arches, vaults, domes -- designing and planning

[Tomas Lipps <tmlipps@xxxxxxxxxxxxx>]

re planning arches: given the diameter of the semi-circular arch you can, with
a wire or chain attached to the center point, lay out the arch on the floor
and make templates for each stone (cardboard works just fine). or it can be
done as you build. as you place each stone on the shuttering or formwork,
stretch a string line from the center point, mark that line on the stone, then
take the stone down and remove the excess material.  thus all joints radiate
 from the center.

a vault can be said to be an arch extended along a horizontal axis; the form
is complicated, however, by the bonding required to integrate these arches. A
dome can be said to be an arch rotated around a vertical axis... and it could
be built like that, I guess.  I've never built a dome, but I don't see why it
couldn't be done by building a series of arches, repositioning the formwork
each time.  after the first two are in place though (N/S and E/W), the
subsequent arches would not carry across the form, but would end with pointed
stones fitting into the intersections of adjacent arches (eventually, as these
intersections narrow, perhaps becoming too pointed to cut).  interesting
concept.

Tomas Lipps
stonefoundation.org