In recent years, large infrastructure projects have increasingly struggled with limited market capacity,
contractors unwilling to bear excessive risks, and the ambition to involve small and medium-sized
enterprises (SMEs). These challenges force, and at times motivate, public clients to divide projects
into separate segments that can be tendered individually. Such segmented contracting offers
flexibility and makes projects accessible to a wider range of contractors, but it also fragments
responsibilities and creates numerous interfaces between contracts. This raises a fundamental
question: how should contractors collaborate across segments, and how can the client ensure that
coordination is effectively organised?

This thesis investigates how clients address these challenges by making segmentation and
coordination choices. Specifically, clients can opt for horizontal (geographical) or vertical (technical)
segmentation, and decide whether design and execution are tendered in parallel or phased over
time. In addition, they must determine whether coordination remains a responsibility of the client or
is delegated to one of the contractors. The research combines a literature review with four case
studies of Dutch infrastructure projects and a series of interviews with legal experts. Together, these
sources provided insights into how these choices shape the division of design and execution
responsibilities, the organisation of planning, and the allocation of risk.

The case studies showed that horizontal and vertical segmentation often create complex technical
and geographical interfaces, requiring careful management to avoid disputes. Phased and parallel
segmentation affect the alignment of schedules and information flows, with parallel strategies in
particular demanding strong coordination to manage interdependencies. Clients employed both
formal mechanisms, such as coordination agreements, overarching covenants, and escalation
procedures, and informal mechanisms, such as steering groups and joint decision-making. The
interviews with legal experts showed that without legally enforceable coordination agreements, the
risks of fragmentation and conflict increase substantially for the client.

The findings demonstrate that segmentation choices cannot be considered in isolation but must be
supported by a contractual and organisational framework that enables effective coordination. This
thesis contributes by clarifying how clients can adopt segmented contracting effectively, by analysing
how their choices in segmentation and coordination influence responsibilities and risks, and by
formulating key elements for structuring coordination agreements. In doing so, it provides both
theoretical insights and practical recommendations for clients seeking to implement segmented
contracting in complex infrastructure projects.

The Recent advancements in digital transformation within the Architecture, Engineering, Construction, Owner, and Operator (AECOO) sector emphasize the potential for creating public value through strategic IT implementation, particularly when driven by public clients. Public clients play a pivotal role in driving digital adoption across the AECOO industry, leveraging procurement practices to encourage sustainable and innovative outcomes. Digitalization, exemplified by tools such as Digital Twins (DT) and Building Information Modelling (BIM), offers the means to achieve long-term sustainability goals, including real-time energy monitoring, lifecycle asset management, and circular economy transitions. However, the transition remains complex due to inherent industry fragmentation and limited integration of digital systems, particularly in the Operations and Maintenance (O&M) phases.
While BIM has demonstrated efficiency improvements during the design and construction phases, its benefits are less pronounced in O&M, where information continuity and integration remain challenging. A socio-technical approach, integrating people, processes, and policies, is essential for effective digital adoption, especially to address organizational silos, behavioural barriers, and knowledge gaps that hinder technological integration. Public clients, positioned as agents of change, must adopt tailored, holistic data management strategies that align with life cycle needs and public values. This research focuses on enhancing BIM's role across the AECOO lifecycle by formulating a comprehensive framework to bridge existing gaps between data requirements, project phases, and client expectations.
Through theoretical research and a case study, this study develops a multi-level framework incorporating hierarchical policy alignment, knowledge management, and information exchange protocols to address the “practical-knowledge gap” seen in digital implementations. Findings suggest that a client-led approach with strong social integration mechanisms is crucial for overcoming industry fragmentation and driving sustainable digital transformation in the AECOO sector.

