An increasing awareness of sustainability problems urges the need for more sustainable practices within the infrastructure industry. Organisations actively engage sustainability in strategic missions and objectives. However, how these visions translate proactively to the tactical and operational levels of decision-making is still considered an exploratory area for the extant theoretical body of knowledge. Therefore, this research aims to support managers in tactical and operational decision-making for sustainability by means of a diagnostic research in the context of a long-term Strategic Partnership between client and contractor at Schiphol Airport. Their collaborative agreements based on Best Value aims for synergy by close cooperation between the partners and valuing professional expertise. To become highly committed to sustainability, organizations need to take responsibility over decisions regarding their organisational processes, in terms of dedication, motivation, and long-term investments to achieve effective solutions. Interventions require the direction of efforts into an organization-wide approach, meaning that both tactical and operational level management are internally aligned and stimulated to involve sustainability in their considerations. Also, a future directed mind-set and long-term investment approach are required to overcome technical and respectively cost related barriers. Fragmented decision-making can be overcome by engagement of stakeholders in sustainability ambitions. Moreover, proactivity in strategic partnering collaborations also requires extending responsibility towards supporting the partner’s responsibilities in order to achieve the best outcome for all parties involved. Therefore, it is key for both parties to allow each other to showcase their expertise within the set boundaries and ambitions of the Best Value principles. Currently, the client initiates new projects in which utility infrastructure projects play a role, whereas the contracting organization becomes involved after scope, budget, and planning are mainly determined. A mutually structured approach of formal meetings in the initiation process needs to be enhanced to collectively explore opportunities and define ambitions. Based on the gathered elements on proactive implementation of sustainability in decision-making levels, a conceptual framework is developed to test the case studies by analyzing sustainable outcomes in terms of their level of effectiveness. The analysis framework introduced by this study connects the different levels of proactivity with a chronological order of project phases, ranging on tactical and operational decision-making levels. This developed framework provides a practical solution for the collaborative setting between client and contractor, as it stimulates the development of mutual ambitions, substantive opportunities and directions for sustainable outcomes.

Public clients in the Netherlands have committed to dramatically reduce CO2 emissions. To achieve that, Circular Economy is proposed and more specifically a tool that can lead to Circularity, called Product Service Systems (PSS). PSS is a business tool that is innovative for infrastructure, and public clients are investigating the transition towards service-oriented projects. Literature suggests that when public actors undergo transitions, their public values are also affected. It is yet not thoroughly studied how the public values are coupled with PSS. Aim of this research is to investigate how public values are affected when public actors that own infrastructure assets implement PSS. Firstly, a literature review concerning public values is conducting. Then, the PSS characteristics, barriers and benefits are theoretically studied. A framework that couples public values with PSS is designed. To analyze and enrich this framework, a real-life implementation is studied. The Province of North Holland (PNH) served as case study, and more specifically the guardrails pilot that PNH realized within the Circular Road Program. Interviews were conducted to collect the data. To analyse the interviews, thematic analysis was utilized. Two rounds of analysis were conducted, a deductive and a reflective round. The findings of the thematic analysis were validated and generalized by an expert panel consisting of three experts. As a result, the empirical findings of the results were found. An overview is designed and the theoretical and empirical results are presented and compared. The values that are mostly affected when PSS is implemented are Lawfulness, Accountability, Collaboration and Innovation. The overview is a useful input for public clients, because they can gain knowledge about how they can include the values perspective in their decision-making process.

