The usage of tanks has been quite common throughout the industry during the last decades. They fall into the category of shell structures and this is how they need to be studied. The focus of this thesis is concentrated on ground based thin cylindrical tanks filled with water made out of steel. Thin shells are susceptible to buckling, a phenomenon that takes several forms and calls for extra attention. The one which is investigated is shear buckling through the application of a static horizontal ground earthquake force on a clamped at the top tank. Such a problem is quite common nowadays to be tackled by engineers with the aid of FEM programs for practical purposes, something which on the other hand deprives the engineer of getting a deep understanding and insight of the phenomenon. For that reason, an analytic approach will be followed, in which shear buckling is studied within the boundaries of elasticity for a nonlinear shell theory in order, in that manner, to simulate reality in the best possible way. The first chapter is devoted to help the reader understand the basic aspects of buckling found in the literature, which are vital for someone who desires to investigate buckling in general. Also, a synopsis of the modern structural codes and standards given regarding the matter, showing the lack of information on shear buckling for liquid filled tanks. The next chapter starts by demonstrating the initial step towards formulating the problem which is no other than the choice of an appropriate displacement field along with a suitable middle surface strain theory. After the most common shell theories are discussed, it is concluded that a deep nonlinear thin shell theory would fit the case under study. For educational purposes, the applied theory is developed from scratch, despite the fact that popular shell theories, which meet the aforementioned criteria are thoroughly described. Moving on, the equations of motion are derived and a discussion is held on how a solution can be reached in order to acquire the critical-buckling load, revealing all the different methods found in the literature regardless if they were used or not. In the third chapter, the strong form of the initial problem is converted into a weak formulation due to the high complexity of the nonlinear partial differential equations of motion. For this reason, the perturbation method is utilized, an approximation technique which by expressing the displacements in terms of a very small perturbation parameter ε, it allows the breakdown of the nonlinear problem into an infinite number of linear sub-problems. The simplest equations that could describe the problem are employed and the solution is divided into two different cases based on the order of ε; the linear and the nonlinear one. At first, the solution of the 1st order in terms of ε linear problem is determined, in relation to the unknown buckling force, which serves as a tool for the 2nd order problem. The resulted EoMs, despite the linearization process that has taken place, are still hard to tackle due to the existent variable coefficients. For that purpose, calculation of the buckling load is searched numerically, a procedure which requires the final system of EoMs for the desired number of modes to be converted into a system of 1st order odes. Due to the high computational cost, the numerical approach has been implemented solely for a beam clamped onto the ground under the application of a distributed load along its length and a concentrated force on the top, as an example to demonstrate the methodology. The steps of the numerical procedure that should be followed for the case of the cylindrical tank filled with water are then extensively described and illustrated. In that sense, it is crystal clear of the method in which instability due to shear can be investigated in complex problems such that of a shell tank. After this thesis, the future researcher is provided with all those tools that will allow him to follow the correct path in order to extract some quite interesting results like; the effect of the tank’s geometric characteristics, the various boundary conditions, the different levels of water as well as the effect of the miscellaneous existing non-linear shell theories on shear buckling. Such conclusions will definitely fill the gap in the current structural codes and standards and will contribute largely in the field of research regarding the cylindrical liquid tanks.

The Segment barrier is a conceptual design for a storm surge barrier consisting of individual concrete segments which can be combined to form a barrier. The structure is designed with the ability to expand in size to deal with the uncertainties of global mean sea level rise by stacking the individual segments into various configurations. At its core, the Segment barrier is a temporary structure that can be assembled before the advent of a storm surge and dismantled afterwards with the intent of mitigating the long-term environmental and ecological impact associated with permanently fixed hydraulic structures. However, the Segment barrier is equally able to function as a typical structure with a long design life if necessary. Long Island Sound served as a case study for the development of this concept. The severity and frequency of annual hurricanes is expected to increase within this century and recent examples of hurricanes have already shown the devastating impact to New York City and the wider coastal region. The area of Long Island Sound is expected to have a crucial role in providing protection for millions of people through the development of flood protection measures. The development of this concept involved analyses on the structure’s overall stability, local wave climate, structural design of prestressed concrete elements and the applicability of the barrier for this region. An important aspect of this concept is optimization for which a number of suggestions are provided to inspire further research and design efforts. This thesis establishes the foundation for a new type of storm surge barrier and aims to convey the potential of this concept for wider applicability around the world.

Building failure incidents are occurring within the Netherlands and these incidents can be a valuable source of technical data regarding improvements in structural safety. This research has attempted to utilize this information gained to develop a tool to aid the building construction sector in identifying hazards during building construction projects. For that purpose, this research has investigated risk assessments and structural failure incidents. To be able to develop a tool, deeper knowledge of risk assessments is required and therefore risk assessments were studied to understand how they should be performed and what characteristics makes them effective. The research of Terwel (2012) on the Cobouw database formed the basis for the analysis of structural failure incidents. This thesis investigated how other research used structural failure databases to improve structural safety and studied the data available from the Cobouw database for developing a tool. The analysis of risk assessments has shown that identifying hazards is a crucial step in the assessment process. It was concluded that it would be beneficial to a project team if it had information on which hazards related to structural failure can occur, the probability of occurrence of hazards and the possible impact they can have. An investigation into structural failure databases showed that no other research could provide a tool that fulfilled the above requirements and in addition it was concluded that the database available to this research was only sufficient to provide information on which hazards can occur. There was not enough data available to make a justified estimate regarding the consequences of a hazard or probability of occurrence. Therefore it was chosen to use a different approach to analyze the database. The Cobouw database has been restructured into a fault tree format, to relate hazards to specific components of a building structure. Afterwards an attempt was made to discover why many hazards have occurred or which building components were prone to hazards. There was not enough data available to draw conclusions on that subject either. Finally this research concluded that the most efficient way of developing a tool, from the data available to this research, is to create a guide which can be used during the design phase to caution the project team about frequently occurring hazards. The method that was used to create the tool can also be used as an inspiration for future research, because this research was limited not only by the amount of available incidents, but also by the source of the incidents, which was from a news site that would most likely not focus on low-profile failure incidents and the reporting of precise technical details. Therefore the most important recommendation this research has, is to introduce a large scale collaboration in the construction industry focused on gathering accurate data on structural failure incidents.

