nigelswift wrote:
having the circle broken would weaken the rest of the arc.
There would be as much work involved getting the angles right on a 30-sided polygon as curving each stone to a set pattern, though quite how the curve could be translated from a 30th of a circle with primitive measuring techniques and sloping ground is beyond my 20th-Century brain...but certainly the overall effect would be more impressive with a curved arc than multi-sided.Yes, although describing it as a ring beam was probably a misdescription as it actually probably only lends local support, not all-round support like a single solid beam would. My guess is that the primary intention was aesthetic more than engineering - why else make the lintels curved? No engineering advantage in that.
And I wonder how much was done as the building progressed - start off with a plan and amend it as they went - like adding lightswitches and a different bathroom suite ?
