No seriously,
I'm building a structure based around a large center pole. I'm guessing the center pole is going to be approximately 16-25 ft. tall. Once up I plan on suspeneding triangular shaped pieces of fabric to provide shade. Here are a few of my questions.
1. What's the best material to use for such a project? My guess is that PVC would bend too much and not be strong enough.
2. How deep should the pole be buried? My plan was to use rebar inside the pole and then guy wires to add stability. Other ideas?
3. Anything else?
Erecting a pole
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herrdirektor
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You are totally correct that PVC is a bad idea. I would think you would want something like a mast (i.e., wood). There were several large poles made out of wood (usually spliced together at BM) in 2003 that I saw.
If you are going to guy wire it sufficiently, you probably don't need to go too deep. Theoretically if you can keep it stable at the base so that it won't move in any direction, you probably don't need to bury it at all. For instance, you could create a relatively large "mast step" say about 2 feet high with triangular pieces of plywood that you anchor to the playa with rebar and place the mast inside that and secure it with bolts. If the anchoring of the step is sufficient, you probably don't need to bury it at all. You WILL need to have guy wires that go out pretty close to the same distance from the mast as the mast is tall (i.e., you don't want your mast to be the longest side of the triangle).
Caution: I am not a structural engineer and there are probably people who can give you more information on wind loading and sheer forces and stuff like that. However I have built a number of structures and often times common sense leads you to the right conclusions (then again, sometimes not).
If you are going to guy wire it sufficiently, you probably don't need to go too deep. Theoretically if you can keep it stable at the base so that it won't move in any direction, you probably don't need to bury it at all. For instance, you could create a relatively large "mast step" say about 2 feet high with triangular pieces of plywood that you anchor to the playa with rebar and place the mast inside that and secure it with bolts. If the anchoring of the step is sufficient, you probably don't need to bury it at all. You WILL need to have guy wires that go out pretty close to the same distance from the mast as the mast is tall (i.e., you don't want your mast to be the longest side of the triangle).
Caution: I am not a structural engineer and there are probably people who can give you more information on wind loading and sheer forces and stuff like that. However I have built a number of structures and often times common sense leads you to the right conclusions (then again, sometimes not).
Jon
[color=blue][i]The difference between theory and reality is that
in theory, there is no difference between theory and reality,
but in reality, there [b]is[/b]![/i][/color]
[color=blue][i]The difference between theory and reality is that
in theory, there is no difference between theory and reality,
but in reality, there [b]is[/b]![/i][/color]
-
herrdirektor
- Posts: 11
- Joined: Wed Sep 10, 2003 10:29 pm
- Location: San Francisco
- Contact:
You are totally correct that PVC is a bad idea. I would think you would want something like a mast (i.e., wood). There were several large poles made out of wood (usually spliced together at BM) in 2003 that I saw.
If you are going to guy wire it sufficiently, you probably don't need to go too deep. Theoretically if you can keep it stable at the base so that it won't move in any direction, you probably don't need to bury it at all. For instance, you could create a relatively large "mast step" say about 2 feet high with triangular pieces of plywood that you anchor to the playa with rebar and place the mast inside that and secure it with bolts. If the anchoring of the step is sufficient, you probably don't need to bury it at all. You WILL need to have guy wires that go out pretty close to the same distance from the mast as the mast is tall (i.e., you don't want your mast to be the longest side of the triangle).
Caution: I am not a structural engineer and there are probably people who can give you more information on wind loading and sheer forces and stuff like that. However I have built a number of structures and often times common sense leads you to the right conclusions (then again, sometimes not).
If you are going to guy wire it sufficiently, you probably don't need to go too deep. Theoretically if you can keep it stable at the base so that it won't move in any direction, you probably don't need to bury it at all. For instance, you could create a relatively large "mast step" say about 2 feet high with triangular pieces of plywood that you anchor to the playa with rebar and place the mast inside that and secure it with bolts. If the anchoring of the step is sufficient, you probably don't need to bury it at all. You WILL need to have guy wires that go out pretty close to the same distance from the mast as the mast is tall (i.e., you don't want your mast to be the longest side of the triangle).
