Mechanical hardiness of arches

1

1pet2_9

Active member
So first off, hi. :) This is my first post here.

We just pulled off a successful drive-through arch tunnel using 3/4" PVC. 100 feet long, each arch was 34 feet circumference. On a $500 budget (we are a non-profit). I'd like to do better next year.

Two areas where we fell short:
1). The lights tend to break a lot, because they are tied to the outside of the pipe. If I can put them inside a transparent pipe, they'll last longer.

2). The tunnel could hold up to 35mph winds, but it fell in 55mph. It was pretty spectacular.

I have never tried your solutions with PEX and HDPE, but I keep seeing pictures of pipe all curled up in a ball. Can a 34-foot arch of that hold up under its own weight? I would also kind of like to hang icicles off the top, and I have a hard requirement that I have to drive passenger vans through it. I can probably get more budget next year, but not like $36,000.

What kind of frame is needed and/or required at that size, for those kinds of translucent pipes you use?
Thanks!
 
Hi hi,

I used store-bought C3's--mostly because I was on a tight schedule. The breakage was during transport and assembly/disassembly--and, of course, the catastrophic windstorm damage. Not during the static display itself. I was thinking that if I put the lights inside of the pipe, I could just let the storm blow it down. I have some China-made, $2-per-10m LED strips and fairy lights on order right now. I don't have the budget for WS2815's, but with that size tunnel I also figured I have enough channels to play with that I don't need pixels, anyway.

The arches also serve a hidden, practical purpose: power routing. I've got traffic driving through a commercial parking lot. So rather than have hundreds of cars drive over my wiring, I route over the arch. Unfortunately, that comes with yet another challenge: I'm on a hard parking lot, that is not mine. Hammering rebar stakes into the ground is almost never an option. What killed the tunnel in wind was when the wind direction went directly along the length of the tunnel. It lifted all of our 50-pound buckets holding it down at once, then...crash!

Instead of guy wires, I opted to use PVC cross-couplers to connect twin PVC spines going down the length of the tunnel. This stopped compression and twisting action along the tunnel, but it came at the expense of making the whole thing top-heavy. To negate that threat, I devised a suspension-bridge system of ropes, much like you see on yard inflatables or a suspension bridge. Which got it to 35mph, but 55mph overpowered all the buckets. (p.s. I probably shouldn't say "instead" of guy wires--there were plenty of lights going along the length of the tunnel)

Now I'm thinking I need an aluminum frame with a truss on the sides, with clamps welded on to mount transparent piping. The thing is: 1. expense. 2. how to make a drive-through arch out of it. 3. the strongest aluminum is a hollow, circular rod anyway. And 4. the transparent piping is untested (where I thought this forum might know more).

Fortunately, I am able to experiment on just one arch section at a time. If I can make an arch out of one, then I can probably repeat. Also, not every arch section may need its own aluminum frame. But I would like to hang some icicles from 15-feet in the air on them all, if I can help it, and that adds some top-heavy force.
 
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We got 15 feet height (at the zenith) out of the 34-foot arches (which consisted of 2x 12-foot PVC sections, each coupled with a 10-foot section in the middle). With that, we were able to clear all of our traffic. We had a volunteer dedicated to checking each vehicle's clearance, but in the end we didn't have to turn anybody away. Although we did have one van who had a bunch of stuff on their roof, who came close. I made pure arches for aesthetic reasons, so if I do the math, that gave us about 22 feet width (only the 10 feet in the middle of which would have been driveable, in the worst-case). I did look at other shapes that could have been structurally stronger, but I just didn't like the way they looked. Except for one: there was a gumdrop shape that I liked, which looks kind of like an arch with a curved steeple up top. I achieved that by using these brand new (but a bit expensive) PVC couplers, which could bend at any angle. I opted against that because I felt we needed two couplers on the arch--not one. Wind tends to blow diagonally on the arch, and that creates a twisting motion.

I don't know what options in the way of transparent tubing couplers are even available.
 
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I have a 20ft by 20ft canopy over my pool. it uses 1" steel pipe and standard couplers like used for the canopie at swap meets.

