Design Build PEMB Foundations
Design Build PEMB Foundations
(OP)
We recently started working for a contractor that specializes in Pre-engineered Metal Buildings. We provide the foundation design based on soils information and loads from the PEMB manufacturer as well as other features from the architect. The first couple were cake.
With winter approaching we are feeling pressured to submit drawings based on preliminary reactions from the PEMB supplier, not loads sealed by a structural engineer. We are contemplating adding a note to that effect and that "Final footing sizes must be verified by the foundation engineer with sealed loads from the PEMB".
When we design a foundation for a "design-bid-build" PEMB, we get estimated loads to base our design on and note that the footing will be reviewed based on loads from the successful PEMB contractor. In those cases we have some control over the contractor and can enforce the provision. In this case it will be more difficult.
How have others handled this situation? Thanks for the help.
With winter approaching we are feeling pressured to submit drawings based on preliminary reactions from the PEMB supplier, not loads sealed by a structural engineer. We are contemplating adding a note to that effect and that "Final footing sizes must be verified by the foundation engineer with sealed loads from the PEMB".
When we design a foundation for a "design-bid-build" PEMB, we get estimated loads to base our design on and note that the footing will be reviewed based on loads from the successful PEMB contractor. In those cases we have some control over the contractor and can enforce the provision. In this case it will be more difficult.
How have others handled this situation? Thanks for the help.






RE: Design Build PEMB Foundations
RE: Design Build PEMB Foundations
RE: Design Build PEMB Foundations
A phone call to your client with a written followup would help. You cannot force the client to react but you can at least put him on notice.
RE: Design Build PEMB Foundations
Do you think the contractor is going to hire and engineers to evaluate the footings based on final reactions from PEMB? I have not met a contractor who will read most of my notes on my plans. They read them when they get in trouble.
As EOR, I do my own frame calculations based on prescribed frame spacing. I determine the loads and I use load combination of WL + 0.6 DL to size my footings. This yields conservative results. I re-evaluate my foundations when i get the signed and sealed calculations from PEMB supplier. I get them because I request them and stay after the contractor till I get them.
I am not a big fan of PEMB and I do not care if they read my comments. They get by with lots of stuff that other structures had to meet and they do not. Next time you check lateral drift, see what their allowable is (h/45!!!). They do not compete if you impose normal loads (over 20 PSF reducible live load). May be they can support few PSF of collateral loads such as sprinklers. You cannot support more than 500 pounds of concentrated load from the light gage “cee or zee” purlins.
After saying all of that, people love them because they are cheap and will go up fast.
Regards,
Lutfi
RE: Design Build PEMB Foundations
I too, do not care for PEMB. there is only one fabricator in my area that follows the construction documents and provides what is performance specified for loads, lateral drift, location of x-bracing or portal frames. Most PEMB suppliers sell what they want to sell and force the owner to buy it.
RE: Design Build PEMB Foundations
RE: Design Build PEMB Foundations
At one time some of the PEMB catalogs had footing and hairpin sizes for various loads and thrusts. I suspect they were removed for liability reasons. I think one local contractor still uses an old catalog for his foundation design.
All,
Thanks for the input.
MWPC
RE: Design Build PEMB Foundations
Previous editions of PEMB manual also USED TO promote that only 70% of the wind load reaction will make it to the foundations!
On positive note, PEMB association gets lots of credit for promoting low rise wind tunnel testing. Most of the results of this testing can be found in building codes.
Regards,
Lutfi
RE: Design Build PEMB Foundations
RE: Design Build PEMB Foundations
RE: Design Build PEMB Foundations
Is there any logic to this or was he just flying by the seat of his pants? If there is, I can't see it.
RE: Design Build PEMB Foundations
RE: Design Build PEMB Foundations
RE: Design Build PEMB Foundations
RE: Design Build PEMB Foundations
I'm going to give him my design, which basically involves removing what he did and replacing with column piers and a trench with horizontal reinforcing. I'm sure he won't like it, but I wasn't the dope that put 58 yds of concrete in the ground without any design or a permit.
RE: Design Build PEMB Foundations