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.

The Circular Arch Bridge is a pedestrian bridge consisting out of four different recycled materials: cast glass, ceramic, circument and geopolymer concrete. Due to an increasing amount of vibration problems in modern pedestrian bridges they should not only be designed for static loads, but dynamic loads have to be considered as well. There are currently no guidelines in the Eurocodes for the dynamic assessment of a bridge like the Circular Arch Bridge. Therefore, this paper provides a research on how the dynamic assessment of the Circular Arch Bridge should be conducted.

The Circular Arch Bridge is considered a dry-stacked masonry arch bridge. A full dynamic assessment is conducted, with the use of finite element software, according to the guidelines for pedestrian bridges. The eigenvalues of the Circular Arch Bridge are not within the critical range for pedestrian induced dynamic loads. It is found that for everyday use the Circular Arch Bridge is within Comfort Class 2 from the Eurocode, thereby providing a medium comfort level. A special load case is added to the analysis representing a group of 60 people dancing on the bridge during experimental testing of the bridge. For this load case the Circular Arch Bridge is within Comfort Class 3 from the Eurocode, thereby providing a minimum level of comfort.

With a sensitivity analysis it is determined that the most sensitive input parameter of the finite element model is the modulus of elasticity of the interlayer. An investigation of the effect of large stiffness differences between the interlayer and the stones on the dynamic properties of the bridge is conducted. It is concluded that the large stiffness differences have a positive effect on the dynamic properties of the bridge. The effect of the dry-stacked assembly of the bridge on the dynamic properties is also investigated. This as a negative effect on the dynamic properties of the bridge.

Cast glass has great application potential in the architectural realm, yet, despite its possibilities and attractiveness, designers, engineers and developers are, from an early design stage, hesitant to employ it; the limited available and craft-based manufacturing facilities, the questionable quality of the product, the missing engineering data and quality control processes and the uncertainties linked with the structural application of cast glass, lead to discouraging high cost/ high risk solutions. Within the listed challenges and uncertainties, perhaps the most striking is our inability to answer the most obvious question: what is the strength of cast glass? A simple answer to this question does not exist, as the mechanical properties of cast glass vary from product to product, and are directly influenced by the employed chemical composition, thermal history, and casting process. Adding to this complexity, further questions over the mechanical properties and quality arise, once waste (contaminated) glass cullet and lower processing temperatures are used, in the efforts of reducing the environmental impact of cast glass components.

Focusing on this knowledge gap, the aim of this work is to develop an understanding of the effect of the casting parameters on the meso-level structure of cast glass, and thereupon of the relationship between this meso-level structure and the strength, stiffness and fracture resistance of cast glass components. Towards this aim, the dissertation adopts an experimental approach based on physical prototyping by kiln-casting, and destructive and non-destructive testing. The experimental work shows that by kiln-casting, a larger variety of chemical compositions can be cast, even at relatively low processing temperatures. As a consequence, a broad range of mechanical properties arises, especially when waste cullet is employed. Based on the casting parameters, combinations of different defects, grouped in meso-level structures, are commonly found in cast glass, yet these can often be tolerable when situated in the glass bulk. The dissertation highlights the potential of recycling-by-casting of currently challenging to recycle glass waste into reliable and aesthetically unique structural components, and the advantages of engineering composite cast glasses. It also underlines the need for manufacturing guidelines, test data, product certifications and quality control protocols, for the successful implementation of cast glass in the built environment.

Purpose: Additive manufacturing has enabled innovative, cost and resource efficient mass customization of products over a wide range of manufacturing industries. Under the broad spectrum of options for manufacturing of metallic components, Wire + Arc Additive Manufacturing, WAAM, offers the combination of high design freedom and productivity at a comparably low cost. As a maturing technology, the application in the building industry of steel and stainless-steel products becomes increasingly interesting. Research is nevertheless necessary for the identification of the material’s performance under dynamic loading. It has been demonstrated that the manufacturing procedure inherently produces a heterogenous material matrix and wavy surface, which may be susceptible to fatigue. Methodology: Based on a broad literature review concentrated on the material performance of stainless steels as welding consumable, stainless-steel SAE316L is chosen as the material of interest for characterization. Test coupons are extracted from heat-treated wire+arc-additive-manufactured single-bead walls to perform monotonic and fully reversed strain-controlled fatigue tests in both longitudinal and build directions. The material’s microstructural characteristics are documented. Test methods include Wavelength Dispersive X-Ray Fluorescence for chemical characterization; X-Ray Diffraction for phase identification and quantification; and Scatter Electron Microscopy and Optical Microscopy for qualitative sub-grain and grain microstructural characterization. The latter methods are subsequently used to characterize the monotonic and fatigue fracture surface morphology of post-mortem test samples. A constitutive model for the material is described based on the results of the monotonic and cyclic behavior in both orthogonal directions. Inspection of the fracture surface of the tested coupons is realized to validate the assumptions made for the application of the fatigue models at hand. Addressing a commonly cited problem, the macroscopic surface waviness of the printed material is quantified, and its effect as a stress concentrator is numerically modelled and verified through a smaller group of tested coupons retaining the original surface waviness. Finally, suggestions for the extrapolation of these results are done for the design of structural components produced with the studied material and designed for Fatigue Limit State. Findings: Microstructural characteristics include a strong metallurgical texture in the build orientation, limiting the validity of X-Ray diffraction results. Ferrite is quantified at approximate 13% volume ratio through image analysis of SEM micrographs. Possible traces of σ-phase are identified through optical microscopy, specifically in inter-grain boundaries, although further work is necessary to confirm their constitution. Fracture surface analysis indicates mostly ductile material deformation, confirmed by the elongation capacity of tensile test results, and a predominantly smooth fatigue fracture surface populated by ridges with isolated striation locations, indicating crack propagation at a low stress intensity amplitude. The material shows marginally lower performance in terms of quasi-static characteristics when compared to the one cited by the consumable manufacturer for all-weld material. This remains nevertheless consistently higher than the allowed design values published by commercially available standards. A notoriously low elastic modulus is observed, source of which remains unidentified; the elastic modulus is measured between 54% and 58% of that of commercially available hot-rolled stainless-steel alloys. Cyclic material performance corresponds with all-weld predicted performance for ferritic-austenitic stainless-steels, where the first few cycles are characterized by a slight material hardening, followed by a consistent softening throughout the cyclic life of the material. Average fatigue performance is undistinguishable from mean design values proposed for structural stainless steels under standardized testing conditions. At a 95% reliability and 75% confidence interval, the material performance is superior to the design curves proposed by ASME. The theoretical stress concentration obtained through numerical analysis of the surface geometry is modeled as a function of maxima between 3.150 and 3.927 in the build orientation with a 75% reliability for component lengths of 20 mm for the former value and 100 mm for the later value. Similarly, the values 1.944 and 2.413 in the longitudinal direction describe the stress concentration effect for 20 mm and 100 mm component lengths correspondingly. Originality / Value: The research contributes to the characterization efforts made for the improvement of Wire+Arc additive Manufacturing technologies. This work is carried out both at a microstructural and a bulk level, allowing to establish a correlation between the manufacturing parameters, the microstructural morphology and the mechanical behavior of a given material. Design aids are presented at a typically cited reliability level for engineering practice, accompanied by a thorough description of design considerations based on the material’s inherit characteristics as a product of WAAM process.

