It has long since been a desire of mine to build a geodesic sphere out of bamboo inspired by the 9m diameter one Chris Wise built with Imperial College London students a few years ago. I mentioned this to Mark and we quickly worked ourselves into a ‘must do this’ frenzy.

I know that we are only doing what Wise has already done, and many others, but I say if they had so much fun why can’t we?

Mark and I finally got organised with geometry, materials, people and (a notion for) construction. With a junior hack saw Adam, Mark and I cut all 600 canes to length in some sort of production line of measuring, sorting, cutting and counting. Never again.

This morning all the friends we managed to rope into this nonsense turned up eager and willing and by this afternoon we had built this:

A geodesic sphere is “an almost spherical structure based on a network of struts arranged on great circles (geodesics) lying on the surface of a sphere. The geodesics intersect to form triangular elements that create local triangular rigidity and distribute the stress.” (Wikipedia.) I think the label geodesic was coined by Richard Fuller (better known as Buckminster Fuller) although they were developed by several people, including Kenneth Snelson, at an experimental arts college in 1940’s America. Fuller and Snelson fell out over who should take the credit.

Geodesic spheres are extremely strong for their weight and inherently stable so are a superior use of materials when compared to traditional “beam and post” construction (which often rely on gravity to stand up). In fact Fuller hoped they would end the post war housing crisis and indeed lived in a “dome home.” Needless to say dome homes are ugly. The first famous “bucky ball” I suppose was the American Pavillion at Expo ‘67 which was designed by Fuller and 76m diameter (but is steel, not bamboo….).

Chris Williams insists this a poor use of bamboo although I am not sure why, but he is right that they are out of vogue.

Our one is an 8m diameter class I frequency IV icosahedron geodesic sphere. It has 540 members (60 x 1.300m, 120 x 1.252m, 120 x 1.178m, 90 x 1.195m, 60 x 1.181m and 90 x 1.013) but as we built complete symetry triangles we had overlapping members and so used 600 canes. The total length of bamboo used is 705m but I had to order 1300m as they ran out of certain lengths. I had bought eight rolls of 50m gaffa tape but early on we realised this was not enough and my dear mother came to our rescue with the purchase of another five rolls of, superior quality, gaffa tape.

One notable advantage of the icosahedron family of geodesic spheres is the lower variation of strut lenghts and so better distribution of curvature (more uniform) and so less points of potential weakness. Their main disadvantage is a lack of a natural equator, but I suppose that depends on the application.

Anyway…

Dave, Gerald and Emily building one of the twenty triangular dishes.

Hold in place, tape, voila.

Chris Williams pops in for a sneak peek. At 12.30 we had the dishes done and enjoyed a well deserved BBQ. This being my first BBQ using my own BBQ set now makes me truly South African.

First five dishes go together to form the top dome bit.

Tip up the top dome bit and add more dishes.

We had to push the sphere in to counter the outward thrust - it could yet take the tension horizontally.

An emergency repair high up led me stand on two ladders braced by Adam and Kash, in turn held fast by Nige, Sarah and Nick.

The last five dishes were slid underneath and attached.

Looking good.