Earth anchors

[bluedog225]

I’m working on a solution to anchor my two conex boxes to the ground. One 40’ high cube and one 20’ standard.

I’ve got them both off the ground about 18” for airflow, critter control, and a storage underneath.

The smaller 20‘ will have some solar panels mounted in a way that’s going to catch some wind. It’s a wooded area on one side and the design wind loads for the area are 70 mph. I’ll (maybe) get around to figuring out the actual wind loading if I’m able though given the uncertainties regarding the actual soil conditions at the site, close enough is probably going to have to do.

I’m looking at these 66” long 1” helix anchors with a 10” plate. 12,000 pull out in hard pan soils….something less in my undisturbed, dense, sandy clay.

From experience, It will be a bear to dig the holes even at 6” to accommodate that big 10” plate but I can do it. No way to twist it in with no starter hole.

The other idea I had was to take a 3’ piece of 3” angle (.25”), cut the ends to 45 degrees, and attach a heavy galvanized chain to the side near the middle. Drop it down a smaller 4” hole, pound it sideways with a landscape timber, and proof it with the engine hoist and a crane scale. The 4” hole will be significantly easier.

Another option is digging old fashioned concrete piers or pads. Calculating pullout on piers is over my head. But there is no arguing with a big 4’x4’x2’ lump of concrete in each corner.

I’m leaning towards the angle iron idea though I’ve not done this before.

What you y’all think?

 

[jack stand]

Are you loading the box at all?
I'm very familiar with these for 30+/- years for jobsite storage and have a very hard time thinking about wind troubles even with the solar panels.
I've picked them out to buy them and they're stacked up 2-3 high and empty in their "yard" completely unsecured.

 

[strutaeng]

Those look kinda too light in opinion.

I have seen these screw-type anchors that you drive in with a heavy impact gun. They have published load values for different soil types. I think they use them for utility pole tension wires. I'll see if I can find the website.

Edit: https://americanearthanchors.com/pe46-guy-46-inch-penetrator-with-2-inch-guy-head/


There's also Manta-ray soil anchors. Used them once at a 45 degree for a warehouse tall exposed grade beam that was bowing outward. Good stuff.

 

[bluedog225]

It will be loaded. Not too heavy. Mostly solar support equipment. We do occasionally get some impressive winds. Moderate tornado risk. Seems unwise to leave them unanchored.

Thanks for the links. The idea of not digging has a lot of appeal.

 

[bluedog225]

I have a hard time understanding how this is the right answer. 90 degrees to the load would have been my instinct.

 

[strutaeng]

I have a hard time understanding how this is the right answer. 90 degrees to the load would have been my instinct.

That makes sense to me. Those are designed such that the threads are engaged in the soil. The reaction is pure axial tension.

If the load is at angle to the anchor's axis, you'll get bending and shear, in addition to axial tension. You'll never be able to develop the same tension as if in pure tension.

Any other anchor follows this simple rule.

Regarding the "contents" of what is inside the enclosure, I would treat them the way the building codes treat live loads on buildings for lateral analysis: they are neglected in some of the load combinations involving wind overturning.

 

[gregs]

I have seen anchors that the end is toggled. Basically you drive in a straight "rod" and when its at the proper depth you use a smaller diameter rod driven in the center to "flip or toggle" out the anchor part. I think I came across them when researching deadmen for a seawall project.

The other option is to find a mobile home installer to do it for you. The have the correct tools to drive the helix ones in the ground.

 

[reader2580]

I have two solar ground mount arrays at home. They have large helical anchors that were spun in with an auger drive on a skid steer. There are companies that install helical anchors/piers in most areas.

 

[scofo]

If your ground is anything like mine, I'm NW of Austin. There is no way your pictured helical stake can be turned into the earth without a large pilot hole, if then.


I had a half dozen come with a fairly lightweight, fairly large area, temp shelter. 12x20 Shelter logic "garage in a box"

I trimmed one down to about an 1.5" dia. heli and got no where.

I tried some different types of lags and construction bolts, albeit for wood but as a proof of concept for those anchors from your second pic. Still couldn't get purchase.

I think your idea of a homemade toggle, if you can drill a hole, might be your best bet.

I ended up cutting the helical part off at angle and was able to pound them In the ground at a slight angle. I also used 2 or 3 12" galvanized nails at each of the legs.


The only reason I could drive them in was because the area had been back filled by my pickup and a little kubota tractor 20 years before. If it had been undisturbed, no way in hell I could have driven them in.

Maybe a utility company can put in those guy line anchors for utility poles??? I dont know if they are driven or twisted in but they seem to do the jobs. I've seen a few cars parked up on guy line cables.

Goodluck

 

[Youngandfree]

I have seen anchors that the end is toggled. Basically you drive in a straight "rod" and when its at the proper depth you use a smaller diameter rod driven in the center to "flip or toggle" out the anchor part. I think I came across them when researching deadmen for a seawall project.