Drying shrinkage can cause structural damage to concrete industrial floors. Shrinkage is caused by evaporation of moisture from the drying material. In the design- and construction-standards, this complex process is not described on a fundamental level. Using finite element modelling to simulate the flow of Moisture through the concrete, it is possible to simulate drying shrinkage. The research question of this thesis is: ‘How can a parametric FEM model efficiently simulate drying shrinkage in industrial concrete floors?’. Verification of the produced model is performed. The outcome is compared to shrinkage
measurements of concrete prisms. The theoretical framework presented in this thesis is based on the fact that the relative pore humidity is changing during drying. In a finite element model, the changing relative pore humidity (pore-RH) over time is calculated. Drying is caused by internal diffusion of moisture, which is driven by differences in concentration. The moisture flow is modelled using the transient heat equation. The resulting pore-RH values are used to determine the hydrostatic capillary pressure based on the equations of Kelvin and Laplace. The material response of cement paste subjected to the capillary pressure is calculated using Bentz law. At last, the models of Pickett and Neville are used to include the restraining effect of aggregates and determine the absolute deformation of concrete subjected to drying. The initial conditions of the material are determined based on HYMOSTRUC cement simulation and Powers’ volumetric model. The results of the presented theoretical framework are reasonable. Usage of the framework and the heat equation for modelling drying in FEM, proved to be successful. A significant uncertainty is found in the restraining effect of aggregates. The theoretical model is based on material modelling of drying cement paste. However, the deformation of concrete is only
16%~23% of the total deformation of cement paste. Recommended is to further research the (local) effect of aggregates on drying shrinkage. Drying shrinkage has been calculated according to the construction standards and compared to the measured drying shrinkage of the concrete prisms. From this, it can be concluded that calculations by structural engineers on drying shrinkage are preferably done according to the ‘Model code 2010’.

Cities like Amsterdam and Rotterdam are located on top of a compressible clay layer. Most of the buildings in these cities are founded on the foundation layer above the compressible layer. Therefore this compressible layer can induce problems when the soil pressure increases significantly due to the weight of the high-rise buildings. This deformation can cause inclination of the floors, damage to the structural and non-structural elements of the building. Therefore the structural design of a building must appropriately be designed to respond or resist these deformations.

The deformation, which causes the problems in the building itself, is the differential deformation (sagging). This is unequal deformation over the entire plot of the building. The uniform deformation of the building does not induce problems in the structure itself, but it can damage the adjacent buildings because the soil under these buildings will deform (hogging). The construction sequence decreases the problem for the higher levels because the deformation of the compressible layer start occurring during construction, and these levels are constructed horizontally independent on the amount of deformation of the
soil.

For this research, the following mitigating measures are considered: changing the construction sequence; increase the length of the foundation pile; application of a camber; increase the stiffness of the foundation slab; increase the stiffness of the superstructure; application of a jack-down system.

The primary factors which are affecting the applicability of the mitigating measures are the amount of settlement, the soil structure, and the time-dependent behavior. By a significant settlement of the soil, the mitigating measures of applying a camber and increasing the stiffness of the structure are not possible or less favorable. The soil structure determines if increasing the length of the foundation piles is possible, this mitigating measure put the foundation piles in the second foundation layer, which is situated under the compressible layer. With this measure, the problem of the compressible layer is solved, but it is an expensive mitigating measure. Adjusting the construction sequence depends on the time-dependent behavior of the settlement. It can be an option when the settlement happens mostly during construction. When the settlement of the soil takes longer than the construction time, the jack-down system can be applied to adjust the structure when needed, even when the building is finished.