The current practice of bridge maintenance decision-making is informed by subjective visual inspection data with a long time interval between measurements, which creates inefficiencies and possible loss of value in the maintenance entity’s capabilities. New opportunities from technology-related innovations for measurement devices are available for better-informed decision-making and for improved knowledge on the condition of a bridge. Even though, the adoption and use of these opportunities seems to be disregarded by the market and the main focus of innovation pushing organisations is mostly on the technical capabilities of these systems. This research presents a study on the effects of using technology-related opportunities on maintenance decision-making from a usercentric perspective. It performed a serious gaming experiment where bridge maintenance decision-making professionals were questioned to set up maintenance advices based on different types of data. No previous similar research was found through extensive literature search. Bridge deterioration scenarios were presented to experts throughout a within-subject fractional factorial experiment design. The experiment treatment groups consisted of data presentation from new innovative or potential bridge condition assessment mechanisms and the experiment control group consisted of the current data source, which is visual inspection. To observe the effects, the experiment used a quantitative and qualitative approach that considered expert judgement, maintenance decisions, and explanations of the experts for observing whether differences occurred between the different settings. It was indicated that significant differences were present if new data sources were added to the current visual inspection data, but no significant differences were observed between different types of data sources. It is expected that the differences are caused by the ability to observe quantified values of important performance indicators better, and that they provided indicative values that can be used during decision-making. It is expected that the latter described indifferences were caused by a lack of guidance by the market on how to use new data sources properly and consistently. These outcomes mean that for efficient and effective adoption of new data sources, more standards and guidelines about threshold values and causal links between deterioration parameters and possible deterioration causes are needed for practical guidance during maintenance decision-making. It suggests that in order to provide a broad facilitation for adoption of new data sources, long-term strategy behaviour must be considered by the market in order to provide a safe space for pilots and trials to learn about these innovations.

The building industry is stained as unsustainable due to the linear economy model of “take, make and dispose”. There is a need to switch to Circular Economy (CE). One of the ways in which the public clients can stimulate this transition is by implementing the Design for Disassembly (DfD) principle in the public procurement process. However, this stimulation is underexploited, and public clients seem to lack in having an effective system for implementation. Therefore, the objective of this research was to conceptualize a system for the implementation of the DfD principle in the public procurement process to achieve circular ambitions. A mixed research approach was adopted where first a literature study was conducted on the general procurement process of buildings and the aspects of DfD to conceptualize the DfD based procurement process. Following this, two case studies were conducted to understand how public clients have implemented DfD in the public procurement process of known circular buildings. Based on the results of the case study, the conceptualization of the DfD based procurement process was refined. The main findings from refined conceptualization are: firstly, the client needs to hire a design team specialized in DfD. This design team needs to formulate an ambition primarily for flexibility in design and beyond that for future reuse. Secondly, for the tendering phase, the client needs to set eligibility requirements for the selection of the design team asking for training and experience. They also need to set requirements for the inclusion of deconstruction professionals in the consortium. Finally, the client needs to award the contract based on the design principles of DfD. The client needs to assess the offers for these design principles using BIM-based tools. Also, for the assessment of the cost of the offers, the client needs to use life cycle costs. In conclusion, the implementation of DfD does not lead to a fundamental change in how the procurement process is conducted. Only in certain phases, the activities need to be conducted in line with DfD.

The construction sector, as one of the world's greatest waste generators, is responsible for a cascade of events such as global warming, climate change, and natural resource depletion. Raw materials are continuously extracted from nature, and the rate at which they can refill is insufficient to meet demand. This system suffers significant losses across the value chain (Ellen MacArthur Foundation, 2013). On the contrary, the circular economy concept proposes a circular model of 'reuse-refurbish-recycle' that focuses on reducing waste and optimizing resource value retention. The strategy is ideal to adopt in a high-growth, high-waste sector like the built environment. The reason this research was taken up is because a significant gap is seen within valuation practices. The current valuation methods, although efficient, collect data and provide property valuations based on previous studies. For example, when using a comparative method of property valuation, we compare one asset with a neighboring one, that has similar features. This process incorporates the older values already provided to this old building, without accounting for innovations such as reusability or adaptability of the components How different would the sector be if we incorporated the value of circular interventions to the original value determined, rather than looking back at older valuation standards? Will there be a significant difference, and, more importantly, would it impact the way real estate investors viewed circularity? On conducting the research, The primary hypothesis of this study was that there is a link between circularity and valuation and that this link can be incorporated within present valuation procedures. The thesis research explains how the connections can be made, as well as specific actual instances for each. The number of possible scenarios are endless.

Current linear economic model entails coupling of economic growth with resource constraints and degradation of the Earth. In order to combat these negative aspects and to ensure prosperous and sustainable future, a new economic approach is emerging - Circular Economy. Besides neutralizing threats of the linear model, it also promises additional financial, societal and environmental benefits. This is recognized on (inter)national level with numerous action plans and legislation. However there are almost no actions that are aiming at implementing the notion of circular economy on the level of supply chains/ Therefore, inertia is observed in supply chains in relation to changing towards circularity. This thesis looks at the underlying reasons for this with the research methodology designed around the Social Network Analysis approach. Two main reasons for inertia in supply chains stemmed out of research: differences in perceptions of the actors within a supply chain and diffusion of responsibility phenomenon. Going one level deeper, four causes for these developments were uncovered: 1. Lack of incentives for companies in supply chains for making a change towards Circular Economy. 2. High uncertainties and risks that a change to circularity implies for companies in supply chains. 3. Lack of mutual interests between actors in supply chains for making a change towards circularity 4. Clashes of perceptions on all levels in supply chains, as well as between supply chains and government.