Despite the increased popularity of the application of load bearing glass in the built environment, its design does rarely address sustainable or circular aspects. This Master’s Thesis analyses what the influence of connections is on the sustainable performance of structural glass and informs about the limitations and possibilities of sustainable glass design. To answer this question, sustainability has been defined from literature which resulted in ten sustainable, circular design methods. The role of load bearing glass and its connections is discussed in these methods, and it is concluded that there are two main possible design strategies for a sustainable design. First, the biggest impact in design can be made when focus is on reuse as an afterlife application to increase the lifetime of glass elements. Secondly, impact can be made by limiting the
environmental footprint of the structure in the initial design by material minimization and selection. Recycling is left out of the scope since recycling on a world-wide scale barely occurs. Even in a country with a well developed recycling network like the Netherlands, just 5-10% of discarded flat glass waste ends up back in the float glass industries and the rest is downcycled to container glass or glass fibres. Besides, the sustainable impact from recycling compared to reuse is far smaller, and measures to limit contamination are out of control of the designer. At first, in order to design for reuse as an end-of-life application, demountable connections are essential and adhesive based connections should be avoided. Although demountability is a key to the circular economy, this study concludes that there are various technical barriers to overcome to make glass elements actually reusable. One important barrier is the lack of standardization in glass structures. As is shown in the redesign of "Kasteel Ruurlo", implementing standardization leads to a modular design and is integrated by using minimum size deviation and the use of a single type of connection. However, as a result of standardization, the design freedom of the architect is taken away and the mechanical connections lead to a less elegant design. Therefore, it is recommended to further development these modules and discuss elegance and design freedom in standardization. Another technical barrier to overcome is the performance and quality of glass elements which makes current reuse impossible: insulated glass units will loose their insulating performance due to failure of the edge sealant after 20 to 25 years, and laminated glass is prone to delamination over time. There is a lack of legislation which sets requirements to the quality and performance of these elements. Only for laminated glass, there is a potential reuse strategy which has been used in the redesign of "Kasteel Ruurlo". It is proposed to use a high quality interlayer as SentryGlas or Trofisol. For both interlayers, delamination problems should be further researched in order to assure a long technical lifetime.
Secondly, in order to minimize the environmental impact of the structure, the impact has been quantified using Life Cycle Analysis data and Environmental Product Declarations. With the method by "Stichting Bouwkwaliteit", this data is converted to shadow costs which is used to calculate the environmental footprint of a connection. Different structural connections are considered: various facade connections, different moment rigid frame connections and various ways to connect a panel. From this calculation, the different connections are compared and it is concluded that adhesive based connections have both a smaller environmental footprint than mechanical connections, and that these result in less material use in the overall structure and thereby limiting the environmental footprint. This is also reflected in the redesign of "Kasteel Ruurlo", where due to the mechanical demountable connections, the environmental impact increases compared to the current design. With current possibilities, the relation between the connection and a sustainable design depends on the type of connection: an adhesive based connection will result in an overall low environmental impact but makes reuse unlikely. A mechanical connection could be an outcome here, but with current possibilities, reuse cannot be guaranteed either. The application of current demountable connections on the reuse possibilities can therefore be argued. In order to succeed with structural glass in the circular economy, this research emphasizes the need for legislation, standardization and to solve problems like delamination and leaking insulated glass units which now determine the lifetime of glass structures. It also shows the need for demountable connections which increase the reuse potential and which ideally do not increase the environmental footprint.