The application of the jack-down system is definitely worth considering when a high-rise building is built on compressible soil. The other mitigating measures can be applied too, however, only under very specific conditions. This makes the jack-down system the most favorable mitigating measure.

In the current built environment, the three main glass elements are glass window blocks, (structural) float glass and (structural) glass bricks. Float glass is the most used type of glass element and it is evolving from a skin material to a structural material. Glass hollow blocks became popular in the 1930s, but have lost their appeal due to little structural capacity and outdated aesthetics. A new and upcoming technique is the usage of cast glass bricks, which provides high structural performance without the use of substructures. The 21st century is unmistakably characterized by climate change and the effort being put into the battle against it. It is the duty of engineers to design in a sustainable way. ‘Sustainable’ can be interpreted in many ways; the focus within this paper lies on the usage of recycled materials, the recyclability of the final product and the energy usage during the lifespan of the façade (linked to thermal performance). When looking at the material itself, glass is a very recyclable material. This is widely done for glass bottles. However, the recyclability of float glass is very limited. Windowpanes and structural glass panes both consists of several layers of glass, combined with a PVB interlayer. Mostly, these combined panes are themselves processed further into insulated glass units, or IGUs. This end product consists of many different materials, that are hard to separate and for this reason, IGUs are seldom recycled at this moment. Additionally, not only the end product is rarely recycled, little recycled material is used for the production of float glass. The tolerances for using waste cullet in the production of float glass is very limited. Since the lifecycle cannot easily be changed for float glass, it is interesting to look into cast glass. The production technique is different from the production of float glass. Glass is melted into a mould, rather than spread along a bath of tin. The latest research shows the possibilities of using glass cullet and thus casting waste glass. One opportunity that arises from this, is the development of waste glass bricks. One main problem of cast glass bricks is its thermal performance. Due to the lack of cavities, as present in IGUs or hollow glass bricks the thermal performance is not optimal, especially with the increasing need for high-performing facades to meet sustainability demands. There are several strategies to improve the thermal performance of glass structures. The most simple solution for reducing the thermal transmittance is the introduction of air pockets or cavities. Air is a relatively good insulator, especially in small confined geometries. Convection reduces the thermal resistance of air and the bigger the air pocket, the more convection can occur. Not only air can provide insulation, this can also be done with other materials. Inert gasses, like argon and krypton, have a lower thermal conductivity than glass, but are more costly and would require a more complex production process to fill the cavity and to ensure complete sealing. Translucent solutions can be achieved with materials like aerogel and glass fibres. Light transmittance is still present, but the result is not transparent. If transparency or translucency is completely ignored, traditional insulation materials, like rock wool and polystyrene, could increase the thermal resistance too. Improvements can also be made with either reducing the amount of as long-wave, infrared energy going through the glass utilizing coatings or by reducing the conductivity of the glass itself by changing the molecular build-up. The glass recipe influences the thermal conductivity. This thesis focuses on the thermal performance of cast glass bricks and in specifically the investigation of the impact of cavities on the thermal performance and the development of a relevant production method for cavity cast glass bricks. Air cavities can be added on either system-level or element-level. On a system-level, the design of a singular brick does not change, but the typology in which it is used does. Cavity walls with either a double brick wall or with an additional float glass wall will improve the thermal performance but will utilize a lot more material. When changing the geometry of the brick itself, one or more cavities can be introduced to improve the performance. Since smaller cavities have a relatively better performance, multiple small cavities will automatically perform better than a singular larger cavity. Several designs are drawn, varying from a single or double cavity to an arrangement of glass shards, providing lots of encapsulated air pockets. Thermal bridges within a design influence the overall thermal performance. The heat will choose the path with the least resistance, which is via the glass. It is possible to lengthen the path that the heat must undertake, by introducing multiple air chambers and increasing the overall thickness of the brick. This increased thickness will also aid the structural performance. Creating multiple air pockets is directly linked to many glass-air transitions and thus a more complex geometry and production process. Producing such a brick with current standard manufacturing techniques would require glue. Glueing is not very environmentally friendly. The glue is not easily (if not impossible) to remove and therefore the final product is not recyclable. With experimental research, the potential of tack fusing glass is highlighted. This ‘tack fusing’ is done at a temperature below the actual fusing temperature, where the glass still creates a permanent bond, without relaxation and shape loss. This temperature lies around the dilatometric softening point of the specific glass type. The potential of the tack fusing method is explored employing shear tests of fused specimens. Three types of specimens are tested: two different series of tack fused specimens at 650˚C (1hr, 3hr dwell at top temperature) and one series of glued samples (DELO 4468) to be used as a reference. DELO4468 is a high-performance glue, which is mostly used for its high strength. Nine design concepts are drawn, based on a solid brick of 200x200x100 mm. Seven element-based designs are limited within these boundaries since increased thickness (even with only glass) would lead to higher thermal performance. Two system-level alternatives are not in-depth researched but are still examined as reference. These two alternatives cannot be kept within these boundaries and are thus at increased depth of the finished wall. All nine designs are scored in a multi-criteria analysis. The main focus is the thermal performance and therefore the thermal transmittance of each design needs to be analysed. This is for eight out of nine designs done with TRISCO, a steady-state 3D thermal analysis software. The last design, a fused shard brick, consisting of a random arrangement of random-shaped shards and is not easily modelled in 3D software. For this reason, it is not analysed in TRISCO but analysed through an experimental analysis. This experiment replicates a situation in which one side of the brick is warmer than the other while measuring the temperatures and heat fluxes. With these measurements, the thermal transmittance can be estimated. The last part of this thesis is the multi-criteria analysis, or MCA, in which all alternatives are scored against several criteria. One of these criteria is the thermal performance, others are sustainability, producibility, aesthetical potential and transparency. The sustainability is scored against several checks, related to the recyclability and the required temperature for production. The producibility and the aesthetical potential is scored utilizing a small expert survey. Both criteria are subjective of nature, but by including the opinion of several experts, the outcome is inter-subjective. The transparency is scored regarding the number of refractive surfaces (because with each air-glass transition visibility is lost due to reflections) and the percentage of non-transparent materials in the cross-section. The result of this thesis is not a single design, but insights in the potential of each concept. All designs are not ready for direct application but would require further structural verification and thermal optimisation, depending on the governing thermal requirements. There is not one perfect solution since each façade has different performance requirements, but the results do provide insights for an improvement from the current technologies.

