Equilateral Pointed Vault
This equilateral pointed vault has been built above the present office of the Auroville Earth Institute and it is the living room of the house of Satprem Maïni, director of the Auroville Earth Institute. It has the shape of the typical naves used in the European Gothic cathedrals. But these types of naves were built on ribbed arches and were buttressed by flying buttresses. The construction of this vault was an attempt to build the same shape as the gothic vaults but as a barrel vault, without formwork and without flying buttresses. This had been possible with the optimisation method developed by the Auroville Earth Institute.
The vault does not require any flying buttresses because its stability is insured by the varying thickness for the bottom to the top and with a well studied keystone. The vault starts at the bottom with 34 cm thickness and it ends on top with 7 cm thickness. The weight of the keystone is essential for the stability of such a vault. A difference of a few kilograms per meter long can cause deformation and ultimately collapse of the structure.
It has been built in 36 days with 4 masons and it presents these features:
• All courses are entirely laid horizontally with the free spanning.
• 3.6 m span, 3.12 m rise, 8 m long
• 34 to 7 cm thick
• The vault ends with a half cloister dome.
• The vault has 2 catenary lunettes of 1.2 m span and 7 cm thick.