The goal of this thesis is to research multi-purpose, re-usable timber structures as a step towards sustainable construction. To reach it, the work was divided into four parts.
The project starts with an introduction explaining the motivations behind this work. It continues by grounding the problem in the context of major sports events. Indeed, the temporary quality of such manifestations, as well as their promotion of innovative solutions made it ideal for this study. Moreover, reviewing Olympic legacies showed the need for a structure capable to be re-used in different contexts.
The second part of the research englobes a literature review on two subjects. Exploring sustainable construction highlighted the main principles in environmentally friendly structural design. Life cycles assessments are identified as the main tool for evaluating the ecological performances and their process is therefore described. Moreover, reviewing existing LCA on timber constructions showed hotspots in the manufacturing of timber such as the importance of local sourcing.
Additionally, the second part examines existing work on designing for re-use. Multiple factors should be incorporated to ensure the re-usability of a construction. The most essential one, demountability was explored in length and a table showing the related design criterion, such as minimizing the number of different connectors, was devised. A review of existing constructions designed for re-use concludes this second part.
The third part applies the findings of the second to the selection of timber solutions. To narrow the possible products, the roof structure of an indoor arena is preselected for the case study. Locally sourced glue-laminated timber is chosen for its dimensional stability, whereas assemblies using glued-in rods and steel connectors show great versatility and are therefore preferred. Considering the structural system adapted for multi-purpose re-use, a truss was selected for the origin structure because of its inherent standardization. The third part is concluded by the development of a structural solution for the case study.
The fourth part concerns the design of the roof and façade structures of a badminton arena. To maximize re-use options, the structural elements are designed to be applicable to different contexts such as the main structure of a high school. The designed solution was finally assessed using the developed guidelines and an LCA-based study.
The study shows that multi-purpose re-use is a structurally feasible alternative. Indeed, through careful planning, and by using the developed guidelines, it is possible to re-use the structural elements from a 60-meter span roof in a 6.3-meter span high school with relatively high efficiency. Moreover, the environmental study, although superficial, showed a reduction in global warming potential of 60-90% depending on the re-use scenario compared with a one-off design.

Timber and complex designs are making a move in the building industry, as the building industry is on the brink of a significant change toward a 100% customized, more sustainable architecture. Robotic fabrication and Cross-Laminated Timber (CLT) can play an important role in this change, but there is a lot of uncertainty and ignorance about the design process of robotically fabricated CLT elements. This uncertainty is primarily caused by the application of linear workflows instead of integral ones. Within the fields of robotic fabrication and CLT, the research narrows down to the robotic milling process of CLT connection panels. Therefore, this research intends to answer the following question by means of four different parts: What does an integral workflow for robotically fabricated customized CLT connection panels look like, that promote exploration of the structural performance of CLT structures in the preliminary design phase? Part I Literature Study Part II Pilot Study Part III Integral Workflow Development Part IV Discussions The Literature Study focusses on two fields, namely the field of CLT and the field of robotic fabrication. In the final chapter of this part, the mutual affordances and constraints of these fields are discussed as these significantly influence the design space of the integral workflow. The second part concerns the production of a small mock-up to explore the process of robotic fabrication. The literature and pilot study together serve as input for the development of the integral workflow in the third part of the research. This workflow is developed in the parametric environment of Grasshopper and is divided in three modules: Global Structure, Joint Design, Robotic Fabrication. For the Joint Design, focus is laid on CLT connection panels of which the principle is derived from a reference project in Alblasserdam (NL). The main conclusions on the research question consist of the relationships and (in)dependencies between the different modules. Another important conclusion is that one cannot apply CLT in the outdoor environment without applying shedding to ensure complete moisture control. To increase the integrality of the workflow as developed in this research, more feedback loops across the three modules should be integrated. For instance, the affordances and constraints of the robotic fabrication process should be integrated within the relationships between the three modules. Hence, if doing so, this information was available in an early stage of the design process and would decrease the uncertainty of it. This implementation could be investigated by producing a mock-up study along the integral workflow.

A research into the influence of the main parameters in the preliminary structural design on the wind-induced dynamic behaviour, including soil-structure interaction effects, of high-rise buildings in the Netherlands. The dynamic behaviour becomes more and more important for higher and more slender structure. The dynamic response is controlled by the maximum acceleration at the top of the structure. The maximum acceleration is determined with a spectral analysis for a large amount of building variants, ranging from a 100 meters to 300 meters high. The influence of each parameter can be obtained from the generated data in this research within the considered domain. Having insight into the influence of design decisions on the dynamic response already in the preliminary design, can be beneficial for the whole design process and can result in a higher comfort level our high-rise buildings.

Nowadays glass is more commonly applied as structural element, either as a replacement for, or in collaboration with conventional building materials such as steel, aluminium, timber and concrete. Key arguments to opt for glass in structural design are sustainability, aesthetics and transparency. As for all structural elements, glass elements are required to be structurally safe, even in extreme conditions such as during a fire. Building regulations demand a structural element to be able to withstand a fire for at least 30 minutes. There is however a lack of experimental results on the material properties and performance of structural glass elements at elevated temperatures. One of the key material properties that determines the performance of glass at elevated temperatures is its stiffness (Young’s modulus). In this research the Young’s modulus of both Sola Lime Silica (SLS) and Borosilicate (BS) glass is experimentally determined for temperatures up to 700°C. The transmittance time of high-frequency sound waves (ultrasound) is measured for both BS as SLS glass rods during heating in a tube furnace. From this data the Young’s modulus has been derived mathematically. Additionally, the effect of a low-E coating and an intumescent coating on the performance of laminated glass panels is experimentally determined and assessed. During heating of only one side of the laminated glass panels, the time until the interlayer starts to form gas bubbles is recorded, whereas the temperature of the glass has been measured on both sides of the glass panels. From the experiments it is observed that glass performs well up to temperatures of 500 °C, provided there are no distributed thermal stresses present in the glass. Given this condition, the remaining stiffness at a temperature of 500 °C is 90% for SLS glass and 102% for BS glass. As for structural steel this is only 60%, it is concluded that both SLS and BS glass outperform steel in terms of relative stiffness at elevated temperatures. Between 500 and 600 °C a sudden deformation is observed. Therefore the structural safety of a glass element cannot be guaranteed for temperatures beyond 500 °C. The heating of a glass element can be delayed by the application of an intumescent coating. For low-E coating, an improvement in fire resistance is however not proven in this research. Instead, a negative effect has been observed and therefore the application of low-E coating is not recommended. It was shown that the PVB interlayer is the weakest point of the glass element. At temperatures of 200 °C the PVB interlayer is already completely molten, while at 500 °C the glass is still intact. The fire resistance can be improved by applying glass without an interlayer.

