Flat glass is a widely used material in the construction industry. However, its production has a relatively high carbon footprint due to the high melting temperature required, and most of it is still sent to landfill or down-cycled at end-of-life. The reuse of glass therefore has a great potential, given its lower carbon footprint and the number of existing buildings with glass panes that would be suitable for reuse.
This research project aims to propose a novel methodology for estimating the potential of tempered glass for adaptive reuse. It is illustrated with a case study of a historic building in Paris, built over 50 years ago with about 2500 fully toughened glass panes for potential reuse.
Firstly, a brief environmental impact assessment quantifies the impact of reuse compared to recycling and down-cycling to provide a more critical understanding of the benefits of reuse.
Secondly, a probabilistic equivalence of the Heat-Soak Test (HST) is justified for thermally toughened glass. Based on statistical analysis of spontaneous breakage due to nickel sulphide (NiS) inclusions over time, a safety level over time is estimated. This level of safety can already be considered quite high from 20 years after installation and is equivalent to an HST after 50 years.
Finally, the residual strength of aged tempered glass is estimated. This strength is based on the combination of the pre-stress level and Linear Elastic Fracture Mechanics (LEFM). The pre-stress level and the largest flaw depth are measured on-site using portable optical devices on a representative sample. A visual inspection procedure is then defined to speed up the evaluation of the flaw depth. Once trained, the observer should be able to qualify the glass panes relatively quickly following different 'Quality Levels' with associated characteristic strengths (95% confidence level).
This methodology was applied to the case study. Pre-stress and flaw depth measurements were carried out on 70 glass panes. Visual inspection was tested and the margins calibrated to reach a 95% confidence level. The glass panes have an average surface pre-stress level of 81.41 MPa with a standard deviation of 4.17 MPa, which is consistent with other values reported in the literature for fully toughened glass. The largest flaw depths ranged from 4 µm to 147 µm, also in agreement with other publications. All of the glass panes analysed are suitable for reuse as heat-strengthened glass, and potentially better for some of them.
The proposed methodology has been summarised to be generalised to other reuse projects. Typical fully toughened, heat-strengthened and annealed glass (average pre-stressing level and surface quality based on previous measurements) have a great potential for reuse at the same characteristic strength if the surface quality estimated by visual inspection has flaw depths smaller than 20-40 µm. Qualification for reuse of these three types of glass with a reduced strength is also proposed. This could allow reusing glass panes with flaw depths of up to 500 µm for several design scenarios.

Climate change is one of the most urgent global issues, with the construction sector contributing nearly 11% of global CO2 emissions. Cross-laminated timber (CLT), is proposed as a sustainable alternative for concrete and steel that, can reduce carbon emissions. The primary objectives are to identify the main drivers and barriers to using CLT in multi-storey buildings in the Netherlands and to propose strategies to overcome these barriers. The results indicate that timber’s natural ability to store captured carbon dioxide was the most important driver. Besides, CLT's lightweight nature allows for precise, modular prefabrication in factories, enabling quick and safe on-site assembly.

The biggest barriers are related to financial and political aspects, but also to technical and sociocultural aspects. Some of the regulatory barriers are CLT’s unfair representation in the MPG system and its incompatibility with building codes. Additionally, CLT is oftentimes more expensive than concrete and steel, making it less attractive. Moreover, there is still till some extent a lack of knowledge and experience across the AEC industry regarding CLT, leading to perceptions of risk and reluctance to adopt it. Some of the technical challenges are related to fire-safety, acoustics, moisture, and connections.

Five sets of strategies have been developed to overcome the aforementioned barriers. The first set of strategies is aimed at increasing industry-wide knowledge and awareness on CLT. The second set of strategies is focused on changing the industry by promoting collaboration and reorganizing the timber supply chain. The third set of strategies addresses the cost barriers by offering new financial models to overcome the cost surplus of CLT construction. The fourth category is focused on overcoming technical barriers by making technical advancements like improvements and innovations in prefabricated systems and increased standardisation. The last set of strategies is aimed at addressing regulatory barriers. Strategies include revising the MPG system to better account for biogenic carbon storage, expanding the national environmental database to include more timber products, establishing building codes that support timber construction, and setting timber building quotas.

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.

The transverse stability of timber terraced houses can be provided by CLT stability walls where decoupled timber terraced houses are preferred to meet acoustic requirements leading to rather large thicknesses for the CLT stability walls and many large connections for anchorage to the foundation. The main goal of this research was to investigate the transverse stability behaviour of timber terraced houses, using a case study provided by WSP.

Models to assess the transverse stability of timber terraced houses are simple schematizations with hand calculations of the decoupled and coupled timber terraced houses and FE models of decoupled timber terraced houses with and without T-section and coupled timber terraced houses with and without T-section. The coupling of the houses can be achieved by 4 Straviwood Modulink 6.0 kN connections per floor level. The T-section can be realised with double screws with diameter Q = 12 ZZ with a spacing of ` = 100 ZZ.

