The complexity inherent in large infrastructure projects often results in project delays, cost overruns, and failures. Managing this complexity, particularly in the construction industry, is essential for improving project outcomes. This research aims to contribute to the body of knowledge on project complexity by exploring the interdependencies between elements of complexity in infrastructure projects. Using a case study of the Zuidas-Tunnels project in the Netherlands, this study applies a hybrid fuzzy method to identify the most significant elements contributing to project complexity and analyze their interdependencies.

A literature review and exploratory interviews were conducted to assess existing complexity management strategies. The research utilizes the TOE (Technical, Organizational, Environmental) framework to categorize 47 complexity elements. The Decision Making Trial and Evaluation Laboratory (DEMATEL) and Interpretive Structural Modelling (ISM) methods were applied to model and analyze these interdependencies between these elements.

The results reveal that understanding the relationships between complexity elements is crucial for effective complexity management. This insight can help project managers develop more targeted strategies to mitigate complexity's impact, thus improving the performance of large-scale infrastructure projects. The study concludes by recommending that such methods be integrated into project management practices for dynamic assessment and management of complexity throughout the project lifecycle.

Current societal and construction challenges, combined with limited time and the scarcity of people and resources, require solutions in the construction industry. This research focuses on repetitive tasks and contributes to that. Furthermore, this research is necessary because the literature on repetitive tasks is limited and needs to be supplemented. The research objective was to increase the understanding and knowledge of the design elements aimed at exploiting the potential of repetitive tasks in assignments where public clients and contractors collaborate. Based on the literature review, repetitive tasks and associated potential were defined and a theoretical framework was established. The empirical research consists of studying three cases, the programmes WL, IPS Schoolgebouwen and WOUW, using case documents and eighteen interviews conducted with public clients and contractors. This provided a picture of repetitive tasks in different construction sectors (residential, utility and infrastructure construction) and at different phases of the asset life cycle (new construction, maintenance and renovation). Separate analysis of the three cases, combined with cross case analysis and the established theoretical framework, then formed the basis for the "Innovative approach to repetitive tasks" framework. Through an "innovative approach to repetitive tasks", consisting of a cross-project inventory of repetitive tasks and the application of the design elements and advices proposed in the “Innovative approach to repetitive tasks” framework, the forces of the public client and the contractors are combined and the potential of repetitive tasks is unlocked.

With the expansion of infrastructure projects in the Netherlands in terms of size and complexity, government bodies are increasingly inclined towards adopting a programmatic approach for managing multiple projects. This approach incorporates innovations to enhance efficiency and effectiveness in achieving program objectives. However, the development and implementation of innovations within these infrastructure programmes encounter various challenges, leading to not optimum utilization of innovations. One significant challenge stem from the limited practical experience in utilizing the programmatic approach, resulting in a limited understanding of both the programme's context and innovation process in multi-projects. Consequently, innovations tend to be developed and implemented using a project-based approach, which poses issues. Project-based approaches are inherently rigid and time-bound, while innovations necessitate time and flexibility. Furthermore, the discontinuous nature of projects impedes the effective utilization of the progressive learning curve essential for innovation development. This project-based approach creates an ongoing dilemma for suppliers, who face high risks and a lack of incentives to innovate, despite their pivotal role.

To bridge the gap between understanding and implementing innovations within infrastructure programme, this research aims to address the issue of ineffective innovation utilization in multi-project settings based on suppliers’ perspective. The research approach involves conducting three case studies where innovations are developed and implemented in multi-projects as part of infrastructure programmes. 11 suppliers, including engineering companies and contractors, were interviewed to identify the elements of innovation in multi-projects, including barriers and enablers.

The study reveals seven specific barriers and five enablers related to innovation in multi-projects within infrastructure programs. Notably, it highlights the previously overlooked challenges related to time in innovation, arising from prolonged processes and programme durations. The primary innovation challenge in multi-projects revolves around technical challenge, tied to iterative processes and uncertainty management, irrespective of the type of innovation. These challenges, inherent to innovation, emphasize the need to strike a balance where time supports rather than impedes innovation. The study also confirms known barriers and enablers from project literature. With the choice of a suitable contract form, such as framework or alliance contracts, emerges as a significant enabler. However, contracts can become barriers when they lack risk-sharing mechanisms and still promoting competition, hindering knowledge exchange with external parties. Client-related barriers include the client’s organization size/structure and clients’ inflexible demands. Additionally, the study identifies drivers, inputs, preconditions, outputs, and outcomes of innovations in multi-projects. Preconditions unique to multi-projects include strong organizational leadership, vision, commitment to innovations, financial capabilities, and the selection of an appropriate contract form. Beyond the typical inputs, suppliers stress the importance of certainty regarding the volume of work or the number of projects within multi-projects.

