I was wondering if anyone knew if there was a code for temporary bracing of a non-residential building before it is permanently braced with plywood? I was curious to know how far apart each "A" brace shoud be on an agricultural building in Minnesota, used to store machinery, that is 50'x80' with 18ft sidewalls?
I would suggest that you brace as required to keep the structure straight and square. The sidewalls will be affected by how straight the lumber is in the first place and also by the process of installing the side wall sheathing. You will need bracing as required to push the shape of the framing into plumb and square and then hold it there.
Also be aware that since the integrity of the structure is not complete until the roof trusses are placed and fastened to the upper plate of the sidewalls you will need bracing in place to deal with forces of nature. As you begin to install the side wall sheathing even moderate amounts of wind can place significant pressure on the wall structures so bracing will be needed to make sure that a strong gust does not come by and flatten all your work.
More. Braces. Because I'll huff....
When the contractor showed up to come take over building our summer home for us (we got as far as the first floor walls), he said one word to his crew, "Braces." We had them every 10+ feet or so. They put them every 5' or so inside and outside, one to the deck and one to a post sunk in the ground, forming an 'A'. Lots of 'em, as I've learned. I wouldn't sheath anything until the trusses were up (the manufacturer of them is whom you should consult on the bracing required for a 50' span). The bracing used to plumb the trusses (the laterally run 1x4's) is not temporary, it becomes part of the structure as blocking.