Simple schematizations with hand calculations of the decoupled and coupled timber terraced houses result in overdimensioning of the connections since bending of the floors due to deformation of the stability wall, providing resistance to the deformation of the stability wall, is not considered. This resulted in 6 hold downs per CLT stability wall.

Compared to the FE model of decoupled timber terraced houses without T-section, all FE models have a positive influence on the design of connections in terms of reduction of number of hold downs and improvement of the total tension support reaction. Coupling of the houses is better compared to application of a T-section for decoupled houses. An improvement of the total tension support reaction of 83% and 67% for respectively the house on the left and the house on the right, compared to the decoupled timber terraced houses without T-section, can be achieved by coupled timber terraced houses with T-section. This also resulted in a reduction of 5 hold downs per CLT stability wall and the possibility to reduce the thickness of the CLT stability wall.

To stick to climate change targets and reduce global carbon emissions, the building sector needs to adopt a circular economy. In the steel sector, reuse or elements can reduce carbon emissions which are created in today's steel scrap recycling practices. This thesis contributes to closing the knowledge gap on design, costs, and environmental impact score for working with reclaimed steel elements. The tool Steel-IT is created to research the business-case and environmental impact score of low-rise office buildings. Steel-IT uses a donor element database and new office design, which are specified by the user, and generates new and reclaimed steel design alternatives. Using a weight and activity-based costing method, the costs of these design are estimated. Life-cycle analysis is used to quantify the impact. By generating results and analysing the effect of the input in the tool Steel-IT, the following conclusions can be made regarding the business-case and impact score of reclaimed steel in low rise office buildings. A case study using Steel-IT shows that a 25% impact reduction against minimal cost increase is possible. For this, the match between design and donor elements needs to be good. This match can be searched for using Steel-IT. In terms of design, connection detailing is the most critical factor in the success of a donor steel skeleton. Donor steel elements should be sourced from an existing building to limit storage costs and should not have toxic conservation systems applied to them. Both induce extra costs and make the business case of donor steel less competitive with new steel. In the future, currently suggested emission taxes do not affect the business-case significantly as these taxes are low compared to the total building costs. The most helpful action to increase the business-case is to apply donor steel more often. If the experience with donor steel and its availability grows, reuse will become easier. Steel-IT can contribute to this as it contributes to closing the knowledge gap on costs and impact and can help to match demand and supply.

The reuse of insulating glass plays a crucial role in promoting sustainability and circularity within the construction sector. CO2 emissions must be reduced according to the Climate Agreement. Reusing materials can help achieve this goal. Reusing glass without reheating it can provide environmental and cost benefits, making it a suitable option. In this study, 36-year-old insulating glass panels (double-glazing) from an apartment building in Amstelveen have been tested for strength through destructive testing. This is done to see what the strength of the glass is after the glass has been in the building for 36 years and has been exposed to opportunities for damage. Various patterns of damage on both the interior and exterior side of the glass panels from an insulated glass unit affects the strength that can eventually be assigned to the glass. The aim of this thesis is to be able to show whether and how insulated glass units can be reused and what the strength is of naturally aged glass after a certain lifetime. From six insulated glass units obtained, specimens measuring 150mm x 150mm are extracted and tested for strength using a Coaxial Double Ring test. Prior to the destructive tests, a number of specimens were viewed under the Keyence VHX 7000 digital microscope to see how the damages are and whether they vary between the four sides of an insulated glass unit. This revealed that the outer side of the outer panel (side #1) contains the most and homogeneous damage. Weathering, especially rain and wind, which can bring sand particles, for example, create homogeneous damage on the glass surface. The entire surface is exposed to this type of weathering. The outer side of the inner panel (side #4) also contained quite a lot of damage from probably cleaning and (human) touching. Despite the fact that the inner sides of both panels (the sides in the cavity, side #2 and #3) theoretically had little potential for weathering, damage could also be seen on these, although it was more localised, meaning it probably occurred during the production process or preparation of the specimens for this experiment. During the Coaxial Double Ring tests, 406 specimens were tested for strength. The strengths of the specimens ranged from 16.8 MPa to 243.7 MPa, with an average strength of 67.5 MPa. The average strengths of side #2 and #3 (sides in the cavity) are slightly higher than those of side #1 and #4 (outer sides), between 9% and 17%. A tin-tester was used to determine which side of each specimen was the tin-side prior to the strength tests, to include this in the analysis of the results. The specimens tested on the tin-side were found to be on average much weaker than the specimens tested on air-sides. The average measured strength of the air-side is 31% higher than that of the tin-side. In a number of tests carried out with new glass, this large difference is already present, while literature states that the difference in strength between the air- and tin-sides can be considered marginal. Fracture statistics were used to analyse the data and find a strength for each series tested. This was done using Weibull theory. The two-parameter Weibull distribution has proven to be very conservative at low failure probabilities, resulting in a very low design strength (failure probabilities of 0.8% and 0.12%) for a series of specimens when there is a large spread in data. The spread in data was often of greater influence than the values of the measured strengths. As a result, the design strengths for series tested on the air-side were usually lower than specimens tested on the tin-side, while the average strength measurements were actually higher. The greater variation in strengths of specimens coming vi from the inner side #2 and #3 results in lower design strengths than the outer sides (#1 and #4), which contain more (homogeneous) damage. The values of design strengths of the naturally aged glass tested were almost always lower than the design strength of new glass according to current standards. The design strengths of new glass are 22.5 MPa according to NEN2608 and 25.0 MPa according to EN16612. When looking at how many specimens failed at stresses lower than these values, there are only three and six respectively. So, there are very few spots in 36-year-old glass that are weaker than the design strength that can be assumed according to NEN2608 or EN16612. These lowest values are not consistently found in specimens tested on either the air-side or the tin-side, so based on this study, the influence of this can be ruled out. By this means, a more realistic and less conservative option seems to be to take the strength of the weakest specimen in a test series and then assign it to the entire panel from which that test series comes. Reuse options are discussed in the final section of this thesis. Using a number of common glass structures, it explains the ways in which weathered glass can or cannot be reused and in what function. How the results obtained can be handled and used is a point of discussion, as the values are not always representative of the strength of the entire glass panel. Further research will have to show whether the current design standards and the parameters used in them are well chosen or whether they should be different for used glass. For example, use a lower material factor of 1.35 instead of 1.6 – 1.8 when calculating the design strength or use a higher failure probability than 0.0012 to determine design strength in a Weibull distribution. The efficiency and effectiveness of the method used can also be optimised in further research.

