Project delivery in the German construction industry is strongly shaped by phase-oriented structures. Although the HOAI is not a project management method, its service phases are often used in practice to structure planning tasks, approvals, responsibilities and handovers. This provides orientation and transparency, especially in projects with clear requirements and stable conditions. However, many construction projects do not follow a strict linear process. Infrastructure projects, public projects, renovation works and technically complex buildings are often characterized by uncertainty, interface prob-lems, late changes and parallel coordination. This thesis examines which requirements and opportunities flexible, agile and holistic project approaches offer in construction and how they can complement a HOAI-oriented project structure. Agile approaches are not understood as a replacement for the HOAI, but as additional elements that can improve communication, feedback, coordination and change management. The study combines a literature review with nine semi-structured expert interviews from different areas of construction practice, including client organizations, project manage-ment, architecture, specialist planning, renovation and infrastructure projects. The inter-views were analyzed using qualitative content analysis. The results show that the HOAI service phases are still regarded as an important struc-tural framework. Their limits become visible when phases are applied too rigidly. Infor-mation losses, incomplete handovers, unclear decisions and late changes often occur at the interfaces between clients, planners, authorities, contractors and project manage-ment. Flexible elements such as regular coordination meetings, workshops, shorter deci-sion cycles, digital task boards, BIM-based collaboration and early involvement of key participants can help to identify open issues earlier and improve coordination. The thesis concludes that future-oriented construction project delivery requires a hybrid approach: the HOAI service phases remain a useful basic structure, but they should be complemented by flexible, iterative and collaborative elements where uncertainty, change and interfaces are particularly significant.      «

Project delivery in the German construction industry is strongly shaped by phase-oriented structures. Although the HOAI is not a project management method, its service phases are often used in practice to structure planning tasks, approvals, responsibilities and handovers. This provides orientation and transparency, especially in projects with clear requirements and stable conditions. However, many construction projects do not follow a strict linear process. Infrastructure projects, public proje...     »