Bridges are exposed to dynamic forces – such as pedestrians crossing a bridge or the wind force acting on a bridge – which cause vibration of the structure. When a structure is forced at one of its eigenfrequencies it deforms into a corresponding shape leading to major deformations, which, in the worst-case scenario, can lead to collapse of the structure, as happened to the Tacoma Narrows bridge in 1940. It is thus very important to know the dynamic characteristics of a structure. For glass structures no specific limit values are defined, this is why it is interesting to investigate the dynamic behaviour of a glass bridge This thesis aims to predict the structural response of TU Delft’s Glass Truss Bridge when subjected to static and dynamic loads. The studied bridge is a footbridge, connecting the TU Delft campus to the Green Village, and is unique in the aspect that glass diagonals have been used in its construction. Through an iterative procedure of modeling, virtual testing and updating the model of the bridge, the dynamic response of the bridge is predicted. The study shows that the response of the bridge is between the European Guidelines’ limits for (steel) footbridges. Maximum acceleration of the bridge is found at 500mm/s and the lowest eigenfrequency is out of range of that of joggers. The sensitivity analysis shows that the parameters having the most influence on the bridge’s response are the diameter of the glass diagonals and the soil density. Using the outcome of the sensitivity analysis a dynamic testing protocol is recommended that outlines the optimal test setup for modal testing of the bridge. Through the simulated dynamic tests ten of the twenty eigenfrequencies of the bridge are found. For each of these frequencies, the damping is approach and modeshapes are reconstructed based on the imaginary plots of the Frequency Response Functions. The latter show a good correlation with the modeshapes obtained from the model.

The investigation of new glass compositions is crucial to expand the possible applications of glass, from the typical applications for building engineering, in the form of cast blocks or floated glass, to more advanced technologies, such as 3D-printed glass or glass to metal connections. Despite the intense research activity and new glass compositions being investigated every day, there has been little innovation or evolution in the composition of architectural glass. This is partially explained by the fact that a substantial part of glass research is not relevant to practical large-scale applications. This thesis is more concerned about the development of compositions with optimized properties than the studies of the short- and intermediate-range structure of a theoretical glass that would hardly find a practical application. Thus, these compositions are inexpensive and appropriate to mass production, utilizing conventional melting techniques. Since the high melting temperatures and the brittleness are two important drawbacks of glass, this work aims to improve both properties. The modification of the properties is achieved via changes in the composition of the glass, using compounds such as phosphorus pentoxide, aluminium oxide and boron oxide. Then, the choice of different glass formers and modifiers contributes to the development of compositions with lower melting and glass transition temperatures. The reduction of the melting temperature allows a saving of energy during the manufacturing and recycling processes. The structures of the glasses differ from the standard soda-lime and borosilicate glasses, leading to a different mechanical behaviour. For instance, an anisotropic structure, which could exhibit a better mechanical performance than standard glasses. Furthermore, these new compositions incorporate up to 35% of slag and fly ash in their formulas. The valorization of these by-products that would otherwise have been previously discarded reduces costs and gas emission. The developed compositions have high water resistance, amorphous structure proved by x-ray diffraction and indentation toughness comparable to a standard soda-lime glass. The coloration of the samples varies depending on the composition and, for the samples containing slag, depending on the melting temperature. In this case, melting at higher temperatures allows the production of colorless glass. The color of the glasses is mainly influenced by the presence of sulfur and iron oxide. In conclusion, this thesis describes the development of new glass compositions containing fly ash and slag. The focus of the work is on the improvement of the properties and a comparison of performance of these new compositions with the glasses currently used in building engineering. The promising results point to the possibility of expansion of the current applications of glass.