Flat glass is a material which is used extensively in almost all the buildings, mainly as infill for windows or facade panels. However, neither glass production nor its recycling are sustainable processes, as both incorporate the use of gas furnaces, which produce high amounts of CO2 emissions. Thus, the re-use of glass seems the only way to minimize the environmental impact of this material.

The greatest challenge in the safe reuse of glass elements lies in the assessment of their strength after several years of use. This strength is reduced, compared to the inert strength, due to the damage ("defects") that the environment inevitably introduces into the glass surface. According to the Linear Elastic Fracture Mechanics (LEFM), one of the defects in a stressed brittle material, which in this case is glass, will initiate the failure. Therefore, in order to assess the residual strength of weathered glass, it is essential to quantify it in terms of defects. The aim of this thesis is to develop the understanding on the performance of weathered glass, and to propose a methodology for the prediction of its residual strength, based on its surface defects.

The examined material is a 55-year-old annealed glass, which was used as facade elements in a building in the Hague, in the Netherlands. The X-Ray Fluorescence analysis showed that the composition of this glass meets the common float glass recipe but no tin residues were found on its surface.

This research firstly, focuses on the detection and characterization of the defects on the examined weathered glass. Both sides of glass were examined through non-destructive tests with the mobile optical profilometer Traceit® and the digital microscope Keyence VHX 7000. These tests revealed that the weathering induced mainly dense pits, digs and fine linear scratches on the surface exposed to the outside environment (external surface). The depth of these defects, as measured with Traceit®, ranged from 19 µm to 161 µm, which is aligned with the depths reported in literature, which range from 20 µm to 200 µm (Schula et al., 2013). The internal surface had occasionally some large defects which were probably man-made defects. Overall, Traceit® showed a potential for detecting and measuring the defects on weathered glass, whereas with the used microscope it was not possible to measure the defects nor to scan larger surfaces.

Subsequently, 90 specimens of weathered glass were subjected to Coaxial Double Ring tests, with either the external or the internal surface in tension, to assess the effect of weathering on strength. The specimens were of two different dimensions and they were loaded with two different rings to investigate the "size effect". In addition, 81 similar specimens of new glass were tested, with either the tin or the air side in tension, and they were used as a reference. These tests showed that the strength of the 55-year-old glass ranged from 22,9 MPa to 138,2 MPa, whereas that of new glass ranged from 38,3 MPa to 219,2 MPa. In particular, the average strength of the internal surface of the small weathered specimens was 53% higher than the external, but no major difference was observed in the tests of the large specimens. Furthermore, the average failure stress of the air side of new glass was approximately 45% higher than that of the tin side, while in literature that difference was characterised as marginal. Finally, although the size effect was clearly observed in the tests on new glass and in those on the internal surface of weathered glass, the strength of the external surface was found independent of the size of the loaded area. This implies that the defects on this surface are similar and uniformly distributed, so the probability of encountering a critical flaw is equal regardless the size of the loaded area.

Fracture statistics were used to derive the design strength of the glass of each testing series. Among three probability distributions, the Weibull distribution was found to describe the strength data of glass better. However, for low probabilities of failure, the data did not fit well to the Weibull distribution and thus, the resulted design strength values are probably very conservative.