Daytime radiative cooling (DRC) is a very novel passive cooling method for buildings that utilises the recent technological advance in wavelength selective-emittance material research and takes advantage of a transparency window that exists in the atmosphere between 8 and 13 μm. Application of DRC in locations where warm weather prevails for most of the year and cooling requirements of dwellings outweigh the respective heating ones could result in saving significant amounts of energy. Such a location is the small Mediterranean island of Cyprus. Designing an ideal radiative cooler is a challenging task and so it is to design an appropriate system that exploits the benefits of DRC. In such a design, a stratified thermal storage water tank can have a detrimental role. To identify whether it is possible to apply such a system in Cyprus, this project exploits the use of Matlab Simulink which has been used to run more than 6000 simulations, for a sensitivity and a varied analysis, taking into consideration different parameters with particular emphasis on the physical properties of the radiative cooling apparatus According to the data obtained, for the efficiency of a daytime radiative system to be maximized, the longwave transmission and emissivity coefficients of the cooler should be maximal while the shortwave transmission coefficient and the effective heat transfer coefficient to the environment should be minimal. Additionally, larger volumes of storage tanks achieve better results.

The re-use of building components and structural elements is an underdeveloped practice which could be an important strategy in the global paradigm shift towards a circular economy. Steel is one of the most important structural building materials which combines incredible strength, favourable mechanical properties and excellent durability characteristics. It is practically infinitely recyclable and raw materials required for the production of steel are abundantly available in the Earth’s crust. This makes steel one of the most interesting sustainable engineering materials. However, the production process requires vast energy investments and produces considerate environmental pollution. To make steel an increasingly sustainable material and a frontrunner in the global transition towards a circular economy, significant investments and process improvements are necessary. The global environmental challenges of the 21st century demand rapid and far-reaching changes from the steel industry but it also poses opportunities for creative thinking and development of alternative strategies. The re-use of structural steel elements could offer great potential in reducing both the embodied environmental impact of construction works as well as the vast waste streams that result from demolition. There is general consensus on the technical feasibility of this circular alternative across academic literature and the idea enjoys widespread scientific support. Actual implementation is however limited, presumably due to the existence of several multi-level barriers. A diversity of actors along the value chain have indicated that various attitudinal, financial, structural, operational, technological and legislative barriers are preventing widespread adoption. Although some of the identified issues are of a practical nature, various perceived barriers have been identified which were found to be rather subjective. It is to be expected that providing additional information on the risks and opportunities, and by quantitative demonstration of the potential benefits of re-use, several of these perceived barriers could be alleviated. This thesis aims to integrate the potential use of circular steel elements in the structural design process for steelworks as a sustainable alternative to the use of new steel. The developed method allows structural design & engineering professionals to assess the environmental impact of structural steel frameworks with increasing accuracy. Furthermore, it improves the current practice by making the design process reuse-inclusive. It thereby provides design professionals with a tool to assess and communicate the possibilities of improving a design with regard to their inherent sustainability. It was found that the currently prescribed ‘fast-track’ LCA method, aimed at quantifying the embodied environmental impact of building structures, is highly sensitive and the current method could be leading to large inaccuracies and spread of misinformation. Two dominant national LCIA methodologies have been extensively compared and a sensitivity analysis has been performed for a variety of data resources. It could be concluded that the prescribed national data for steel products contained in the NMD is unverifiable and inconsistent with other resources. This raises serious concerns with regard to the accuracy and reliability of currently used ‘fast-track’ LCA methods for the Netherlands. It was calculated that the specific LCIA method used and the selection of modules included in the assessment can cause deviations of the estimated shadowprice up to approximately 424%. Subsequently, a tool was developed based on the CML methodology to validate the potential deviations that could arise from selecting a specific data resource. The application analyses and evaluates structural steel frameworks with regard to their inherent environmental impact. Furthermore it allows the engineer to select and substitute new steel elements with remanufactured counterparts found in a circular steel database. A case study was performed for four different scenarios. Both the LCIA method as well as the considered modules were consistent for all scenarios. From the results it could be concluded that the estimated shadowprice is also highly sensitive to the specific data considered. It was indicated that the input data can lead to deviations of the shadowprice of up to approximately 281%. Furthermore, it was calculated what the potential benefits of reuse would be. It was calculated that substituting 25% of the required steel could lead to reductions of approximately the same magnitude by eliminating the required process for production and cutting the transportation requirements. From the results of this thesis it could be concluded that there is serious inconsistency and limited transparency among the various data resources used for quantifying the environmental impact of steelworks. It is to be expected that the actual shadowcosts deviate significantly from the estimations provided by current assessment methods used in the Netherlands. Failure to accurately quantify the impact of primary building products could lead to significant errors as these materials have a relatively large contribution to the total impact of a building structure. Subsequently, this could lead to misinterpretation of LCA results thereby providing a misleading message for policy- and decision makers. However, it was also illustrated that the remanufacturing and reuse of structural steel profiles could offer significant environmental benefits and has the potential to significantly cut the environmental impact of structural steel framework constructions.

