Public entities face the challenge of improving the way infrastructure assets are managed. Recent legislative changes emphasize digitalization as the key to addressing this issue. In this context Digital Twin (DT) has emerged as a promising technology allowing for monitoring, analysis, and prediction of performance and maintenance needs. This thesis aims to test, through an actual case study (retaining wall on a category C road), a 5-layer system architecture for developing the Digital Twin, using as base the BIM model required by the current Italian regulation. The BIM model was developed following the guidelines provided by the contracting authority, and it was evolved into a DT following the 5-layer system architecture.