Thickened edge slab for barn

[karp2005gmail.com]

I'm building foundation for steel barn, manufacturer recommended slab with piers for columns. Contractor asking to pour in 2 pours since edge of slab should go 42 in deep till frostline. I have attached a and b (his recommendation how to separate).

I think both of this options should be fine. But I personally will do option c: combination of a and b: extend piers only till finished slab level (only pier portion size where baseplates located, 12x12in, so piers for columns will have no cold joint and still be strong enough for column forces, then just put slab like (A) on top of the trench wall. What do you think?

 

[dik]

Why not something like...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[karp2005gmail.com]

my state require "rat wall" what is 2ft deep minimum to exclude animals live under the slab, so it is not big difference for contractor if it is 2ft or 4ft from pouring side. for unheated building if go with shallow foundation amount of soil need to be extracted is around the same, since foam need to go under all the slab below the footer and extend outside. Thereby I would like to stick with traditional frost protected foundation.

 

[phamENG]

karp -

1) Are you the engineer responsible for the foundation, or the owner of the building?
2) Are the piers/columns independent from the slab?
3) Will the wall be supporting any load? I realize the steel frame will carry most of it, but some of these buildings have details around the edges that can impose a small but not insignificant load on the slab/foundation.

 

[karp2005gmail.com]

Thanks all for reply,
1. I'm owner and builder.
2. On drawing detail supplied by the building manufacturer they are not looks independent. That's why I have question.
3. Wall doesn't support any load directly by my understanding: all columns are located on piers. But pier with wall going to be poured together any way: so even if there is some reactions they will work fine. Only slab is the issue. But I may miss something.

 

[DayRooster]

Ask the structural engineer responsible for the design.

 

[karp2005gmail.com]

>>>Ask the structural engineer responsible for the design.
I do not have that option.

 

[DayRooster]

Why, what happened to them?

 

[dik]

So you set D = 24"...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[HTURKAK]

 

[karp2005gmail.com]

Thanks everyone for reply.
Will answer my question myself: after I recalculated wind load, it happened that pad is not enough to to hold tip over: thereby slab is working here. But if take into consideration slab even just with pin hair, it should do the job. Thereby answer should beption (b) with adequate pin hair reinforcement.

 

[dik]

How big is the barn and what height? It's hard to imagine one of these things tipping over.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[karp2005gmail.com]

Hi Dik, barn is 30x40. On long wall spacing is 20ft between columns. I assumed load is applied on pier only without slab to simplify. Wall is 14ft high. On the most loaded pier loads are next: Deadload is 2651 lb live: 10975 lb. Wind: 2352 lb. Pier size is 4'x4', 42in deep. For calculations I assumed standalone pole with vertical load live+dead+pear weight, it is ok assuming 1500psf soil. + Horizontal wind load to the pier as 2352lb distributed by the pole length. It happen that with my pier only it will not enough to hold that. Of course that can be reduced but I do not know correct reductions, so I assumed worth case.
But if assume that pier is supported by slab horizontally, it will be fine if add rebar at the pier and slab connection using b option. It should be no issue with a as well, but it will hard to maintain joint place clean between 2 pours: 1st rain will add dirt to it.

 

[dik]

Can you transfer the lateral loading to the walls and endwalls to act as a diaphragm? then just use anchors?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[karp2005gmail.com]

Dik, actually that is no need: I missed that pier is not freestanding but embedded in the earth and supported by slab from shifting inwards. Side and front/back walls work as diaphragm already what I did not take into consideration in my calculations. Basically after talking to some engineer he pointed that any of my options will work just fine for my structure. But he recommended go with option A but use long anchor rods to embed them into the pier through slab. Same recommendation I found in materials from building manufacturer after revisit all the papers. it require less work for contractor on forms. On this video exactly option A is done with long anchor rods: [URL unfurl="true"]https://youtu.be/V2SvGw6c4CQ [/url]
Let me finalize the answer with A option.