This report includes all the research conducted during the last phase of the Master of Science Building Engineering within the faculty of Civil Engineering. The main aim is to form a strategy for designing demountable unitized curtain walls; one that could actually be used in practice by future engineers and architects. This is why this graduation project includes an application on 4 chosen adaptive concepts. Having already been applied in a comparison study of these quite complicated and costly designs, this framework can provide one extra consideration that will be critical in the near future at the very early stages of designing a building: the Design for Disassembly.

During the past decade, durability and sustainability has become more and more important in the building industry. By using no steel reinforcement, which has with high carbon emission and is sensitivity to corrosion, the structure should have a longer life span with less maintenance and a lower carbon footprint.
To get more information on unreinforced concrete structures, a literature study is done, focused on old Roman structures made out of Roman concrete. Besides historic concrete, research is also done on modern concrete and its capacity.
The new bridge is designed for the "Hoofdvaart", a canal in the polder called, "Haarlemmermeer". The design consists of three arches are connecting the two abutments and two piers. In the connection of two arches, above the piers, so called flood openings are placed. Romans used flood openings to let water pass, but in this case they are used for the reduction of weight. Wooden piles form the foundation to the stiffer sand layers. Calculation of the design is done in a few steps. Firstly, the original design, as explained above, is calculated. Results show stresses, that are more than 7 times higher than the capacity of the concrete. The biggest contribution to the stresses are coming from self-weight and load model 1. Load model 1 is a heavy vehicle placed at the most unfavourable position of the bridge. Lowering self-weight is an option, but load model 1 has fixed values, so they cannot be lowered. Next, six optimizations are designed and calculated to create a structure that should fulfil the requirements. It turns out that the structure still exceeding the capacity by approximately 28%. After these optimizations can be concluded that for the given location, this design is not totally satisfying. To find out what contribution soil has to the structure, a few extra calculations are done for the last optimization. Based on overall calculations, the conclusion is that the top soil layers of the "Haarlemmermeer" are not capable of generating enough horizontal support for the unreinforced bridge. To finalize the design, a cost analysis and Life Cycle Analysis, LCA, are made. In both analysis a comparison is made between the new design and a reinforced bridge over the "Hoofdvaart" in "Nieuw-Vennep". The cost analysis show a difference of approximately "170.000,- in advantage of the new design. Especially the material costs of steel and pre-cast elements in the existing bridge, contribute to this difference. So an unreinforced structure has less labour and less material costs, compared to a reinforced structure. Of course this difference is also depending on the type of structure and the design. The LCA shows around 30% less carbon emission for the new unreinforced bridge, compared to the existing reinforced bridge. Especially material use and demolition contribute to this decrease. This shows that an unreinforced structure is 30 to 40% more sustainable than a reinforced structure.

This master's graduation project researches the potential of upcycling waste glass into glass-ceramic components through casting techniques and thermal treatments. To explore its potential and possibilities, the process of crystallization, the material glass-ceramic and influencing parameters are studied at first. A glass-ceramic is a glassy yet crystalline material consisting of inorganic and non-metallic compounds. A glass-ceramic can be produced through different controlled crystallization methods, whereas in this research heat treatment of casted components is applied. Upon heat treatment, crystallization occurs when the right temperatures are applied for the two-steps in crystallization; nucleation and crystal growth. Crystallization may occur spontaneously or along preferential sites, whereas this research makes use of the latter. Many parameters affect the crystallization process, whereas this research only focusses on glass composition, temperature and dwell time. The parameters are set through literature study and trial and error of melting experiments. This research focusses on the crystallization of soda-lime-silica bottle glass, the results of each melting experiment show the effect of the parameters. Each glass from another manufacturing has another glass composition. The amounts of glass formers, modifiers and fluxes are various, resulting in diverse temperature curves and thus diverse melting temperatures and crystallization temperatures. Through the melting experiments are noticeable that the applied melting temperature were of bigger influence than the crystallization temperature. A melting temperature too low resulted in an undesired fused sample, while a too high melting temperature resulted in no or little preferential sites for crystallization to occur. Through the results of the splitting experiment the mechanical characteristics could be observed, which are fracture toughness and fracture behaviour in this research. The fracture toughness seems better of samples with a higher quality crystal polymorph or with a higher amount of crystallinity or high amounts of glassy phases, whereby the material acts as one material upon loading rather than as a composite. While for samples with little and unconnected crystallization it does not seem to benefit its fracture toughness. The fracture propagation through glassy and crystalline phases is very different. A fracture propagation through a glassy phase is conchoidal, while the fracture propagation in the crystalline phase follows the crystalline structure, reaching its extremities or can be conchoidal, depending on the crystal polymorph. Observable from the fracture propagation from glassy to crystalline and from crystalline back to glassy is the discontinuity. The crystal or crystalline surface acts like an obstacle once the failure propagation reaches from the glassy phase. The failure does propagate but once it continues over to the glassy phase again, a change in energy and direction is noticeable. All by all, there do is potential in upcycling waste glass into structural cast glass-ceramic components. Crystallization does influence the fracture toughness and fracture behaviour in a cast glass-ceramic component, but the effect is highly dependent on the amount and distribution of glassy and crystalline phases.

