09-19-2023, 01:23 AM
It seems like with slight modifications a ferrocement water tank would make a serviceable round hut. There is a common design for round huts in Africa. One of the more common names is a rondavel. It is essentially a one story cylinder of mud or stone at ground level with a conical roof, usually thatched. All the outward hoop stresses are taken by circular purlins so the walls see only vertical loads. There are no beams that span the diameter so it is completely open inside. I think that a cone on top of a cylinder is the ideal shape in terms of minimizing loads. With a bunch of rafters all pushing out at the base the bottom of the cone would tend towards a round shape. That being said I have a friend who had a bed and breakfast with a small spa building. It was square with a pyramidal roof. There were 4 rafters that came from each corner and met at the peak. The downwards forces on these rafters forcing outward at the top of the walls would naturally form a square and so this too was a sort of ideal shape. Once again the entire interior was open with no crosswise joists.
Modern catamarans are made of carbon fiber and are astonishingly high performance. Nevertheless the claim to fame of traditional multihulls of polynesia was that they too had astonishing performance for their time and this was because the designs made the best of the relatively weak materials available. In the same fashion properly reinforced concrete is incredibly strong but the shape of these wood and thatch cone-on-mud/stone cylinder rondavels likewise achieves exceptional strength and performance with very modest materials. As to whether these designs are strong enough for seismically active areas or whether the local building department can be convinced of such, I don't know.
I think a simple cylinder with cone roof or square with pyramid roof would be a good basis for any construction with local materials.
Modern catamarans are made of carbon fiber and are astonishingly high performance. Nevertheless the claim to fame of traditional multihulls of polynesia was that they too had astonishing performance for their time and this was because the designs made the best of the relatively weak materials available. In the same fashion properly reinforced concrete is incredibly strong but the shape of these wood and thatch cone-on-mud/stone cylinder rondavels likewise achieves exceptional strength and performance with very modest materials. As to whether these designs are strong enough for seismically active areas or whether the local building department can be convinced of such, I don't know.
I think a simple cylinder with cone roof or square with pyramid roof would be a good basis for any construction with local materials.