The standard NEN 3215 contains a certain rain intensity for the rainwater drainage from roofs. By making use of the rainfall predictions for 2050, the consequences of this new intensity for the standard are analysed. Based on this analysis, a change of this rain intensity in NEN 3215 is recommended.

The aim of this thesis is to investigate and quantify the efficiency of high capacity self-stabilising modules in mid-rise residential buildings. These modules have a higher stabilising capacity than modules that are currently being used in the Netherlands and other countries and can therefore be used for more storeys without requiring an additional stabilising structure such as a concrete core. In the first part, reference projects and case studies are looked at to get a good understanding of the current applications in The Netherlands and the United Kingdom. After analysing four case studies, an assessment is done on the functional efficiency, structural capacity and environmental impact of these modules. By doing so, the load-bearing structure of self-stabilising modules that can be used at a greater height can be identified. Design variants can now be drafted with different bracing configurations, which are later verified on strength and stability requirements. To effectively design a suitable braced frame, it has been researched what the displacement components for braced frames are. This has been done for simple frames without eccentricity as well as frames including eccentricity. Apart from single-cross frames with a relatively large span, double-cross frames are also looked into due to their increased stiffness. As part of the total structure of the building, a design for the foundation as well as the inter-module joint, which is required to be demountable, has been made. These parts of the design are required to calculate the horizontal displacement during lateral loads. A structural assessment is done on the stabilising capacity of each variant at 8 storeys. The design adjustments that are required to further increase the number of storeys up to 10 are looked into as to see whether or not an efficient structure can be maintained. It turns out that each design variant requires adjustments that reduces the efficiency. These changes are the result of a large increase of braced span, resulting in either inefficient use of beam profiles or a too large length when there is more than one braced span along the length. Apart from a structural assessment, the functionality and environmental impact of the design variants has been analysed as part of the overall efficiency of the modules. The functional assessment includes several criteria such as wall-to-floor area and space efficiency factor. Using the required material use in partition structures and load bearing elements, the environmental impact is calculated, resulting in values for the embodied energy and embodied carbon per square meter in each design variant. Since the differences between the design variants are relatively small, they are also compared to four case studies that were done before. On the basis of the results of this research, it can be concluded that self-stabilising modules can be constructed with different possible bracing layouts and an efficient load-bearing structure up to 8 storeys.

The orthotropic steel deck (OSD) is a deck system applied regularly in steel bridges all around the world. It consists of a steel deck plate which is stiffened by structural elements placed in two orthogonal directions. The deck plate can be used as an integral part of the structure, causing OSDs to achieve a high material efficiency and therefore low self-weight. However, this structural integration requires a large number of welded connections between the deck plate and stiffening members, which also make the system susceptible to fatigue. The fatigue evaluation of these connections is complex and time-consuming, hindering the manual optimization of orthotropic deck designs. The use of structural optimization could be a solution for this. With parametric optimization, the best possible ratio between structural dimensions may be searched for automatically, while topology optimization could assist in finding new design concepts that could form alternatives to the traditional deck layout. This thesis investigates how these techniques could reduce the self-weight of the design of a case study (the renovated Van Brienenoord bridge) without reducing its fatigue service life. The two methods are treated in separate parts. In the first part, considering parametric optimization, the traditional OSD concept is maintained and the values of seven selected dimensions are adjusted to obtain a design with a minimized weight. A workflow is developed in which an existing mathematical optimization solver (the artificial bee colony algorithm, a metaheuristic) is coupled to a parametric model, finite element program, and fatigue damage calculator. This enables an iterative process in which designs are generated by the solver and then evaluated in the remainder of the workflow. The information gained from the evaluation is returned to the solver and used to search for lighter designs. In the second part, the deck remains a stiffened steel plate, but the location and orientation of stiffeners may be changed. Two possible leads for finding new structural concepts are explored. The first considers a topology optimization using the ground structure method, which can find the optimal orientation and size of stiffeners in a plate. This thesis evaluates the method’s current applicability on steel bridge decks. The second lead interprets the results of a topology optimization from existing literature. This gives a new design concept in which the crossbeams curve directly towards the supports instead of being indirectly connected by main girders. A weight minimization using the workflow of the first part and a study of the force transfer in the deck are performed to assess the new concept’s potential. The first part showed that a 17,4 percent lighter deck structure (280 kg/m2 instead of 339 kg/m2 ) could be obtained for the case study by breaking with the general trend for designing orthotropic steel decks. The optimized design uses smaller and more rectangular troughs than commonly applied, but the largest differences are found in the deck plate thickness and stiffener spacing. For the latter, a value of 300 mm has been in use since the introduction of OSDs in the 1950’s and is present in almost any bridge using an orthotropic steel deck. When fatigue issues started to appear from the 1970’s onward, it was generally decided to increase the deck plate thickness. The results in this thesis strongly suggest that decreasing the stiffener spacing and trough top width is the preferred option when material efficiency is considered. A cost estimation further showed that the price of the optimized design would be comparable to that of the preliminary design that was suggested for the case study. The topology optimization using the ground structure method showed that the optimal placement of stiffeners for a plate-like bridge deck contains two distinctive zones. Between the supports, the traditional longitudinal-transverse orientation is preferred, while the optimal direction of stiffeners in the middle of the bridge segments is arbitrary. The conventional OSD concept could be seen as optimal based on this result, but for definitive conclusions more research is needed towards a non-linear relation between cross-sectional area and resistance in the applied method. The similar support conditions of decks in other bridges make it likely that these conclusions will apply to those cases as well. The optimization of the curved crossbeam concept showed the versatility of the workflow developed in the first part of this thesis, as only minor adaptations in the parametric model were needed for the application on a significantly different design. Despite the successful optimization, the potential of the new design to replace the traditional OSD concept is considered low. In its optimized form, the concept was 9,8 percent heavier and less than half as stiff as the best found result in this thesis’ first part. The comparable support conditions for plate girder bridges in general again suggest similar outcomes for other cases, while a different setup of the optimization would not tackle the fundamental stiffness problem of the design. Further research towards the curved crossbeam concept should therefore stick to the original application of box girder decks.