Caution: I am not a structural engineer and there are probably people who can give you more information on wind loading and sheer forces and stuff like that. However I have built a number of structures and often times common sense leads you to the right conclusions (then again, sometimes not).
Jon
[color=blue][i]The difference between theory and reality is that
in theory, there is no difference between theory and reality,
but in reality, there [b]is[/b]![/i][/color]
[color=blue][i]The difference between theory and reality is that
in theory, there is no difference between theory and reality,
but in reality, there [b]is[/b]![/i][/color]
Gas Pipe
I have been putting up a wind generator for a number of years. The tower is 15' tall and made out of gas pipe. The gas pipe is it is a bit heavy and you might find something lighter, Though the handy issue with gaspipe is that it is threaded at each end so you can add 8' sections as needed. I don't have to bury the pole at all. I have a floor flange screwed in at the bottom so the pole dosen't dig into the ground. I have 4 guy wires made of aircraft cable that extend out about 7' to rebar. At the top of the pole I tapped holes so that eye hooks can be screwed where the guy wires can attach. Each wire has a turnbuckle attached to get each wire fairly snug. The thing is super solid.
heavy pipe (like gaspipe) is more stable than conduit and therefore is less likely to strip out at the threaded connectors, but I have had this happen with lighter materials and it wrecks the fittings, leaving YOU screwed....Nesting smaller, hollow pipe inside of bigger, hollow pipe works fine, providing that you: A) Use lots of "inside pipe". B) Fasten the inside pipe with a screw or wraps of tape or something, to keep it from sliding.
Use relatively thick pipe or rebar, which won't bend as readily. If you're flying a really big flag or banner cutting vents in the material will reduce the windload on the flagpole- Don't worry about having enough wind......
Use relatively thick pipe or rebar, which won't bend as readily. If you're flying a really big flag or banner cutting vents in the material will reduce the windload on the flagpole- Don't worry about having enough wind......
Howdy From Kalamazoo
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Bob
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I can think of many ways PVC would work for a 16- to 25-foot-tall pole-like support, using either large-diameter pipe, multiple small-diameter pipes in parallel, or jointed truss-tower construction, but all might overload your roof rack. PVC pipe, compared to other materials or structural elements, is relatively weak, brittle, and prone to bending in the heat, but anything can be made to work with enough material or brute force.
In using any kind of standard pipe or conduit, I'd be as wary of completely relying on the standard threaded or sleeved joints, as of any garage-built solution such as sleeving w/ larger pipe or adding guy lines at the level of the pipe joints. In any case, test it in a strong wind with people hanging on the guy lines.
What you need also depends on the skin -- the more "opaque" it is to the wind, the stronger a pole and guying system you'll need, possibly with cross-cabling to attach all the tarp edges. Shade mesh, rigged flat or on a shallow angle, would offer much less of a wind-catching problem than waterproof tarp, sailcloth, or a parachute rigged vertically or on a steep angle. Pyramid and dome shapes are somewhere in between.
I'll stick my neck out and say 4-inch PVC, at least sched. 40, preferably sched. 80, or 6-inch sched. 40 PVC, would work if the joint at the 8- or 10-foot height level is reinforced with a strong 4-foot-long close-fitting sleeve inside or out. The problem is configuring a sleeve out of odd-sized pipe (I can't think of anything off-the-shelf that would fit), or an ugly cobbled-together arrangement of struts and clamps. I suppose you could also just glue the pipe and saw it up when you leave.
I basically agree w/ the prev posts on steel pipe. Two-inch-diameter pipe would be the smallest I'd use on anything taller than 15 feet.
Commercial tent poles of heavy steel conduit (thinner than plumbing or gas pipe) are commonly 2-1/2 inch, AFAIK. Might consider finding commercial tent manufacturers on the web that sell "accessories" as well as tents, and ask about sleeving that kind of pipe.
Flags are big these days, so competition might be driving down the prices on sectioned aluminum flagpoles (just Google for "flags"). As with steel conduit, I'd go for a minimum of 2-1/2 inch diameter. Ask for the veteran's discount -- as far as I'm concerned, we're all veterans of foreign wars, at least for the purposes of patriotic household items.