Based on research findings, a solutions framework was developed to facilitate the implementation of innovations in multi-projects. It consists of practical action plans and innovation boundaries designed to address barriers to innovation in multi-projects. Suppliers and public client organizations are recommended to use the Innov-Infra framework during project/program initiation (Part I) and project/program implementation (Part II), led by a designated person within the organization involved in multi-project innovations. Future research should explore public clients' perspectives in similar research across various programme types and sectors, employing qualitative research methods to delve deeper into procurement for innovations and the bundling of supply and demand in contracts.

In traditional models of project delivery, stakeholders have clear assignments of risks, responsibilities, and liabilities. However, in today's large and complex infrastructure projects, these allocations are often uncertain and difficult to determine at the project's outset. Consequently, many of these large projects experience inefficiencies, such as exceeding time or budget. Thus, it is necessary to shift away from a 'predict and control' project delivery approach and adopt a 'prepare and commit' approach instead. Alternative project delivery methods subsequently require other contractor selection tools. This study examines the selection tool of team assessments to evaluate the collaborative potential of project teams during the tendering phase. A team assessment is a tool in which predefined collaboration competencies are assessed by independent assessors using one or more fictitious cases. Prior to constructing the cases the client and assessors identify critical moments that may arise during project execution and integrate these unforeseen moments in the cases. The client should possess a comprehensive understanding of the preconditions and limitations associated with team assessments and identify the project's characteristics and goals. Only then, a proper decision can be made on if a team assessment should be used and how the assessment should be designed and implemented. The crux is that all these considerations should be underpinned and aligned by appropriate substantiation and expert guidance. This thesis provides a framework including preconditions, restrictions, and process steps for the implementation of team assessments. Recommendations for clients, contractors, and assessors involve adequately preparing the assessment, using tailer-made competencies, developing a scoring system in which proper differentiation can be achieved, allocating a sufficient amount of time using a start-up phase to establish collaboration and streamline processes effectively, using lessons learned from the assessment in the design phase, creating consistency by having an assessor as a team coach in the design phase who reinforces the initiated collaboration, properly dealing with team member changes, maintaining a concerted emphasis on collaboration by transparently addressing it, fostering an environment of psychological safety in which mutual expectations and requirements are shared.

The existing high level of greenhouse emissions and raw material consumption are the current concerns in the infrastructure sector. On the other hand, the programs for renovating the aged and overloaded infrastructures are currently under progress as substantial national programs with circularity targets in the Dutch context, involving various public-private networks. Implementing the circularity strategy of re-use in conducting the infrastructure projects will be beneficial to reduce the amount of emissions, minimize the raw material consumption, and facilitate the formulated national programs. Currently, there are just a few re-use projects, and running a higher number of these projects and accelerating the re-use transition in the infrastructure sector are urgent topics in the global and Dutch context. Public client organizations (PCOs) have determining role in this regard, as owners and commissioners of infrastructure projects. There are wider networks of actors and extra stages to follow in re-use projects, which can create barriers and make the organizational aspects of these projects extremely important. Most attempts are locked at the tactical level of PCOs, and a gap has emerged between the tactical and operational levels of these organizations in the implementation of the re-use strategy, which prevents acceleration of the re-use projects. There is less attention in the current studies to the existing gap between the tactical and operational level of PCOS in conducting re-use projects in the infrastructure sector, the required procedures to fill that, and accelerating the re-use transition, which are zoomed in and investigated in this research. The research is conducted through a qualitative method, following three different phases of theoretical study, empirical study, and solution development in the context of a PCO. This research recognized that the existing gap between the two levels is rooted in different fields, and the most urgent ones have been identified. It revealed that tackling such gaps requires following specific organizational procedures by actors within each of the two organizational levels and between them. Following such procedures to deal with the addressed gaps can be easier through using a framework. The required framework, provided in this study for public clients including organizational procedures and their relevant re-use implementation factors embedded in certain categories. Among the existing gaps in practice, three gaps are recognized as the most urgent ones, which are placed in the two top categories of ‘culture, communication and behavior’ and ‘contract, manuals and guidelines’. The top three gaps addressed by three re-use implementation factors of ‘target formulation, follow-up & evaluation’, ‘internal & external communication’, and ‘collaboration with external parties’. The provided organizational procedures are interrelated in implementing the re-use strategy, and the result of implementing some procedures should be followed by the work of actors at the same or another level. The strategic level should also intervene to fill the gaps specifically in formulating and re-visioning the targets. Structuring the communications, collaborations, and target formulation stages through implementing the procedures recommended in the presented framework in this research, and consistency with that, will prepare the organizational context, and link the tactical and operational level of PCOs in implementing the re-use projects. As a result, the re-use activities at the operational level of public client organizations will be more structured. With well-linked tactical and operational level and structured re-use activities, the re-use transition will be facilitated and can be accelerated at the operational level of the public client organizations. To address a circular solution for the national programs of renovating infrastructures, the active networks in them can consider the networks as the national context for re-use transition, and customize the framework to structure the inter-organizational procedures between the involved parties in the tactical and operational transition levels. Through structuring collaborations & communications between tactical and operational parties, developing clear and detailed targets, and evaluating them, the re-use transition can also be accelerated on the national scale.