Among the current targets of the building sector, one major goal is to maximize the resource efficiency (in terms of material use and in terms of energy used to produce the buildings); furthermore, the circular economy model aims for maximizing the reuse of the structural elements; thus, minimizing the material waste and avoiding a second production of elements. The high-rise building sector faces the challenge of considering a design that is flexible and adaptable to meet the functional requirements along its life span; and additionally, to consider a design for deconstruction, where the benefits and challenges that arise form reusing and recycling the material can be considered and addressed from early design stages. This research addresses these trends and challenges by evaluating and comparing the environmental impact of different structural systems for a high-rise building in the Netherlands (151m). The comparison of four different structural systems with two core variations provides eight different stability systems. The scope of the stability systems considers foundations, core, columns, beams, bracings and floor slabs. The design of the structural systems was performed by the elaboration of 3D FEM models with parametrical tools to ensure the structural safety and serviceability of the building. Furthermore, the assessment of the environmental impact (global warming potential) was performed by means of a Life-Cycle Aseessment comparing three scenarios of the structure: cradle to gate, cradle to cradle, and cradle to cradle with 100% reuse of the structural elements; with data from the Nationale Milieu Database and with information from a technical report from the Joint Research Center. The analysis of the results demonstrated that the environmental impact of the structural systems with steel core is 21% higher than the one that corresponds to the structures with concrete core, However, this variation is only 4% for the two variants of the diagrid structure. Furthermore, by including the average recycle and reuse rates form the market and current construction practices, the benefits at the end-of-life stage of the building can represent up to 17% of the impacts from the production phase. Moreover, when the reuse rate is considered as 100% the benefits increase up to 42% of the impacts from the production phase. The results indicate that the improvement of the environmental impact of high-rise buildings can be achieved by means of sustainable structural design from the early phases of the design; where the choice of materials and of the structural system play and important role on the outcome of the total environmental impact of the building, which is becoming an important driver for the decision-making of new projects.

The Netherlands aims to have a fully circular economy by 2050. The construction sector in the Netherlands is only 8% circular (Circularity Gap Report Bouw, 2022). Reuse within construction projects presents various challenges, which will be discussed in this thesis. In the current market, there is more supply than demand (BAMB, 2020). One possibility to stimulate demand is the use of digital marketplaces. This study investigates how a digital marketplace can support the demand side in the design process, leading to the following research question: How should a secondary ‘digital’ product marketplace function within the construction industry? Before addressing this question, a literature review is conducted on various aspects. These include the concepts within digital marketplaces and platforms, as well as those within reuse projects, focusing on specific information about materials and products in the context of reuse. Additionally, the current state of the industry has been examined in terms of challenges, opportunities in general, and those related to digitalization. This is done to get a better understanding of the surroundings in which the marketplace must operate. The literature research concludes that the core interaction is the most important form of activity on a platform – the value that attracts the most users to the platform in the first place (Parker et al., 2016). It consists of three parts: Participants + Value Unit + Filter. Fundamentally there are two participants on the platform, namely producers and consumers. In this case, producers are building/construction elements and their owners/sellers. Consumers are the ones that are willing to buy them (potentially; architects, engineers, contractors, or suppliers). Where the value unit starts with the exchange of information that has value to the participants. This information delivery to consumers depends on filters. A filter enables the transfer of appropriate value units between users. A well-designed filter ensures that platform users see only information units that are relevant and valuable to them. No filters or a poorly designed filter overwhelms users with units they find valueless and irrelevant, which causes them to abandon the platform. No research has been done to the specific design of the core interaction of a secondary product marketplace within the construction industry. In addition, few scientific articles investigate software interfaces, ease of use and the user's role and experience within the construction industry. An action- and design-oriented research method is a new approach to this problem/goal. The information system framework is chosen to combine rigor research and the application domain within a design practices. To structure this research the research question is divided into three steps (based on the core interaction). In step 1, the input for the design is investigated, which includes determining the participants who should use the marketplace (champions), how they should search for products, and what improvements can be made in the design process to promote reuse. In step 2, the filters and interfaces of the marketplace are designed. Within step 2, solutions for situations with limited data or, conversely, when there is sufficient data in the future are also explored. In step 3, the chosen champion validates if they can use the designed solution and whether it provides value. To define the main users/champions (step 1), potential users-(roles) are interviewed about their needs for such a marketplace, assuming reuse becomes the norm. The literature review covers all aspects of digital (construction) applications and reuse in the construction industry. This is supplemented with expert interviews in IFC (an open data standard), user interface/user experience (UI/UX), current construction marketplaces, and material passports. In addition, various roles from several reuse projects are interviewed, including designers, project developers, purchasers, demolition specialists, and engineers, in line with the information system framework and action design. This is done to get an complete overview of all the stakeholders involved within the process of selecting/buying reused products. The information of the literature research and the first interview phase is used in the design process to create ‘search and facet’ filters. Therefor a division based on the Brand/shearing layers (site, structure, services, skin/facade, space, and stuff) is made to improve the design the facet filters. The engineer and the architect is chosen as the primary user but in consultation with the design team. For all the engineers responsible or related to the a Brand layer a recommendation is made for a first set a (search) parameters. Concerning the information need (step 2) of the structural engineer, the primary focus is on the elements' functional and physical properties (moment-of-inertia, material type, strength, and dimensions). Thereby the core interaction disregards environmental or economic properties. These are of secondary interest for the core interaction. The three main materials, wood, steel and concrete, require all different ways of working for reuse but share common properties which makes the design of filters less complex. Capacity, dimension, grid size, floor height and more properties could influence the structural design decision, increasing the demand for reusable structural products. However, more traditional engineers prefer to filter within one type of material. Even more in-depth material and product knowledge for reuse could is a next step for the core interaction, thereby evolving into a knowledge marketplace. The other Brand layers (skin, services and space) information need should also focus on their functional and physical reusability properties, which are covered and designed in this thesis but not validated with real users. The skin and the space layer are more visually oriented; images support the architect's and engineer's decision-making. Aesthetic filters to filter on certain styles, colours, types and tags will support the architect where functional filters relating to dimension are of first need for the façade engineer. Secondly the physical filters benefit the search tremendously, such as; U-value, fire resistance, Rc-value, sound resistance, waterproofness etc. The service/building engineer wants to filter into three categories. Namely the machine, the distribution point (ventilation grille, water tap, heating element) and the transport (cable tray, pipe and wires). The machine (e.g., heating, cooling and air filters) has a more dynamical environment with a high change in regulation, expecting a low reuse pattern. The other two categories, distribution and transport are more suitable for reuse; these filters contain service type (energy, water, air, data and heating), minimum length and the capacity of distribution and transportation. After step 2 (design) various structural engineers are interviewed using a working digital prototype to examine whether the search filters are effective for their reuse process (step 3). Besides various side notes on the design culture, system changes and the willingness of a client to reuse products. The interviewed users made recommendations which should be taken into account for a next design iteration. The proposed design is usable and could meet its goal/value proposition when reusing products becomes the norm. This research is a small link in the bigger picture of a ‘circular’ construction industry. Still, many challenges remain that a digital marketplace could not solve. When interpreting the results, the following points should be considered as well. The interviewees in this research are involved or interested in reusing products. When less interested engineers/users must use this marketplace, other items could be of more importance or totally different obstacles could arise. Further research should examine the other Brand layers and their primary users. Additionally, to succeed as a marketplace, choices need to be made. Which users and product categories will be supported in first place. What is the business plan and initial investment? Building and rolling out a marketplace requires entrepreneurial skills and courage. This research hopes to provide the readers with a holistic view of all the challenges related to a digital market platform that address the construction market for secondary materials. Together with a set of validated user interfaces of such marketplace.

