What a great idea
Do you have any cross framing too between the ends? I found that's what really strengthens the arch.
No, I don't. Simply the ridge pole. I found that with the bend of my panels, a 2 x 4 would fit perfectly under the center wire at top. I stapled this to that center wire. This ridge pole is then supported by 2 x 4's on end walls. The 2 x 4 fit perfectly between the horizontal grids under the ridge pole. I simply marked these 2 x 4's with correct angle to match up with the arc of the panels, and cut them, rounding off the bottom edge, while leaving it long enough to be supported by the horizontal wire below it. Framing in the rest of the end wall was easy, using triangulation, and horizontal supports as needed. For doors, I either built a door, or in the case of the green house, I bought aluminum combination windows (complete with screens) for $10 each at Habitat for humanity restore.
I discussed your plan with my hubby, who designs trusses for a living. He is well versed in dealing with design to work with snow loads, and building a strong structure. But, of course, working with CP introduces an element into the design process that makes all warranties, implied or otherwise obsolete!!! His suggestion was to put a ridge pole part way down your arc, and cross brace from that ridge pole back to the building. Remember that the strongest most stable support is going to take advantage of a triangular shape.Using prop boards would be easy enough it sounds like. Although i have a hard time getting my head around that in a half hoop set up. There won't be a "peak" to put them into. At least i don't think there will unless it arcs differently than i envision. Only a test will answer that unless someone pops up who did this. Me and my ideas.
someone did this.. they put a 2x4 on the barn wall at the height that worked... made a base.. stuck one end of the cp under the wall 2x4 and put the other end in the base... I am looking for that build...
Putting the CP UNDER the 2 x 4 would hold it against the building. But, any kind of load on it would force it to creep down the wall. I think it might work to put it under the 2 x 4, and staple it in place (to the 2 x 4), then put a second 2 x 4 UNDER that to keep it from creeping down. Essentially, it would be fastened, and sandwiched between the 2 x 4's.
I wonder if using the off set ridgepole, as suggested by my Hubby, bracing that back to the building, and placing a vertical support here and there, kind of like building a knee wall, would do the trick. Think about the support system in place for a gambrel roof. Basically, you would be building 1/2 of a gambrel roof, but it would be "curvy"!