Maybe frame this with taller verticals and secure the arches to it along the way.
 
Absolutely, but how much did the canopy run? Thanks for chiming in. If there's a good way to bring in steel that's not $10,000, I've got a bunch of kids who will be very grateful. I know a guy who is a recent grad from welding school, if I can come up with the materials and the drawings.
 
First post-apologies for any errors. I don't know if this would help you but there is a company called Maker Pipe. They make connectors for 1/2", 3/4", and 1" EMT. The connectors have varying configurations and have been used to make some incredibly creative projects. The company website has a community forum for ideas and assistance. There's also a YouTube channel, all under Maker Pipe. It's a small family-owned company and the owners are pretty responsive. The connectors are all removable so disassembly and reuse/reconfiguration is easy.
I came here to learn about the PEX arches so I can't help with that but from what I've seen from Maker Pipe that might be an option for you for the framework.
 
There are many companies that sell canopy fittings and you can build a frame using EMT, fence posts or other types of rigid conduit depending on the size of the couplings you buy and how rigid a structure.
 
1pet2_9 said:
Absolutely, but how much did the canopy run? Thanks for chiming in. If there's a good way to bring in steel that's not $10,000, I've got a bunch of kids who will be very grateful. I know a guy who is a recent grad from welding school, if I can come up with the materials and the drawings.
Click to expand...

Sorry for the late reply to your post in the spring. I built a 20x20 canopy system a few years ago for under $400. It uses 1-3/8" fence rail (cheap) for the pipe members. I used this company for the fittings. https://www.canopiesandtarps.com/ca...c_K7rAiwhPjUl761iAkbDsa0JfAZ5AD4aAoUWEALw_wcB They have a wide variety of fittings including different slope angles.
I'd never thought about using this kind of structure for supporting parts of the show, but now you've got me thinking. I bet it'd be a great support structure for an arch tunnel.
 
jchuchla said:
Sorry for the late reply to your post in the spring. I built a 20x20 canopy system a few years ago for under $400. It uses 1-3/8" fence rail (cheap) for the pipe members. I used this company for the fittings. https://www.canopiesandtarps.com/ca...c_K7rAiwhPjUl761iAkbDsa0JfAZ5AD4aAoUWEALw_wcB They have a wide variety of fittings including different slope angles.
I'd never thought about using this kind of structure for supporting parts of the show, but now you've got me thinking. I bet it'd be a great support structure for an arch tunnel.
Click to expand...

To borrow from millennial-talk: Awesomesauce.
 
jchuchla said:
Sorry for the late reply to your post in the spring. I built a 20x20 canopy system a few years ago for under $400. It uses 1-3/8" fence rail (cheap) for the pipe members. I used this company for the fittings. https://www.canopiesandtarps.com/ca...c_K7rAiwhPjUl761iAkbDsa0JfAZ5AD4aAoUWEALw_wcB They have a wide variety of fittings including different slope angles.
I'd never thought about using this kind of structure for supporting parts of the show, but now you've got me thinking. I bet it'd be a great support structure for an arch tunnel.
Click to expand...

Hey,

I looked at your site. The prices on all the fittings are great--those only cost about 2-4X the cost of equivalent PVC fittings. But I don't particularly see the frames for sale a la carte on that particular site? To purchase full-blown canopies on that site, the price comes back out again to the $10k range for 120' of tunnel. You mentioned fence railing (since only the frame is needed--not the cover).

During the quiet period since I last asked about it, I was looking at using 3/4" conduit, and then buying a conduit bender for $75. That came out to about $1,000 for 400 feet of it. What kept me from following through with it was all the talk about PEX arches; since PEX has that translucent quality. I found out the hard way that 1" PEX doesn't hold up under its own weight too well past a 10' circumference. What I need for this application is 10 meters, since it is to drive through. You can get away with smaller if it's just for your driveway, but I'm dealing with a venue where hundreds of cars drive through, of different shapes and sizes. The last two years we had a van drive through which just barely cleared.

I thought of affixing PEX to the conduit frame, but that doubles the cost, and I didn't know what that would look like if the opaque frame was affixed to the translucent PEX. That's where I left off.
 
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