Interface management (IM) is an emerging construction management practice that is mainly concerned with the integration effort of (mega)projects through the management of project interfaces. Even though a plethora of benefits is attributed to IM, a clear overview of how to effectively manage interfaces is non-existent. Without a general understanding on what IM entails, false expectations about its use are created. At the same time, IM developments from academic research are facing obstacles in their adoption in practice, for practitioners are often not represented in these developments.

The absence of situated knowledge (i.e. knowledge found and created in practice) in IM development is problematic, for a profession, or professionalism in general, builds on a body of knowledge comprised of integrated knowledge from theory and practice. For this reason, this research has attempted to take a step in the professionalisation of IM by converging the knowledge from theory and practice. That is, enriching the professional content by creating uniformity on the concept of IM and its key principles. The following research question underpinned this effort: What step can be taken in the professionalisation of IM, based on the perspectives from theory and practice?

For this, the theoretical perspectives on IM and its professionalisation were studied first, by means of a literature review. Then, practitioner perspectives were studied on the same topics through semi-structured interviews with twelve practitioners involved in the different domains of integral project management. These practitioners were all employed by a large Dutch engineering and consultancy firm. The gathered data was then subject to thematic analysis.

A comparison of the findings revealed a similar dichotomy in IM in both theory and practice: a distinction between the technical and organisational aspect. As the results showed possibilities for professionalisation from both sides, it was argued that professionalisation should ultimately happen on both fronts.

To create a basis for professionalism, an appropriate means to integrate the theoretical and situated knowledge needed to be found. To this end, literature on the professionalisation of related construction management disciplines was consulted. Inspired by the professionalisation of risk management, a set of key principles was deemed an appropriate medium to integrate the theoretical and situated knowledge of IM. Hence, a rough guide to IM has been created containing key principles. These principles have been validated by two IM experts in separate validation interviews.

Concluding, the development of a set of key principles of IM is the answer to the research question, which in itself provides a step towards professionalisation. Uniformity on the topic has now been created by the convergence of knowledge from theory and practice. The principles thereby lay a foundation for (professionalism in) conducting IM, while leaving room for customisation at the same time. Practitioners from the different roles of integrated project management are recommended to use the principles at the start of (infrastructure) construction projects to create an understanding of interfaces and IM in general. It is believed that in this way the established uniformity on paper can be translated to practice.

The construction industry has been, throughout time, heavily hindered by cost overruns and delays in the delivery of projects. This picture has only been magnified by the increased size, complexity, and urgent demand for their delivery. Responding to this circumstance has taken different paths. One of these has been updating and improving how the relevant parties of a project interact to achieve the intended results. This way, alternative delivery methods have emerged with different adaptations depending on the country's legislation and policies. A general acceptance has been gained over those systems where the parties interact more closely to reach a final product. This moves away from the classical division between Client and Contractor. Usually, the first takes a controlling role, while the second proceeds on the elaboration of the documents and works. The alternative approach requires from the participants a high component of collaboration. As a scheme where the Contractor is involved from an early stage of the project, the Dutch construction industry has used for a long time the Bouwteam agreement. However, the original drafted model lags from the updates implemented into the country's legal framework. This situation resulted in two independent organizations releasing their interpretation of this concept. The developed agreements give a good perspective on the activities to be done by the different parties during its implementation. However, these do not provide a clear insight into the Allocation and Control of the risks among the participants. Intending to incorporate the missing aspects of the Risk Management process within this collaborative setting, a model was developed to help identify hot spot areas of Risk when Bouwteams are used as a Project Delivery Method. The research also proposes a set of control strategies to help effectively tackle these. A multimethod approach was implemented, with different techniques following the same epistemological perspective. First, a Literature Review was used to build on the concepts relative to Project Delivery Methods and Risk Management methodologies. An empirical study with the analysis of four infrastructure projects in The Netherlands was carried out. During this second phase, the documentation of the projects was examined, and interviews with the project participants were held to investigate the risk management process when using this agreement. The result was a preliminary model consisting of three elements linked to the steps of the Risk Management Process; a set of Risks for the Bouwteam clustered in Risk Groups; a diagram to help assist in the allocation decision; and Control Strategies for these risks. The model was validated through an expert review, and insights into its possible implementation were discussed. The research concludes with a final model and a roadmap for its implementation. Procedural aspects and a set of contractual provisions are needed to incorporate the allocation and control of risks before and throughout the design phase. The elements presented in this research could work as the blueprint to include these within the Bouwteam setting.