Anchoring a Tensegrity Structure--Auger Earth Achors?

ilmarinen · Post by **ilmarinen** » Tue Jun 17, 2008 11:57 pm

My friends finally convinced me to go to BM with them this year. As the engineer in camp, I've taken-on a lot of our "infrastructure" design. However, I'm a little hampered by having never been on the Playa. I expect to learn a lot there this year, but bringing backups for all experiments would get expensive and difficult.

My current problem is cost-effective and secure anchoring for our tensegrity structure(s). We took the Pentacle to Critical Massive and it worked great, but know we'll need to upgrade the stakes for BM.

Photos here

Currently considering helical/auger earth anchors, such as these.

Questions: Anyone have experience installing these for structures of similar size, without power equipment? Would the 15" model get deep enough into the playa to have good "bite"? From what I've read, I fear it might be difficult to get the 30" model fully inserted.

Thanks!

Bob · Post by **Bob** » Wed Jun 18, 2008 9:04 am

Can't rely on the top 6"-12" of playa soil for a large load. The Cafe and DPW crews use 4" x 40" helical anchors with welded eyes. They hold a half ton to a ton or so on a guyline. Larger anchors are used for the Man. Can be spun in by hand with a length of pipe if you start them in a small hole picked out w/ a pointy object. Turn them straight into the ground, not at an angle.

I suppose 30" anchors might work for you, or 15" if you spin them flush w/ the ground surface or deeper, if the load is very light. Alternatively, could use 3/4" concrete form stakes or whatnot, and group a couple stakes together to hold larger loads. Eyes or large chain links can be welded at the top of stakes, bla bla bla.

Ron · Post by **Ron** » Wed Jun 18, 2008 10:15 am

Circus tent stakes. You can get them from a large tent rental place here in Seattle. I don't remember the name but I found 'em with an internet search. Each stake is about 2.5 to 3 feet long. They look like giant double headed nails and they do a great job. In fact, since I'm not brining Shady Tower to the playa this year I may even have some you can borrow. Drop me a line if you're interested.....

Ron

Token · Post by **Token** » Wed Jun 18, 2008 10:17 am

That looks like one very loud shade structure.

I bet on windy days, everyone flees the flapping noise that will produce.

I would suggest you consider an alternate roof type, like shade cloth, aluminet, real camo netting etc. for burning man. And put more tension into the roof; you don't really need the water drainage feature on the playa that often.

ilmarinen · Post by **ilmarinen** » Wed Jun 18, 2008 10:50 am

Should have mentioned that the silver tarp was strictly a last-minute purchase upon reading weather reports for Critical Massive. For BM, we don't propose to make the pentacle a rain structure--it will fitted aluminet or similar on it, stretched tight.

But actually, it wasn't very loud or flappy in the gusts we did get at CM--and that's with pretty marginal guying. I'm confident that if we needed to, we could lash-down a tarp to the top of it successfully and comfortable.

-B.

Token wrote:That looks like one very loud shade structure.

I bet on windy days, everyone flees the flapping noise that will produce.

I would suggest you consider an alternate roof type, like shade cloth, aluminet, real camo netting etc. for burning man. And put more tension into the roof; you don't really need the water drainage feature on the playa that often.

ilmarinen · Post by **ilmarinen** » Wed Jun 18, 2008 10:57 am

Yeah, know DPW uses the *big* ones, don't think I'm anywhere near that league yet. I could use straight stakes of some kind, but the kinds of loads I expect out of the tensegrity guys are going to still be pretty "pull up" (w/o guying them out forever far, which has its own hassles). I could cross a couple of big stakes, but for the price of two big stakes, I can buy a good helical anchor that I suspect will be more reliable.

I'd be nice if I could get by with the 15" (West Marine has a really good sale on them right now) but sounds like the 30" would be more reliable. My group is wrestling with budget right now, so I'm sharpening my pencil.

-B.