As the effects of climate change have been negatively impacting the environment, several industries have started to work towards minimizing them. The construction industry is responsible for 40% of the global carbon emissions and many companies are currently working on net-zero and other sustainability goals. As several sustainability practices are implemented in sustainable construction projects, complexity, as well as opportunities, can arise in the front-end phase of projects. The positive impact that complexity can have on projects, as well as the link between complexity and opportunity are overlooked in the literature. The main objective of the study is to fill these two knowledge gaps by developing a framework which illustrates how complexity can generate opportunities. This is achieved by using three main qualitative research methods: literature review, case study analysis, and expert evaluation, in the context of sustainable construction fit-out projects in the private construction sector, with the focus on the front-end phase of projects. The current study shows that complexity in sustainable construction projects is different from general construction projects, due to factors such as the project sustainability scope and goals, sustainability strategies that are implemented, and required team and knowledge. By comparing four projects in the Netherlands, Ireland, and the UK, it is found that the most common elements of complexity in sustainable construction projects are fixed project schedule, project team’s lack of expertise in implementing sustainability, difficulties in implementing sustainable project management, and stakeholders’ lack of understanding of sustainability. The link between complexity and opportunity is illustrated through the connection between complexity and risk, while the way to generate opportunities from complexities is suggested by using management strategies to deal with complexity. The main management strategies found in the study are analysed in terms of the control and interaction allowed in each of them. Some of the strategies are the clear understanding of sustainability requirements, engaging the relevant stakeholders early upfront, and analysing and suggesting different scenarios and methods. Some of the most common opportunities in sustainable construction projects are related to sustainability management, work processes, lifestyle, training and education, costs, and quality. The CMO opportunity-identifying framework is developed, which shows that project members can generate opportunities from complexities in sustainable construction projects by using combinations of management strategies based on control and interaction. A few recommendations for project members in the industry are to be aware of complexity and to actively look for opportunities. Clients are advised to clearly translate sustainability into project requirements and to allow flexibility in the project schedule and budget. Further research can be conducted to test the CMO framework and analyse complexity, opportunities, and management strategies in different types of projects, countries, and by considering other stakeholders.

The construction sector's reliance on raw materials and the generation of waste necessitate a shift from the unsustainable linear economy to a circular economy (CE). Adopting Product-Service System (PSS) business models is crucial for achieving this transition. However, contractor companies in the building sector face barriers to implementing PSS, and there is limited knowledge about PSS in this context. This study aims to understand the state-of-the-art in PSS, assess barriers, and propose potential solutions specifically for contractor companies in the building sector.
A qualitative research method was employed, including a literature review and semi-structured interviews. The literature review encompassed 774 studies, with 45 meeting the inclusion criteria. Semi-structured interviews were conducted with professionals in the building construction sector to supplement the literature findings. This study highlighted that PSS in the building sector has the potential to enhance sustainability and circular economy efforts by promoting economic growth, reducing resource consumption, and minimizing waste.
The practical implementation of PSS in the building sector is hindered by challenges such as technological and supply chain changes, lack of financial support, organizational restructuring, establishing new customer relationships, developing new contracts, and adopting new economic models. Insufficient policies and regulations further impede PSS adoption. Nonetheless, this study highlights that sustainability, circularity, and CO2 reduction can drive the adoption and implementation of PSS.
The research identified 41 barriers to PSS adoption through the literature review and 20 barriers through interviews grouped into ten categories. These barriers encompass customers, supply chain financial, organizational, resource, knowledge, regulation or policy, environmental, social, and technology-related challenges. To overcome these barriers, nine potential solutions were proposed, including effective leadership, separated business units, training existing personnel, hiring additional personnel, cultivating long-term relationships, horizontal and vertical integration, leveraging knowledge and experience from other sectors, and learning by doing.
This study contributes to understanding PSS in the building sector and provides recommendations for practice and further research. By implementing these solutions, contractor companies in the building sector can overcome barriers to PSS adoption and increase their chances of successful implementation. The study offers guidance for efficient resource allocation and prioritization of solutions based on their effectiveness in addressing specific barrier categories. Future studies can explore customers' perspectives, conduct in-depth research on specific barrier categories, and focus on specific building systems or products to investigate potential barriers and solutions.

