The monolithic dome starts with a concrete ring foundation, reinforced with steel rebar. Vertical steel bars are embedded in the ring and later attached to the steel reinforcing of the dome itself. Small domes may use an integratal floor/ring foundation. Otherwise, the floor is poured after completion of the dome.
The airform is attached to the foundation with a steel strap that is bolted to the ring beam or slab. It is inflated with special fans to the shape of the completed dome. Polyurethane foam is applied to the interior surface of the airform. Entrance into the air-structure is made through a double door airlock which keeps the air-pressure inside at a constant level. Approximately three inches of foam is applied. The foam is also the base for attaching the steel reinforcing to the dome.
Steel reinforcing is attached to the foam using a specially engineered layout of hoop (horizontal) and vertical steel rebar. Small domes need small diameter bars with wide spacing. Large domes require larger bars with closer spacing. The very large domes might require two or three layers of steel reinforcing and concrete. We can build the domes anywhere from 10 to 1,000 feet in diameter.
Shotcrete is a special high-strength spray mix of concrete. It is sprayed onto the interior surface of the dome. The steel rebar is embedded in the concrete and when about three inches of shotcrete is applied, the monolithic dome is finished. Large domes will require considerably more depth of steel and concrete. The blower fans are shut off after the concrete is set.
The Completed Structure
At that point, the dome is finished, and the inside is partitioned as needed. The dome is completely self-supporting. There are no posts or beams. It can be left open, or partitioned.
For more information please contact Maurice Dubois