Amid global climate change challenges, the construction industry faces an urgent  transition from a linear production model to a Circular Economy (CE). Initiatives  and recommendations in Dutch transition roadmaps and literature predominantly  focus on ensuring a future circular built environment, while lacking concrete actions on leveraging the existing assets for reuse. Dutch CE roadmap timelines  and interventions are developed based on Material Flow Analysis (MFA) studies with highly uncertain data input, this uncertainty impacts either environment or  economy with inaccurate interventions on the CE-transition. Secondly, the Replacement & Renovation (R&R) task of civil structures poses a threat for the  industry due to the limitations of capital, contractor capacity, and material  resources required to facilitate this peak. There is currently a lack of centrally  stored high-quality physical asset data available at public organisations. This data is essential in effectively managing the decommissioning peak and reduces risk for reuse realization. Lastly, Asset Management (AM) is transitioning towards a 3D-centralised strategy in line with Building Information Modelling (BIM) and  digital twins, while existing assets are still in 2D with often incomplete and  fragmented data documentation. Consequently, a large data quality gap is forming between new and existing assets. This led to the research question: How can centrally stored, quantified, and visualised asset data of existing infrastructure impact the CE-transition, bridge R&R-task efficiency, and AM practices? An upgrade towards 3D-BIM is required for existing assets to bridge this data gap. In doing so, facilitate higher quality- and more accessible asset specific  information that can be used in reusability scanning and structural assessments,  material quantification for CE-transition roadmap accuracy, and numerous AM  benefits. The costs for upgrading the existing assets using manual modelling or  3D scanning technology are currently too large to justify. An opportunity was  identified for modelling 3D-BIM of existing beam & slab bridges from 2D drawings using a modular approach to Parametric Engineering, aiming to reduce the investment threshold, and accelerating the digitization transition. Preliminary testing executed by the author showed a potential for 50-80% reduction in modelling efforts compared to conventional modelling practices with a volume  accuracy of >97%. The prototype calls for further development, validation, and similar efforts for other infrastructure types. The tool also showed potential for 3D structural & reusability assessments, reinforcement approx., and ptioneering & circularity scoring for the design phase. To put the tool’s use in perspective, a roadmap towards 3D centralized AM and a reuse economy was developed for AM.

The number of raw materials consumed and waste generated by the construction industry is no longer a viable solution in the future. It is required for the construction industry to move from a linear towards a circular economy (CE) by circular construction (CC). The unfamiliarity in actions that need to be taken for CC is still new terrain for many companies since the whole life cycle of a project needs to be considered and is plagued with technical, legal and cost issues that obstruct CC. Contract forms such as Early Contractor Involvement (ECI) involve contractors in the design phase of a project, such as suppliers, builders, and demolition contractors, to engender a better design by sharing and creating new knowledge. There are, however, no sources directly indicating that the benefits of ECI also regard circularity. At the same time, issues that emerge with CC remain an obstacle for fully transitioning to a CE. This research aims to understand better the issues regarding CC and if ECI would be beneficial in solving them due to the knowledge contribution of contractors and their collaboration with other parties in the design process. Therefore the research question is framed as follows: “How is contractor’s knowledge contribution improving circular construction in ECI context?” The research consists of a literature study and an empirical study. First, the literature study was conducted to define the relevant concepts such as ECI, CC and knowledge processes. Next, to understand the knowledge contribution of contractors to CC in the design process, interviews with practitioners involved in CC projects were conducted according to the Critical Incident Technique (CIT). In CIT, research participants are asked to recall and describe a time when a behaviour, action, or occurrence impacted a specified outcome positively or negatively. From the empirical study, there can be concluded that contractors' knowledge contribution plays an essential role in the feasibility of a circular design solution. However, the dynamics in collaboration between multiple parties can lead to better circular results. Since the collaboration can result in knowledge creation and sharing, developing a good work relationship between contractor and client and problems can be jointly solved when there is mutual support. This, however, also requires trust and transparency between the parties, and if lacking, it can obstruct CC.