Construction projects have become increasingly complex, requiring effective management strategies to navigate challenges related to project contexts, interdisciplinary integration, and procurement processes. The Dutch Ministry of Infrastructure and Water Management (Rijkswaterstaat) has introduced the two-phase model to address these complexities. This model emphasizes client-contractor collaboration and differs significantly from traditional project management strategies. Emotional Intelligence (EI), particularly the competence of empathy, has been recognized as a valuable factor in improving collaboration and project performance. Additionally, Early Contractor Involvement (ECI) has gained international recognition as a project delivery model involving the contractor earlier in the project. ECI in the Dutch construction sector corresponds to the two-phase model of which the Bouwteam is a known example. This research aims to explore the role of empathy in improving project performance through client-contractor collaboration in the first phase of the two-phase model and provide a practical framework for practitioners. The research approach consisted of selecting four cases to conduct 16 semi-structured interviews. Qualitative data analysis software is used to research the research variables: empathy, two-phase model, collaboration, and project performance.

The research findings reveal two key relationships: the relationship between client-contractor collaboration and project performance and the relationship between empathy and client-contractor collaboration.

The relationship between client-contractor collaboration and project performance: the study indicates that client-contractor collaboration significantly influences project performance in the first phase of the two-phase model. Collaboration affects the actual performance of quality criteria and the perception of time and cost criteria. Key differences in the collaborative process within the two-phase model are a shift towards process-focused outcomes, shared responsibility between the client and contractor, and flexibility in criteria. Affective trust, communication, and cohesion are identified as crucial factors for successful collaboration. Tools such as Project Start-Up and team-building sessions facilitate collaboration and should be utilized to enhance project performance.

The relationship between empathy and client-contractor collaboration: empathy plays a pivotal role in facilitating understanding at the team member and organizational levels, fostering relationships, and promoting collaboration. It is particularly important in project phases where unfamiliarity between client and contractor exists. Empathy influences factors essential to the collaborative process, such as trust, communication, and cohesion. The research identifies factors that influence the occurrence of empathic behavior, including the work environment, team relationships, communication, and team size. A proactive attitude towards empathy and continuous development of empathic behavior are recommended for project success.

The research findings support the hypotheses that client-contractor collaboration and empathy positively contribute to project performance in the first phase of the two-phase model. A practical framework is proposed, consisting of four strategies, to improve project performance through empathy and collaboration. The framework should be applied collectively by project managers at the start of the first phase and throughout the project. Future research should explore quantitative testing of the hypotheses, validate the framework in practice, and investigate additional relevant competencies...

In the last decade, the Bouwteam concept has become increasingly popular in the construction industry. A Bouwteam agreement is a bilateral agreement between a client and a main contractor, in which the main contractor is involved at an early stage. An advantage of a Bouwteam collaboration is that risks which occur in the construction phase are mitigated in the design phase. In practice, both the client and the main contractor can employ third parties to transfer parts of their design responsibilities. In the recent Bouwteam models, there is the possibility that a substantial part of the design responsibility is passed on to the main contractor and his third parties. These third parties have an increasing influence on the achievement of project goals, which are usually the design quality, design costs, design planning and client satisfaction. Hence, this research is focused on the implementation of contractual incentives for the designing third parties, who are employed by the main contractor in a Bouwteam. The contractual incentives are used to influence the performance of these third parties, in such a way that Bouwteam goals are achieved.

In the past decades, sustainability has become increasingly important for the construction industry, in particular highway infrastructure, as it can generate both positive and negative impacts on the social and physical environment. As a result of the impact on the environment and the growing awareness of environmental protection, the effects on society and economic development, there is a pressing need and sense of urgency for the sector to become more sustainable. For a highway to be truly sustainable it needs to take the social, environmental and economic dimensions of sustainability (People, Planet, Prosperity) into account. Over the past decades, some sustainability assessment (SA) approaches have been developed in an attempt to integrate sustainability in the assessment of infrastructure projects. Despite these attempts, these SA approaches do not address all the dimensions of sustainability thoroughly and are biased to either an environmental or an economic assessment, while the social dimension is taken less into consideration. However, how designers and decision-makers can integrate these dimensions into the assessments of highway design options is less known. This lack of integration of the three dimensions of sustainability makes it impossible to evaluate and assess the sustainability consequences of highway design choices and options and thus represents a significant limitation.

