Securing 3 4x8ft 80+lb panels on the playa

[featherless]

Hallo! I'm part of camp Pixel Heart, a new camp this year that will be making its way to the playa with our 12x8ft audio-reactive LED display.

Here's what it looks like:


I'm posting this here with the hopes of gathering some insights on a challenge we've set for ourselves. Historically we've been leaning the display against walls or cars. This has proven to work well and likely will prove to work well again on the playa, but we want to try to see if we can set up the Pixel Heart without needing a car.

The specs of the challenge:
- The Pixel Heart is composed of three separate 4x8ft vertical panels, each weighing approximately 80 pounds.
- We need to be able to lean the Pixel Heart against a structure so that it can stay reasonably vertical without risk of falling forward or backward. In the past we've solved this by tying it down to a van. There are eye rings on the top and bottom of each panel for securing.
- We don't want to spend thousands of dollars on new equipment.

Thus far we've begun research on a few options:

1) Trussing equipment. From what we gather it's super expensive to buy, so we'd want to rent it from someone.
2) Build our own structure. We've never built a support structure like this, so we've been bouncing around ideas (not really knowing what will work best)
- Swing-set-style frame, with two A frames on either side of the structure and a beam going across.
- L shapes behind each of the panels with sand bags as counterweights.

So our questions to you wonderful folks of eplaya:
- If you have experience building structures like this, what frame design have you found to work best?
- Is there a cheap obvious solution that we're completely missing (other than using a car)?

Thanks so much!

Some videos of the Pixel Heart in action:

[GreyCoyote]

Neat! Cool idea!

The reality of this however is that when the wind REALLY blows, you need to just lay these panels down. You can fight the wind, but you cant win the battle. So bow-out sooner than later and save the expense of having one come crashing down.

There are any number of ways of bracing these things, but it all comes down to your needs. If it was me I'd make a 2x4 "A"-frame and put sandbags on the bottom. Would this resist 75 MPH winds? Nope. But if you do it right, they just might fall down in a controlled manner with no damage to the panels. And that is the important part. Make these self-toppling in a controlled manner if possible. You may not be there to stow them manually.

It's surprising how much force a 4x8 sheet can generate in a good breeze. There are on-line calcs for computing this type of load. Google is your friend, and it's the classic "flat-plate" paradigm.

Good luck! And neat idea!

[Canoe]

...when the wind REALLY blows, ...Would this resist 75 MPH winds? ...

To give you an idea what GreyCoyote means, wind pressure on a vertical wall (4' x 8' = 32 sq.ft.) from a 75 mph wind:

• 14 lbs./sq.ft. (the force in an open field), 32 times 14 = 448 lbs. of force
• 28 lbs./sq.ft. (the force possible with wind channeled by surrounding objects/shelters), 32 times 28 = 896 lbs. of force

And the wind can exceed 75 mph.
All bets are off for micro bursts.

We probably won't get winds that strong, but...
(and I think I recall seeing that we had winds above 70 mph there within the past month?)

Engineer it for failure.
Whatever structure you choose, and even if pegged down to the ground and designed to tip over should those fail, considering adding a cable to each panel with it's own anchor to the ground, so once tipped over it can't blow away and hit anybody. I know 80 lbs. is a lot, but if the wind hits it wrong...
Note that these http://eplaya.burningman.org/viewtopic. ... 39#p919139
are threaded, so you screw it into the playa (cordless drill makes for easy in and easy out, or a ratchet). Upscale the size to what you need.

[FIGJAM]

Are there 2 eye rings at the top and bottom of each panel?

How large are the eye rings?

Now here's the answer!

Get enough EMT so that you have a stick for each eye ring at the top of the panels.

Pound 3"s of each end flat and drill a hole through it to bolt the eye ring to at one end, and to lag bolt it to the playa on the other.

You will have to bend the tabs to adjust for the angle that you want. (think of it like a sandwich board)

For the bottom of the panels, cut some chain into 2 link pieces, maybe 3 links since you need to bolt these to the eyerings.

One for each eye ring at the bottom of the panels

Bolt these to the eye rings on the bottom eye rings and lag bolt them to the playa.






I would be surprised if this could move if you use 14" lag bolts.

[lemur]

4x4 posts 2 feet deep.

[SouthernExposure]

Positioning the panels in a Southwest/Northeast orientation will align them parallel with the prevailing winds and reduce the occasion of tangential winds which put the most load on them. Of course, the winds blow in all directions out there, but the SW/NE winds are prevailing.

Cheers

SE

[Canoe]

...the SW/NE winds are prevailing...

06 dust devil.jpg

[some seeing eye]

EMT does have a structural spec, but it is designed to support small weights of wire with strapping to buildings.

So EMT is risky in any structural use. Suggest you look at renting or buying on Craigslist scaffolding. Properly guyed and staked it does make a nice sleeping platform, but also an attractive nuisance for climbing. I'm sure many dome builders would like to share its use pre and post the event. Wheels on for dome building wheels off and anchored for sign supporting.

There is no substitute for trained structural engineering to calculate the forces, in your case overturning and sliding. Mr Canoe, always a great technical resource, gives an idea of the forces involved. But if it falls and someone is injured it is tragic all around.

[featherless]

Lots of info already! Thanks everyone Looks like the two primary options are the A frame and scaffolding (EMT sounds like it won't be strong enough). Either way it seems like we're going to have to spend a few hundred dollars at best.

Back to researching frames and scaffolding!

[Token]

I'd venture a guess a lot if blood sweat and tears went into building the panels.

You really need someone skilled in the engineering craft to help you out.

If you choose to wing it, remember that triangles are your friend.

Look at how barn rafters are constructed for ideas on building a truss.

[Canoe]

... remember that triangles are your friend. ...

+1000