Project management is essential for competitive companies in the market, providing a structured approach to effectively achieve organizational objectives. This technical article examines the importance of organizational structures, focusing on the projectized structure, in complex and large-scale projects. The case study involves a multinational company in the electricity sector that faced significant challenges after winning an auction to build two 230kV transmission lines in Santa Catarina. The adoption of a projectized organizational structure was analyzed through an action research approach, which included detailed assessment, critical analysis, intervention, and monitoring of results. The restructuring allowed exclusive focus on the project, facilitating efficient resource allocation, effective communication, and agile decision-making, resulting in the successful completion of the project within adjusted deadlines. The findings demonstrate that for time-sensitive infrastructure projects with strict contractual penalties, projectized structures provide valuable advantages in terms of authority, coordination, and dedicated focus, despite potential challenges related to resource duplication and knowledge transfer. This study contributes to understanding how organizational structure choices impact project outcomes in complex environments and offers practical insights for organizations facing similar challenges in large-scale infrastructure development.