The life cycle of a building has a tremendous impact on the environment. This is due to its energy demand, production and transportation of building materials, and its maintenance. Actually, the building industry is one of the most polluting industries that contribute to climate change. In the Netherlands alone, this sector is chargeable for 50% of the materials consumed, 40% of the total energy used and 35% of the total CO2 emissions. To limit the effects of climate change, the Dutch government has set several requirements for new buildings concerning energy use and emissions. The energy performance of buildings is a requirement to minimise the energy demand of buildings. The environmental performance is a requirement to reduce the environmental impact of materials used in the building. These requirements correlate negatively. Therefore, when the regulations get more strict, it will not be possible to satisfy both. Thus, the requirements will adversely affect each other. This thesis ‘When energy savings become a waste’ describes research about the design of facades to increase the sustainable performance of office buildings steered by the regulations energy performance of buildings and environmental performance of buildings. It is about the conflicting demand and how to design a facade in such a way that no energy will be lost because the energy reduction is less than the energy needed for the production of an element. The main research question that is answered in this research is ‘How can the Dutch building industry achieve sustainable buildings by designing according to both the energy performance and environmental performance of buildings applied on facades?’ First of all, the relation between sustainability, energy performance-, environmental performance- and circularity of buildings is established. In this research, sustainability is defined as a goal to minimize harmful emissions to the planet. This goal can be achieved in different ways , one of which is the circular building principal. A circular approach of building aims to no longer use new resources and produce no more waste. The energy performance of buildings and the environmental performance of buildings can help steer towards sustainable buildings. Next, the concepts of the environmental performance of buildings (MPG) and the energy performance of buildings (EPC) are introduced, and their current use in methods and tools is analysed. Several methods exist in which the energy performance and the environmental performance are combined. For this research, the ‘sustainability performance of buildings’ (DPG) will be used, which is an objective method combining the energy and material by converting the total CO2 emission in the energy performance to shadow costs and by adding this to the shadow costs as calculated in the environmental performance. Therefore, the sustainability performance indicates the total emissions of the whole life cycle of a product, process or building and the total costs required to bring the environmental impacts of a product, process or building to an acceptable level. The sustainability performance of buildings is expressed in shadow costs per square meter, €/m2. In a one-factor-at-the-time analysis, the environmental- and energy performance of buildings is calculated in different scenarios with a varying parameter in the design of the facade. For this analysis, a reference office building was used as a study case. This is a medium-sized office building with a curtain wall facade of aluminium and triple glazing. Eight variants are examined, in particular: type of glass, insulation value and insulation material, the ratio of open and closed parts in the facade, use of PV-panels on the facade, sun shading, facade composition, orientation and changing the building process from linear to circular. The most important results of the case study are as follows: •In types of glazing, vacuum glazing has the best sustainability score. Also, triple glazing with a total glass thickness of 12 mm is an improvement compared to the current thickness of 16 mm. The performance of HR++ glazing is only 1% worse than triple glazing and can, therefore, also be considered in use. •The insulation value, as well as the insulation material, has no significant influence on the sustainability performance. The reduction in energy by adding more insulation material is almost equal to the energy needed for the production of the extra material. •The percentage of glass in the facade has a tremendous impact on both the environmental performance and energy performance. Both the performances get worse with a higher percentage of glass. The trend in the design of office building is, however, to increase the percentage of glass. •The use of PV panels in the facade is beneficial for the sustainability performance. The revenue is small for PV panels on the north facade, and the investment will not pay off. In the other orientations the PV panels the payback time is between 11 and 15 years. PV panels on the south facade achieve the most improvement. •The addition of sun shading will only slightly improve the sustainability performance when no louvres are included in the design and the control system is optimal to reduce the heating and cooling demand. •A change in the facade system and materials can significantly reduce the sustainability performance. However, this is mainly caused because no louvres are added in the other facade designs. Therefore the addition of louvres is not sustainable; neither is increasing the height of the floors. The facade with wooden cladding has the best sustainability performance. •The orientation of the building can influence the sustainability performance without changing other parameters. For the reference building, the most optimal orientation is achieved by a rotation of 90 degrees. The windows are then orientated north and south. •The effect of different circular scenarios is calculated and compared to the reference scenario with a service life of 50 years. The scenario considering the reference situation with a realistic service life of 20 years, has the highest score of all. In the next scenario, the percentage of reuse is increased to 60% and the service life of the facade is 20 years, resulting in an improved sustainability performance of 2%. In the last scenario, the service life is extended to 100 years, causing an improvement of 4%. Conclusions of this research are only based on the sustainability performance and do not take into account social and financial aspects. Therefore in some variants, the most sustainable solution might not be feasible in practice. For example, vacuum glazing is very expensive, and consequently, triple glazing with a thickness of 12 mm is advised to use. One realistic variant is calculated with a combination of variants. In this scenario, financial and social feasibility are taken into account, and an improvement of 15,5% is achieved, showing the value of this integral approach. Based on this research, it can be concluded that the Dutch building industry can achieve sustainable buildings when the design is focused on decreasing the sustainability performance of buildings. An integral approach considering both energy and material use is essential when enhancing the sustainability performance of buildings. The goal of the Dutch government to steer on CO2 emission can help to improve the sustainability performance. However, the relationship between the sustainability performance and CO2 emission is not entirely linear. Energy and material use need to be balanced together to accomplish a sustainable built environment. To be able to use this knowledge in a broader context it is recommended to conduct this research for a combination of the used variants, take into account design aspects of the whole building, and perform analysis on multiple buildings. In this research, only the aspects of sustainability concerning the planet are taken into account. Aspects regarding people and profit should also be considered to determine the feasibility of sustainable measures.

This research investigated in which ways the material environmental impact of the main load-bearing structure of a high-rise building can be reduced. To determine this material environmental impact, the shadow price for each material and product has been determined by using ten environmental impact categories. One of these categories is global warming potential.

In this research the material environmental impact of the main load-bearing structure for the building for the European Patent Office has been determined and optimized. The originally designed main load-bearing structure for this building consists mainly of steel columns and beams, and Slimline floors.
The optimisation has been done for a design lifespan of 50 years and for 200 years. Additionally, a higher live load that creates more flexibility for the 200-year scenario is examined. The original function for the building is “office” and the other considered function is “meeting”.
As alternatives for the beams and columns, steel, concrete, and timber elements have been considered. Hollow core slabs and Lignatur floors were explored as alternatives for the Slimline floors.

