Throw us a bone!!!

LGSI=Light gauge steel or some such?

Correct, Light Gauge Steel Institute.

http://www.acronymfinder.com/LGSI.html

I just saw a metal building going up this weekend at a buddy's place. The installers could not decipher all the acronyms on the prints and web searches on my iPhone were no help either.

LGSI is now abandoned by Loseke, so all you can do is call Central States http://www.centralstatesmfg.com/

It was Light Gauge Steel Institute at one time, right? With specs for fastener and girt spacings on panels that were Continuously Braced vs Thru-Fastened vs Laterally Braced? And all kinds of data for wall heights and roof pitches and you could plug into AutoCad and all kinda everything. Doesn't mean squat if you don't have the secret spy decoder ring.

Best guess is try Central States or one of your local "metal mart" supplies and see if they will translate the LGSI specs into pen and paper english for you.

Or, hope another CR4 member has a better memory than the two guys I met this past weekend. Their mantra was "if there's still screws in the box, it's probably not as tight as it could be". Glad that's not my barn.

I wonder why Loseke abandoned LGSI.

Good morning CaptMoosie,

I am using Loseke's LGSI recomendations, which I assumed were based on the AISI's Specs, since the AISI's was started in the 1920's.

For an agricultural building, say you have 25' long roof purlins 5' oc with paneling screwed to the top flange, with nothing attached to the bottom flange between rafters. This would not be Continuously Braced, agreed?

If the purlins are attached with an angle screwed to the rafter and thru the purlin web, it becomes Thru-Fastened?

If a small straight angle is attached from purlin bottom flange to purlin bottom flange, within the LGSI oc limitations, it is now considered Laterally Braced, or does the brace have to go from the bottom flange of one purlin to the top flange of the adjacent purlin?

After 1-1/2 mugs of Java, YMMV.

Sorry, I'm not familiar w/ the LGSI specs or standards and will have to do further research......I only follow AISI standards. A whole lot depends on the fastener spacings and the purlin shape, be it a Z, channel or C-stud type.

When all else fails, follow the manufacturer's written installation instructions. Not all manufactured light gage steel sections are made the same same nor load tested equally.

I'll have to get back to you regarding your specific questions, but it would help to know the particulars, especially the type, size and spacing of the fasteners and the type and section of the rood purlins. Was the roof framing designed by a registered PE, specifically a SE?