To address the observed problem, the main objective of this research is to not only provide designers and decision-makers with a SA tool that integrates all three dimensions of sustainability, but also with an understanding of how this can be used.

The triple bottom line (TBL) theory coined by John Elkington, a well-known concept in sustainable development (SD) was selected as a sound theory regarding the three interdependent dimensions of sustainability. A total of 64 SA criteria from the construction and infrastructure sector were identified through surveying recent literature, which formed the preliminary list of SA criteria. This was followed by a filtering process on the SA criteria and subsequently a questionnaire survey to establish which are relevant to the Dutch highway context. This resulted in the conceptual SA framework which consists of 36 SA criteria categorised in their corresponding dimensions of sustainability and related 9 themes. Next, the assessment procedure was provided for the conceptual SA framework, to form the proposed SA tool. In this tool, the best-worst method (BWM) is used to determine the weighting factors of the themes depending on the project. The tool was tested by applying it to a reference case (a highway project in the Netherlands). Based on the results from the reference case, the applicability of the tool was evaluated by an expert involved in the project. In the developed SA tool, the three dimensions of sustainability are integrated into one comprehensive framework specific for the Dutch highway context.

The conceptual SA framework provides a systematic overview of all possible aspects of sustainability that can be taken into account during the planning- and design phase of a highway project. In addition, it can help designers and decision-makers understand how the dimensions of sustainability can be used to decrease the negative impacts of highway projects and embrace the principles of sustainability with respect to environmental protection, economic profitability and human well-being, to make their highway designs more sustainable and to contribute towards SD.

The proposed SA tool can assess, compare, evaluate and rank design options based on the SA criteria. The SA criteria assess to what extent a design choice and option contributes to the creation of sustainable added value. In this tool, design options can be explicitly weighed upon all dimensions of sustainability, related themes and corresponding SA criteria which can support the decision-making.

Currently, the infrastructure industry is in transformation and moving towards new project delivery approaches. Aiming to improve the predictability of projects and due to a growing desire for collaboration between clients and contractors, the two-phase model has made its entrance in the industry and has been gaining popularity.
During the first phase of the two-phase model, client and contractor work together on the design. The first phase results in a detailed design including the price for execution. After a successful first phase, client and contractor come to an agreement for the execution phase. The price determination of the execution costs is delayed until after the first phase. The contractor therefore has a better grasp of the project risks and is in a better position to offer a more reliable price. The two-phase model is relatively new on the market and therefore has not yet been standardized. The elements of a two-phase model have not been identified scientifically. This research contributes to making reasoned choices on how the elements of a two-phase model can be operationalized in infrastructure projects in a way that the two-phase model contributes to achieving the project's objectives.
The main research question of this study is: What is the optimal operationalization of elements in designing the first phase of the two-phase model in infrastructure projects?

In recent years, the concept of sustainability has grown in popularity and has become a critical strategic component for businesses (Garza, 2013). Corporate organizations, as the industry's productive drivers, play a crucial role in attaining sustainable development. Thus, the problems have shifted from "WHY" to "HOW" to integrate sustainability into management decisions at all organizational levels (Epstein & Buhovac, 2014). Corporate entities, such as EPC contractors, tend to realize their strategic goals and produce value for their shareholders through projects. However, for sustainability to be evident in all organizational practices, these methods must be well adapted at the operational level. Organizations are increasingly struggling to translate their strategic goals into project-specific activities (Marcelino-Sádaba et al., 2015; Engert & Baumgartner, 2015). In practice, there is a significant gap between strategy formulation and project implementation (Økland, 2015). The problem addressed by this study is the gap between the formulation of strategic level objectives and its implementation at the operational level. According to researchers, integrated ways to putting sustainability into action are inadequate, and there is no systematic approach to effectively incorporating sustainability into projects (Silvius et al., 2012; Sabini et al., 2019; Epstein & Buhovac, 2014). As a result, sustainability goals often remain confined at the strategic level.