In this research it has been found that it is beneficial to prolong the design lifespan of building. The environmental impact per year is much lower for a lifespan of 200 years than for a lifespan of 50 years. In order to increase the chance of a longer lifespan, it is wise to create flexibility concerning the function of the building. A higher live load will result in slightly more material needed, but still, the environmental impact per year is much lower than for 50 years.
Additionally, there can be looked at choosing the best material for each application. For a design lifespan of 50 years, the difference between the materials is such small, that no preference can be determined. For a lifespan of 200 years the differences are still small, but an entire steel structure or a combination of steel beams and concrete columns result in the smallest environmental impact. For floors, no matter the lifespan, with a big span and where no in-situ concrete can be used, hollow core slab floors proved to be the best choice.

Philippine low-income housing is uncomfortable since it is not built to deal with the hot and humid climate in a passive way. Since local vernacular architecture is known to have a good climatic responsive performance, the aim of this research is to learn how Philippine vernacular design strategies can improve thermal comfort for low-lying, sub-urban and rural, low-income housing. The strategies studied are openings, eaves, stilts, orientation, roof insulation and roof angle.
 Two-day in-situ thermal measurements are used to study the comfort performance of the housing typology. To study the influence of the strategies or combinations of them on comfort, numerical predictions are used consisting of energy and CFD, wind-driven simulations. The numerical models are validated before the strategies are varied on a general case or a case study. The average exceeding temperature (AET) in Kelvin is used to assess comfort. It is calculated by accumulating for every hour of the year the exceeding temperature in Kelvin and divide this by the amount of hours that could be uncomfortable. A conceptual implementation study is performed to take disaster resilient and practical considerations into account. The impact of varying the strategies on the case study resulted in a reduction in AET of about 5 K for openings, 0.7 K for orientation, 0.6 K for eaves, 0.5 K for stilts and 0.1 K for roof insulation. On this basis, it can concluded that applying the guidelines as stated below, comfort increases significantly. More impact can be obtained if the strategies are implemented and combined as described by the passive design guidelines below. • To increase wind driven ventilation in wind direction, openings should be made on the wind- and leeward facade until ground floor, have an opening height (O_h) based on the facade height (F_h) by the rule of thumb: O_h[m]=0.85·F_h[m], include a leeward roof opening and include openings on the remaining facades. • Dependent on the wind direction, the openings should be opened accordingly. If no wind is present, all roof openings should be opened. During typhoons, they should be closed. • As much open area on facades in the main monsoon wind direction is advised. The openings on the other facades should be placed in the middle of the width to increase the performance with wind coming from the other directions. • Hinged eaves with a 15° angle and length calculated by the rule of thumb:  E_l,15°[m]=0.6·F_h[m] should be used. During typhoons they should be folded in to decrease the related pressures.
• Increasing stilts height increases comfort by an exponential decay. To determine the height, a comfort increase of about 0.17 K for 1 meter, 0.30 K for 2 meter and 0.40 K for 3 meter in AET reduction are obtained. Braced, wooden stilts are advised to protect against floods and increase earthquake resilient behaviour. • A roof insulation with an Rc-value of 1 m²K/W is advised to gain about 0.2 K AET. Further research is needed on buoyancy driven ventilation to improve the provided design guidelines.

In recent decades, gas production has caused numerous human-induced shallow earthquakes in the province of Groningen, The Netherlands. The buildings in this area were not designed for these unexpected earthquake loads and have shown to be vulnerable. However, current strengthening measures are considered to be time-consuming, expensive, and a great hindrance to the residents. Consequently, the question rises whether unconventional strengthening measures can offer relatively simple and quick-to-implement alternatives. This thesis researches if replacing existing windows by structural windows could provide an effective strengthening alternative. The structural window design aims to increase the in-plane seismic force capacity of an existing masonry structure by utilising the glass pane as a structural element. The structural window is designed to be composed of a timber frame, a semi-rigid adhesive, and a double glazing unit. The structural layer of the double glazing unit has a thickness of 20mm and is composed of two laminated annealed glass panes with equal thickness.

The potential of the structural window is investigated in various numerical studies, using DIANA FEA 10.2. The numerical studies are split into validation studies and seismic strengthening predictions. In the validation studies, results from numerical models are compared to and validated against experimental results reported in literature. Subsequently, the potential of the structural window is assessed by seismic strengthening predictions that combine and extrapolate the validation studies. A mass proportional one-directional monotonic pushover loading scheme is adopted. The seismic strengthening predictions address masonry walls and one type of terraced house (Dutch: “Rijtjeshuis") with two rigid floors, masonry spandrels, and two large windows in the front façade wall.

The numerical strengthening predictions of the masonry walls and the terraced house indicate that a structural window improves the in-plane seismic performance significantly. It is found that strengthening not only greatly increases the seismic force capacity, but also reduces the expected damage. For example, the strengthened terraced house with openable window sections reaches 205% of the seismic force capacity of the unstrengthened terraced house. Furthermore, it is found that the stress levels in the glass pane are expected to remain well below the stress levels at the onset of glass cracking. The numerical strengthening predictions are promising. Therefore, it is recommended to validate these numerical predictions with an experimental testing campaign.

