Concreting the deck

As part of the project to build the new railway tunnel between Twann and Ligerz, INGPHI was commissioned by the IBD Consortium (Implenia – Bernasconi – DeLuca) to design and build the temporary bridge. This structure allows the N5 entry and exit slip roads to be temporarily diverted and maintained while the tunnel is being built.

The temporary bridge comprises two spans, 18.50 m and 13.20 m long, with a complex geometry featuring a variable longitudinal and transverse slope linked to the road alignment, and a significant skew. The piers and abutments consist of concrete shells founded on 800mm-diameter bored piles. The deck is simply made up of metal sections on which formwork plates are placed to accommodate the variable-thickness running slab. The surface of the slab is simply ribbed with brushes, increasing surface roughness and guaranteeing good skid resistance without the need for a bituminous coating.

The structure will be commissioned at the end of 2024.