Researchers of TU Delft have been designing and engineering with columns created out of multiple glass rods that are bundled together to form a single column. These aesthetically attractive and slender columns were tested to ensure safety before implementation in the real structure: the Glass Truss Bridge located at the campus of the university. However, the ultimate capacity and structural behaviour of such columns remained unknown. In this studies the structural behaviour of two designs of such columns is researched. It appeared that, among others, the differences in length between the rods within the columns caused an unequal distribution of stresses. This resulted in a large range of ultimate capacities of bundled glass columns that were designed according to the same design principles. Using a special approach in finite element modelling of the glass until failure, furthermore, resulted in more thorough knowledge regarding the failure behaviour of glass and the best way to model this behaviour.

Recently, sustainability is becoming a more important aspect in the building sector. The use of performance-driven approaches are progressively growing interest among architects and engineers. Proper design of a large span roof shading system can positively influence the micro-climate of the space underneath, representing a significant source of daylight and reducing the building energy demands. To support the decision making process and steer towards high-performing solutions, the adoption of computational design processes has the potential of being a fast and reliable approach. This project was undertaken to propose a computational workflow and evaluate its effectiveness as supportive decision-making tool from the early design stage of large roof shading systems. The proposed Computational Design Exploration (CDE) is adopted to evaluate three different concept alternatives in terms of daylight and thermal performances. Based on the visualization and analyses of the data, the best performing morphological features of the three alternatives are identified and the design is refined to create an optimal fourth concept. In a second phase, the Computational Design Optimization (CDO) workflow is applied to obtain high performing solutions in terms of daylight objectives, by varying geometrical and material inputs. 50 configurations are selected as optimal. The post process of the CDO consists of a second CDE, in which the selected samples are evaluated in terms of energy performance. The final shading system is chosen by identifying the input settings that allow the lowest energy consumption. As result, the daylight requirements are fulfilled and the thermal properties are used as final decision criteria. The steps described in the CDE and CDO workflow are followed through the combined use of a parametric modelling tool (Grasshopper) and a multidisciplinary design optimization platform (modeFRONTIER). Post-processing tools are adopted to help the identification of interaction effects of the variables on the performance targets. By a series of data visualizations and sensitivity analyses, it is determined whether the final optimal selected design configurations improve the visual and thermal performances. The most important identified trends and variables are used as main inputs to produce a more structured and integrated computational workflow. The final proposed workflow is meant to be a versatile method to assist the designer in the decision making process, yet maintaining his/her autonomy of judgement. Future research is needed to prove the validity and effectiveness of the proposed workflow. The integration of other design variables and performances objectives could lead to an holistic method, suitable for every kind of multi-objective design problem.

Fibre reinforced polymers, or FRP, are increasingly used in structural engineering applications. Permeating the construction field from the aerospace industry, FRP are applied in both the rehabilitation of existing degrading structures as well as the conception of new projects such as pedestrian and traffic bridges or building facades. The increase of interest and use in FRP in recent decades is driven by the material’s advantageous properties. Its tailorable mechanical properties, long-term durability, customizable free-form design, and its light-weight feature have engrained FRP as a noteworthy alternative to traditional construction materials such as concrete, steel, or timber. This is of paramount importance in light of the climate change challenge facing structural engineers today. While the material properties have been extensively investigated over the past decades, the structural use in FRP have remained limited to specific applications. As such, FRP, material of the future, has fallen short of its aspirations, disappointing its most ardent proponents. A rift is identified between the academic setting of laboratory testing and the pragmatic essence of the construction industry. This research situates itself as part of the efforts interrogating the industry limits and attempting to bridge these two spheres. It proposes to answer the following research question: What strategies capitalize on FRP’s favorable mechanical properties in order to promote formal exploration with the material in the preliminary phase of a design considering its durable and sustainable potential? This research proposes then a tool that capitalizes on the advantageous mechanical properties of FRP and encourages formal exploration in FRP at the conception phase of a design. Considering the climate change threat, the stakes of such a catalyst framework are high. The Wilhelminaberg Viewpoint, a landmark project in Landgraaf (NL) designed by Ney & Partners, is used as case-study to implement the proposed framework. It also allows to draw a contrast between what is structurally feasible in FRP and what is realistically buildable in FRP. A multi-step single-objective optimization is developed. First, stiffness for a certain design boundary is maximized. Using a brute force algorithm, the first level iterates through all the possible laminate layup combinations to find the combination which generates the stiffest structure. The second level of the optimization finds the lightest geometries using a genetic algorithm. This suggested framework offers an answer to the research question, mentioned hereinabove. Completely integrated in one interface (Grasshopper 3D), the developed tool stimulates formal exploration in FRP structures exhibiting shell-like behavior. The user defines the design boundaries, design constraints, load-cases, and material properties and implements the framework.