Bob wrote:Can't rely on the top 6"-12" of playa soil for a large load. The Cafe and DPW crews use 4" x 40" helical anchors with welded eyes. They hold a half ton to a ton or so on a guyline. Larger anchors are used for the Man. Can be spun in by hand with a length of pipe if you start them in a small hole picked out w/ a pointy object. Turn them straight into the ground, not at an angle.

I suppose 30" anchors might work for you, or 15" if you spin them flush w/ the ground surface or deeper, if the load is very light. Alternatively, could use 3/4" concrete form stakes or whatnot, and group a couple stakes together to hold larger loads. Eyes or large chain links can be welded at the top of stakes, bla bla bla.

Teo del Fuego · Post by **Teo del Fuego** » Wed Jun 18, 2008 1:30 pm

I like those yellow plastic stakes that came with my 2-Man Coleman tent

phil · Post by **phil** » Wed Jun 18, 2008 2:15 pm

> Can be spun in by hand with a length of pipe if you start them in
> a small hole picked out w/ a pointy object.

I tried augur stakes one year, and they weren't worth the effort over rebar for my tent and shade. Just too hard to augur into the playa.

ilmarinen · Post by **ilmarinen** » Wed Jun 18, 2008 2:18 pm

What length were you using and did they seem strong? At what depth did they become difficult to turn?

The level of effort isn't of concern to me, the structural integrity is and costs. I may be buying up to 28 of the things. Hence the concern between 15" and 30". And transport weight also.

-B.

phil wrote:>

I tried augur stakes one year, and they weren't worth the effort over rebar for my tent and shade. Just too hard to augur into the playa.

capjbadger · Post by **capjbadger** » Wed Jun 18, 2008 4:11 pm

Some people don't like them, but I swear by "candycane" rebar. It's never let me down.

Badger

phil · Post by **phil** » Wed Jun 18, 2008 4:42 pm

ilmarinen wrote:What length were you using and did they seem strong? At what depth did they become difficult to turn?

I can't remember the length. Two or three feet. It became too difficult when the augur met the playa. Seriously. Getting that blade into the ground wasn't worth it for me. I got in zero inches. I didn't try Bob's idea of digging a hole first, but I'm back to forget it if I have to dig a hole, then screw the augur in. I'll hammer in the rebar.

Bob · Post by **Bob** » Wed Jun 18, 2008 11:49 pm

Apropos of nothing, I had a crew put in thirty of the 4"x40" anchors by hand out there for a funded project that involved ten 30' tall truss towers. Because the "artist" was paranoid about deflection, we also pounded car axle shafts a couple feet behind the anchors & wired the anchors back to them. He didn't trust the playa, either, so we built stiff wood platforms to support the base of the towers, and of course we pinned the platforms down with a few form stakes.

Fun... crew had a great time... just don't ask me about the "art", it was rather feeble.

gyre · Post by **gyre** » Thu Jun 19, 2008 12:22 am

Axles?
That's a tent stake.

A friend used the spiral type attached to straps over his mobile home.
Storm hit and his was one of the only ones to survive.
Soil was very different from the playa though.

TomServo · Post by **TomServo** » Thu Jun 19, 2008 2:49 am

Maybe it's cause im drunk, that i cant visualize your structure...But! if T-posts can be used use them..DPW also uses them. I noodled 500 posts at the ranch..just look for the orange tubed posts. Pulling them is a bitch though.. unless you use a t-post puller and hi-lift jack. And whatever other anchoring you use..deeper is better, but go for easy driving and easy removal. liked the loop auger anchors, but thesame in rebar, without the threads would be better. Bout 2 1/2' should be good at a 45 to 90 degree angle. AND! even if you don't need it, use duct tape..to look hardcore.

