Solidity and security, in every phase.

Works: Natural Tunnel

Location: Bardellini, Imperia

Project features: the natural tunnel was part of the works for doubling the S. Lorenzo al Mare - Andorae railway line. The tunnel profile has a radius of 4.3 m. ALPI supplied a mobile structure with an overall length of 12 m. To guarantee the flow of traffic to and from the worksite the structure had a central portal measuring 3 m x 5 m.. It was mounted directly on site assembling Omega beams, plywood and subsequently the MECCANO framework, then positioned by crane on the tracks in an arranged area. The formwork was pulled into the tunnel using hydraulic Tirfor winches, and then raised into position. The tunnel invert was done earlier using the MIDIPLUS ROUND frame system. Having closed the stop-ends, the tunnel segments were cast in a single phase. With a total of five alternate phases, the natural tunnel was completed and the work was terminated with the cut and cover portal. As expected, ALPI assured the solidity of the formwork and managed the structural joints by jumping the casts and making them alternately along the tunnel length. All the worksite phases involved ALPI assistance, from pre-assembly to moving the structure, with the company responsible only for its removal on completion of the works. The utmost attention was paid to the issue of safety: the walkways were built to make the company's work easier, providing access for positioning of the pump pipe and the vibrators and to the inspection windows.