A study on the fire safety concepts used in car parks. To asses the possible damage as a result of a fire, case studies were performed and changes in the car industry were analysed. The new type of fuel systems have resulted in new risks, which are not yet covered in the current design methodology. To understand the probability of a car park fire an analysis was done on occurred fires in car parks. The changes in the car industry had resulted in larger fires and bigger fires will likely occur in the near future.

The innovative shear strengthening method using externally bonded CFRP reinforcement to strengthen prestressed concrete I-girders has been investigated in this thesis. These girders potentially have insufficient shear capacity because of the combination of thin webs and insufficient shear reinforcement. Shear failure of these girders should be prevented because they do not warn before the element fails in shear. Shear strengthening using externally bonded CFRP reinforcement seems promising because of low installation costs, negligible increase in weight, no decrease of clear height underneath the bridge and minimising the hinderance. The aim of this thesis is to investigate the feasibility of shear strengthening prestressed concrete I-girders using externally bonded CFRP reinforcement. The shear behaviour of prestressed concrete I-girders strengthened using externally bonded CFRP reinforcement has been investigated with the nonlinear finite element analysis (NLFEA) software DIANA. A three-dimensional finite element model of a 1.0 m high prestressed concrete I-girder with a kinked tendon profile and no shear reinforcement has been made to investigate several parameters and aspects of the CFRP reinforcement. Shear strengthening of prestressed concrete I-girders with vertical CFRP sheets and CFRP anchors is a feasible strengthening method because of the demonstrated potential increase in shear capacity. The externally bonded CFRP reinforcement was especially effective to increase the flexural shear capacity of prestressed concrete I-girders. The numerical analysis showed a promising increase in flexural shear capacity between 40-55% and an increase in ductility of more than 80% compared to the I-girder without CFRP reinforcement

