Underpass, Mestre Venice

Roofing of the monolith of the railway line near the A4 Dolo/Mirano tollhouse, and Vetrego flyover to access the motorway bypass.

For the works near the A4 Dolo/Mirano tollhouse, the customer required constructing a railway underpass in short times without interrupting train traffic.

Tecnostrutture made a precast underpass on site, which then pushed underneath the railway underpass in order to avoid disrupting the public transport service. It is the largest monolith single-tunnel built in Italy, with a width of 23 m and length of 65 m. The upper slab of the monolith was made using joined mixed steel-concrete truss beams, 1.5m high. It took 15 days of pushing to complete operations to set up the monolith, which reached a top speed of 4.5 m/day. The mixed steel-concrete self-supporting technology allowed roof slab construction times to be shortened without having to wait for concrete to cure before stripping, and to make the underpass immediately open to transit dispensing with the hindrance of temporary shoring.