So I hope from now on I can put a curve at least somewhere into every building I build. We are experimenting with a curved roof in the training centre for the main training room. My Timorese mate, Anen, somehow continues to take my crazy ideas in his stride and together we weld up a curved set of 'rafters' or roof members.
I was asked how I knew it would be strong enough. I replied that once it was built we would get up on top and jump around a bit and see if it wobbles. Its a non-technical approach but it might work.
My curved trusses are 200mm wide using 1" (25mm) gal steel water pipe. This was flexible enough to bend around in a curve by itself. 4 lengths are curved and welded to some zig-zag 10mm reo-bar steel. Then for the purlins that hold the roof sheeting, 2 C-channel 100mm steel lengths are welded together and slid in and attached to the 'trusses'. East Timor Roofing, in Baucau, kindly agreed to curve their zincalume sheeting to a 12m metre radius. The whole thing is a bit of a pig to put together but it is a bit fun.