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.

The undeniable benefits of urban open spaces, such as parks and urban forests, has triggered a steady increase in “natural capital” demands. Nevertheless, the uncertainties surrounding open spaces and ecosystem services jeopardize their consideration in public decision making. Certain of their aspects are not fully translatable in economic terms, primarily due to the absence of proper valuation tools. This results in not only under-provisioning of natural capital, but also unsustainable urban development. Hence, an imperative need to incorporate efficient ecosystem valuation tools emerges. The objective of this research is twofold. Firstly, it aims to prove and quantify the influence of urban open spaces on the surrounding real estate’s market value. Secondly, it investigates which characteristics of these spaces bear the largest impact, with a particular interest in ecosystem services. The methodology employed in the present study is a combination of both quantitative and qualitative methods. The quantitative part, designated as Phase I, includes the establishment of a hedonic pricing model, which quantifies the added value of proximity to the selected clustered open spaces, which are also called “Ecosystem Service Hubs” (ESHs). The qualitative part, addressed as Phase II, swifts the focus from the housing samples to the ESHs. It consists of activities attempting an ecological profiling of the ESHs. Phase I’s Hub Hedonic Pricing model revealed that ESH1 bears the largest influence on surrounding real estate, followed by ESH3 and ESH2. Notably, a 1% increase in distance would lead to approximately 2,7€, 0,8€ and 1,6€ per m2 for each hub respectively. Inserting the distance variable as a dummy variable, instead of a continuous one, displayed a similar behaviour. Thence, each housing sample is divided into categories in order to execute a distance effect sensitivity analysis. It is suggested that “young, large, row houses in greener neighborhoods” exhibit the largest distance decay effect sensitivity. Lastly, the overarching monetary values are roughly estimated. These are 5,81, 1,98 and 3,28 million € for each hub respectively, whereas the average value per m2 per house is 77,44€, 57,68€ and 107,47€ respectively. Concerning Phase II, the ESHs’ core components and characteristics are identified. Then, an association between the economic benefits and the core characteristics is attempted, through qualitative correlations. These are summed up in the following statement: “Ecosystem Service Hubs generate higher economic benefits when they are larger and more diverse, in terms of both composition and ecosystem services, with a significant sensitivity to recreational opportunities”. This research’s findings could prove to be insightful for urban planning, since they could be applied in two major ways. Firstly, given an identified Ecosystem Service Hub, the development of the surrounding area could be adjusted to encompass primarily the optimal house and neighborhood characteristics. Secondly, given the “house composition” of a certain area, the optimal location and profile of a new Ecosystem Service Hub could be selected. In both cases, maximizing the value of surrounding real estate is achieved through optimal spatial configurations. In conclusion, the added value of urban open spaces is plural and reflects the use and non-use value derived from residents. This research’s rough estimation of an average of 80,86 € per m2 per house is an indication of this added value, subject, however, to the narrow scope of the study. Attributing this added value to particular open spaces’ characteristics could only be executed through qualitative correlations. In order to enrich the previous results, an integration of multiple valuation methods (social and ecological), which incorporate the various value dimensions, is recommended. More conclusive and definitive results will motivate planners to opt for polices revolving around ecosystem services and natural capital, thus, satisfying the steadily increasing demand.

