Staking down a 40' dome

MikeVDS · Post by **MikeVDS** » Mon Jul 09, 2007 1:09 pm

We're finishing up our 41 footer as I write this and it should be up by this weekend. Some people have said that they do not stake down their domes of this size. We, liking to do things overkill, will be staking it down, but would like to get a general idea of what other people do, so we can do a little more. Our 21' covered with a parachute, we just use "J" shaped rebar. Our 41' is much heavier but with a 64' parachute can catch a lot of wind. So what does everyone else use to stake theirs down? Have you ever had any problems with your method? What size and what do you use as a cover?

joel the ornery · Post by **joel the ornery** » Mon Jul 09, 2007 1:45 pm

my friends use bags filled with playa, bungy corded to the frame work instead to staking it out. no guylines or tent pegs to trip over.

capjbadger · Post by **capjbadger** » Mon Jul 09, 2007 2:02 pm

I currently have a 1v dome stacked on top of a 2v dome, fully covered with "silver" tarps (custom fitted). The whole thing is about 15' tall and 17' across. I have "candycane/J" style rebar that I pound in over half the vertices at the bottom of the dome (5 of them, 2ft in to the ground each). It hasn't budged.

You just have to be careful not to hit the EMT struts while pounding in the rebar.
I have a new idea for this year to avoid that though. I'm going to put the rebar in just inside the dome edge, then tie the rebar to the inside of the dome with ratching straps.

Badger

Post by **mdmf007** » Mon Jul 09, 2007 3:29 pm

I am back -

So to stake or not to stae? A dome is an invitation to disaster if it is not staked. I have personally seen large domes ripped loose form the ground that were staked in, better yet they had metal rebar stakes attached to ten foot lines flailing inthe wind like little maces loking for a face to rip open.

Also - the larger the dome, the lower the weight to surface area ratio. making it more likely to fly away than a small dome.

later

capjbadger · Post by **capjbadger** » Mon Jul 09, 2007 3:41 pm

mdmf007 wrote:Also - the larger the dome, the lower the weight to surface area ratio. making it more likely to fly away than a small dome.

later

Yep. I think it's something on the order of if you build a geo sphere 1/2 mile wide with a clear cover on it, a 1 degree temp difference inside is enough to get it to float away...

Spheres have the highest volume to surface area ratio of any shape, followed closely by domes. in our case, surface area is directly related to the weight of the dome. Plus you have airfoil and "parachute" type issues in a wind.

Stake it twice as much as you think you need...

And for the love of god, stake it before you cover it. I don't know how many times I've seen people trying to cover a shelter before they stake it to get some shade to work in, only to have to chase down their now flying shelter.

Badger

MikeVDS · Post by **MikeVDS** » Mon Jul 09, 2007 6:19 pm

Stake it twice as much as you think you need...

That's why I posted this, to get a gauge of what has worked for others and what hasn't.

Bob · Post by **Bob** » Mon Jul 09, 2007 10:47 pm

A 60-ft dome eggshelled at the 2000 event partly because it wasn't staked adequately, partly because they used 3/4 EMT. Feeble rebar stakes loosened up, allowing the windward edge to flex & pound on the ground, and a 20-ft circular section dimpled inward. Awesome carnage all around that year. I'd use a few stakes, ya.

Isotopia · Post by **Isotopia** » Mon Jul 09, 2007 11:26 pm

I'd go for a minimum of 2.5' rebar stakes pounded into the ground at every floor level vector point. Follow up with 920 lb cable strength airline cable attached to your frame and each (possibly every other) piece of rebar.

MikeVDS · Post by **MikeVDS** » Tue Jul 10, 2007 6:21 am

A 60-ft dome eggshelled at the 2000 event partly because it wasn't staked adequately, partly because they used 3/4 EMT.

I saw pictures of that one. That thing would have gone, with or without stakes. 3/4" emt is just too flimsy in 10' struts. It is a good reminder though that things can easily be destroyed out there.