The information collected during the non-destructive tests, namely the size and the shape of the defects found on the surface of weathered glass, was used for the identification of the critical defect which will initiate failure. At this step, the assumption that the largest defect will be the critical one was made. Then, the theory of LEFM was used to relate the size of the found critical defect to the failure stress, through the critical stress intensity factor KIC and the geometry factor Y. The predicted values for the failure stresses were analysed with fracture statistics and compared to the actual failure stresses of weathered glass, as emerged from the Coaxial Double Ring tests. In this way, the accuracy of the predictions was evaluated.

The effectiveness of the methodology for the detection of the critical flaw was evaluated through post-fracture analysis. This analysis showed that the critical defect was successfully detected in the 23% of the examined specimens. This suggests that the visually largest defect on a glass element could be the critical one. Furthermore, even if most of the specimens did not failed at the measured defect, the average predicted failure stress differ by less than 9% from the average actual failure stress. This outcome suggests that the defects induced by weathering on the glass surface are similar. Thus, a defect which was identified as critical for one specimen but eventually it was not, it was probably very similar to the critical defect of another specimen.

To conclude, this thesis examines and proposes a novel methodology for the prediction of the glass strength, based on LEFM, applied to defects found on the surface of naturally aged glass. If the defects on the glass surface are studied according to this methodology, a good estimation of the average failure stress can be obtained. For lower probabilities of failure the methodology gives conservative estimations, so it has a potential for use in design applications. Overall, the defects on the surface of glass, and especially their size and geometry, appear to have the greatest effect on the strength of weathered glass so far. Further experimental investigation on the parameters which affect the strength of weathered glass should be carried out, as well as further research on the automation of the proposed methodology, which is expected to increase its effectiveness and efficiency.

The buildings construction industry is demanded to reduce its ecological footprint to mitigate its contribution to climate change. In this context, a novel sustainable design strategy for the reuse of timber was developed in this Master thesis. The design strategy focuses on the utilization of the material “reclaimed timber” (RT) in the structural system “reciprocal frame” (RF). RT is timber which is harvested from the load bearing structure of dismantled buildings. Large quantities of RT are currently fixed in the building stock. RFs are a family of structures that boast with a rich variety of forms and diverse functions. The utilization of RT in RFs is favorable because RT items which are relatively short can span distances longer than their length when combined with RFs.

To inform the development of the design strategy a literature review on both RT and RFs was conducted. These theoretical studies were supplemented with more practical methods of investigation: RT was inspected first-hand during a visit of a salvage yard that stores RT. Throughout the project physical modeling was used as tool to explore and illustrate the characteristics of RFs. Moreover, during a three-day workshop in which a RF canopy structure from RT was built, important design aspects of RFs were investigated. This first part of the research concluded with describing the state-of-the art of the structural utilization of RT and providing a comprehensive overview of the structural design with RFs.

Key findings of the theoretical and practical studies on both RT and RFs were that the limited stock of available RT items and the geometric complexity of RFs are the two major problems when designing a RF with RT. To solve the two problems a novel RT database configuration that archives the properties of specific RT items was developed. This RT database was applied in conjunction with a novel bottom-up geometry generation model for Rainbow RFs. The Rainbow RF was identified as advantageous for the combination with RT. It can be used to generate expressive spatial assemblies with a relatively low geometric complexity and a high degree of regularity. From a structural perspective the Rainbow RF has the benefit of efficiently transferring axial forces, which reduces the bending action that is typical for RF. Moreover, it achieves flexural rigidity without using expensive moment resistant joints.

The key findings were integrated to form a preliminary design strategy. In a case study the preliminary strategy was used to design a RT RF for a railway station canopy that spans an area of 14.0 m x 27.0 m. The RT stock of the case study was defined by a database that is comprised of 30 stacks of RT items. Based on the material stock 118 geometric design proposals were generated using the bottom-up model. Three of the proposals were developed into safe structural designs. The three safe structural designs demonstrate that the RT items compensate their low strength grade with their relatively large cross-sections.

Based on a discussion of the case study’s design process, a complete design strategy for the structural utilization of RT in RF structures is derived. In the first design phase the shape of the building and the flow of forces through the structure are established. The material stock is defined using the novel RT database configuration. For each RT stack multiple geometric design proposals are developed with the bottom-up model in design phase 3. The bottom-up model is set up in “Grasshopper 3D” and “Python”. For the fourth phase, a versatile algorithm is programmed that automates the structural design to a large degree. This enables to assess many geometric design proposals with considerable accuracy in a short time. The Structural Design concludes with a complete design of the RF structure. The structural design algorithm is also programmed in Grasshopper 3D and Python, the plug-in “Karamba3D” is used for finite-element analyses. The Detail Design rounds the design strategy off by detailing the structure’s joints.