A traditional Trombe wall is known as a high thermal-mass wall, situated behind a window of a room and separated by an air cavity. The idea behind using a Trombe wall is that heat, ventilation and comfort can be passively generated by using the ‘free’ energy of the sun. The surface of the wall absorbs solar radiation when the sun shines, stores the energy and releases the heat at night to the room, when the occupants need it (Saadatian, Lim, Sopian, & Salleh, 2013). In addition, a Trombe wall can be used as natural ventilation system, of which its power is generated by the buoyancy effect in the cavity. Because a traditional Trombe wall is heavy, blocks daylight and cannot be adjusted to changing environmental conditions and seasonal differences, a new and innovative version was devised by the Double Face research team (4TU). The innovative version is called a lightweight translucent adaptable Trombe wall (LTATW) and is about five times lighter than a traditional Trombe wall. In addition, the wall is translucent and can rotate around its axes. The lower weight and translucent character are achieved by applying a phase change material in combination with aerogel, instead of stone or bricks. Phase change materials can store a large amount of (latent) heat during the change from solid to liquid state and thus, increase the thermal inertia of the system. The translucent elements are located in front of a glass façade and act as a thermal buffer in both winter and summer by rotating the elements towards the source of incoming heat or towards the sink for heat release (4TU.Bouw, 2014). In the winter, the layer of PCM is oriented towards the outdoor environment at daytime and is thermally charged by the low winter sun. At night, the system rotates and releases the accumulated heat to the interior. In the summer, the LTATW is oriented towards the interior at daytime to store the interior heat loads and during the night, it rotates again and releases the heat to the outside environment by means of (passive) night ventilation (4TU.Bouw, 2014).In this thesis, the results of a numerical spin-off study of the Double Face research project are shown, in which the influence of eight parameters (climate, building function, orientation, age, building method, room size, window size and type of glazing) on the energy and comfort performance of the innovative Trombe wall has been studied. First, an initial simulation model was developed in Matlab/Simulink, which was subsequently validated using a cross-comparison with results from DesignBuilder. After validation, the initial model has been extended to a suitable and reliable final version, with which more than 6000 different situations were simulated. The results of the simulations are values for the reduction or increase in energy demand for heating and cooling, expressed in percentages or in kWh. All results are processed in multiple designer tables, which interested designers can consult to assess whether installing the Trombe wall is useful for his or her situation, or not. In addition to the development of designer tables, the influence of each individual parameter on the performance of the Trombe wall was investigated using modeFRONTIER. It was found that in case of heating only a cold and temperate climate support a proper operation of the Trombe wall, since no heating is required in the other climate types. From the analysis, it was concluded that in relative sense (%), the Trombe wall performs best in a temperate climate, and that in absolute sense (kWh), the Trombe wall performs best in a cold climate. In case of cooling, the system performs best in a temperate climate and in a dry climate. Because the LTATW is designed to be both a passive cooling system in the summer and passive heating system in the winter, it has clearly been proven that only the temperate climate is the most logical choice. The average reduction of the heating energy demand in a temperate climate equals 36.1% (or 181.3 kWh per year) and the average reduction of the cooling energy demand equals 49.9% (or 115.0 kWh per year). Analysis of the second parameter, building function, has shown that in case of heating the function is not of great influence. The system performs well in both an office and a residence. In case of cooling, higher reductions of the energy demand are achieved in residences. Thirdly, the influence of the orientation of the Trombe wall was investigated and it was found that the best performance in case of heating occurs on a southern orientation. In case of cooling, the orientation is of less importance. The study shows that the age of a building does not have a major influence on the performance of the Trombe wall. Only in case of cooling, a slight preference can be expressed for new buildings. Studying the influence of the construction method on the performance of the wall has shown that this parameter has the least influence of all studied parameters. In both light-weight, medium-weight and heavy-weight buildings, a good performance can be achieved. For the size of the room, it was found that both room sizes perform equally well. It could be concluded that a Trombe wall can be installed in both small rooms and big rooms, but that when a room is too big, the capacity of the Trombe wall will no longer be useful to reduce a large amount of the initial energy demand. The same applies to cooling. Research has shown that for heating purposes, a room with a smaller window is more often preferred and for cooling purposes, a large window. Because the innovative Trombe wall will have to serve as both a passive heating and cooling device, an average size window will therefore probably be the most suitable. Finally, the influence of type of glazing was studied. It became clear that in relative terms the largest reductions of the heating energy demand are achieved with clear glazing. In case of cooling, the type of glazing is of less influence. Multiple sensitivity analyses were carried out to study the influence on the results of conditions that are easily affected by building occupants, and finally, a side-study was carried out into the influence of the Trombe wall on the energy demand for artificial lighting. It was found that even under slightly different circumstances the same conclusions can be drawn with regard to the influence of the parameters. The influence of the Trombe wall on the energy demand for artificial lighting is not negligible and should be carefully considered too.

