Precast

The bridge used precast concrete girders.

The new culvert, 200 ft. long, was constructed with precast reinforced concrete segments, similar to those used in building the London tube railway tunnels, and is being lined internally with reinforced concrete placed in situ to give a finished internal diameter of 9 ft.

Except that in their case, the logs are made from precast concrete shaped and painted to look like the real thing.

Each TBM installs two-metre-wide rings made up of seven precast concrete segments produced on-site. Each ring takes approximately 45 minutes to one hour to install.