Footings and piers

[Mannfamilywoodworks]

I’m trying to figure out if my piers I’ve built are strong enough to hold my shipping container.

The 45’ container empty weighs 5 tons.
I have roughly 50 pieces of drywall, over 100 or so 2x4s, appliances, furniture etc etc. I’d say around 2 additional tons of materials inside.

So 7 tons total weight roughly.


My plan is to start with two piers on the high end of the container.
I dug down as far down as I could go for my footing.
The frost line in my area is at 42” below grade.

I got about 20” down below grade. I hit a massive rock face.

I went to the other corner.
Same situation.
I went 8 feet back.
Same situation.
8’ to the other side.
Same rock face 20” or less below grade.

Okay I’m building on top of a ginormous rock.

So I drilled into the rock with a 1/2 bit and I stuck re bar into the rock. I poured a 32”x32” footing with the rebar into the rock.

After that I began stacking 8x8x16 cinder blocks to get to my desired height of around 40”.

Now I’m going to make a temporary support system out of 6x6 timber’s and jack the container up an additional 10” and it will be perfectly level and I’ll continue with my block pier foundation.

I tied the re bar into the rock, through my footings, and tied an additional piece of rebar through the cinder blocks, I then filled those solid with concrete.

How much weight do you think one of these piers can handle?
I’m going to be putting them every 8’ on each side of the container.
when I’m done I’ll have 10 piers total.
Thankyou if anyone has any structural knowledge.

 

[MurphyGuy]

The only place the container should be supported from is on the corners. Anything in the middle is likely to cause damage. If the corners fail, the middle will just bend and twist the box.
If a corner fails and the box twists a little, it will twist right back when the corner is fixed. But if the corner fails and the middle is holding it up, it can bend the sidewall panels, the beam under, and it will never go back into shape. Corners only...

My cargo container is a standard 40 footer and it is packed to the gills with everything from machinery and wood to steel beams and 1/2 inch thick steel plates. There is but a 24 inch path down the center and its full from floor to ceiling.

I dug down 20 inches and poured a solid 24" x 24" block for each corner. My container is on a slope where there is about 24 inches difference between the high and low sides, so the blocks up by the doors are just 2 or 3 inches above ground level, but the blocks in the back are almost 30 inches tall.

Our frost line is 42 inches in Michigan, but I only went down 20 inches. Yes, during the winter, the container does lift up an inch or so here or there, but it settles right back down in the spring. Been there for 10 years and no issues.