Footing & Pier Pour Questions / Options.

[NWOhioChevyGuy]

So I'm wrapping up the plans for moving a shop from my parents farm to mine. See https://www.garagejournal.com/forum/threads/moving-a-free-steel-building.521286/ for reference.

My concrete situation is looking like I will be utilizing pier & footers for the steel framed structure of the building.
The End walls will get 2x8 4ply Perma Column's with footing "cookies".

I have the footer & piers sketched out and plan to propose this to the building inspector when I apply for my permit.
Using square forms to allow me to attach my skirt boards to the exterior edge and pour the 5" floor level with top of piers.
I'm confident the design will fly, my questions are around the steps to pour them.

What I am thinking.
1) excavate oversized square holes for forms
(sandy soils so I doubt I can use the excavation as my footing form)
2) form 36" x 36" x 12" footers
3) Install rebar
4) Pour Footer
5) Remove footer forms
6) Install Pier forms
7) Pour Piers
(includes setting J bolts)
8) Remove Forms
9) Backfill / Compact to grade

There will only be 6 of these, and concrete will be minimal. (My calcs on the sketch)
Is their a way to pour these footers & piers at one time? I know forms would be different, I'm upto building them if its possible.
Like they do with the "bigfoot" footers with the Sonotubes.

Something like this but formed & poured in place?

 

[Joemctag]

It’s probably actually easier to form the pier and footing as one. No “top” on the 9” wide footing out past the pier. Your pier is only 30” over the top of footing. Not sure if you can pour all that at once with 5” slum. With a pump and boom like they use for house foundations, you could do halfway and then start back at the first one, filling them up. Without a pump, maybe just fill the first one as high asylums can without footer overflowing and start on another one. Maybe can swing chute and do 2 or 3 without moving truck.
Probably also would depend on how cold it is, too. Someone in your area might know.
On commercial work, at least in my area, if you tell the concrete plant that you’re pouring footings, they might short you, figuring that there’s no way you could know the volume accurately with a dirt trench being the “form”. Then you’d have to pay for another partial truck. So be clear when you order that it’s formed up and you’re really sure of the volume and are adding at most 10%, say. Maybe they don’t bother cheating on 3-1/2 yards or so. Good luck!

 

[NWOhioChevyGuy]

It’s probably actually easier to form the pier and footing as one. No “top” on the 9” wide footing out past the pier. Your pier is only 30” over the top of footing. Not sure if you can pour all that at once with 5” slum. With a pump and boom like they use for house foundations, you could do halfway and then start back at the first one, filling them up. Without a pump, maybe just fill the first one as high asylums can without footer overflowing and start on another one. Maybe can swing chute and do 2 or 3 without moving truck.
Probably also would depend on how cold it is, too. Someone in your area might know.
On commercial work, at least in my area, if you tell the concrete plant that you’re pouring footings, they might short you, figuring that there’s no way you could know the volume accurately with a dirt trench being the “form”. Then you’d have to pay for another partial truck. So be clear when you order that it’s formed up and you’re really sure of the volume and are adding at most 10%, say. Maybe they don’t bother cheating on 3-1/2 yards or so. Good luck!

Your comments have my wheels turning.
1) excavate oversized square holes for forms
(sandy soils so I doubt I can use the excavation as my footing form)
2) Install footer forms
3) Install rebar
4) Pour Footers (all 6)
5) Install pier forms w/ footer "lid" if needed. (premade ready to screw in place)
6) Pour piers from same truck, same day, starting back at first pier
(includes setting J bolts)
7) Remove Forms
8) Backfill / Compact to grade

 

[bb29510]

done it both ways. some like perfect square footers so they can pull lines, other will just dig a hole and fill with concrete

got think about price of plywood to form

 

[NWOhioChevyGuy]

done it both ways. some like perfect square footers so they can pull lines, other will just dig a hole and fill with concrete

got think about price of plywood to form

They are small, so investment for form material is minimal.

 

[Zeke]

You might be thinking the concrete will go down the center and rise up all around the pier. It usually doesn't on this principle:

 

[Rusted Nut]

Forming and pouring in two separate parts is easier, but you’ll get two short load charges. You could mono form/pour this pretty easily, but you’ll have to wait for the footing to cure a bit before you pour the column; maybe 1 - 2 hours, use a hot mix. A third option is to form a cap over the footing to hold the concrete from pushing out, but you’ll have to be sure you get the footing filled up and consolidated properly.

 

[Zeke]

The truck will arrive with a stiff mix and good slump. If not pumping then place that mix in the bottom of the mono pour form. By the time you get all the bases in chances are you can fill the columns. You could add a small amount of water but since this is all below grade some surface voids won't show.

You do know that they pour stairs in open forms one story high all at once starting at the bottom, right?

 

[NWOhioChevyGuy]

I will likely pour the Footings 1-6 then
Add forms for piers as we go with a "lid" on the footings
Then pour the Piers 1-6 from the same truck

Cost of the material to form this way would be less than the short charge on a second truck.
Also doing the form work in two steps will prevent the potential of the concrete not flowing into the footings fully with a single form set up.