The search for a transparent, reusable, innovative, architecturally aesthetical, structural material that could be used as consolidation system for decayed historic buildings led to the ambition to test a topological interlocking (osteomorphic) design by using numerical calculations. In the last decennia glass has evolved to be a structural material that could be implemented in diverse structural elements. The mechanical properties of glass, in particular the high compressive strength, offer today a competitive solution that can be used for the purpose of restoration, allied to its transparency and aesthetics. The use of glass as a material is also aligned with the recommendations laid down by the international agreements for restoration. Due to its transparency it allows the ruin (Schaesberg Castle) to be perceived in its damaged state keeping the identity and at the same time being distinguishable from the original material in a subtle and immaterial way.
A literature research gave the technical background necessary related to glass, and how by choosing cast glass in the form of topological interlocking (osteomorphic) this would improve its strength and stiffness by introducing a 3d dimension and optimizing the use of compression. The case study’s main purpose was to give a context for the architectural and structural design and evaluate the technical consequences of applying a topological interlocking structural assembly to replace the missing parts of the existing castle. A design was proposed based on the topological interlocking osteomorphic stability system. The design criteria obtained by the literature and case study were then combined to obtain a model to be tested using numerical calculations.
A global model in Finite Element Analysis, with Diana FEA was chosen to test the whole structural integrity and performance by looking at the stresses and the maximum capacity of the system to check if it fulfilled the strength and stability requirements and to test the influence of two types of connections between the materials.
The results suggested that the system performed well and was strong enough but are based on the assumption of a monolithic system which resulted in a less accurate outcome, unable to predict the failure mode by delamination. According to the results, this system can be implemented to replace the missing parts of a monument but a more detailed model is needed to study more accurately the local failure behaviour.
This can serve as a starting point for future research in similar situations. The study of the connections, although conceptual, can support decisions for detailed design proposals.

Glass is a fascinating material that has also been used as a primary construction material in various remarkable buildings since the last century. Unfortunately, a lot of carbon dioxide is released during the production of glass because of the extreme heat required. The construction industry accounts for ten per cent of global CO2 emissions. If a focus in this sector is put on recycling, reducing and reusing, emissions can be drastically reduced because of less needed new building material. However, structural glass is currently hardly reused. A second challenge arises with existing demountable structures made of glass like the LocHal: these are not weatherproof, thus unsuitable as sheltered accommodation.

In response to the absence of adequate standardised structural glass building systems, this research project proposes a preliminary design for a modular, transportable art pavilion with an appropriate structural verification. The research question is therefore: ’How can glass be applied as load‐bearing material in temporary modular building units to realise easy‐to‐ (dis)assemble, transparent and transportable structures?’.

A case‐study is introduced to find an answer to the main research question. The fictive scenario is sketched to design a temporary art pavilion which stands for one to three months in a city centre in the Netherlands. After this period, the pavilion should be demounted and transported to the next destination. The information described here determines the boundary conditions for the design and calculations. The imaginary pavilion is 24 m in length, 10 m in width and 2.5 m in height. The inner walls in the pavilion are retained to create a natural walking path inside. On the short side of the pavilion, doors are inserted as an entrance and an exit. From the available literature, the transportability of the building elements and the requirement for thermal insulation appear to be important preconditions for the final design.

The design is based on four different types of prefabricated building elements: roof panels, wall panels, floor panels and base profiles. The roof panels are of 220 mm thick cross‐laminated timber (CLT), in length six or three metres and have a width of 2.5 m. The wall panels are of laminated glass, 2.5 m in height and come in two types. Insulated glass units (IGU’s) of 6 or 5 m long function as exterior walls. These consist of an outer sheet of 10 mm fully tempered glass, a 15 mm cavity of 90% argon gas and a triple laminated inner panel of 5.10.5 mm heat‐strengthened glass. The inner walls are of a composition of 5.10.5 mm heat‐strengthened glass. The glass is laminated with a SentryGlas® interlayer of 1.52 mm. CLT is also used for the floor panels, now with a thickness of 210 mm and lengths of 6 and 3 m. The base is defined by steel ’cap’ (RHSFB, lengths of 6 and 5 m) and ’hat’ (THQ, length of 4.25 m) profiles. Both profiles are 265 mm in height.

Roof connections, wall connections and base connections were designed and dimensioned, in total seven different types. The most innovative and structurally interesting joints are two wall connections. These connections consist of a so‐called ’coffee‐ cup‐hand’ system; titanium elements laminated 30 mm into the middle sheet of the wall panels. The wall panels are checked on maximum deflection and tensile stress, as well as the local tensile stress in the glass and in the SentryGlas® interlayer around the laminated titanium elements. All checks comply with the maximum allowable values described in the Eurocodes and in literature.

The conclusion is that the proposed design, with some enhancements to be made, satisfies the structural‐, building physics‐ and practical requirements as a transportable and a relative transparent building system for structural glass. With this building system, glass can be integrated as a load‐bearing material for designs of temporary structures.

Engineers who wish to apply this building system in practice are advised to first enhance the roof connections. For transportation means, the grid‐measurements should be decreased by 8% to fit the components in a regular container. For practice, it is also advised to deal with factors such as installations and drainage systems, which were not included in this study. Follow‐up research could focus on the adaptability of the building system when the building is used with a more permanent function. In addition, it is mechanically interesting to further investigate how the wall connections interact with each other in a 3D analysis and lab experiments.

