In 2024, HB developed the structural rehabilitation design for the Val di Riga Bridge, located at km 0+103 of the SS49bis highway in Naz-Sciaves, South Tyrol. Built in the 1970s using reinforced and prestressed concrete, the structure had reached an advanced state of deterioration that led the Autonomous Province of Bolzano to close the bridge to traffic and initiate a major rehabilitation and strengthening program.
The design was based on an extensive diagnostic investigation campaign, which made it possible to identify the critical structural issues and define the most effective strategies to restore the bridge’s safety, reliability, and long-term durability.
The most innovative aspect of the project was the introduction of an external unbonded post-tensioning system, specifically designed to re-establish the original compression state of the cantilever brackets and restore the proper functionality of the Gerber hinges. The strengthening works were complemented by the repair of deteriorated concrete and reinforcement using high-performance fibre-reinforced materials, ensuring enhanced mechanical performance and greater durability over time.
The result is a renewed and safer infrastructure, capable of meeting current operational requirements while significantly extending its service life. The project demonstrates how innovative and sustainable engineering solutions can preserve and enhance existing infrastructure, while fully respecting the original structural concept.