 

[strutaeng]

I think you have a good plan and that's how it's normally done. I would call the piers plinths though, but that doesn't really matter...

So the plinths are not continuous, right? Just at each location of the columns? What's between the plinths? A wall? How's that connected to the plinths?

Maybe consider a wall with plinth (or call it a pilaster?), but that will require a continuous footing instead of a isolated footing. Much more work, but I don't see how you would retain that much soil from the grade difference without something similar?

 

[NWOhioChevyGuy]

I think you have a good plan and that's how it's normally done. I would call the piers plinths though, but that doesn't really matter...

So the plinths are not continuous, right? Just at each location of the columns? What's between the plinths? A wall? How's that connected to the plinths?

Maybe consider a wall with plinth (or call it a pilaster?), but that will require a continuous footing instead of a isolated footing. Much more work, but I don't see how you would retain that much soil from the grade difference without something similar?

These will be to support the central steel structure of the building, end walls will have the perma columns & 4 ply 2x8 poles.
There will be a 5" concrete slab between them.
Two 2x6x15 T&G skirt boards to form slab fastened to the outside edge of pier, top of 5" slab will be same level as top of bottom 2x6 & Pier.
The walls will be 2x6x15 Girts w/ steel sheeting.

 

[Rusted Nut]

I will likely pour the Footings 1-6 then
Add forms for piers as we go with a "lid" on the footings
Then pour the Piers 1-6 from the same truck

Cost of the material to form this way would be less than the short charge on a second truck.
Also doing the form work in two steps will prevent the potential of the concrete not flowing into the footings fully with a single form set up.

Sounds like a good plan. You could build footing caps and column forms nailed together, then after pouring the footings; nail cap and col forms on and pour. Yes, way cheaper than two short load charges.

 

[readhead]

There is a tremendous amount of thrust outward at the base of the rigid frames that I don't think you have taken into account.

 

[NWOhioChevyGuy]

Sounds like a good plan. You could build footing caps and column forms nailed together, then after pouring the footings; nail cap and col forms on and pour. Yes, way cheaper than two short load charges.

Yup that is the current plan of action.
Footers formed and steel in place before truck arrives.
As the footers are poured, add the remaining forms and pour the piers. (or Plinths )

 

[NWOhioChevyGuy]

There is a tremendous amount of thrust outward at the base of the rigid frames that I don't think you have taken into account.

Reviewing several builder sites that do metal buildings, this configuration is an option of foundation that they offer.
What I have patterned this after.

Steel Building Foundation Designs and Installation Advice

View the Different Types of Steel Building Foundation and Concrete Slab Designs. Sunward Provides Install Tips and Advice for Pouring Concrete Foundations.

sunwardsteel.com

 

[readhead]

The configuration is an option but thinking that a picture is the design for your structure may be short sighted. That photo is the result of a specific design for that specific building. Most often there is a tie between the piers for each rigid frame.

 

[billconner]

I don't know your grade situation but
based on what I've seen and read, the bottom girt should be a 2x8 and should project above the slab 4". This allows the metal siding to be well above dirt. Just a thought. Maybe your slab is a lot higher than grade.

Found this composite (think Trex) bottom hurt. https://www.menards.com/main/buildi...gradeboard/1122197/p-1444441497877-c-5713.htm

Are you planning on heating? If so,I'd think you'd want the slab edge insulated. I'd probably put a 2' wide 2" rigid foam board vertically at edge of slab to keep frost from under slab.

Random thoughts.

 

[NWOhioChevyGuy]

It will have a radiant tube heater in it at some point. Only heated while working out there.

The two T&G 2x6 will be 5 1/4" above the slab & 5 1/4" forming the slab. Slab will be just above grade, with a gravel boarder around building for help with drainage. We are on a sand "hill", drainage is EASY, and build site will be completely level with the yard.

 

[billconner]

Sounds good. I'm assuming t&g is pressure treated. I'd probably lay a bead if caulk between them.

 

[NWOhioChevyGuy]

Sounds good. I'm assuming t&g is pressure treated. I'd probably lay a bead if caulk between them.

Yes it will be pressure treated ground contact rated.

 

[C-S-H]

Did you design this pier yourself? Can you post your calculations? Your pier drawing looks odd in both proportion and bar layout. These piers look woefully inadequate for the gable frames photographed in your other thread.

 

[Rusted Nut]

OP - Both readhead and C-S-H have brought very valid points, that I think you should give careful consideration to.

 

[NWOhioChevyGuy]

Yes I did the layout / design myself.

Depth is down to frost requirement here, same as my attached garage build.
NO real calculations, it was based off of similar builds I have seen using Sonotube's and Bigfoot type footings for structures in my area.

I suppose I could have someone do the calculations and footer design.

 

[NWOhioChevyGuy]

Just a follow up on this. I touched base with the Architect who designed my garage build for the Shop foundation and pad.

Essentially his design is what I had planned, I have a cement contractor working up a quotation for what he laid out.
If the price is not crazy I will likely just have them do it start to finish. Other than clearing site and prepping level ground.

To be honest his design is a little bit simpler than what I had sketched up.