Very little research has been done on the potential use of glass bottles in a structural system. Knowledge gathered from past projects showed that individuals or communities usually tend to create structures with glass bottles with a cementitious material, which is usually concrete or mortar. Under vertical compressive loading, the corresponding failure mechanisms should predominately be fractures in either the heel or the shoulder. Using two different finite element models and Weibull Analysis, a characteristic tensile strength of abraded container glass of 20 MPa was found. When structures are created out of glass waste, designs should be made with the abraded state in mind.

Connections concepts are created to connect glass bottles together, i.e. 'Masonry', 'Stacked' and 'Bundled'. The 'Stacked' concept was considered the most suitable for this thesis. Eight different configurations of the Stacked concept were created, of which four were tested in a hydraulic displacement controlled compression machine in Stevinlab. These four configurations were called 'Whole-Up', 'Whole-FF', 'Whole-BB' and 'Cut-Double-BB'. The results showed that the Whole-Up had the highest vertical failure loads, followed by the Whole-FF and Whole-BB configurations, and the Cut-Double-BB have much lower failure loads, which is most likely due to the imperfections at the cut surface.

Following these results, two different design options were created. The final prototype contains a demountable glass bottle column with intermediate plates and plastic elements. A proposed design formula for the vertical compressive design load was created based upon collected data and safety factors. The limitations of the bottle column are mainly the tolerance issues due to the different bottle heights and connections, the costs of the connections and the capacity in comparison with more conventional materials. The bottle column could however be an interesting options for smaller or temporary projects.

To climb up the circular economy hierarchy and meet the goals of the European Green policy in the construction sector, steel profiles may be reused instead of recycled, which is currently the most common practice. An overarching digital database to efficiently match supply and demand of reclaimed structural elements will stimulate their application. To efficiently use the limited availability of reclaimed steel elements in a new structural system, the design process requires a different approach: form following availability. This thesis presents an algorithm to generate truss bridge designs using only reclaimed steel, optimising the material usage in relation to the function and avoiding cut-off waste. The algorithm is inspired by the growth method, a truss topology optimisation method in which truss designs are grown without the need to fit elements into an initial design or grid of possible positions, like the commonly used ground structure method. The growth method is a more intuitive starting point for stock-constrained design, as by attaching available reclaimed elements to each other, a geometry can be generated which effectively follows from availability. The algorithm has been scripted in Python within Grasshopper, resulting in a user-friendly parametric design process. By defining the required width and span of a truss bridge and providing a stock of reclaimed elements, a solution cloud is generated of locally optimal truss bridge designs in terms of capacity utilisation and which comply to Eurocode provisions and constraints regarding the manufacturability of connections. From this solution cloud, an optimal design can be selected with given objectives, e.g. the design with the lowest environmental impact. A comparison shows that the developed growth method, using reclaimed steel elements, can lead to a steel truss with 17% less embodied carbon than a truss design whereby reclaimed elements are fit in afterwards, and 63% less embodied carbon than a traditionally designed new steel truss.

Cold-bent insulating glass units (IGU) have the potential to be one of the answers to current needs and wishes of modern and sustainable architecture. Curved glass is stiffer against out-of-plane loads and therefore the structural behaviour of cold-bent IGU’s is different compared to flat IGU’s. Structural behaviour of flat glass in buildings is assessed using standards such as EN 16612 and NEN 2608. Within these norms, isochoric and load sharing cavity pressures are assessed using simplified analytical equations. In case of cold-bent IGU’s, the additional assessment of increased stiffness, permanent cold-bending stresses and optical distortions are of importance. Currently, no standards are available for building envelopes containing curved glass elements. Methods from current standards have proved to be sufficient to quantify the complex role of cavity pressure in flat IGU’s. The goal of this research is to develop an analytical method to determine the effect of cavity pressure on the structural behaviour of cold-bent insulating glass units.

For the structural assessment of cold-bent IGU’s three stages are defined: ’Bending phase’, ‘Fixation moment’ and ‘Use phase’. Numerical models are developed to gain insights into the structural behaviour of cold-bent glass plates. Insights are then used to derive and validate simplified analytical methods.

The bending phase is numerically modelled with a geometrically nonlinear analysis in which curvatures are realized by prescribed displacements along two opposite edges of the plate. Results show that maximum cold-bending stresses are independent of plate size. By defining a tensile bending strength, insights are gained into the maximum radius of curvature of a plate with a specified thickness. A closed form equation is derived, which is used to calculate cold-bending stresses considering plate thickness and radius of curvature as input parameters. Resulting principal stresses have an average accuracy of 99.1% compared to numerical outcomes. Validity of the cold-bending stresses is limited to linearly fixed plates, up to a size of 6x3m, with equivalent plate thicknesses ranging from 4-20mm and design radii ranging from 3m to 25m.

