concluded that the adaptive thermal comfort model is more accurate and closer to the reality of a residential environment in comparison with the steady-state PMV model, where no adaptations take place. However, it is highly recommended that instead of improving the existing thermal comfort models, personalised comfort models could be developed for each single person separately by gathering data using sensors. This would help to trace all different parameters that influence the thermal comfort and the energy use as well and lead to more accurate prediction and lower actual energy use.

The starting point of the thesis relates to the “Rotterdam Mountain” Project, envisioned by the Rotterdam Dreamers, which proposes an artificial mountain in the otherwise flat landscape of the Netherlands, supported by a cable network that is spanning between multiple high-rise towers. This network has the double function of supporting the weight of the mountain and connecting and stabilizing the towers. With the “Rotterdam Mountain” Project as a starting point, the thesis aims to investigate the structural feasibility and performance of a new typology for the design of high-rise towers, where a cable network interconnects and stabilizes them. The goal of the thesis is to investigate the design of such a system with respect to relevant parameters, as the relative position of the cable-net (RPC) or the spacing between towers (SBT). Such, a core system to which the cable-net is connected is used throughout the thesis. To understand the relative influence of different parameters, a parametric approach (in Grasshopper) is used, that allows for a rapid change of the initial properties of the system. The Grasshopper script is linked to the Robot Structural Analysis (RSA) software, where a non-linear analysis is performed. The outputs of the RSA analysis refer to both the serviceability limit state and ultimate limit state, as both the core and cable-net are designed to meet the stability and strength requirements imposed by the Eurocode. Based on the Eurocode checks, conclusions are drawn on the preliminary design of the system, by identifying multiple design zones with respect to the two relevant parameters: a zone where the stability of the core is governing (for a SBT of up to 90 meters, and an RPC of up to ~0.6), a zone where the strength of the core is governing (for a SBT higher than 90 meters or an RPC higher than ~0.6), or a zone where the influence of the cable-net is negligible (for an RPC lower than ~0.1). Conclusions are further drawn on the performance of the system, by comparing it to the simple core and outrigger systems. It is observed that the proposed core + cable-net system performs (at least) as good in terms of stability and strength with less material usage. A concrete weight reduction of the core of up to 50% is observed when compared to the simple core and a steel weight reduction of up to 20% is observed when compared to the outrigger. From an economic point of view, preliminary calculations have shown a reduction of the total weight of the structure of up to 14%, due to the increase in slenderness when the cable-net is placed. This is equivalent to a number of up to 5 extra floors that can be constructed with the same amount of material. With these remarks in mind, it is concluded that, based on this preliminary study, the cable-net stabilized towers can pose a feasible alternative to the design of high-rise towers, and they can be efficiently used for the ambitious “Rotterdam Mountain” project.