Bridges, overpasses and underpasses
Produits préfabriqués en béton

Closed-frame underpasses (PICF) are rectangular reinforced-concrete frames combined with retaining walls to hold back the earth that forms the embankment of the trackbed being crossed (figure 29 ).

These structures can be built using prefabricated components: monolithic frames, pedestal and cover slab assemblies (figure 31 ) or U-shaped channels and cover slabs. Headwalls can also be prefabricated.