Bob · Post by **Bob** » Tue Jul 10, 2007 9:51 am

It had ~6-ft struts, the cover was strapped on pretty tight, and without pulling off of its feeble rebar stakes, lifting up, flexing and pounding back on the ground repeatedly I don't think it would have eggshelled. But it is true the builder, Pacific Domes, went to 1 inch EMT for similar domes after that.

capjbadger · Post by **capjbadger** » Tue Jul 10, 2007 11:52 am

The problem you run into with bigger and higher frequency domes is that the higher the frequency, the "flatter" the dome gets, and thus verticies can pop in (dimple) much more easily. If you look at high frequency domes in other places, you see that they "nest" a slightly smaller dome in the bigger one and connect them. Your happy 2-D triangles are now 3-D Tetrahedrons. Super strong.

(Now here's a fun trick... Can you force your mind to see the image rotate the other way?

I can, but damn that's hard. lol )

Badger

MikeVDS · Post by **MikeVDS** » Tue Jul 10, 2007 1:53 pm

It had ~6-ft struts

Ahh it was a different one than I saw I guess. The one I saw was 3/4"emt 60' and a v4. It looks flimsy even before it collapsed.

MikeVDS · Post by **MikeVDS** » Tue Jul 10, 2007 1:55 pm

It had ~6-ft struts

Ahh it was a different one than I saw I guess. The one I saw was 3/4"emt 60' and a v4. It looks flimsy even before it collapsed.

Teo del Fuego · Post by **Teo del Fuego** » Tue Jul 10, 2007 2:36 pm

capjbadger wrote:(Now here's a fun trick... Can you force your mind to see the image rotate the other way?

Pretty cool little graphic. I could see it spin the other way. I could see it spnning to the right, but after I refocused, the default spin is now always to the left. That's funny. Im left handed. Wonder if there is any correlation with others between dominant hand and direction of spin.

Teo del Fuego · Post by **Teo del Fuego** » Tue Jul 10, 2007 2:37 pm

capjbadger wrote:(Now here's a fun trick... Can you force your mind to see the image rotate the other way?

Pretty cool little graphic. I could see it spin the other way. I could see it spnning to the right, but after I refocused, the default spin is now always to the left. That's funny. Im left handed. Wonder if there is any correlation with others between dominant hand and direction of spin.

capjbadger · Post by **capjbadger** » Tue Jul 10, 2007 2:50 pm

Teo del Fuego wrote:
capjbadger wrote:(Now here's a fun trick... Can you force your mind to see the image rotate the other way?
Pretty cool little graphic. I could see it spin the other way. I could see it spnning to the right, but after I refocused, the default spin is now always to the left. That's funny. Im left handed. Wonder if there is any correlation with others between dominant hand and direction of spin.

I'm right handed and the default spin is to the left for me as well. I found the trick is to force your brain to think the back corner is trally the front corner as it passes behinf the object, and suddenly it's switched.

Badger

(what's with all the double posts all of a sudden?)

MikeVDS · Post by **MikeVDS** » Tue Jul 10, 2007 4:38 pm

Yep, pretty neat. It spun right for me to start with.

Here is the dome I was thinking you were talking about. It looked like a disaster to start with.

http://ironwolf.dangerousgames.com/burningman99/

capjbadger · Post by **capjbadger** » Tue Jul 10, 2007 5:12 pm

MikeVDS wrote:Yep, pretty neat. It spun right for me to start with.

Here is the dome I was thinking you were talking about. It looked like a disaster to start with.

http://ironwolf.dangerousgames.com/burningman99/

Holy fuck... They built a 60', 4v dome with 1/2" conduit???

The 3/4" stuff maxes out at about 5 or 6' let alone 1/2". Those look to be full 10' struts! *facepalm*

Fucking stupid... The first vertice popping in should of been a clue. And building it with the cover on, but not staked. Fuck. They're lucky they didn't kill anybody.

I hope they learned they're leasson.

I'll give them credit for the cool salvage of the project.

Badger

Bob · Post by **Bob** » Tue Jul 10, 2007 10:38 pm

MikeVDS wrote:Here is the dome I was thinking you were talking about. It looked like a disaster to start with.

No, that was '99, some genius project in Center Camp that blew down pretty quickly when the winds came up. The 60-ft dome was out near 10:00 in a rave camp.

A few things had trouble in Center Camp that year -- Media, Checkpoint Salon (aka Playa Info), Earth Guardians, etc. We talked the org into flat-roof wood-frame shade structures the following year, for better or worse. All you have to do to add floor space is add more posts & beams & shade cloth, not more height and a completely different geometry as with domes. Boring but practical.