This research has explored the potential of segmentation and segmented contracting as a solution for managing the complexities of infrastructure projects in the Netherlands. As the country's civil infrastructure ages, innovative approaches are required to address the extensive challenges of renewal and renovation that lie ahead. This study has examined the benefits, challenges, and key considerations of segmented contracting, providing a comprehensive understanding for clients and contractors. The research has begun by reviewing various project delivery methods, including traditional, integrated, and co-contracting approaches, to establish a theoretical foundation. It has then analysed how segmentation is applied in current and recent projects, identifying its impact on project complexity and potential solutions. A segmentation framework has been developed to guide the application of segmented contracting. The framework demonstrates the impact of horizontal and vertical segmentation on project complexity elements. Additionally, a typology of segmented project delivery methods has been introduced, categorising approaches such as the segmented traditional project delivery method, the segmented integrated project delivery method, the segmented design team (2.0) project delivery method, and the segmented two-phase project delivery method. Expert insights have been incorporated to validate the findings and provide strategic approaches for effective implementation of segmented contracting. Segmentation, segmented project delivery methods, and segmented contracting offer several solutions to address complexity elements in complex infrastructure projects. By breaking down projects into smaller, manageable segments, clients and contractors can allocate resources and expertise more effectively, tailor risk management strategies, and maintain better control over budgets and schedules. This approach facilitates specialised focus on specific tasks, enhances project manageability, and improves the predictability of project outcomes. However, segmentation also introduces significant challenges, requiring robust coordination, communication, and integration efforts. Without these, projects may face inefficiencies, increased risks, and potential delays. Ultimately, this research has aimed to enhance industry practices, improve market competition, and support the civil engineering sector in addressing the significant infrastructure renewal and renovation challenges ahead. The findings have offered both practical and theoretical insights, promoting better management and fostering a more resilient and adaptive built environment.

The Dutch construction sector is confronted with a complex and challenging situation. The majority of the infrastructural elements in the Netherlands were built in the 1950s and 60s, which means they are approaching the end of their lifespan. This state, in combination with backlogged maintenance and budget cuts, created a significant and urgent renovation and replacement wave that the sector is now facing. Additionally, other challenges like the tightness of the labour market, increasing material prices, the sector’s substantial emissions of CO2 and nitrogen and it’s limited learning capacity only exacerbate the complexity of the situation.

One of the key solutions emerging in this context is the implementation of the contractual portfolio approach (CPA), where multiple works are bundled into one tender. This approach shows potential to efficiently tackle the renovation and replacement task, while at the same time creating a healthier situation in the sector. However, it is a very novel strategy about which both stakeholders and researchers possess limited knowledge. Therefore, this research fills this gap by exploring the implementation of CPA for the civil engineering sector. This exploration is done by analysing what CPA exactly entails, the objectives clients pursue when implementing a CPA and the choice options they have when doing so.

Out of this study, a clear definition of CPA emerges, which is:

The bundling of a logical set of similar works into one initial tender, with the purpose of reaching certain work-transcending objectives.

Next to this, eight main objectives are identified, accompanied by eleven key choice options that clients have at their disposal. These objectives include enhancing standardisation, increasing efficiency and stimulating a learning curve. The choice options, among others, are the selection and award criteria of the initial tender, the composition of the bundling of works and the implementation of performance management. Clients tend to lack a concise list of objectives while at the same time having a shortage of an overarching view on available choice options. Next to this, the links between choice options and objectives bring about certain dilemmas. This happens when a specific choice has a positive effect on one objective, but a negative one on another. As an example, the implementation of performance management provides the client with a certain degree of control over the quality of the portfolio, while at the same time decreasing the contractor’s willingness to invest. Next to these dilemmas, certain situational factors prove to be influential for the effectivity of choice options. For instance, a high complexity of the environment of a work hampers the workflow within a portfolio.

Concluding, clients can adopt the contractual portfolio approach as a way to achieve a variety of objectives. From sustainability to efficiency, and from risk reduction to standardisation. To effectively do this, it is important to explicitly define objectives and limit these to the most important ones. Furthermore, it is important to consider all the available choice options and to position the buttons in a way that it aligns to both the portfolio situation and the specific objectives. Then, it is vital to consider the circumstances of the specific case and to carefully weigh the trade-offs associated with certain dilemmas. Ultimately, clients are advised to use the CPA Decision Guideline that is constructed in this research as a tool that supports the decision-making.

