Domes are nothing more than a lot of arches rotated about a center axis. Arches are designed to remain in compression pushing the loads down the arch into the arch supports.  The arch delivers a downward force and an outward force. The outward force must be contained by the rigidity of the supports. The arch remains as long as the supporting structure does not push out. In our structure we have both a rigid support contained by the earth but also a tension ring placed at the base of the dome (arch)

Wet mix concrete is pumped to a nozzle where compressed air propels the concrete at velocity . The concrete contains little water and has silica fume to create a non sag material that hangs on the vertical surfaces. For more information on shotcrete visit american shotcrete association www.shotcrete.org

Two methods were used to get concrete into the pump. First method shown is from ready mix truck

The second method of concrete preparation is the hand mix method. Try to avoid this method. Takes a lot of back breaking labor to get this done.

2" concrete hose attached to air nozzle propels the concrete quickly to the surface. 9 cubic yards can be placed in one hour. The shell thickness varies from 6" on the sides to 4" on the topside

Hand mixing of concrete slowed down the dome placement. If you can use ready mix concrete the placement can be completed in one day. A total of 30 cubic yards of concrete was used in the dome construction

Down side of hand mixing of concrete may allow foreign objects to mix . This golf ball was mixed and pumped to the nozzle where it glogged the line and shut down the operation. Note the safety glasses used during placement of concrete

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