The construction industry is a large generator of waste. The interest in improving the resource efficiency is growing. A move towards a Circular Economy (CE) has been assigned as the solution for a more efficient use of resources in the construction industry. The aim of a circular economy is to create a system in which waste and energy leakage is minimised and resource input is avoided by closing the material and energy loops. Despite the advantages of CE, the construction industry has not yet made a significant step towards the CE. The theory of Reverse Logistics (RL) could be the enabler of circular economy in the construction industry. RL in the construction sector is defined as the management of collecting, sorting, processing and reusing construction waste. In the field of RL, quantitative models have proven to be a successful tool to combine environmental goals with financial constraints. However, such models are missing in the field of construction industry. In this context, this research proposed a general applicable RL-model that supports decision-makers in implementing circular principles in the return flow of their assets while minimising the costs. Literature review has been conducted to obtain a theoretical framework for the model design. The first part of the literature study has provided a framework to prioritise different waste management strategies based on their level of circularity. The second part of the literature study has been conducted to get an insight in the characteristics of the reverse logistics in the infrastructure and how the principles of circular economy can be included in the RL-process. The most suitable modelling approach for the proposed problem has been found to be linear programming. The proposed RL-model has been designed as a transhipment model and is based on mixed integer linear programming (MILP). The proposed model design simulates the reverse flow of one asset moving from a deconstruction project, through the processing facilities to the final redistribution. The proposed model has been complemented by a guideline that supports the application of the model for specific cases. To test the applicability of the model and the proposed guideline, the model has been applied on two different types of assets in the infrastructure: concrete and street lights. The model for both cases have been run for multiple scenarios, based on the developments in the industry. The results of the model provides two types of information. Firstly, it provides a trade-off between the level of circularity and the costs. Secondly, it gives the corresponding network-design for the different outcomes. It was found that technical innovations in combination with efficient transportation will help to create return flow in the infrastructure, according to the principles of circular economy, which is financially feasible. Overall the model has been proven to be general applicable and it supports decision-makers in making decisions about the reverse flow. The outcome gives information about the financial impact on implementing circular principles. The corresponding RL-network provides an insight in which aspects in the RL-process influences the outcome.

Professionals in the Operations and Maintenance phase of national road infrastructure projects are making decisions with large consequences based on low frequency measurements and subjectivity prone expert observations. A solution is expected in sensor innovations, IoT and User Generated Data to generate more frequent measurements and less subjective observations. The use of these methods has been researched and proven, however the main focus of these studies was often improvement of the technological capabilities or implementation in current practises with limited research into their contribution and effects on professionals in the construction sector. This research describes an experiment that tested the effects of more data and more diverse data on the decision-making of professionals in the construction industry. An attempt to answer this question is made by modelling different data sources into a Serious Game and testing the assumptions. After analysis of the gaming data, the questionnaires and the debriefing it can be concluded that in this experiment there was a correlation between better assessments and higher scores. However experts did not assess damage differently when presented with extra information, nor did they make significantly different decisions. From the qualitative section of the experiment the explanation was found that the extra information proved too much and experts were able to extrapolate with the marginal data that represents the current industry practise. This suggests that new information requires training, as our built environment gets richer in terms of data, the assessment of this built environment becomes too much for humans to cope with and solutions can be sought in the application smart algorithms, Machine Learning and Artificial Intelligence.

2020 is a strange and disruptive year. The pandemic virus COVID-19 controls people’s lives. It influences the way we live, love, and work. Offices are empty while people work from home. When, and if people are going to work in an office again like they were used to, is the question. The events of 2020 are an extra showcase that the way we use offices is subject to change. Therefore, offices should be designed in a way that they are adaptable, reusable, and can respond to changing needs. Circular design can help to make our offices future-proof. However, since the circular economy gained attention in the office building sector, only limited progress has been accomplished. A problem within the office building sector is that insight into the possibilities of circular design is lacking. Moreover, in literature there is no circular design model specific for the building industry. Therefore, this research aims to develop a decision support tool that stimulates the communication between client and designer and provides clarity about the possibilities of circular design. This resulted in three main insights. First, a building consists of different layers with different lifespans that should be able to be refurbished, replaced, and recycled without damaging other layers. Consequently leading to an extended lifespan of the complete building and increased adaptability and reusability. Second, practical circular interventions can be categorized into four themes which are based on circular theory. Those themes are adaptability, reusability, materials, and process. Third, decisions regarding circularity should be taken early in the design process. Especially when the lifespan of the building layer is long. Understanding which possible interventions could be taken in what stage of a design process helps prioritising them and thus creating windows for circularity.

