Yesterday, we were looking at one of my favorite sculptures (right word?) at our art museum: Andy Galsworthy's Stone Sea. Stone Sea is a collection of keystone arches constructed with Missouri stone.
http://www.architecturaldigest.com/stor ... -stone-sea
We were talking about the amazement of a single stone at the top supporting an entire arch. A friend with us was wondering if the builders have a support underneath while building the arches. I have found that modern keystone arch builders do indeed use some forms of support and one of the pictures on that page seems to show a support form which is not there now on the finished sculpture.
What about when Romans were building these arches? Did they use supports until they got the keystone set? Can a keystone arch ever be built using no form of support? Our science museum provides foam blocks for anyone to try to build without any support underneath. I've seen many try but not seen anyone succeed.
Can it be done?
By the way, there is no cement of any kind between those stones. Fortunately, the entire sculpture is in a walled-in courtyard where no one can climb on it.