The Dutch construction industry faces the recurring issues related to delays and conflicts, resulting in adverse effects on construction projects. Researchers have proposed pain/gain sharing mechanisms as a potential solution to address these issues. However, there is a gap between theoretical suggestions and practical implementation. This empirical study aims to bridge this knowledge gap by investigating the practical implementation of pain/gain sharing mechanisms in the Dutch construction industry. The objective is to explore how these mechanisms can provide value to contractors.

The literature review reveals that the NEC4 contract ECS4 Option C is commonly used for implementing pain/gain sharing mechanisms. Additionally, secondary option clauses such as Option X6 (bonus for early completion) and Option X20 (key performance indicators) are identified. While these mechanisms have primarily been applied in alliances or client-contractor relationships, they can also be adapted for contractor-subcontractor relationships.

Through in-depth analysis of three case studies and eleven semi-structured interviews, it is found that essential conditions for successful pain/gain sharing mechanisms are often missing. Transparency, aligned objectives, consideration of each other's interests, and early involvement of parties are identified as crucial factors for success.

To address the identified gaps in the implementation process, a comprehensive framework is developed, which is well-received by industry experts. The framework aids in selecting the most suitable pain/gain sharing mechanism and ensuring all parties understand its benefits and implications. Two options, an escape plan or commitment to the mechanism, are proposed to provide flexibility.

The developed framework enhances the understanding and implementation of pain/gain sharing mechanisms in the construction industry. By respecting and guaranteeing agreements, the optimal effectiveness of these mechanisms can be realized. This research contributes to bridging the gap between theoretical suggestions and practical implementation, paving the way for more successful construction projects in the Dutch construction industry.

As climate change and resource shortages increasingly threaten our planet, the built environment sector is under scrutiny due to its significant contribution to carbon emissions and global raw resource extraction. A transition towards a circular economy, replacing the prevailing "take-make-dispose" model, is crucial. This research explores the concept of Product-Service Systems (PSS) in the built environment, wherein products are provided as services, thereby increasing supplier responsibility and closing the resource loop.
This study answers the research question: "How can Product-Service Systems (PSS) be applied in the built environment and expanded to their fullest potential?" It delves into the various characteristics and properties of products within PSS and factors influencing these systems. Furthermore, it analyses the roles of different stakeholders within the circular chain of PSS, current implementation of PSS in the built environment, and future possibilities.
Adopting a qualitative research method, the study begins with an extensive literature review to provide an overview of current concepts and existing PSS models. This review forms a basis for identifying critical properties and characteristics necessary for successful PSS implementation. In-depth interviews with experts further provide insights into potential new opportunities for PSS in the built environment.
The research highlights the modularity, environmental sustainability, and economic viability of various building products, ranging from windows and doors to smart building technologies. A comprehensive table analysis reveals the potential for PSS implementation and the degree of circularity for these products. This research contributes to the field by presenting new possibilities for expanding PSS in the built environment. It emphasizes the need for pilot projects to better match practice with literature, increase the understanding of individual products, and uncover currently unknown factors. By enhancing our knowledge of PSS, this study propels us one step closer to achieving a circular economy in the built environment.

The construction sector is experiencing a fundamental shift towards greater digitization. Building information modeling (BIM), augmented and virtual reality (AR/VR), the internet of things (IoT), Artificial Intelligence (AI), and Digital twins are all becoming more prevalent in the architecture, engineering, and construction (AEC) industry. Greater digitization introduces additional data flows in construction projects that are collected, analyzed, and exchanged. Furthermore, the construction process, procedures, responsibilities, and obligations of the various stakeholders change. Dealing with the large volumes of data and the changing process necessitates a more robust and efficient data strategy than ever before. Tender documents will comprise, in addition to the standard documentation for physical construction work, several new or revised documents or regulations related to digital construction and data exchange. By understanding and controlling data exchange in projects, project advantages and organization-wide success may be realized. Currently, limited research is done in the field of public procurement and data exchange. Comparative case studies, in particular, have received little attention in this area.