Being one of the world’s largest waste generator, the construction industry is responsible for a train of events such as global warming, climate change, and depletion of natural resources. Materials are exhausted globally to a large extent and the waste produced in the process is not treated properly. A “take-make-dispose” or popularly known as linear economy is the process that is adopted to treat the waste currently, where large quantities of resources end up as waste after demolition of the building. This grabs our attention towards the concept of Circular Economy (CE) with the goal to potentially minimize the pending issues arising from the construction sector through recirculation of building materials. However, due to the unfamiliarity of its economic feasibility, many are still reluctant for investing in circularity as they believe circular construction to be more expensive. The main challenge is to overcome the lack of understanding of the available circular strategies and their effect on their business. Therefore, the objective of this research is to investigate how buildings can be made more circular. Furthermore, the aim is to compare the alternatives based on the life cycle costs and a circularity measure, so that stakeholders are in a better position to invest/favor circularity in general. Finally, the objective is to present a way to invest in circular projects by merging the methods used in this study. Firstly, literature review was conducted to develop a better understanding of the most important concepts in relation to this research. It reveals the need for several methods to conduct the research, and hence three methods are further elaborated. An inventory of possible circular interventions was made and categorized based on strategies and layers of the building. The methods discussed were applied to a case study. The application of interventions on the base case intends to gradually increase the circularity of the building. This gradual increase in circularity calls for a comparison of a traditional building with its circular twin. Based on the analysis, it can be concluded that a comparison as such can help in a parallel tracking of both circularity level and life cycle costs of a building, which in turn aids in taking both the factors into account for decision making. Thus, both the costs and circularity of a building are quantified. The main findings are: A building can be made more circular by searching for circular activities that can replace a non-circular activity by using a circular strategy framework- in this case, R-strategy was used. The application of circular activities or interventions can be categorized layer-wise to carefully examine the impact of the activity on the circulatory level and costs associated with the building. This can be done by diving the building into different layers- in this case, Stewart Brand layers was used. The circularity of the building is to be increased gradually. Further, several alternatives can be generated to analyze the best-case scenario that can justify both the circularity and cost of a building. This is done by using a circularity measure and life cycle costing- in this case, material circularity index and discounted cash flow analysis were used respectively. Finally, the results can be analyzed by quantifying both circularity and cost. This makes sure circularity in a building is not compromised for the costs associated with the building. This way, stakeholders are better aware of the opportunities and can make better decisions in selecting circular projects which could lead to enhance the acceptance of circularity within the building sector.

The construction sector is one of the biggest consumers of raw materials and generates large amounts of construction waste as well. CE is a way to delink the construction sector from the consumption of finite resources of the earth and excessive waste generation. Despite of the fact that there are a lot of interventions, such as Commodity agreement, Transition Agenda, it is not clear how CE can be executed in practice. This research aims to develop a guidance and a framework on the adoption of more circular innovative technologies in construction projects and to propose an approach that can support involved parties in order to realize more circular construction projects. This research adopts a unique approach in transitioning the construction sector to a CE using Service Dominant Logic (SDL). One of the key sources of non – adoption of CE is the lack of harmony or agreement on a suitable definition of CE for the construction sector. This may compromise the process of decision-making and eventually lead to ineffective policy interventions. Successfully implementing CE in the construction sector needs a definition that covers the whole construction supply chain to provide understanding of material flows in the economy.

Movable bridge decks experience critical expansion in summer, leading to uncertainty and unpredictability in its availability doe to improper docking and safety hazard. If the bridges are not cooled soon, the inertia of expansion stays, causing prolongation of availability problems. Structural health monitoring of such bridges with a predictive maintenance approach can help plan remedial measures on the exact day and time. For the efficient design of such a structural health monitoring system, a combination of sensor system data and weather API data is tested. A machine learning approach of Gaussian process regression which can give the results on the prediction of critical expansion of bridge deck has been evaluated in this research project. Finally, a check on the transferability of the prediction model is conducted by application on another bridge data and its performance is discussed. Scenario analysis with savings in cost per scenario is also conducted with varying levels of potential unavailability penalty costs, which could be levied on an asset manager of a bridge if the prediction models of sensor system data set or/and weather API data set gives incorrect estimation. Such an analysis is done to justify the use of the prediction models in assumed scenarios to predict expansion of movable bridge deck