The purpose of this research is to provide solutions to the EPC contractor to overcome the barriers to enhance the integration of sustainability in projects and bridge the implementation gap. The results will provide a structured approach in connecting high-level sustainability objectives to more concrete and tangible solutions for the project. This research is an attempt to respond to the lack of empirical studies on the implementation of organizational sustainability strategies and helps reveals how organizations can move towards translating strategy into action and overcome the barriers to sustainability implementation.

To achieve this objective, the research is divided into three main phases. In phase one, literature review and document review was conducted. Through literature review five elements essential for implementing sustainability strategies were identified i.e., organizational decision-making, lifecycle thinking, balancing the triple bottom line, stakeholder engagement, and proactive approach. Through document review the gap between strategic and operational level was highlighted. In the second phase, semi-structured interviews were conducted with people in the top management and project managers to identify the barriers to sustainability implementation resulting in the gap between strategic and operational level. In total 20 barriers were identified. The interviews also included understanding the application of elements identified from literature review in practice. The third and the final phase, synthesised all the findings from phase one and two, and proposed solution to the EPC company to integrate sustainability in projects. This was done by providing mitigating actions to overcome the identified barriers and proposing a framework to translate strategy into action, thus bridging the implementation gap. Using the suggested framework to make the strategy explicit has the following benefits: it encourages communication and strategy execution, allows for strategy discussion within the organization, and tracks progress toward long-term goals to determine whether the strategy is clear or needs improvement.

Programmes in the Dutch infrastructure sector can contribute to overcoming the industry’s lagging performance and the increasing amount of renovation of work it is currently facing. Additionally, they have the potential to integrate the fragmented supply chain while facilitating better coordination of the projects being executed more effectively and efficiently. However, they also introduce chaos to the collaboration that can be detrimental effect on the programme’s outcome. Although there is extensive literature on inter-organizational collaboration in projects, little attention has been paid to the programme context. It is still unknown how governance should be organized to facilitate inter-organisational collaboration in programmes Therefore, this study responds to the call for research. Two Dutch infrastructure programmes were studied to understand the governance approach used and how it facilitated inter-organizational collaboration. The results from the case studies showed that inter-organizational collaboration in the early phases of infrastructure programmes is facilitated by an interplay of relational and contractual mechanisms corresponding to the six dimensions of governance: goal-setting, capability building, rewarding, roles & decision-making, coordination and monitoring. This governance mechanisms are established by the programme level and the contracting authorities’. They intend to provide a framework for organizational processes, decision-making, and coordination in the programme, while integrating the different levels of the programme. Additionally, this research provides a model that aims to provide a structural way to organize future programme governance while allowing public clients to analyze their choices better

Sustainability is seen as one of the most important challenges faced by the world today (Silvius, 2017). Within EPC companies, there are quite some ambitions at the strategic level to integrate sustainability into project procurement, but implementation at the project level is still quite limited. Additionally, existing literature focusing on sustainable procurement or sustainability within supply chains (i.e., suppliers/(sub-)contractors), in the domain of EPC companies in the oil, gas and petrochemical industry is also quite limited. This research study thus aims to develop a strategy on how EPC companies in the Energy & Chemicals (E&C)/Process industry can integrate sustainability into their project procurement practices, thereby adding to academic literature and practice. To achieve this objective, this research study was conducted in three main phases. In phase one, a thorough literature and document review was conducted, resulting in a conceptual sustainability framework that could be integrated into an EPC company’s project procurement practices such as prequalification and supplier/(sub-)contractor selection. The sustainability framework consisted of a set of sustainability criteria and performance indicators which can be used to assess the sustainability level of an EPC company’s suppliers/(sub-)contractors. In the second phase, semi structured interviews were conducted to understand views from practice regarding the topic of sustainable procurement. Main insights gathered included understanding the enablers and barriers encountered by EPC companies during implementation of sustainability into procurement, the prioritization of the identified performance indicators, incentives to stimulate sustainable procurement and suggestions for improvement. The third and final phase synthesized all the findings gathered so far, to propose a strategy or solution for EPC companies to integrate sustainability into their project procurement practices. This research study concluded by providing a holistic set of recommendations to all actors involved in executing a project, such as clients, EPC companies and supply chain actors on how sustainability can be effectively and efficiently integrated into project procurement practices.