Currently, most of the modular building can be fabricated off-site, except for the stability system. Therefore, the question arises: Could modules be designed such that there is no need for an additional stability system? As modules are typically built in a rectangular shape, incorporating stability elements such as bracings along the longer side of the module is not the problem. The main challenge lies in the limited length available for stability elements on the shorter side of the module, combined with the fact that this shorter side is commonly used for windows and openings for door frames. This introduces a conflicting interest between structural capacity and daylight within the module. This conflicting interest becomes more and more prominent as the building height goes up. A possible solution to this problem can be found in the use of a load-bearing window frame with glass infill as a stability element, often referred to in literature as a timber-glass shear wall (TGSW). Therefore, this thesis will answer the main research question: 'To what extent can the structural performance of a timber-glass shear wall as a stability element in a timber module be used to accommodate for the stability of a mid-rise modular timber building?' The approach to answering the main research question consists of several steps. First, a literature study was conducted on modular buildings and TGSW's. The outcome of the study has provided insight into how modular buildings are constructed in general and how relevant aspects such as progressive collapse, fire safety design, and foundation design influence structural design. The study also resulted in an analytical prediction model for the load-bearing capacity and stiffness of the TGSW. Through this prediction model, it became clear how the properties of individual components relate to the load-bearing capacity and stiffness of the total TGSW-system. The second step was to propose a design for a modular timber building composed of timber modules. To save on computational time, the stability elements of the building are modelled using steel diagonals as an equivalent system for the TGSW. The cross-sectional area of the steel diagonals is directly related to the properties of the TGSW. Therefore, the steel diagonals have identical stability properties as the TGSW. In this study, varying the type of adhesive and the spacing of the screws was found to have the most significant impact on the overall structural properties of the TGSW. The horizontal connections are made of steel plates fastened with screws. The vertical connections are realised by shear plate connectors. The entire building was modelled in a 3D FEM programme to assess the structural behaviour of the building and its compliance with building regulations. Several building configurations ranging from 1:1 to 1:3 height-to-width ratio were investigated. For each building configuration, the cross-sectional area of the steel diagonals was adjusted within a specified range. This range corresponds to variations in adhesive type or screw spacing. As a result, design graphs were produced, which present the requirements for the load-bearing capacity and stiffness of the stability system. These can be compared to the load-bearing capacity and stiffness of the TGSW. This comparison can be used as a validation method to determine the viability of the TGSW stability element in a modular building. The results of this study indicate that a modular building can be stabilised by a TGSW up to six stories within the height-to-width ratio of 1:1 to 1:3. The minimum building configurations per story height are: 3 modules high by 5 modules wide, 4 by 8 modules, 5 by 12 modules, and 6 by 18 modules. These slenderness ratios were governed by the strength of the TGSW. The limiting factor in the load-bearing capacity is the shear strength of the adhesive. These slenderness ratios could only be reached with elastic adhesives such as silicones. The next step is to create a more extensive FEM model that could predict the load-bearing capacity and stiffness of the TGSW in a more accurate way compared to an analytical model. Furthermore, exploring the performance of the TGSW under different horizontal loads, such as earthquakes, would give valuable insight.

Problem definition: In the car park industry, a new trend has emerged, shifting the demand for parking from permanent one-of-a-kind parking structures towards temporary modular structures (Drenth, 2020). Meanwhile, the building industry faces a transition into a more sustainable industry. This requires rethinking of the design process, taking into account possible reuse of a building or its elements as well as potential use of different materials. Timber is a renewable material and as a result of developments in timber engineering, now allows the construction of taller and larger structures. Given these trends and challenges, the objective of this thesis is to provide a structural system proof of concept for a temporary multi-storey car park, using timber as primary structural material. Approach: A broad literature study provides background information on the various relevant topics and is followed by a refinement of the objective, substantiated by two sub-studies. This has resulted in two sub-goals: the minimization of total deck height (< 700 mm) and minimization of the structural systems weight (column load < 1,000 kN). A proof of concept is developed through a parametric study with structural validation into four main design variants (consisting of a deck and framing system), for which the effect of altering four geometric parameters (parking deck span, use of struts, distance between columns in transverse direction and minimum distance between joists) on these sub-goals is studied. Furthermore, a sensitivity analysis is performed on the effect of altering the requirements concerning fire-safety, vibrations and deflections on the deck height and weight. Finally, the proof of concept’s performance is compared to five alternative modular and/or timber car park concepts in a case study. Evaluation: It is concluded, that design variants using long-span deck systems result in a relatively small deck height, but high self-weight. A CLT rib deck should be applied under “standard” assessment criteria, but significant reductions in deck height (31%) and weight (49%) can be achieved by using LVL rib decks when vibrations are not considered and deformation limits are increased. The total deck height of design variants with short-span decks, which use solid LVL panels, highly depends on the supporting framing system, but its self-weight is roughly halve of the long-span design variants. The effect of alternative assessment criteria on design variants with short-span decks is rather limited. It is concluded that the use of struts significantly reduces the total deck height (17-30%) and structures weight (5-11%) and a transverse column distance of a single parking bay width is preferred. The distance between joists is of less relevance, but a bigger parking deck span increases both deck height and total weight. The resulting proof of concept consists out of a short-span solid LVL deck system, which spans two times 2.5 m (single parking bay width). It is supported by glulam main girders, spanning the entire parking deck, which are simply supported by a set of columns at a transverse distance of 2.5 m and are additionally supported by slanted struts between the columns and main girders. The results from the case study show, that the total deck height of the proof of concept (666 mm) is smaller that the sub-goal of 700 mm and comparable to alternatives with decks made of steel, concrete and GFRP. Furthermore it is 40% thinner than the alternative in timber as a result of the use of LVL and struts. In terms of weight, the use of timber is much lighter than using concrete decks (<25%) and only 17% heavier than the extremely lightweight GFRP decks. Furthermore, it results in the smallest loads on the foundation (678 kN which is smaller than the sub-goal of 1,000 kN). A first extremely simplified durability analysis on amounts of embodied carbon in the main structural elements indicates timber has significantly lower amounts of embodied carbon in comparison to the alternative concepts. Implications: Based on the results presented, it is concluded that timber is applicable for almost all main structural elements of a temporary and modular multi-storey car park. The case study has shown that the proof of concept can compete with alternative modular car park concepts in terms of deck height and outperforms most alternatives in terms of the structures weight. It is also indicated, that timber has the potential to significantly improve the performance of a structure in terms of sustainability. For future research, it is advised to further develop the proof of concept, focussing on the connections and durability risks and study the incorporation of circular design strategies into the design and construction process of the proof of concept. Furthermore, alternative assessment criteria should be validated. Finally, it is advised to study the potential use of other innovative sustainable building materials like BauBuche and make a detailed LCA study assessing the performance on sustainability.

