VAULTS & DOMES

Vaults & Domes

Background:

Vaulted and domed construction is one of the oldest forms of constructing spaces and has been around for millennia.
Generally, one finds a history of vaulted and domed structures wherever timber is scarce and hard to come by for roof construction.
There are many ways of constructing these structures, which can involve complicated formworks as well as very simple compasses or strings to set things out.

Benefits:

Their construction is typically done with heavy masonry elements as their forms typically work with compressive load bearing forces rather than lighter weight tensile materials, which lends itself to using locally sourced masonry brick and stone materials.
The centre of the dome is typically left open for light and is known as the oculus. This helps illuminate the space and can be used for natural ventilation the utilization of the stack effect where heat naturally rises upwards, helping to set up convection currents where cooler air is drawn in from below and pulled upward toward the top.
Climatically domes are unique in that a part of the exterior is always in the shade. This helps to cool the space and it establishes a microclimate around the surface of the outer shell where the air currents are created by the differential temperatures between the hot and cold areas of the roof. By building up parapets around the sides of the dome the shaded areas can be increased, leading to a highly level of thermal comfort in hotter climates.

Technical Information:

Due to their inherent strength these structures are extremely stable and are seismically very resistant to the ravages of time.
Very precise geometry must be employed in order to work with the compressive forces that need to flow through the heavy masonry, which results in aesthetically pleasing curved structural and roof forms.
Due to the reflective nature of masonry coupled with the radiating geometry of vaults and domes, these structures exhibit very unique acoustic properties, where the sound is focused back toward the radius points of their geometries.
The flatter the shapes the more outward lateral forces are exerted, which requires the use of heavy buttressing, tensile ties or else ring beams can be employed. Ideally a catenary shaped curve is followed in order to help avoid tensile forces from causing distortion and structural failure.

Company Track record/examples of work:

Alliance Francaise Cultural Centre – Cape Town 1997 (Project Architect for ACG Architects)
Muslim Women Federation Cultural Centre, Phillipi, Cape Town, Sim office