05-02-2016, 06:07 AM
They didn't - the pillars are off to the side and used to retain the earth on the sides. The walls were a separate dig/pour that occurred after the dome went up (ie; we didn't see it).
Constructing the bridge like this means the earth now being excavated did all the work of supporting the mass of the wet concrete, as opposed to having to build a massive support scaffold like you sometimes see with highway overpass construction. The support was already there - may as well use it.
Constructing the bridge like this means the earth now being excavated did all the work of supporting the mass of the wet concrete, as opposed to having to build a massive support scaffold like you sometimes see with highway overpass construction. The support was already there - may as well use it.