The prediction of structural vibrations in vibration sensitive laboratory structures is a complex problem involving computationally heavy 3D models with long computational times. However, in the early design phases of a project long computational times are undesirable. Therefore the problem statement of this Master thesis concerns the development of a practical engineering tool which can be used in the early design phase of a vibration sensitive laboratory structure. The resulting tool is called EDDABuSgs (Early Design Dynamic Analysis of Building Structures by Gerwin Schut) and is the final product of the thesis research. The main focus of EDDABuSgs is on structural vibrations induced by heavy traffic at geological locations with soft soils (e.g. Amsterdam, the Netherlands). The thesis research concerns the four interrelating parts: source of vibrations (truck), transmission of vibrations (soil), soil-structure interaction and the structure (receiver of vibrations). The software FEMIX is used for computing the 3D soil response (source and transmission). The soil response is then used as input for EDDABuSGS, which computes the 2D structural vibrations by the aid of a Python script. The global structural response is computed from a rigid 3DoF system which is supported elastically by the soil and a pile foundation. The local structural response (ground floor) is computed from a flexible frame, composed of the analytical solutions of Euler-Bernoulli beam elements. The flexible frame is excited by the global 3DoF structural response by means of the boundary- and interface conditions. The results of FEMIX and EDDABuSgs show good agreement with the used verification projects. Several iterations have been made using EDDABuSgs to see how several parameters change the 2D structural response. The results of these iterations are well in line with general known theory about structural dynamics. From this Master thesis research one can conclude that soft soils excited by heavy traffic have a responsive frequency spectrum generally in-between 3 and 15 Hz. Therefore it generally holds that the eigenfrequencies of the global building response should be made relatively low (< 3 Hz), while the eigenfrequencies of the local structural elements (e.g. floors) should be made relatively high (> 12 Hz). Additionally, the resistance against vibrations (impedances) of the structural elements should to be as large as possible, which might sometimes contradict the preferred shift of the eigenfrequencies.

This research investigated how traditional foundations of buildings can become circular and thus contribute to a circular economy. The current linear take-make-dispose economy results in waste, exhaustion of finite natural resources and environmental degradation. A circular economy is one way to cope with these trends. This type of economy is based on closed material cycles, renewable energy and system thinking. For the building industry, recycling of materials and reuse of products are most relevant. Reuse of products is preferred because it requires less material and energy than recycling. Reuse is facilitated by flexibility. Forms of flexibility are versatility, changeability and expandability. For building foundations, versatility and changeability are distinguished. Expandability should be incorporated in both. Within the circular economy, many design methods have been developed. The tools Design for Disassembly and Design for Adaptability help to design buildings for changeability and versatility, respectively. Corresponding assessment methods have been developed. An easy-to-use method suitable for the assessment of building foundations was sought and found: Alba Concept. Four foundation variants were defined by combining deep and shallow foundations with versatility and changeability. Based on the soil condition, loads, future scenario, function and desired level of flexibility, the foundation type can be determined. Hereafter, a design guideline can be followed, considering material, dimension, load bearing capacity, connection and transportation. One should strive for longevity, standardization and uniformity at the material, element and system levels, respectively. Because the assessment method of Alba Concepts focuses on changeability and buildings in general, it was modified. This method focuses on circular foundations in particular and values changeable and versatile designs. To determine whether the theoretical concept of circular foundations leads to foundations that are more circular than the traditional ones, two case studies were conducted. The considered buildings required a deep and shallow foundation. For both projects, a changeable and versatile foundation was designed. All foundations were assessed by the Alba Concepts’ method and the alternative method. Independent of the assessment method, the traditional foundations have a low level of circularity. Because Alba Concepts focuses on changeability, the versatile and changeable foundations obtained a low and high score, respectively. Based on the alternative method, all circular foundations obtained a high level of circularity. Finally, the structural similarities, differences, challenges, preconditions and feasibility are discussed. A versatile foundation appeared to be similar to a traditional one. Differences and challenges arise in case of changeable foundations. For example, the standards of dimensions and connections must be determined. Despite the disassembly, the strength, stiffness and stability must be maintained. Also, the reusability of foundation piles can be improved. More generally, finding a balance between uniformity and freedom of form is both important and challenging. Circular foundations require precise documentation of characteristics and availability. Altogether, the traditional foundation can be more circular with some achievable changes. Regardless of the building, adding a certain degree of circular value to the foundation is always possible but requires willingness and innovative thinking. This cultural change is not simple, but it will be beneficial.

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.

In the last decade, maintenance and adaptive reuse, of the existing building stock, have gained ground in the construction sector. For the adaptive reuse of a building, it is required to analyze, meticulously, the existing structure. Unreinforced masonry structures are indicative of the Dutch built environment. For the assessment of their structural capacity, the European Standard EN 1996 is, currently, applied. Masonry walls of high slenderness, often, comprise the structure of existing buildings, in the Netherlands. It has been noticed that the EN 1996 norm underestimates the vertical resistance of slender walls. This study attempts to extend the applicability of the EN 1996 norm to slender masonry walls, since the norm serves for the assessment of existing structures. Particularly, the research objective is to find an appropriate verification method for existing slender masonry walls, in one-way bending. Literature research is, initially, conducted, with respect to alternative formulas for the calculation of the vertical resistance of slender masonry walls. The formula in the EN 1996 norm and the alternative formulas are reviewed, considering a case study. The case study is one of the slenderest interior masonry walls, that form the structure of a relevant existing building block in Amsterdam. The latter was constructed in the late 19th – early 20th century. The engineering firm STRACKEE BV Bouwadviesbureau provided the technical drawings of the building block. Reference values for the vertical resistance, of existing slender masonry walls, are necessary to develop an appropriate formula for their verification. Therefore, the next step of the research is the numerical analysis. The response of slender masonry walls, subjected to combined vertical and lateral loading, is estimated according to the results of FE analysis. The case study is the reference for the geometry of the FE model. Indicative, for the construction period, properties of masonry are the input for the initial material model. Further, models of slender masonry walls with different geometrical and material properties are analyzed. Specifically, a parametric study is done, to define the influence of geometrical and material properties on the vertical resistance. Based on the FE analysis results, a new formula is proposed. The formula estimates the vertical resistance of existing slender masonry walls, subjected to combined vertical and lateral loading.