Well-stocked military surplus outlets such as Twin City Surplus in Reno have 4-foot tent pole sections, 1-3/4-inch-diameter, aluminum or fiberglass, made to easily sleeve together. This would probably make the lightest possible tent poles using commonly available materials. I doubt whether they're entirely suitable for extending taller than 12 feet in desert conditions without some additional engineering.
A set of three skinny poles of any sort could either be bundled tightly together with padded hose clamps, or as a small-based tripod (or rigged in parallel) with plywood stabilizers at 4- to 6-foot height intervals. A single pole could be reinforced with four or more lengths aircraft cable stretched from end to end over a spreader at the middle made using plywood or maybe a motocross bike rim.
There's always wood -- such as 4x4s joined with thru-bolted plate-steel or strong plywood splice plates -- but given the weight, the quality of lumber at Home Borg, lack of availability of suitable plate-steel connectors or high-quality 7-ply, and the unknown abilities of users, I hesitate to recommend it for people trying to fit a house-sized tent in a passenger car.
The minimum you need at the base is to pin it in place to resist sideways motion and pullout/liftoff. Two or three steel stakes, driven at angles at least two feet into the ground, securely tied or strapped to the base of the pole should do it. I use 3/4-inch diameter steel stakes (concrete form stakes), which generally suck less than rebar.
In using any kind of standard pipe or conduit, I'd be as wary of completely relying on the standard threaded or sleeved joints, as of any garage-built solution such as sleeving w/ larger pipe or adding guy lines at the level of the pipe joints. In any case, test it in a strong wind with people hanging on the guy lines.
What you need also depends on the skin -- the more "opaque" it is to the wind, the stronger a pole and guying system you'll need, possibly with cross-cabling to attach all the tarp edges. Shade mesh, rigged flat or on a shallow angle, would offer much less of a wind-catching problem than waterproof tarp, sailcloth, or a parachute rigged vertically or on a steep angle. Pyramid and dome shapes are somewhere in between.
I'll stick my neck out and say 4-inch PVC, at least sched. 40, preferably sched. 80, or 6-inch sched. 40 PVC, would work if the joint at the 8- or 10-foot height level is reinforced with a strong 4-foot-long close-fitting sleeve inside or out. The problem is configuring a sleeve out of odd-sized pipe (I can't think of anything off-the-shelf that would fit), or an ugly cobbled-together arrangement of struts and clamps. I suppose you could also just glue the pipe and saw it up when you leave.
I basically agree w/ the prev posts on steel pipe. Two-inch-diameter pipe would be the smallest I'd use on anything taller than 15 feet.
Commercial tent poles of heavy steel conduit (thinner than plumbing or gas pipe) are commonly 2-1/2 inch, AFAIK. Might consider finding commercial tent manufacturers on the web that sell "accessories" as well as tents, and ask about sleeving that kind of pipe.
Flags are big these days, so competition might be driving down the prices on sectioned aluminum flagpoles (just Google for "flags"). As with steel conduit, I'd go for a minimum of 2-1/2 inch diameter. Ask for the veteran's discount -- as far as I'm concerned, we're all veterans of foreign wars, at least for the purposes of patriotic household items.
Well-stocked military surplus outlets such as Twin City Surplus in Reno have 4-foot tent pole sections, 1-3/4-inch-diameter, aluminum or fiberglass, made to easily sleeve together. This would probably make the lightest possible tent poles using commonly available materials. I doubt whether they're entirely suitable for extending taller than 12 feet in desert conditions without some additional engineering.
A set of three skinny poles of any sort could either be bundled tightly together with padded hose clamps, or as a small-based tripod (or rigged in parallel) with plywood stabilizers at 4- to 6-foot height intervals. A single pole could be reinforced with four or more lengths aircraft cable stretched from end to end over a spreader at the middle made using plywood or maybe a motocross bike rim.
