The Netherlands faces a significant challenge in addressing the vast renewal and renovation needs of its aging infrastructure. The portfolio approach offers a methodology to manage this task. By viewing projects as part of a larger portfolio rather than as isolated entities, this approach could improve efficiency and ensure the long-term reliability of infrastructure. This research investigates how the portfolio approach can support the Dutch infrastructure renewal and renovation agenda, focusing on its practical implementation and impact on project execution and outcomes. The research begins with a literature review to identify principles of the portfolio approach, such as collaboration, adaptability, and strategic alignment. These principles form the basis of a case study involving two related bridge projects managed within one portfolio. Interviews with the client and contractor provide an exploration of the practical implementation of the portfolio approach. The case study focuses on five key principles derived from academic and grey literature: improved decision-making through feedback, communication and knowledge sharing, stakeholder involvement, adaptability to dynamic environments, and portfolio-level benefit optimization. These principles guide the analysis, highlighting how actions such as feedback mechanisms and collaborative planning can enhance project execution and stakeholder alignment. The findings result in a simplified framework of actions and effects, showcasing the potential for infrastructure renewal in the Netherlands. The study shows that the portfolio approach could help address the Netherlands' infrastructure renewal and renovation challenge. By fostering collaboration and strategic alignment between clients and contractors, it has the potential to address renewal and renovation issues. However, the research also highlights challenges related to open-book collaboration, particularly in areas such as pricing transparency and allocation of manpower. These challenges can lead to tensions between the public commissioner and the contractor, especially when mechanisms for trust and accountability are poorly established. Addressing these issues requires tailored strategies that balance openness with fairness and efficiency. The research emphasizes the importance of adapting portfolio strategies to the unique dynamics while leveraging the portfolio approach to achieve national infrastructure goals effectively