The Airform is then extracted from the interior of the tunnel and a final finished coat of shotcrete is applied to interior of the tunnel to cover any exposed rebar. These tunnels will cost generally about 30 to 35 percent less than a rectangular tunnel. The Airform tunnel is a very rapid construction process, saving calendar time for the project. A typical tunnel is ten feet wide and eight feet tall and of any length. This is a diagram overlay of a typical 8' square tunnel as compared to a 10' wide by 8' high air-formed tunnel .
Any engineer can verify that the round shape is much stronger than the square.
The tunnel sides are perfect for pipe chases. The Airformed tunnels are faster to construct and save on materials. The tunnel can easily change directions . It can start above ground and dive under a building. These include drop chutes for material above to reach the tunnel conveyors.