There is a grade stamp on an LVL that says: 2650 FB 1.9 E….. What exactly does this mean? How would this LVL compare to an LVL that is marked: 2500 FB 2.0 E? Thank you!
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It's got a hunnert an' fity more Eff Bees an' a tenth less E.
Forrest - trying the help
That's very true! Now I just have to know if I put one in instead of the other will 30% of the house fall on 100% of my head? We've got a call into the engineer -- the buck stops with him -- but I thought I'd educate myself along the way.
You can gain some education by going to the I-Level (Trus Joist MacMillan) site, downloading their specifier guide for LVLs, and reading.
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"A stripe is just as real as a dadgummed flower."
Gene Davis 1920-1985
I don' know about LVLs but I can tell you that various species of framing lumber is rated for the modulus of elasticity (E) and Fiber bending (FB) design value. I'll bet a box of dog cookes it's the same for LVLs.
"fb" is fiber bending strength and "E" is the modulus of elasticity. I don't know which one of your examples is stronger, it may be that one is better for a certain span and load while the other maybe stronger if you change the criteria.
Where did you purchase the LVL's? Around here, the supplier will be able to provide engineering data for you. It won't necessarily be wet stamped by an engineer, but it's better than rule of thumb type of beam-sizing.
Jon Blakemore
RappahannockINC.com Fredericksburg, VA
Thank you. I ordered the LVL's from a lumber yard and I was careful to adhere to the engineer's specs of 2.0 E 2500 FB. But 1.9 E 2650 FB came off the truck. And naturally these things are ripped to a specific width (9 1/4), so I got a little worried about how interchangeable these values are and how much I have to fight with people to return this stock if the discrepancy is a problem. Something tells me there is so much over-engineering that all this won't make a difference, but again I just wanted to learn as much as I can.
Here - they aren't ripped to width - OK - maybe they are at the lumber mill or something... But the yards stock 9.25", 11.75", 14" etc. They are cut to length though. If they didn't give what you ordered though, and the order was in writing, why worry?
The engineer might have used LVL specs from a brand that he had a chart or computer program for. There isn't a lot of difference between LVLs at 1.9 or 2.0.The modulous of elasticity comes into play a lot more on long, slender beams. It can ALSO come into play if you have a BI who's anal about details. It's a lot easier to ask questions now than to deal with it after the beam is in place. A call to the engineer who dewsigned the beam would be a good idea. Make sure you have the brand of the LVL, and he should tell you if it's O.K. or not.
different companies manufacture lvls. For example boise-cascade makes one line.
You can obtain the specs from the distributer, where holes can be drilled, point load tolerances etc.
handy to have. I had an inspector ding me on holes drilled and I "educated" him. Had I not had the paperwork would've been tough. It also allowed me to cut plumbing access that prevented a ceiling drop.
The larger the Fb and E the better. When the engineer calculated the size of the beam, I'm guessing that he specified a min. Fb and E that is required. Some LVL's have an Fb of 3100 and an E of 2,000,000 (2.0 to the 10th.) Depends on the manufacture. Unless you have a very heavy concentrated load and a short span, the Fb is generally not the deciding factor of the beam. The E is usually the critical one. The E comes into play in determining the stiffness and the amount of deflection.
I know this is oversimplified and one of the Engineers out there will straighten me out There other things to be considered, but since you just ask about Fb and E. Buy the way the same Fb and E are use in calculating steel beams. They are just a lot higher. Concrete too. Etc. Etc.
You nailed it, except that 2.0E is 2.0 x 10^6.
You are correct. It dawned on me as I laid in bed last night what I had done. Thanks