There's always wood -- such as 4x4s joined with thru-bolted plate-steel or strong plywood splice plates -- but given the weight, the quality of lumber at Home Borg, lack of availability of suitable plate-steel connectors or high-quality 7-ply, and the unknown abilities of users, I hesitate to recommend it for people trying to fit a house-sized tent in a passenger car.
The minimum you need at the base is to pin it in place to resist sideways motion and pullout/liftoff. Two or three steel stakes, driven at angles at least two feet into the ground, securely tied or strapped to the base of the pole should do it. I use 3/4-inch diameter steel stakes (concrete form stakes), which generally suck less than rebar.
Amazing desert structures & stuff: http://sites.google.com/site/potatotrap/
"Let us say I suggest you may be human." -- Reverend Mother Gaius Helen Mohiam
"Let us say I suggest you may be human." -- Reverend Mother Gaius Helen Mohiam
Another approach would be to construct a tower like microwave or high-tension power towers, using conduit dome techniques to create a tall, slender 3 or 4-sided tower that is then guyed and staked.....I don't think that PVC would be useful for such a structure, though- no resistance to the twisting stresses that towers suffer from.....
Howdy From Kalamazoo
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Bob
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Amazing desert structures & stuff: http://sites.google.com/site/potatotrap/
"Let us say I suggest you may be human." -- Reverend Mother Gaius Helen Mohiam
"Let us say I suggest you may be human." -- Reverend Mother Gaius Helen Mohiam
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unjonharley
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Bob
- Posts: 6747
- Joined: Wed Sep 03, 2003 10:00 am
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If accordions can be polka'd into the ground without undo effort, I see no problem with any other sort of polska muzyka.
Amazing desert structures & stuff: http://sites.google.com/site/potatotrap/
"Let us say I suggest you may be human." -- Reverend Mother Gaius Helen Mohiam
"Let us say I suggest you may be human." -- Reverend Mother Gaius Helen Mohiam
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Mister Jellyfish Mister
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***Bump*** How about PVS black plastic pipe to mount projects like these:
http://www.mutantvehicle.com/paranoia_pikes.htm
Any suggestions on rebar/hardware for art that is seven feet up from the playa? (Trying to avoid guy wires).
http://www.mutantvehicle.com/paranoia_pikes.htm
Any suggestions on rebar/hardware for art that is seven feet up from the playa? (Trying to avoid guy wires).
Art cred: Georgie Boy 2011: www.mutantvehicle.com/georgie_boy.htm ; Ein Hammer 2010; Fluffer 2009; Zsu Zsu 2008; U-Me 2007; Mantis 2006; MiniMan and Pikes Of Paranoia 2005; Time Machine Mutant Vehicle 2004. www.MutantVehicle.com
Re: Erecting a pole
[quote="Chai Guy"....
2. How deep should the pole be buried? My plan was to use rebar inside the pole and then guy wires to add stability. Other ideas?
....[/quote]
That's just what we've done to build our versions of Shady over the past spell. We start out with three six foot steel pipes (bought at Home Depot for next to nothing) that are driven about two or three feet into the playa. Then we slip three 18' steel poles (that someone had laying around their shop) over those and guy them to each other and the ground. Makes for a *very* stable structure that has stood up to some nasty playa wind storms.
And, since they are steel, you could theoretically have your poles cut into shorter sections and threaded at the joints. So you'd have three six foot lengths, say, that you could screw together to make one 18' pole...
Let me know how it works out.
Ron
2. How deep should the pole be buried? My plan was to use rebar inside the pole and then guy wires to add stability. Other ideas?
....[/quote]
That's just what we've done to build our versions of Shady over the past spell. We start out with three six foot steel pipes (bought at Home Depot for next to nothing) that are driven about two or three feet into the playa. Then we slip three 18' steel poles (that someone had laying around their shop) over those and guy them to each other and the ground. Makes for a *very* stable structure that has stood up to some nasty playa wind storms.
And, since they are steel, you could theoretically have your poles cut into shorter sections and threaded at the joints. So you'd have three six foot lengths, say, that you could screw together to make one 18' pole...
Let me know how it works out.
Ron