Lately structural safety is an often discussed subject in The Netherlands. Recent collapses have made people question if our buildings are actually safe enough. Research shows that the individual probability of death due to structural failure is below the limit of 10-5 per year. However, it is unknown if every single building is safe enough as well. The main cause of structural failures are human errors (90% of the collapses). However, the Dutch Building Decree does not mention the unidentified accidental actions (the type the human errors belong to) as those an engineer has to take into account when designing the building structure. The Eurocode does mention unidentified accidental actions and states that for consequence class 3 buildings a risk assessment has to be done to check which accidental actions are hazardous and if the total risk to a building is acceptable. However, the Eurocode does not give a maximum value of an acceptable risk in their risk assessment method. So currently when engineers perform a risk assessment, they cannot verify whether the risks of accidental actions on their designed structure are acceptable according to the regulations. This thesis conducts research for a new method for performing a risk assessment in a quantitative way. First it investigates what the advantages and disadvantages of existing methods for performing a risk assessment are. It appears that the main step missing in existing methods is the verification, based on a quantified limit, whether the risks of accidental actions are acceptable. Based on the known methods, a new protocol for performing a risk assessment is proposed. This protocol includes a determined limit for the probability an accidental action occurs and causes a certain failure mechanism and consequence. This limit is based on the maximum probability the Eurocode gives for failures with a consequence indicated as consequence class 1, 2 and 3 (CC1, CC2 and CC3). By dividing the accidental actions that can occur and their failure mechanisms into the same consequence classes, the estimated probability and the limit of the Eurocode can be compared. In this way the known consequence classes from the Eurocode are used in another way than engineers are used to. Furthermore research on past structural failures has been investigated to establish whether it can be used to predict the probability a certain accidental action causes a CC1, CC2 or CC3 consequence. Not enough research is done to fully trust on these outcomes; in the protocol proposed in this thesis the engineer will have to estimate a part of the probabilities himself, with the help of a classification table. The principal advantage of performing a risk assessment on accidental actions in a quantitative way with a prescribed maximum probability per consequence class, is that it is made clear whether a building fulfills the requirements or not. This can be helpful for communication with other involved parties. However, it will never be 100% clear what the limit should be, because estimating the risks is based on the engineer’s estimations and outcomes may differ as they depend on the person performing the risk assessment. This means a hard line, below which the risks are acceptable and above the risks are considered too high, cannot be drawn. An area in between is needed in which it is up to the engineer and client to decide whether or not they find the risks acceptable.

The sustainability of high-rise buildings is always a point of debate and doubt in current research and literature. Several studies have been performed about the zero-energy potential for skyscrapers, however taking into consideration single functions, particularly office and housing buildings. Realistic and modern tall building design however always involves a combination of uses (offices, accommodation, commercial and retail) for the project to be economically viable. On the basis of the Trias Energetica, the primary goal of the early design for sustainable buildings must be to minimize the demand for energy (heating, cooling, hot water, electricity) by means of active or passive techniques. This translates into design guidelines for the shape, orientation, building envelope and climate properties, parameters that have been already widely investigated by researchers and designers in practice. However, an important feature in order to improve the sustainable profile of a building is to employ circular techniques that aim to avoid wasting energy and re-use / re-purpose it. The main objective of this graduation research is to determine the zero-energy potential for high-rise buildings by taking advantage of a mixed-use scheme and examining the possibilities for energy exchange and cooperation between different functions by means of storing energy in the form of warm and cold-water tanks. This research aims to determine which synergetic combinations between functions can be performed, what type of building systems and technology can be used and, by establishing a complete energy simulation, conclude on what are the energy benefits for the building on a yearly basis . The results will be an important addition to the sustainable design for “MEGA” scale projects, according to the forthcoming Dutch regulation that after 2020 all newly built buildings must comply with the nearly zero energy guidelines.

To reach the European Union climate targets of 2020 the rate of refurbishment must increase. The problem is that there are many barriers to refurbishment, which causes a low rate and low quality. The objective is to overcome these barriers and stimulate facade refurbishment. This thesis looks at the improvement, that can be made when replacing an existing skin by a new facade focusing on improving the structural efficiency and touch upon building physics.
The main driving forces of this thesis are parametric design and optimisation. A parametric design is crucial for this thesis to perform a variation study. Different shapes of the facade are simulated with a custom made genetic algorithm to optimise the shape of the facade. First of all, the cost can be influenced by minimising the amount of material by altering: cross-sections, beam distances, etc. Secondly, by changing the shape of the facade a more aerodynamic building can be created. When the curvature increases, the wind load can be reduced which can make the structure more efficient. The wind load on the facade is determined with the computational fluid dynamics (CFD). The part about building physics focusses on ventilation. A ventilation system is designed which emphasises the importance of integrating the ventilation system with the second skin. The design builds upon the results of the CFD simulation and the structural model. The performance of the system is quantified by determining the usage of natural resources.