The COVID-19 pandemic has affected the construction industry in the Netherlands as projects came to a stop and project teams struggled to collaborate remotely. To cope with the effects of the COVID-19 pandemic and consequential virtual work environment, it is crucial to have effectively collaborating design teams. A renown contributor to team success in design teams is trust. Trust contributes to project success as it aligns the interest of stakeholders, increases the willingness to share information and improves team performance. In previous research it found that prior ties, or interactions in previous working relations could result in an improved level of trust in the design team. Moreover, expectations of future collaboration, or future ties, also improve the levels of trust in teams. These ties could therefore be used to increase the levels of trust and subsequently result in more efficient team processes. In addition, as the design team members were subjected to the restrictions related to the pandemic, it is important to investigate how this virtual work environment affects trust development. This research aims to fill this research gap and utilize its results in order to enable design team members to improve the levels of trust in their teams while coping with the effects of the change to a virtual work environment. By performing the research based on a literature review and a survey analysis, it is concluded that ties are an important factor in the development of trust. By utilizing the individual aspects of these ties, design team members can improve the levels of trust. It is suggested that prior ties are more important for trust development than future ties. However, it should be mentioned that prior ties are no silver bullet. Prior experiences may induce unmet pre-existing expectations and laxity. In addition, the potential non-beneficial effects of virtual meetings on trust in the design team should be considered. To deal with these effects it is advised to organize social and face-to-face meetings as these improve interpersonal connections. The research results indicate that this knowledge is not yet common and should therefore be emphasised. Lastly, it has to be mentioned that when considering this conclusion, it is important to recognize that certain limitations are present. Especially the considerable small sample size of the survey, which resulted in many other limitations like an unequal representation in personal and organizational roles, should be considered.

Already back in 1970s, the Club of Rome concluded that the world would become unliveable for future generations, if population growth and industrialization keep up the same speed (Silvius, Schipper, & Planko, 2012). Despite this, today’s industrialization can not only be observed on land, but also increasingly in the marine environment. The “industrialization of the ocean” accelerates as sectors like offshore wind, deep water oil and gas as well as seabed mining emerge (Kronfeld-Goharani, 2018; OECD, 2016, p. 18). Therefore, more sustainable practices are needed (GPM, 2015; Hahn, Pinkse, Preuss, & Figge, 2015; Ugwu & Haupt, 2007) and the dredging industry is transforming. Next to minimizing impact, the value adding function of marine infrastructure is increasingly recognized. As the ‘productive driver[s]’ of the industry, corporate organizations, like contractors, pertain a key role to achieve such sustainable development (Hahn, Pinkse, Preuss, & Figge, 2015). Moreover, their innovative power provides the opportunity to bring about change in the industry and to leverage long-lasting competitive advantage (Kramer & Porter, 2011; Zhang, Oo, & Lim, 2018). Accordingly, to distinguish themselves during tendering and to thrive for profit maximization, conducting sustainable business becomes more and more important for contractors (R. Peenstra & Silvius, 2017, Tan et al., 2015). Responsible operations are no longer up for discussion, but are becoming central to value creation (Epstein, 2018). This results in corporate sustainability strategies (Peenstra & Silvius, 2017). The problem addressed by this study is the gap between strategy making and integration of sustainability on project level for contracting organizations. At present integrated approaches for sustainability implementation into practice are lacking (Epstein, 2018) and there is no systemic approach, how sustainability can be successfully integrated into projects (Sabini et al., 2019). Although most papers, studying sustainability in projects, provide managerial implications, their highly contextual conclusions can hardly be applied to other projects (Sabini et al., 2019). Therefore, sustainability integration remains fragmented and strongly correlates with the assigned project manager in charge of the project (van Walt Meijer, 2018; Wolfgang, 2017). Based on case study research, the study provides a success factor model entailing seven critical factors for success for pro-actively integrating sustainability into projects of marine contractors. For Science, this study unravels critical strains in managerial decision-making for sustainability on project level, which thus contributes to the scientific discussion thereof. For practice, the findings have the potential to go beyond highly contextual implications, though being derived from marine infrastructure context. This is because the seven critical success factors may provide guidance to other contracting organizations regarding the variables to consider to implement sustainability strategies on operational level. For science and practice, the conceptual C7 implementation approach tackles the need of an integrated systemic approach, which was claimed to be missing. It helps contractors to apply the (sub) success factors of the model in practice. The development areas (not, -or inconsistently fulfilled factors) can be derived and subsequently actions can be taken to close the gaps.

This study explores towards the positive side of project uncertainties i.e., opportunity. Opportunities occuring in such projects has the potential to enhance the project’s initial objective and could add more value to the project. However, due to lack of an effective approach for opportunity identification and several constraints prevailing in such large projects, opportunities are not being identified properly. This study investigates the concept of opportunity in infrastructure projects and crucial factors that could stimulate opportunity identification in such projects along with constraint’s study that hinders such identification process. Here, a roadmap is developed for opportunity identification consisting of a procedure for identifying opportunity during tender phase with an assessment model that could help in identifying value-creating opportunities for the project. This identified opportunities could be then used by the project team to exploit benefit for the contractor involved in execution but also to the client for whom the project will be delivered.