The other option is to find a mobile home installer to do it for you. The have the correct tools to drive the helix ones in the ground.

^^^^^^^^

 

[RaisedByWolves]

Are you loading the box at all?
I'm very familiar with these for 30+/- years for jobsite storage and have a very hard time thinking about wind troubles even with the solar panels.
I've picked them out to buy them and they're stacked up 2-3 high and empty in their "yard" completely unsecured.

This.

My 20'er is 5K LBS empty, never even thought of wind.

 

[bluedog225]

I’m a monkey pressing buttons but it looks like 8900 lbs wind load on one side at 70 mph.

The empty weight is 4500 lbs. And I’m guessing only part of that weight resists it being pushed over.

Something in the 10,000 lb range would seem in the ballpark. For non-extraordinary events.

I wouldn’t mind 15,000-20,000 lbs given the cost of the batteries, inverter, and charge controllers. And being without electricity.

 

[jack stand]

It will be loaded. Not too heavy. Mostly solar support equipment. We do occasionally get some impressive winds. Moderate tornado risk. Seems unwise to leave them unanchored.

Thanks for the links. The idea of not digging has a lot of appeal.

For some reason I "pictured" them on top. This picture would seem to lessen the wind load.
If this is a long term installation and the earth anchors are not feasible in your soil's how about a quick 4"-5" slab ? Either way I would imagine that the solar panels would be in the next county before you need to worry about the container just sitting there on the ground blowing over. (but I really don't know your realistic wind conditions)

 

[steel 35]

I have rolled rods of rebar In footings,
In high load, Thats high load.

 

[ItsNemo]

Do they not have people that put in screw/helical piles down in texas? You can get them with 100k+ lbs pull out (mind you these are the massive infrastructure sized ones).

 

[southalabama]

Oil field guys in Texas should have someone that installs them. A buddy used to install them as contractor in Mississippi in the oil fields

 

[Drill Sergeant Arc]

The wind in our area primarily come from one direction, but we do get cyclone type storm winds that can reach 100 MPH but they are very rare. I would think you could do a little research and strategically position these in a A, T Or L or even side by side configuration and connect the boxes through simple bolts at the contact area. I would think the boxes combined footprint alone in the side x side configuration would eliminate any potential rollover and the T configuration would be exponentially more difficult to flip let alone move horizontally.

 

[bluedog225]

Putting a couple together would work. Unfortunately, only room for one.

I’m sure for enough money I can get just about anything installed. Something diy that doesn’t require a machine on a trailer would be nice. I bet my milwaukee super hawg could drive those penetrator anchors.

I’m close enough to austin that most everybody is in town making big $. Getting folks out to the country is tough and hard to find someone who doesn’t want a fortune.

 

[reader2580]

I find it hard to believe that lag bolt style anchor would do much of anything. That other anchor would probably be okay if you could spin it into the ground. If it were me I would look at putting in round concrete footings with some sort of anchoring point embedded in the concrete. Then run cables over top of your container that attach to the anchoring point in the concrete on the two sides.

 

[BombShelter]

I used Diamond Piers for my deck, all the home flippers up here are hooked on them. Rent the Makita Hammer Drill and special Diamond Pier Bit (Home Depot) for $60 and your done in no time. I have to believe they'll work in your situation.

Diamond Pier

Diamond Pier Foundations - Structurally rated no dig footings for decks, porches, pergolas, posts, and more. Code compliant, and install in minutes. Also available for larger commercial projects.

www.diamondpiers.com

 

[mogandave]

Why not put a little space between the panels, and between the panels and the container?

What direction is the prevailing wind?

 

[rsanter]

Look at the earth anchors they use for mobile homes in high wind, hurricane areas

 

[larry4406]

I used Diamond Piers for my deck, all the home flippers up here are hooked on them. Rent the Makita Hammer Drill and special Diamond Pier Bit (Home Depot) for $60 and your done in no time. I have to believe they'll work in your situation.

Diamond Pier

Diamond Pier Foundations - Structurally rated no dig footings for decks, porches, pergolas, posts, and more. Code compliant, and install in minutes. Also available for larger commercial projects.

www.diamondpiers.com

Never heard of these before, interesting. Thanks for posting.

 

[bluedog225]

Thanks all. The manta-ray anchors recommended by strutaeng seem to be the best of the best as far as hold down power is concerned. I’ll dig a little deeper….

 

[bluedog225]

Edit-in real life, those manta-ray are hard to get for the diy’ers.

These look pretty close and can be ordered online.

Arrowhead Anchors | American Earth Anchors

Arrowhead cabled anchors offer superior holding in hard, compact, and rocky soil. Available in both steel and aluminum.

americanearthanchors.com