Numerical results from the fixation moment show an anticlastic double or triple (w-shape) curvature in single curved plates, that cause optical distortions. The extent and shape of anticlastic bending depend on the Poisson’s ratio, plate thickness, radius of curvature and plate size. Based on regression between the parameters of influence, a result-based approach is developed to determine anticlastic bending displacements at the centre of curved plates. The approach is simplified to a curved plate with a sinusoidal anticlastic bending curvature. The displacements are expressed in a parameter for the radius at midspan and are calculated using tabulated coefficients with an average accuracy of 99.3%. Validity of the radius at midspan is limited to the previously mentioned boundary conditions.

For the use phase, the calculation of cavity pressures depends on the volume of deformation per pane of a linearly supported cold-bent IGU. Interaction between the panes is modelled using pressure loads derived from Boyle’s law. Using numerical models, volumes of deformation (v) from curved plates subjected to pressure loads (p) are presented in P-V diagrams. These diagrams are used calculate cavity pressures ranging from -1 to 1 kN/m2, considering plate sizes up to 6x3m, plate thickness of 8, 10 and 12mm and design radii up to 8m. Due to the increased stiffness of curved IGU’s, a higher load is shared by the pane onto which an external pressure is applied. Furthermore, as a result of anticlastic bending, a permanent isochoric pressure is present inside cavities of asymmetric IGU’s, which increases as curvatures increase.

A simplified analytical method to calculate effective cavity pressures is derived from shell theory. Load sharing pressures of symmetric IGU’s are calculated with an average accuracy of 95%, compared to results from the numerical P-V diagrams. Load sharing pressures of asymmetric IGU’s (91% accuracy) are summed with isochoric pressures due to cold-bending (92% accuracy) to calculate combined effective pressures with an average accuracy of 87%.

The equations are summarized in a guideline, which is complemented by an interactive calculation tool. The developed analytical method is effective in calculating effective cavity pressures and can be used to quickly explore various design options in a wide range of cold-bent IGU’s.

Gas extractions are responsible for mostly all induced earthquakes in the Groningen area and this leads to damage of houses and buildings and issues regarding safety. Current strengthening measurements are mostly very visible. However, this can change by using the window frame as part of the structure, particularly interesting for Dutch houses characterized by large window openings. In this thesis, the focus is on the validation of the numerical model based on experimental testing. From this, the main research question was formulated as “How can the structural window frame be modelled to agree with the experimental results, in order to assess the seismic performance for unreinforced masonry structures?”. The structural window frame is made of a timber frame, an adhesive and a double-glazing unit. The timber frame is made of hardwood on the outside and plywood on the inside. The potential of the structural window frame is researched into several numerical, experimental and design studies using DIANA 10.4. It is concluded that a specific non-linear elastic interface model for the adhesive is the best suitable model. This numerical model is used as a loading protocol for the experiments. The structural window frames have been built and tested at the TU Delft. The experimental results showed that the structural window frame behaves plastically. Concluding, the glass panels and the hardwood are not damaged however, the plywood is pinched due to the glass panel. The numerical model is adjusted to include the pinching behaviour of the inner bar to suit the experiments. The next step is the masonry model. The masonry model including the structural window frame showed an increase of 15% for the in-plane shear force capacity and a decrease of 23% for the crack width for a displacement of 4 mm, compared to the unstrengthened masonry wall. The pushover calculation showed that both the unstrengthened and strengthened masonry wall can withstand the seismic loads in Appingedam. According to assumptions, the structural window frame results in an increase of the shear force capacity of 47% for larger displacements. The ductility of the structure can be increased by increasing the effective mass to 15000 kg. However, the calculation is only valid for the assumed values, these results should not be taken too strictly. The design of the window frame can be improved by using: a stiffer timber frame, a thinner adhesive and a more sustainable design. Using a frame that is twice as stiff and strong has resulted in: similar initial behaviour, higher maximum shear force and later stabilisation of the in-plane shear force. Using a thinner adhesive than 5 mm does not result in more beneficial results. Furthermore, making only screwed connections and maintaining the structural window frame frequently could increase the lifespan of the structural window frame. The structural window frame has potential however, more numerical and experimental research should be done.

