How to Join a Bamboo Pyramid?
I am using guadua as the corner posts for a pyramid. Any suggestions as to how to join these at the top would be greatly appreciated. The lengths of the posts will be 8.5m, the pyramid base 9m x 9m. The height at the apex 6.5m. We need to get the joint exactly right to ensure the energetics of the structure are correct. Suggestions as to how to raise the posts are also appreciated.
⭐ Best Answer:
Here is my advice:
Cut two pole ends in the right angle so that they have a flat surface where they touch. Cut it about 10 cm above a node in the pole to prevent it from splitting. Find a piece of bamboo that is just oversize to fit inside the bamboo poles. Scrape off the outside layer just until you can slide it in but with a tight fit. Insert them into both ends and cut them just above the node flush with the surface you cut at the large pole end. Take a piece of strong wood large enough to cover the (oval) pole ends about 2-3 cm thick. Trim of the excess wood sticking out. Place THICK dowels in the wood sticking out on BOTH ends. Mark the holes on the bamboo pole ends and drill them to the size of the dowels. Don't drill too deep! Put a bucket load of (waterproof) glue on both ends of the wood, on the dowels, and the pole ends. (If you don't find any glue in your underpants a week later, you did not apply enough glue.) Press both ends together and keep the PRESSED together until the glue is DRY. As in fully cured.
Provide a proper foundation for the poles that protects it from ground moisture. Either a concrete foot or a steel pipe in a bedding of gravel might do the trick. Don’t be cheap on the foundation. Unless you want big hospital bills from collapsing roofs etc. For this size, depending on weight of cladding, expected wind loads and snowfall I would say you need AT LEAST 1 m³ for every pole.
Good luck!