Buildings don’t use energy: People do. Do highly efficient homes really save energy? Counter-intuitively, dwellings that use less energy have low energy efficiency, and those with higher energy consumption have higher efficiency. Moreover, even accurate building energy simulation for multiple buildings could not predict the actual energy consumption. This is termed as the ’energy performance gap’. The regulatory energy performance gap is found to deviate by +34% with an SD of 55% based on 62 case buildings. In certain cases, the energy performance gap due to occupant behaviour was 300%. This is attributed to factors such as - climate, indoor design criteria, building energy service systems, building envelope, building operation maintenance and occupant behaviour. Significant progress in all the stated aspects has been made, except the latter - occupant behaviour.
Occupant behavior is complex, stochastic and multi-disciplinary. Accounting for it is challenging. Typical human interventions like heating/cooling, opening/closing windows, use of sunshades, hot water used, number of electrical appliances, lighting and cooking (gas/electric) play an important role in predicting the actual energy usage. Over-simplification and negligence of these interventions during the design phase is responsible for the energy performance gap. 
This study aims to study the impact of occupant behaviour on the energy consumption of three Dutch residential dwellings with an emphasis on data-informed decisions and predictions. Three candidates - senior couple, young couple and family were selected out of 13 interested candidates. Their houses were observed for 2 weeks from 7th - 21st of March 2019 with the help of sensors and meters. This study proposes a novel, flexible and inexpensive method of data collection with micro-controllers and sensors. The cost of one set-up being as low as € 14. With the help of actual data and the dynamic performance modelling tool - IES(VE) 2018, this study informs the readers about the energy distribution in low and highly energy efficient homes. Comparison of the actual energy consumption with energy standards like EPC and BENG has been made to study their reliability. It also discusses the possibility of sensors and actuators replacing sophisticated energy-siphoning HVAC systems. Lastly, the impact of the three households’ behaviour on their energy consumption has been quantified.

In April 2018, a graduation project in the field of architecture was concluded. The project entailed the design of a temporary community centre in the earthquake-damaged historic town centre of L’Aquila, Italy. The underlying social concept was focused on participation of the local population in the construction of the community centre. The design includes a grid-like timber shell structure, built-up out of a repetition of only two main structural and light-weight elements: the members and the joints.
The load-bearing structure of this architectural design formed the basis for this graduation thesis, which is aimed at its optimisation. The optimisation is carried out focused on many objectives, e.g. its weight, its environmental impact, its structural validity. The goal of this thesis can be summarised by the following research question. Given the architectural design, how can the main load-bearing structure be optimised for seismic contexts using parametric modelling, considering the following objectives: maximal demountability and structural simplicity, minimal material use, structural weight and environmental impact?
An optimisation method has been chosen combining automated and manual processes, as this gives a high sense of control to the designer. Using computational and parametric modelling techniques (Rhino, Grasshopper and Karamba), a database comprising 10 836 different structural configurations has been generated with different geometries and materials. The database contains the generated outcomes to structural and environmental analyses for each of the structural configurations. The database entries have been ranked manually based on structural, architectural and social demands, resulting in a top 28 models. Having defined a ranked set of structural configurations, manual checks and iterations can take place. The first step is checking the global and local stability using proposed joint designs as input. The next step is checking the safety of the structure during seismic events using a response spectrum analysis. As the Top-1 design passed all analyses, no iterations were deemed necessary.
In conclusion, with regard to the design, further structural optimisation could take place by reconsidering the shape of the structure. However, the process of automated database generation followed by manual exclusion, ranking and iterations give a great sense of control compared to automated optimisation alternatives. This optimisation process has proven to be very effective in finding a design that balances all objectives well.

Aiming at maximizing the recyclability of glass and integrating the sustainability with glass structural application, the concept of recycled glass beam has been proposed at the beginning of this project. Based on the investigation of existing glass manufacturing and recycling industry, the resource material has been targeting at float glass from building sector. This thesis present the recycling process in the lab, as well as the selection of experiment method. In the view of structural application, the mechanical property of the recycled float glass has been tested and the results has been discussed in combination with chemical composition analysis. The prediction of the material property for this recycled float glass, especially the structural behavior has been raised on account of the empirical data and the computational analysis. At last, the applicability of the recycled float glass has been proved, following by the data of relative mechanical properties. This thesis is end up with the discussion of the possibility for further development and the conclusion of this recycled float-glass beam project.

The additively manufacturing industry is emerging rather quickly and has find its way within numerous fields of expertise. Slowly the building industry is adopting these fabrication methods as well, but there are still a lot of challenges. Especially the bonds within the layered structure are demand more research. Numerous researches have acknowledged the importance of the bonding strength, but only a few have actually examined its mechanical properties of the bonds.
A distinction between the interlayer and intralayer bonds is made. The former indicates the bonds between vertically stacked layers, while the latter is related to the coalescence between filament within one lamina. This report assesses the relevance of the intralayer bonding strength for extrusion-based additive manufacturing by the large-scale printers of company Aectual. Firstly, the complete fabrication process and the relevant parameters for the construction of 3D printed object are elaborated. Based on the layered structure of prints and regarding the desired geometries, the
additively manufactured products are linked to Unidirectional Fibre Reinforced Composites. Subsequently, the international standards of the ISO and the ASTM are consulted for the design of the test specimens for the estimation of the material properties of interest, namely the tensile and
flexural test for general understanding of the mechanical behaviour of the material and a test method for the Interlaminar Fracture Toughness to evaluate the intralayer bond strength.
As the preliminary have shown promising result, the print geometry and the printing settings are optimised to achieve a high print quality and reliable test result as uniform as possible. The results of the flexural and tensile test indicated that this optimisation have proven to be successful. Despite the high number of test specimen, the interlaminar fracture toughness of the intralayer bond is not quantified. The post-processing of the insert relevant for delamination affected the crack front and reduced the probability of deformation. Nevertheless, almost 30% of the samples have delaminated
and have confirmed the dependability of the bonding strength on the height of the print and the printed pattern. Moreover, the print orientation appears to be of significant relevance. Finally, this research appoints the importance of the intralayer bonds for the mechanical behaviour of the total product as well as for the further development of 3D printed structural elements.