The built environment has a huge contribution to the total CO2 and waste production, due to their linear approach of “take, make & dispose”. A shift in construction is needed towards the circular economy to close material loops, decrease and eventually stop the depletion of the earth’s resources. The construction project organisation could be an important vehicle for this transition. The construction project organisation is made up of all actors who, together, realise a project. The outcome of a project is the result of the collaborations, interactions and partner networks within a construction project organisation. Organising these interactions in another way could result in a more effective approach towards the circular economy. The demand for circular projects is increasing and despite this increase in demand, the construction project organisations still approach new types of projects in a linear way. Governments are speeding up this process, by creating regulations, incentives, and deadlines for all industries. The built environment has to change their way of working to commit to these new standards in the future. Product-service systems is a concept which could contribute to this transition in the built environment and reduce the depletion of resources. Consumers will pay for project-use and the producer will maintain ownership which stimulates sustainability. To accomplish this in the built environment and increase project value, construction project organisations have to change their traditional structures and develop new partner networks. The following research question will address this problem: How can construction project organisations change towards the Circular Economy and add value by implementing Product-Service Systems? The purpose of this research is to fill the gap between theory and practice. This is done by restructuring the stakeholder network of a construction project organisation, to meet the circular demand, by implementing the concept of product-service systems. The aim is to get a better understanding of the current state of construction project organisations and how they could implement product-service systems more effectively.

The aim of the thesis investigates and addresses what strategies municipalities can use in relation to collaborative action in a collaborative governance setting to facilitate heat transition at regional scale. The heat transition is a multifaceted problem where fragmentation and a deficient direction role of municipalities is a key institutional challenge. To address the problem, regional energy strategies are established to collaborate with state and non-state stakeholders, but the heat transition is still stagnating today. Collaborative governance is a governing arrangement that engages public and non-public organizations in a collective decision-making process to implement public policy to resolve social-technical problems. However, today the application of the collaborative governance theory is scarce on sustainable transformation. For this reason, the author decided to apply a collaborative governance lense on the current situation for heat transition. The thesis first examines the collaborative governance framework, which is the most suitable to apply in relation to heat transition. In the second step, the selection of a comparative empirical research methodology is selected. Third, two RES regions with rural characteristics are investigated to get insight into the current situation. Lastly, the empirical findings are discussed in relation to current collaborative governance literature and governmental policy. Finally, recommendations for municipalities and other regional stakeholders can be provided. The empirical findings show that collaborative governance conditions are rarely present to facilitate the heat transition at regional scale. The author identified crucial conditions within the system context and collaborative governance process itself, which is explainable by the iterative nature of the model. The conditions include the current deficient policy and legal framework, high level of contention among citizens, inadequate resource conditions. In the collaborative governance regime itself this results in lack of interdependence, trust and high level of uncertainty, through which no shared interest or common language are practiced. The thesis concludes with recommendations for the regional collaboration regarding heat transition for practitioners and for future research on collaborative governance.

The aim of this research was to investigate the effects of implementing circularity in infrastructural construction projects. As a very polluting sector, circularity is becoming a more and more popular theme in the construction industry. Driven by both governmental regulations of reaching a full circular economy in 2050 and intrinsic motivation, construction companies are slowly introducing practices which contribute to circularity. Unfortunately, not much is yet known about the effects on project process and construction costs when implementing circularity. This research has initiated the first step towards understanding what the effects of circularity are on infrastructural construction projects, providing welcoming insights to both the academic world and practice. Based on a case specific comparison, a circular construction project is more expensive than a regular construction project, due to extra activities which need to be executed before a secondhand material can be applied. Regarding the project process, the circular construction project introduced ''gathering of materials'' as a whole new process step which is constantly interchanging with (re)design until a final design has been completed.

It is observed that both cost and environmental impact are underemphasized criteria in the investment decision-making process of Institutional Real Estate Investment Funds (IREIFs). The limited adoption of Life Cycle Costing (LCC) and Life Cycle Analysis (LCA) within IREIFs' Performance Management Systems (PMS) hampers improved investment substantiation. This study aims to develop an LCC tool that accounts for environmental impact and to explore its potential implementation within an IREIF's PMS. The research question addressed is: 'How can an IREIF incorporate sustainability, defined here as both environmental and economic factors, into its decision-making process through LCC?' A double diamond design research approach led to the development of an Environmental Impact (EI)-LCC tool that monetizes environmental impact. This tool serves as a performance measurement instrument, offering insights into the environmental and cost implications of building elements over their lifespan. The study also discusses the tool's integration into an IREIFs existing Internal PMS as their Environmental, Social, and Governance (ESG) performance framework. Preliminary findings indicate that the EI-LCC tool, although in a nascent stage, has the potential to enhance the quality of sustainable investment decisions within IREIFs. The results provide a foundation for the tool's further development and broader implementation within the PMS of IREIFs.