vaulted structures equilateral pointed vault - Auroville Earth Institute

VAULTED STRUCTURES
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.
Equilateral pointed vault, built free spanning with horizontal courses
House of Satprem Maïni
Starting the horizontal courses with the window frame as a template
and 2 pipes bent for the cloister dome
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.
Building around the ferrocement ring as a window
Varying thicknesses for the bottom to the top:
34 cm at the base up to 7 cm at the apex
Building horizontally the courses

Starting the catenary lunette
Horizontal courses laid radials to the arch shape
Building the catenary lunette with corbelled horizontal courses
Corbelling courses of the catenary lunette
Horizontal courses built by steps
Bond pattern of the catenary lunette

Laying the keystone of the lunette
Stability limit with the horizontal courses
Completed lunette in 3 days
Building the half cloister dome with stepped horizontal courses
Completed lunette from inside
Vault built free spanning towards the half cloister dome

Pipes of the half cloister dome as templates
First keystones and stepped courses for the cloister dome
Preparing the courses for the keystones
Laying keystones
Laying the key stone (lozenge piece and slab)
Back side with the catenary lunette and the half cloister dome

Laying keystones in progress
Raw construction completed in 37 days with 4 masons
Vault being built free spanning
Completed vault from outside
Laying the last keystones
Varying thickness from 3 cm at the bottom to 7 cm at the top

Completed vault from outside
Living room towards the bathroom
Completed vault, above the office of the Auroville Earth Institute
Lunette of the living room
Completed vault from inside towards the kitchen and the bathroom
Lunette from outside

View on the living room