Glass is a fascinating material which has been used for load bearing structures in the past decades. The development of structural glass has been moving towards more transparent structures.
The thermal properties of glass can be used to create heat bonds. Heat bonds can be produced in two ways: welding and fusing. With welding, the regions that are to be connected are locally heated. With kiln formed fusing, the elements to be bonded will be globally heated in an oven. This results in the research question: What is the best method, among glass welding and kiln formed glass fusing, to produce heat bonded systems for applications in glass structures?
In theory, safety measures consist of three basic strategies: creating secondary load transfer mechanisms, protectioning and overdimensioning.
These strategies can be used on the scale of the system and the structure. The heat bonded system could theoretically be laminated, reinforced and tempered. On a structural level, safety can be ensured by a combination of the strategies.
To produce glass welds, the glass is preheated in an oven. A small opening in the oven is made and a line burner is used to heat the to be welded area from both sides. One element is pressed down on the other to make the connection. The oven is closed and the specimen is annealed.
Finite element models have been used to analyze thermal shock failure during the weld production process. The recommendations for production were to use an additional flame on the bottom of the specimen or to maintain the surroundings at elevated temperature. The latter option is applied in the experiments.
The results were three transparent, all-glass, soda lime T-shaped objects. Little residual stress remained in the products.
The fused objects were globally heated in an oven. The glass was fused in moulds, made of a gypsum plaster. The products were translucent, all-glass, soda lime, T-shaped objects. The objects deformed significantly during production. Little residual stress remained in the products.
Throughout the experiments, factors have changed. An aspect with no direct influence on the product was quenching after maximum temperature. Adapting the mould and polishing the glass edges prior to fusing had an influence on the objects' shape or texture. None of the factors influenced the order of magnitude of the deformation or the seam between the elements.
A structural test has been performed to compare the specimens with a glass T-shape bonded with transparent UV-curing adhesive. The connections were loaded in shear. The results of the failure loads and stress at failure are of the same order of magnitude. The largest spread was among the fused specimens, the smallest among the welded.
The cause of failure is most probably a combination of elevated stress due to the stiffness and support of the test set-up and peak stress due to irregularities on the glass surface. Other causes could have contributed to failure.
The welded glass product requires most time, energy, skill and money. The adhesive product requires least time and energy. The welded and fused objects had neither acceptable dimensional accuracy, nor a smooth fillet in the joint.
In the current state of development, glass fusion results in less residual stress, requires less skill and is cheaper to produce. Glass welding results in a transparent glass to glass connection and its structural performance is promising. Further research is encouraged into the heat bonded and adhesive connections to create fully transparent connections for structural glass.

Nowadays, precast technology is mainly used for the production of concrete shell elements. Computer Numerically Controlled (CNC) milling techniques is the main production method of single or double-curved concrete elements, creating astonishing shapes with high accuracy. However, these techniques are also accompanied with high costs and large material waste. Skilled carpentry or curved steel formwork are other techniques used for the production of concrete shells. An alternative to the aforementioned techniques is the “Flexible Mould” method being developed at Delft University of Technology. This method is based on mass customization of the produced panels, due to the adaptability of the formwork's shape according to the specified geometry. The concept of the “Flexible Mould” will be used as a starting point for the current thesis.

Concrete shells are mainly used for decorative reasons such as claddings and facade elements. Their structural capacity has still to be improved so that they can be applied as load-bearing elements and avoid sub-optimal or even “bad” designs. Several researches are being conducted in order to analyze and improve the load bearing capacity of concrete shells produced with the adjustable formwork technique. Applying conventional steel reinforcement to take up possible occurring tensile stresses in concrete shells produced with the Flexible Mould, has been proved to be possible only with limited diameters due to construction requirements.

In the first part of the thesis, a research was conducted on possible improvements in the production of concrete shells with the flexible mould, so that they could be considered feasible to be applied in real life structures. Having conducted a literature review on production parameters related to the “Flexible Mould” concept, Computer Aided Design (CAD) was used as the main tool to create the digital geometry of double-curved concrete elements. Dimensional limitations imposed from the existing test set-up of the adjustable formwork at TU Delft laboratories, as well as the inherent geometry of shell elements, had to be taken into account. As a next step towards the implementation of double-curved concrete elements in real life structures, non-load-bearing laboratory tests took place. These tests were performed for illustrating reasons with sand to be the main material used instead of concrete. During these tests, a steel wire mesh diamond shaped was applied as the elastic layer of the flexible mould, being a different material in comparison with the previous studies on the flexible mould. Grid distance between the actuators was the main parameter investigated during this part of the research.

In the second part of the thesis, a study was conducted on possible improvements in the flexural tensile capacity of concrete shells via prestressing steel reinforcement. CAD design and Finite Element Modeling (FEM) were the main tools used. Due to shell's complex geometry, the research was conducted first for simple geometrical shapes under linear static analyses. Two and three dimensional elements were investigated being modeled as plane stress elements and solids respectively. Linear or single-curved prestressed concrete elements were analyzed with regard to their deflection and stress field. The number of concrete elements as well as the influence of an intermediate element in-between them simulating a joint, was an additional investigated parameter.

Subsequently, a four-point bending that will take place at TU Delft, was simulated with Finite Element Modeling (FEM), investigating its structural response under both linear and nonlinear static analyses. The created (FEM) comprises of two centrally prestressed concrete elements connected with a mortar joint in between them. No bond interaction between the post-tensioning steel reinforcement and the concrete is incorporated in the FE model. The type and size of the applied reinforcement is investigated in this model. The main goal of this part was to analyze the structure's response for loads exceeding the cracking load of the concrete, taking into account a brittle concrete failure at joint's location.

In the final part of the thesis, a post-tensioned arch structure segmented in a series of concrete elements and joints, was first designed with CAD software and then analyzed under a linear static analysis via FEM. Although more complex, a three-dimensional (3D) modeling was conducted, aiming at describing the three dimensional state of stress and deflection field of the arch. Based on a draft CAD model, several geometrical parameters had to be adjusted in order to meet construction requirements of the final concrete shell structure. Modeling and meshing requirements imposed from the Finite Element Analysis (FEA) software were also taken into consideration for the final shape of the arch.

The current thesis is a part of a research program that is being performed at TU Delft, aiming at developing the Flexible Mould with regard to construction and structural application of concrete shells in real life structures.