Post
by Journeyman » Tue Dec 01, 2009 9:11 am
Hi. A tip of my hat to Ranger Parttime for the reference to my structure. It is not a dome by any means. It's a... well, it's... a tensile structure, supported by a centerpole, which does indeed have a winch hoist system. Kind of like a pleated teepee with no teepee poles. When erected, it's about 18-1/2 feet high at the center, and 38 feet in diameter, octagonal in footprint. It worked well as an experimental structure for two years, but the gusts of 2008 caused some damage. I had rather expected that eventually, because it was an experiment in tensile design, a step toward the development of a much stronger and larger tensile structure. I built it cheaply, utilizing a standard heavy-duty white poly tarp reinforced with two layers of 500 lb. test poly strapping (the stuff used in palletizing freight). The strapping is applied to both interior and exterior surfaces, and metal crimps hold them in place on each of the sixteen tension lines, running from eight anchor points and eight entry peaks. All tension lines were covered with Gorilla tape, and I cut 48 2-foot round openings in the tarp to let wind spill through. Even with all these holes, the interior remained relatively calm in high winds, due to the baffle effect of the design.
The lessons I learned were instrumental in designing the more durable structure that I hope to set up this year. Plastic deteriorates over time and exposure to UV, and I'm sure that the alkaline dust of the playa accelerates that deterioration. Rather than using poly strapping and one very large plastic tarp, the new incarnation of the structure willl be a framework of tensioned cables, with individual canvas panels filling the spaces between the cable framework.
I like the concept of suspended rings, the Japanese lantern idea, but would suggest adding a few more rings to assist in retaining the shape in playa wind. Your most difficult task in building this is gonna be shaping the cover fabric. Have fun, build it, and I will come. I'll email pictures of my original structure, as I have difficulty in posting pictures here.
Infinity = 1; since 1 / infinity = 1, zero is an absolute impossibility. The reason triangles are so unlike other polygons is that a triangle is part of a polygon bridging two dimensions.
