pole barn on pilings

Just wondered if anyone could give me some tips on construction of a pole barn on concrete
pilings. I am beginning process of planning for a 30 x 40 x 12'high pole building.

The plan is to drill 18" holes to a depth
of 36". Fill them with concrete up to grade, then galvanized post anchors
will be lag bolted into the concrete pilings.
The posts will set on these and diagonal bracing
will be installed between the poles for strength
(since they will not be below grade). It is obvious the concrete will have to be low enough
to allow the bottom girt to go to grade. I am
not concerned about grass growing up to the side
of building. A foot or so will have screanings and possibly gravel up to the outside of the building. One of my concerns is the size of lumber to use for diagonal bracing. Will 2x4 lumber be strong enough or should I go to 2x6?
The poles will be 8' OC so the diagonals will
have to be 14.4' long. Those long 2x4's seem
to flex a lot. Any input appreciated.

Tim, Ohio

Thanks for your comments. To answer a few questions: The diameter of the pilings is
18". The depth of the pilings is 36" according
to frost line at 30" in my area. As for the materials, the tin will all be 29 gauge. There will only be 2x4 purlins on the walls and
roof. This is a kit for a 30 x 40 building
and these are the materials being furnished.
I plan to take my plans to the permit police for their approval, even though I am building this myself. I figure they won't have much
to say since I live in the country and my structure will be in the middle of my property.
I assume they just want to make sure of how
much value I add to my realestate so the revenuers get their tax dollars.

The bracing I had in mind would go diagonally from the bottom of one pole across to the top of the other pole, just below the girder. In addition, I plan to run short bracing from between
the two top girders diagonally to the poles.
This might be overkill, but if I figure I will
have a bit of scrap lumber to use up.

Thanks,

Tim, Ohio

I am up near Brownsville, off 668.

Tim, Ohio

http://www.permacolumn.com/images/Rural_Builder_Concrete_Piers.pdf#search=%22concrete%20pier%20post%20frame%22

1. With that width, assuming concrete floor and acceptable site, stick framed on a monolithic slab would probably be cheaper / nicer / better.

2. Usually for this type of construction, 29 gauge siding is used. I would investigate a steel "T" bracing for your diagonals. You would install all of your girts and then sawcut a diagonal line across the girts. The "T" fits into this slot and provides an exceptional bracing. The steel barcing provides an enormous amount of bracing when screwed in the flats. I align the sheets and predrill a small hole to keep the screws in line.

3. I'm sure that there is alot more, if you have questions, feel free to contact me.

Good luck,

Bill