Globally the construction is a major contributor to the severity of the anthropogenic environmental impact. The sector emits 39% of the global CO2 and is responsible of 40-50% of material flows. The focus of reducing the environmental impact in buildings is, in the past, mostly attributed to the operational energy. However, due to increasing renewables and efficiency, that share is declining. Making the embodied impact in a building relatively more significant. The structure encompass the largest part of the embodied impact in buildings. The materials, components, and systems embedded in a structure are often still of high value when the building reaches its end of life, i.e. the technical service life is not yet achieved. To reduce the environmental impact of structures and therefore buildings as a whole, one should integrate design measures for new constructions to grasp the most value out of the incurred embodied impact. Three eco-effective structural design criteria are established that encapsulate the structure's whole life cycle - material environmental costs (product and construction stage), service life (use stage), and residual value (end of life and benefits beyond system boundary stage). These structural design criteria are merged from the following structural design perspectives - material selection and material use (material environmental costs); durability, maintenance, adaptability, and flexibility (service life); and waste effectiveness, disassembly, reusability, and recyclability (residual value). In the eco-effective paradigm, one focuses on the future value of a product. This may entail that more material environmental costs could be made, but in the end you will be rewared with either a longer service life or more residual value. Therefore, the emphasis is put on the latter two structural design criteria. A crucial bottleneck of not attaining the technical service life of a structure on a building level, is the functional service life. The functional service life should be equalized with the technical service life to grasp the full potential of a building structure. Three strategies have been constructed based on the structural design perspectives and the structural design criteria. Design for Durability; thus, equalizing the functional service life with maximization of the technical service life. For this strategy, it is imperative that solely one function will inhabit the building. Examples are churches, temples, museums, i.e. buildings with a sentimental and/or historical value. The second strategy is Design for Multifunctionality. This is for buildings that have proven not to stand the test of time. Therefore, conditions should be created in the structure that it could be possible for the function to be converted (n functional service life = technical service life). These two strategies are on a building level. The following strategy is on equalizing the functional and technical service life on a component level. This is done by Designing for Disassembly. In this strategy, it is known that the service life of the building relatively small. These eco-effective structural design strategies can be used by structural engineers during the conceptual design to reduce the environmental impact on the long-term.

Uit onderzoek naar de ingestorte parkeergarage bij Eindhoven Airport in 2017 blijkt dat het tot die tijd gebruikelijke detail voor voegen in breedplaatvloeren met krachtsafdracht in twee richtingen onder invloed van een positief buigend moment niet goed werd ontworpen en uitgevoerd. Een breedplaatvloer is in eerste instantie bedoeld om een krachtsafdracht in één richting te realiseren, maar de toepassing werd verruimd naar krachtsafdracht in twee richtingen. Daarnaast werd zelfverdichtend beton en gewichtsbesparende elementen geïntroduceerd bij de toepassing van breedplaatvloeren. Hierbij is niet zorgvuldig onderzocht of de bestaande regelgeving afdoende was voor deze toepassingen. De partijen in de bouw introduceerden hiermee onbewust een systeemfout: de constructie kon bros bezwijken doordat er een bezwijkvlak mogelijk was, zonder dat het door constructieve wapening werd doorsneden. Op dit moment bestaat er nog geen nieuwe regelgeving voor dit detail, maar worden er al wel vast aanwijzingen gegeven in de VARCE-rubriek in vakblad Cement. Om inzicht te krijgen in hoe verschillende partijen in de bouw op dit moment omgaan met dit voegdetail bij nieuwbouw, is er in dit onderzoek aan de hand van een literatuurstudie en verkennende interviews een enquête opgesteld die verspreid is onder constructeurs en leveranciers. In dit rapport staan de resultaten van dit onderzoek. Dit onderzoek is in opdracht van VNconstructeurs gedaan.

We are currently facing a transition of economy. Previous years were focused on a linear economy, consisting of the make-waste concept. The products that are made with raw materials are thrown away after its use. Unfortunately the Earth does not contain an unlimited source of materials and we need to focus on reusing materials. Concluding to create a circular economy in which waste does not exist at all. The goal is to start with reusing as of today, instead of in the future. In other words, using the current existing elements. However, to do so it must be known which elements are available. Therefore, a data analysis has been done on the current existing structures as well as the future perspective. These analyses combined concluded in a common scope, visualized as a Lego box. This Lego box does not only consist of all the current existing structures (within the determined scope), but also provides a future perspective on the demolishing plans in the near future. Based on a time-consuming manual research a variety of nearly 70 viaducts have been examined. This lead to the summarization of 5 different girder categories: Box girders, inverted T-girders, Infilled girders, T-girders and remaining. With the specific girders known, design applications can be created. The focus on these applications is to think outside the box and reusing a girder in a different function than the original purpose. The design applications are created with a brainstorm session. For this session multiple different broad-minded individuals had been invited for an open discussion which concluded in over 20 different design applications. Thereafter, these applications have been examined with the help of an MCDA, based on the three main criteria. This MCDA is executed with the help of multiple different experts with a background regarding one of the three main criteria. With these expert judgements the total amount of design applications have been demarcated to a top 5. Reusing a girder as: Bicycle bridges, (non-)residential buildings, retaining walls, sound barriers and culverts In conclusion, this thesis provides valuable outputs and the first impressions regarding reuse in another application seem at least interesting. With the different impact factors determined, the possibility looks very promising. It can be stated that reusing in general will be better for the environment, as well as for your own wallet. Reusing a girder as culvert can in theory be seen as a good reuse application, but not higher in a general value than reusing again as a girder. This is based due to the fact that using the girder as a culvert will take more research in practice, especially regarding structural aspects. However, from this thesis it the first impression conclude in the fact that the impact in costs as well as environmental impacts are bigger when reusing the girder in another function