Glass has become ever more popular in the building industry. Glass is already used in facades, staircases, fins, floors, and beams. Nevertheless, free-standing load-bearing glass columns are rarely used. It needs to be robust, which means that it needs to give a warning before failure so that people can evacuate. Glass is a brittle material and has a sudden failure, which means that it is not directly logical to use solid glass as a load-bearing structural column. Rather despite the high compressive strength, due to complications with manufacturing, spontaneous failure, and lack of satisfactory of fireproof performance, more research needs to be done on the manufacturing, the fire safety, and the robustness of glass columns. In the literature study, the layered tubular glass column was found to be most promising for further investigating. The aim of this research is to design and engineer a transparent tubular glass column as a structural element, which is robust and fireproof. In the literature study a few aspects emerged: the tubular shape, the column needs to be sealed to avoid the column from becoming dirty, end connections, the geometric tolerances in the glass tubes and the robustness. The designs were engineered for the case study Bouwdeel D in Delft, but the designs can also be applied to other buildings: the fire resistance, demountability, the dimensions and the calculated compression loads. With these aspects in mind, three designs were engineered, the MLA (Multi Layered with Air) (2x) and the SLW (Single Layered with water) (1x) which fulfil the defined design criteria/main concerns. Six small samples with a length of 300 mm were produced to test the lamination process with regard to bubble formation and possible breakage of the glass by internal stresses. Three laminated DURAN (annealed) samples and three laminated DURATAN (heat-strengthened) samples were tested. The glass tubes were manufactured by extruding and were made by SCHOTT. H.B.Fuller Kӧmmerling carried out the lamination process. Furthermore, the connection components (steel and POM) were produced and arranged by Octatube, the steel hinges were arranged by Techniparts, and the Hilti mortar was arranged by Hilti. Afterwards, these samples were tested on compression strength, to investigate the behaviour of the interlayer material, the post-failure behaviour of the designs, the differences between annealed and heat-strengthened glass samples, the behaviour of the connections under pressure, and the capacity of the glass tubes and the connections. The first cracks appeared earlier than expected. Nevertheless, the samples seemed to be really robust, because the samples had a large load-bearing capacity even after the first cracks occurred. The first crack appeared between 95-160 kN in the DURAN samples, and after that the samples were still able to carry a load of 700-750 kN. So, after the first crack, the specimens were able to have around 4-5 times more load. The heat-strengthened samples first cracked at 120-160 kN. The maximum force of these samples was 390-490 kN. This means that after the first crack, the specimens were able to have around 3 times more load.

There are two main challenges in the construction industry: carbon emissions and densification in cities. Timber high-rise might prove as a suitable solution to both these challenges. However, there is a lack of implementation of timber high-rise. This research argues that a lack of thorough analysis of timber design alternatives in the conceptual design phase results in the exclusion of further evaluation of timber building designs. This research aims to analyze timber building design alternatives more thoroughly by the development of a tool, based on the Multidisciplinary Design Optimization (MDO) method. In Grasshopper, a parametric model is created with which timber building designs are generated, validated, and optimized. Two main optimization objectives and two constraints are considered in the tool: Firstly, the structural constraint: Each building must be designed according to the constraints as determined in the Eurocode. Secondly, the architectural constraint: Each building must satisfy the architectural design requirements for acoustics, building height, and daylight entrance. Thirdly. the environmental objective: minimize the shadow costs, which are determined according to the MPG methodology. The MPG methodology uses Life Cycle Analysis data to assess the embodied energy impact of structural materials. This embodied energy impact is expressed in shadow costs. Lastly, the economical objective: minimize the construction costs. Based on the mentioned constraints, the tool aims to indicate the design situations in which timber high-rise can be competitive to an assessed concrete design alternative, considering the combination of properties for shadow costs and construction costs. By research and development of the Multidisciplinary Design Optimization tool and analyzing two case studies, a conclusion can be made. Two concrete buildings, which are based on a current Arcadis project, are used as case studies. Both concrete buildings represent a design situation. The main difference between these design situations is the building dimensions. Building A3 represents timber building designs that are created for a design situation with a floor area of 28.8 x 28.8 m and a height of 60 meters. Building B3 represents timber building designs that are created for a design situation with a floor area of 21.6 x 43.2 m and a height of 50 meters. For both case studies, an optimization will obtain timber building designs with an optimal combination of properties for shadow costs and construction costs. This resulted in the following results. For the design situation based on the concrete building "The Rectangle", the Pareto optimal timber building designs, referred to as Building B3, were found to be competitive with "The Rectangle". For the other analyzed design situation, the Pareto optimal timber building designs referred to as Building A3, were not found to be competitive with the concrete building "The Square". Considering the boundary conditions and scope of this research, it can be concluded that a design situation with a rectangular floor plan is favorable over a design situation with a square floor plan and a design situation with a building height of 50 meter is favorable over a design situation with a building height of 60 meter. Also, based on analysis of the case studies the following conclusions were made. Firstly, when the effect of carbon sequestration is excluded in the calculation of shadow costs, the use of timber and concrete in the structural system was found to generate comparable results considering their shadow costs. The inclusion of the effect of carbon sequestration during the lifetime of a timber building results in a reduction of shadow costs of approximately 40% compared to a similar concrete building. Secondly, considering the boundary conditions and scope of this research the ULS is found to be normative for a slenderness up to 2.35. When the slenderness is greater than 2.35, the along-wind acceleration was found to become normative. Next, for all Pareto optimal building designs, the ULS check was found to be normative over the SLS check. Lastly, the mass of the Pareto optimal timber building designs was found to be approximately 8 times smaller than their respective concrete design alternatives, resulting in a foundation with less construction costs and shadow costs.