TomServo · Post by **TomServo** » Thu Jun 19, 2008 2:58 am

Candy cane rebar is excellent, but when both ends are driving, they tend to warp. Unless their tight! Also good alternative!!!

bdeywoo · Post by **bdeywoo** » Thu Jun 19, 2008 2:53 pm

I have had ZERO luck with these kind of anchors I tried 15 and 30". I just cant get them into the playa without tearing up a huge hole rendering them basically useless and the time it took made it less attractive as well. Have not worked for me but i do know people that like them.

I'm just using the concrete form stakes and some ebay bought rebar with welded eye's that i ground down smooth. We put up a 25x50 foot non breathable tarp that catches a ton of wind and never had a problem.

1 stake on each end every 4-6 feet seems to work great.

Xtevan · Post by **Xtevan** » Tue Jun 24, 2008 9:50 am

We used 16-18" long pieces of 1/2" rebar with two 3/4" washers welded on to them to hold a pair of 10X20 cheap carports tents down. They worked great even in the worst storms last year. Candy caned rebar might be better for your application. The double washer allowed us to use rachet straps to pull the poles straight down and pretension the structure. Getting them out was fun

Xtevan

ilmarinen · Post by **ilmarinen** » Tue Jun 24, 2008 9:55 am

I've acquired a bunch of the 18" long military surplus steel "mess hall" stakes (donated by an former burner). They are great, like 5/8" diameter, etc., but not sure they will be long enough to anchor securely into the playa.

-B.

CapSmashy · Post by **CapSmashy** » Tue Jun 24, 2008 12:46 pm

bdeywoo wrote:and some ebay bought rebar with welded eye's that i ground down smooth.

Probably the same one sI picked up last year. I anchored down my carport with these by running a ratchet strap around each pole junction and down to the loop. Stayed solid as a rock all week.

CapSmashy · Post by **CapSmashy** » Tue Jun 24, 2008 12:48 pm

And to second Tom, use duct tape. Even if you don't need it, put some on there anyway just because.

Dork · Post by **Dork** » Tue Jun 24, 2008 12:53 pm

My camp has had a similar structure for the last couple of years. It has a custom canvas top and is wonderful. It's held down by what I believe is 24" candycane rebar. As long as the ropes and top don't droop too much noise shouldn't be a big problem.

Only problems have been figuring out how to hold the bottom of the center pole in position, and the canvas degrading the second year from exposure to playa dust.

CapSmashy · Post by **CapSmashy** » Tue Jun 24, 2008 1:09 pm

Dork, what is the diameter of the center pole?

I'm thinking you could possibly fab up a footer that the pole drops into.

A bolt is used to hold the pole into the footer and then the footer is secured to the playa with long nail spikes.

Think patio umbrella stand for a basic idea of what I am thing of.

Dork · Post by **Dork** » Tue Jun 24, 2008 3:22 pm

The center pole was a 2x4. I wasn't involved in creating the shade so I don't know what he has cooking for this year. Last year he eventually tied it to some rebar and it was just fine - it just wasn't quite as slick looking as the rest of the structure.

Bob · Post by **Bob** » Tue Jun 24, 2008 5:21 pm

ilmarinen wrote:I've acquired a bunch of the 18" long military surplus steel "mess hall" stakes (donated by an former burner). They are great, like 5/8" diameter, etc., but not sure they will be long enough to anchor securely into the playa.

Drive them below the playa surface, and double them up if you're still worried.

Post by **trilobyte** » Wed Jun 25, 2008 1:41 pm

I used 18-inch "hurricane" stakes for the corners of my 20x50 conduit frame structure. Actually, last year I used 8 of the stakes - hit all 4 corners plus two more along the sides. It was dusty and windy as fuck when we arrived and wanted to make sure the structure wouldn't go anywhere if we got another storm that bad. As it turned out, we got several storms that were even worse... and the hurricane stakes held up beautifully. I think they were around $6 apiece from All 4 Canopy a couple years ago.

Pulling them out wasn't too terrible, and didn't use any special tools to do it.

Trilo

Anchoring a Tensegrity Structure--Auger Earth Achors?

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