A transition towards a circular economy is proposed by initiators like the Ellen MacArthur Foundation and architect Thomas Rau, in order to preserve and enhance natural capital, optimise resource yields, and minimise system risks. A circular economy seeks to ultimately decouple global economic development from the consumption of non-renewable resources, and will eventually result in an economy of services. In this transition, the construction sector plays a major role because it is responsible for 50% of the total resource use, 40% of demolition waste and 35% of CO2 emissions. The design of the façade system of a building which is offered as a service is essential. Assembly and disassembly of components of such a building occurs more often compared to traditional buildings, so the components and elements have to be designed so that they can facilitate this. This is especially true for the components of the façade which, due to the relatively short lifespan of a façade have to be flexible. To help incorporate circular principles in the design, a new method or tool is needed to help making design decisions and compare different alternatives. The main objective of this master thesis is to investigate the suitability of cold-formed steel components for circular façade design and to develop an assessment method to measure the degree of circularity of façades. Current assessment methods for determining the circularity of products either focus on the environmental impact or the flow of materials and protecting existing value, and not on the degree of circularity related to certain design options. Also, there is no method which focusses specifically on façades. A circular economy is restorative and regenerative, and aims to keep products, components, and materials at their highest utility and value at all times. This is achieved by controlling finite stocks and balancing renewable resource flows, circulating products, components, and materials, and designing out negative externalities. Circular design criteria are derived from the design strategies Design for Disassembly, Design for Adaptability and Modular Design. Currently used façade systems do have the potential to be used in a circular economy, provided that the design criteria for circular use are met. During the Case Study two designs are proposed: a traditional façade system which uses sandwich panels, and a façade system which uses façade panels designed based on a concept for roof panels developed by CFP Engineering (two alternatives). The aim of this case study is to investigate the suitability of the newly developed façade element for circular façade design. Additionally, it will serve as input for the assessment method which is illustrated later in this thesis, and set boundary conditions for the comparison of the life cycle costs and level of circularity. The most important design parameters to determine the circularity of a façade system are: the amount of materials used, the possibility for reassembly, the environmental impact of the system, the amount of reused and renewable materials, the availability of information and the amount of toxic materials. These parameters can be measured by calculating the Façade Circularity Indicator which, as the name suggests, cannot be considered an exact value. The Façade Circularity Indicator originates by combining an existing method (Material Circularity Indicator, developed by the Ellen MacArthur Foundation) with research on Design for Disassembly (Durmisevic, 2016). A prerequisite of this method is a Life Cycle Assessment calculation. The method can be used during the design phase to help making design decisions. Based on the Life Cycle Assessment, the environmental costs of the traditional façade system are 22% higher than the environmental costs of the case study alternatives, which makes the traditional façade system less suitable for use in a circular economy. When the mass of the components is used as a weight variable, the Façade Circularity Indicator of the traditional façade system is 9 to 12% lower than that of the case study alternatives. When environmental costs are used as a weight variable, the Façade Circularity Indicator of the traditional façade system is 54 to 60% lower than that of the case study alternatives. This also indicates that the traditional façade system less suitable for use in a circular economy. As an overall conclusion, it can be stated that cold-formed components are suitable for use in circular façade design because of their relatively low weight, low life cycle costs and the possibility to (dis)assemble them with relative ease. Furthermore, an indication of level of circularity of façades can be given based on a combination of the Material Circularity Indicator and Design for Disassembly factors.

The purpose of this thesis is to determine the most optimal material use and configuration of structural elements with regard to minimizing shadow costs associated with the main bearing construction of industrial halls. Central themes in thesis are reusability, parametric modelling and generative design. The construction sector is responsible for a large amount of pollution due to its high energy consumption during extraction and transportation of raw materials. Paradoxically, this offers the construction sector a unique opportunity to notably decrease its negative environmental impact. More and more industrial halls are built due to an increase in online shopping and the subsequent need for the distribution of consumer goods. However, the current inefficiency in shadow cost reductions of main load bearing elements presents a problem for the decrease in harmful emissions as a consequence of construction. Shadow costs associated with structural elements decrease as a result of reuse. Connection types have been identified as the most influential factor for reusability. Therefore, a connection reusability factor was developed which was given according to four material independent criteria. Subsequently, a corrected shadow cost (CSC) can be calculated by multiplication of this reusability factor with the original ECI. However, this method is experimental and is not sufficiently corroborated by relevant literature yet. A parametric model of an industrial hall was constructed in Dynamo which could be optimized using a genetic algorithm in Autodesk generative design in order to minimize the shadow costs of the design. No biogenic carbon storage was accounted for during these optimizations and only single span hinged construction elements were assessed. Furthermore, all designs were assumed to be located in a rural part of Dutch wind zone II and no fire protection measures were accounted for in the ECI or price of the designs. Based on these assumptions, several conclusions could be drawn from the optimization of an arbitrary hall and two case studies. For the boundary conditions that were selected for the arbitrary hall, steel elements performed best with regard to the total ECI value as well as the corrected shadow costs. Contrary to popular belief, timber elements performed best in terms of price. A combination of both materials therefore has a high probability of resulting in the most cost effective ECI optimization. The results from the first case study indicate that the ECI of an existing hall could be reduced by 16 % as a result of the optimization methodology as presented in this thesis. The second case study was not accurately comparable enough to the optimized hall as a result of large differences in the connection types that were used. The results that are presented in this thesis are based on specific loads, connection types and boundary conditions and configuration of the halls. The conclusions that are drawn in this thesis are therefore only valid in case similar halls with similar boundary and load conditions are assessed.

