Holding strength of lag bolts

[Wigwam]

Just curious, has anyone ever done a study of how much force a standard 14" lag bolt drilled into the playa will resist? I know it will vary greatly by playa conditions, but it might be helpful in knowing a range (assuming it's not from zero to infinity) so that any structure with an area of X and a wind of Y will need Z number of lag bolts to properly secure it.

Let both the serious answers and the snark begin!

[some seeing eye]

Just for shits and giggles one of my campmates set up a test rig for playa fasteners.

A 2x4 tripod, a trailer jack, a crane scale, and some lengths of chain. Did a live demo on-playa.

to keep it fair we used all 10" fasteners

re-bar
timber screw
lag screw

The re-bar failed under 36 kg of upward force and as soon as it lost grip, popped right out
Timber screw under 91 kg of force but it failed slowly and continued to grip w/ about 40 kg until the last 4" or so

*** Lag screw didn't fail until 202 kg of force was applied (almost 450 lbs of frikken force people!) , and as the close up photo shows it heaved the ground around it to a diameter of about 18" ***

now this is just direct upward force (never mind if the load was lateral to the fastener)
and these are just 10" (I used 18" for my structure - I'm now thinking this was way overkill)
driven in by a cheap Ryobi 18v impact driver

So... "SCIENCE !!! BITCHES"

props to Kevin aka Risqué of camp DIY

There are some photos over on that thread and continuing discussion. https://eplaya.burningman.org/posting.p ... &p=1093297

I always post the find force equation Pressure in pounds = = 0.00256 x wind speed in miles per hour squared. And the local wind building design speeds https://www.washoecounty.gov/building/F ... iteria.pdf.

It is probably better to have the mods delete this continue the discussion over on that thread for which we have to thank Mr Figjam for coolers, and lag screws, and his DIY trailer!

[Wigwam]

Excellent. I wonder if the screw you picture is a lag screw or more likely a timber screw?