Therefore, this thesis addresses the following research question: “How can contracting authorities (re)design the procurement phases to enhance successful data exchange in construction projects?” Through a theoretical study, followed by in-depth interviews and case studies, an attempt was made to gain insight into two important aspects of the tender: (I) the requirements of the product and process concerning data in the demand specification, and (II) the use of selection and award phase. Interviews with experts were conducted to provide external validation.

The research demonstrated that more attention should be paid to data exchange within public organizations, with a specific focus on asset management. The great majority of contracting authorities lack the necessary maturity to deal with the growing data in projects. In the procurement process, accurate data exchange is not or hardly prioritized, because public organizations are uncertain and even unaware of what they want and of the possibilities. As a result, a lot of data is lost during the life cycle of a building. For data and information management to become a component of asset management, a contracting authority must first pay attention to the softer, cultural, and organizational factors and define an associated organization-wide vision. By formulating unambiguous process and product requirements following the vision, it will be clear to market parties what the assignment entails and what is expected of them. In doing so, clients need to collaborate more with each other and contractors to achieve a successful data exchange.

Context
Projects in the construction sector are known for their high complexity. Due to this complexity, disputes in construction are close to inevitable. While these disputes can lead to major project delays and financial costs, they demand for a resolution. Juridical resolution methods like litigation and arbitration have found to be unfavourable in terms of time, money and business relationship costs. Alternative Dispute Resolution (ADR) methods like mediation are viewed to score better on these points.

Problem
Unfortunately, still a big amount of escalated disputes in the construction sector are resolved by traditional juridical methods, where the parties fight each other to win. This results in major expenses, time investments and relational damage.

Purpose
This research aims to gain a better understanding of mediation processes in the construction industry. This could lead to less use of juridical procedures and maybe less escalated disputes in general. This could save disputing parties in the construction sector money, time and business relational damage.

Method
A grounded theory approach has been used in this research, because no research has yet been conducted on factors that influence the mediation process, nor on the course of its process in practice. Four case studies have been carried out in a qualitative fashion, conducting in-depth interviews with the involved disputing parties and the mediator(s). The resulting transcripts have been analysed on contributing factors, allocating quotations to closed and open coding. Furthermore, the cases have been analysed on their course of the mediation process.

Findings
A substantial amount of influencing factors have been found to be influencing the mediation process in practice: a few from academic literature and the majority from the case studies, consisting of internal moderators, external moderators, mediator’s interventions and the action of bartering. Therefrom, conclusions have been drawn which have been discussed with a validation panel to value them and add a level of depth. Furthermore, an enhanced framework of the mediation process has been constructed where these factors have been added to. Since this research has a limited scope and is based on the grounded theory approach, a substantial amount of limitations and recommendations for future research have been given.

Any industry is focusing on creating an environment that is as safe as possible for everyone that is involved. This is no different for the construction industry. However, the construction industry is placed second in the ranking of most dangerous industries. The Dutch Safety Board, being an independent administrative body, has recommended to integrate a third party into the contractual general terms and conditions such as the UAC for integrated contracts. The objective of this research is to examine whether there is any potential to integrate a third party into the UAC-IC 2005 contract. This potential is being examined using a comparison between the UAC-IC 2005 and FIDIC Yellow Book 1999, a contract in which a third party is already present. In this comparison, the main focus points are the "vital tasks & responsibilities" that are necessary in order to safeguard safety on site, safety of the surrounding area & structural safety.