The search for a transparent, reversible, and reusable consolidation system for monuments led to the ambition to test possible cast glass interlocking brick designs using numerical calculations. The focus of this research is hence the design, simulation and evaluation of a possible cast glass interlocking geometry using Finite Element Analysis (FEA). For this purpose, design criteria are formulated from literature; considering glass, polyurethane (used as interlayer) and interlocking systems. As interlocking systems are determined by their boundary conditions, a case study of a monument is chosen to provide additional design criteria. The goal of the case study is to provide a reversible and reusable restoration and consolidation alternative for the current invalid restorations. The design criteria obtained then are combined into an initial geometry, whose parameters are varied to test their sensitivity to its shear capacity, using FEA. Christensen’s failure criterion is used to locate prone areas in the geometry, and to evaluate the theoretical moment of failure. This output value combines the three principal stresses into a failure envelope, hence can generate contour plots to envision peak-stress-prone areas. This is important especially for glass structures, as they are prone to peak tensile stresses. From the results design diagrams are created and applied on a conceptual cast glass interlocking consolidation design for the monument chosen as case study: The Lichtenberg Castle ruin. The initial design is moreover prototyped to check its interlocking capabilities, residual stresses and deviations introduced by shrinkage. Being able to evaluate possible geometries using FEA can decrease costs and time when searching for a new interlocking geometry. Prone areas are easily highlighted using the Christensen’s failure criterion output. Hence peak stress sensitive or invalid geometries can be discarded before reaching the prototyping stage, which is time consuming and costly. The creation of a methodology to predict this behaviour is hence valuable for further research on other cast glass geometries and can moreover be applied in any other field when analysing solid complex geometries. Another goal is to find a cast glass brick design which not only can consolidate the monument of the case study, but is moreover applicable in other projects or configurations. The brick then is not a one-solution design, but can be reused in other projects. The geometry hence is varied using Grasshopper plug-in for Rhinoceros. By exporting the geometry using a STEP-file, a solid can be loaded into DIANA FEA, where it can be analysed using their newly implemented output value of the Christensen’s failure criterion. The geometry of the monument is gained through a 3D laser scan, resulting in a point cloud. The point cloud is adapted using Autodesk Recap, then further processed in Rhinoceros. The Christensen’s failure criterion output is a proper and fast way to evaluate possible cast glass brick designs. Any compressive stresses on the interlocking brick geometry are beneficial for its shear capacity, as is an increase in interlocking amplitude or brick height. Increasing the amplitude however affects the allowable tolerance negatively, which is also the case for a decrease in brick height. Decreasing the brick height hence results in both negative effects. The conceptual design for consolidation of the Lichtenberg Castle tower can replace the current interventions with equal or higher capacity, even for all conservative assumptions and simplifications. The design can still be altered less conservative after more experimental results and simulations come available. The methodology applied can now be further developed and performed on other complex geometry designs. The presented multifunctional cast glass interlocking brick design, and its variations can be further investigated and applied in other projects.

The Netherlands has the vision to be completely circular by 2050 cutting its raw material consumption to half by 2030. To reduce the raw material consumption, materials in use must be reused and nothing should be wasted. However, the construction industry is far from reaching this goal. It is traditional in the EOL treatment of the building. The structure is crushed down into mixed debris and recycling is the highest level of waste management adopted in the sector. 85% of the CDW in The Netherlands is mineral waste which is crushed and typically applied as the foundation in road construction. Reuse, a higher level treatment method, is rarely adopted. Only 3%-4% of the total material demand in the industry is met with secondary materials. It is limited to the reuse of products such as doors, windows and interior installations. Existing demolition methods do not allow for product recovery as it a costlier and time- consuming process. It requires skilled labour, knowledge and collaboration amongst the stakeholders to deconstruct for reuse. The limited knowledge of the know-how of recovering structural components is found to be prevalent. Furthermore, there is no tool or framework to quantitatively assess the economic feasibility of reusing components well before demolition. The available methods for assessing reuse feasibility are found to have a futuristic approach and cannot assess the economic feasibility quantitatively. Therefore, the Feasibility Calculation Tool is developed in this research which is a practical framework capable of quantitatively assessing the reuse potential of the components. It provides clear guidance to stakeholders on how to assess if the components from existing buildings can be profitably extracted for reuse. The FCT can be successfully used to determine the economic costs and feasibility conditions quantitatively allowing for a circular EOL treatment. The reuse scenario and the tipping points for the structural floor elements can be evaluated well in advance of demolition guiding the decision of the owners to demolish or deconstruct for reuse. A well-planned deconstruction can further help find buyers in time and deconstruct with higher precision as per the requirements of the buyers increasing the salvage cost and the need to modify components after deconstruction. The results of FCT show that it is most feasible and economic to reuse components directly on the same site (Reuse Scenario 1) then to transport them to another site for reuse(Reuse Senario 2). However, for the existing building stock, it is more probable to reuse under Reuse Scenario 3 than 2 and 1 as the existing stock is not designed to be reused. Instead, a buyer should be found who has no or minimum modification requirements. Furthermore, taking the environmental impact of reusing secondary components into account improves the reuse feasibility. The reuse cases which are otherwise not economically feasible turn feasible once the environmental impact costs are considered, in other words, once the polluter is made to pay the price. Furthermore, planning for the EOL of the building should be done well in advance to allow for sufficient time and efficient recovery. The owner should be motivated for deconstructing circularly, allow sufficient time and if he fails to reuse materials himself, he should allow for collection and sale of secondary products by the demolition companies to a third party. The demolition contractors, on the other hand, are found to depend on the question from the owner to reuse. However, they must make voluntary calls for deconstruction.