Incremental Launching

The incremental launching method involves constructing the bridge deck in successive segments, typically between 15 and 25 metres in length. These segments are cast in situ behind one of the abutments, in a secure and accessible area. Each new segment is built behind the previous one, and after the concrete has cured and the structure has been integrated, the deck is pushed forward incrementally using hydraulic jacks. To facilitate the launching process and to reduce negative bending moments over the supports, a launching nose — a lightweight steel structure — is attached to the front of the deck. This method is ideally suited to bridges with regular spans and straight or gently curved geometries. It is particularly appropriate for spans ranging from 30 to 60 metres per support, and is commonly used in bridges with a total length greater than 200 metres. It is typically applied in areas with difficult access, such as deep valleys, or when crossing railways or motorways.