This thesis has found that the three types of safety can be improved if the vital tasks & responsibilities are properly performed. These tasks & responsibilities mainly relate to the management of project specific and safety related risks, and to the safety approach that is a result of this risk management system. From a theoretical point of view, the UAC-IC 2005 and the Dutch Building Decree are able to facilitate these vital tasks & responsibilities. The ON is responsible for most of the vital tasks & responsibilities, and the OG has the possibility to use an external control mechanism to verify this. The practical situation is however different. It is not uncommon that other aspects like time, or money can get more important for the contracting party than proper risk management processes and the corresponding safety approach. Work is not executed as intended, but rather as work-as-actually-done. The OG’s incentives in the UAC-IC can be insufficient for him to effectively perform this external control mechanism. This leads to a possible situation in which no internal nor external control mechanism is present, which is to the detriment of safety. The Engineer, being the party that is responsible for an external independent control mechanism in the Yellow Book’s quality assurance system, does have more incentives to actually make him perform this external independent control mechanism effectively. This incentive has its origin in the uncapped liability which the Engineer can be held liable for. If the Dutch version of the role of the Engineer would be integrated into the UAC-IC, he would be able to improve the three types of safety when he takes over the responsibility for the external control mechanism from the OG under the assumption that this external control mechanism will be performed more effectively. This assumption is valid if the Dutch Engineer would have a comparable liability as in the White Book. Since TNR 2011 would most likely be used in the Dutch construction industry, the liability in TNR 2011 must be increased for Dutch Engineers in order to be comparable to FIDIC’s White Book.

Background: The construction sector has a 10-year time span to become 50% circular and to reduce carbon emissions by 49% compared to 1990. This time span is even shorter for public clients, as the Dutch government functions as launching customer, and strives make its own tenders circular in 2023, and carbon neutral in 2030. Utilising public procurement to reduce carbon emissions and increase circularity is not yet common. This is because individual clients have limited buyer power to influence the market, insufficient knowledge or funds, and a lack of ability to take the lead in promoting wanted changes in procurement. Existing concepts and tools to tackle this issue, still have a limited effect on the implementation of sustainable public procurement.

Therefore, the Dutch government proposed buyer groups as a means to harmonise the market demand of public clients, aimed to tackle the existing problems of sustainable procurement. These pilot buyer groups are a relatively new phenomenon in the public pre-procurement process.

Purpose: This study is aimed to create insight into how (semi-) public clients can successfully establish or join a suitable buyer group, and how they can successfully cooperate and harmonise demand within buyer groups.

Research question: How can (semi-) public clients successfully implement buyer groups in the pre-procurement process of construction projects, to minimise carbon emissions and maximise circularity?

Methodology: A dual-method approach is implemented. Firstly, a literature review is conducted to examine relevant existing knowledge related to buyer groups, focusing on aspects of cooperation, legal relationships and legal restrictions. Secondly, case studies are conducted to capture the experience created by pilot buyer groups, focussed on formation, participants, organisational structure, demand harmonisation processes, impact and legal aspects. These case studies are input for a cross-case analysis, which is subsequently used to formulate best practices for buyer cooperation.

Outcomes: This research facilitates public clients with two main outcomes. Firstly, clients wishing to join or establish a suitable buyer cooperation, are supported by an overview of existing literature on this topic. Many different forms of buyer cooperation exist, each with different purposes, considerations and limitations. An overview of these forms is briefly visualised into a decision tree. Secondly, clients already participating in a buyer group are supported with best-practices from case studies. These best-practices provide findings and recommendations regarding buyer group cooperation and the demand harmonisation process.

Limitations: This research specifically focussing on buyer groups in the pre-procurement process of Dutch (semi-) public clients, that aim to reduce carbon emissions and increase the circularity of construction projects. This research is thus not directly applicable to clients with different context or different characteristics, or to buyer groups in other industries and sectors. Furthermore, this research excludes substantive considerations on actual procurement processes, the content of contracts, theory on circularity or carbon emission reduction, theory on conducting market consultations, the perspective of suppliers and the process of steering innovation.