Today’s project complexity is constantly increasing leading to multidisciplinary project teams. Building a truly integrated team in projects where a partnership is necessary in order to achieve the desired outcome isn’t a one-off process that can occur automatically. It’s a procedure that has to be built up over a certain period of time (mostly during the front-end development phase) under a collaboration that will utilize in the best way the benefits of this one-team approach. In international projects cultural differences between the different teams is an important aspect that adds an additional challenge in reaching a successful outcome. It is therefore the project manager’s responsibility to create a team of engaged and committed people that have an aligned project goal and act as a whole and not as a set of wholes. Getting from cooperation to collaboration requires the presence of both a strong project leader and a competent project team.

Cooperation figured prominently in the Dutch construction industry’s agenda over the past years. In 2016, major clients, sector organizations and the relevant market parties officially committed to promote a culture based on good cooperation and healthy relationships by signing the "Market Vision" (De Marktvisie, 2016). This document illustrates the objectives, principles and necessary changes to achieve this ambition in 2020. However, according to the report of Rijkswaterstaat (2019), there have not been structural changes in cooperation within the supply chain where fighting relationships, self-interest and opportunistic behaviours still prevail. The unattractive risk-return profile, i.e. the ratio between the expected return and the amount of risk undertaken by contractors, of large projects in the civil engineering sector is considered to be a barrier that prevent this change. The current approach to risk management is one factor that contribute to decrease the risk-return ratio. According to the report of Rijkswaterstaat (2019), market parties have the impression that risks are not always allocated to the "natural owner". The natural owner is the party that has the knowledge, ability and financial capacity to manage a certain risk. Market parties have more or less consciously accepted risks under competitive pressure although Rijkswaterstaat argue that during the tendering process of large complex projects some risks are taken back based on the contractors’ argumentation. However, construction companies point out that the dialogue focus on limiting risks on the client’s side and they are not yet sufficiently stimulated to discuss their own risks. This research proposes risk sharing to fills the gaps of the current approach with the purpose of stimulating the development of cooperation. The scope of the research is limited to Dutch infrastructure projects procured by public authorities through Public-Private Partnership. The research objective is to provide partner organizations with a framework to share risk at the project level in order to foster commitment and cooperation for the long duration of the partnership. The first step to achieve the research objective is to investigate current risk sharing from a theoretical and practical perspective. This is achieved through literature review, exploratory interviews with employees of WitteveenBos and document review. The results of these activities are compared with the elements mentioned in the literature to stimulate cooperation. Afterward, a conceptual model is elaborated based on the
results of literature review and exploratory interviews. The purpose of the proposed conceptual model is to illustrate contractual and relational elements that can be added to the current risk sharing in order to promote cooperation. Then, the proposed risk sharing mechanisms that constitute the conceptual model are discussed with practitioners. This activity aims to refine the proposed risk sharing mechanisms in order to obtain detailed measures that form the risk sharing framework. Finally, the proposed framework is validated with experts in order to assess whether it meets the economic and functional requirements of its intended users and fits within the restrictions imposed by the current practice. The risk sharing mechanisms applied in the construction sector mentioned in the literature refer to financial incentives such as government guarantees, target cost contracts, etc. However, the literature study suggests that the attitude and willingness of partners to engage in cooperative behaviours is stimulated more by trust and relational norms than formal enforceable rules. Therefore, it can be argued that risk sharing requires additional elements in order to promote cooperation. The proposed risk sharing framework requires certain personal attitudes of team members in order to be effective in promoting cooperation. According to practitioners, partners should: • seek the participation of all team(s)members, internal and external; • take the initiative to help rather than being passive; • show behaviours oriented toward the achievement of common goals and mutual benefits; • be open and receptive to new ideas, different perspectives, external influence; Furthermore, an essential attitude is to accept and embrace the idea that risk ownership does not exclude the chance of managing a risk together. The legal boundary of having one risk owner should not prevent partners from being forthcoming and providing support to control risks. Based on the results of the discussion with practitioners, the proposed risk sharing framework is effective in stimulating cooperation only if partners coordinate with each other and commit to implement these measures together.

Sustainability is becoming an increasingly important aspect of the infrastructure industry, however, incorporating it has proven to be troublesome. As such, this thesis focussed on identifying success factors that influence the implementation process of sustainability from idea up to and including the tendering phase for public infrastructure projects.