A contractor called me and asked me to replace a defective I-joists. He said there was a gap in the OSB in the middle. I told him I hadn’t ever seen an I-joist like that in the 15 years I’d been selling them. So I asked him to cut out the defective section and save it.
He was nice enough to drop it by the office today, so I got a shot of it. I’ll attach a picture to this post.
Just curious if anyone else has ever run across an I-joist with this problem…
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Replies
It looks strange, but if it is in the middle of the span it won't affect the strength. In the middle the beam is stressed with tension in the bottom chord and compression in the top chord and no shear. Tension and compression are handled by the flanges and the web doesn't do anything except keep the flanges in position. That's why you'll see on bridges holes in the webs or open webs (like bar joists or trusses) because material in the webs adds weight but not strength.
At the ends of a beam the load is all in shear (except the very end that bears on the support, which is in vertical compression. Shear is resisted by the web and not the flanges. In fact, you'll often see in bar joists (in the roof of a big box store, for example) that the bottom chord stops short and doesn't even go all the way to the end. And where steel I-beams are welded to steel columns, only the web is connected. The flanges aren't even attached because the carry no load at the ends.
I would say it's defective now.
Ozlander
Im no i joist expert but i disagree with your statement of the i joist being not affected if this was in the middle of the span.
seems to me the middle would be the last spot you would want it.
the open web joists are designed completly different than an i joist.
any how theres no way in hell id put in one of my jobs and warranty it.
In the middle of the span there is no load in the web so it's fine to use it there. However, I wouldn't expect a builder to be comfortable using it not being an engineer. And I think very few customers would think well of a builder who did use it.
Actually, there is load on the web in the middle of a span. Just considerably less than at the ends, and pure compression.
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If it's in the middle of the span, it MIGHT be O.K. Or maybe not. (Depends on the loading situation + other things)But no way am I gonna trust an average carpenter to make engineering decisions like that. This particular one was in a 40' I-joists that was to be cut up for smaller pieces. So they were able to cut the section out and not use it.
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how'ed it get thru QC?
bobl Volo, non valeo
Baloney detecter WFR
I kinda wondered that myself. We sell GP brand I-joists, so I went to the GP website so see if they had any email contacts. They have a place where you can submit comments/questions, so I sent a message to them about the thing and offered to email them a picture. But that was only a half hour ago, so they likely haven't seen it yet..I'm not surprised that the guy in our yard didn't catch it. They pick I-joists several at a time, so they likely never saw it. Even if they did, they probably have no clue that something like that is a problem. You don't get brain surgeons when you only pay $7.50 an hour. (-:
Baseball player Pete Incaviglia: "People think we make $3 million and $4 million a year. They don't realize that most of us only make $500,000."
anymore it seems like the consumer is the QC deparment...
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> This particular one was in a 40' I-joists that was to be cut up for smaller pieces.I would guess that the joists are often shipped in 40' sections, with the expectation that they will be cut up further at the yard. And the yard would be expected to notice and cut out the splice when cutting to order.OTOH, I once stripped down about a 5-foot piece of romax to get the individual wires, and inside I found a splice in the black wire. About 6" of the black were stripped bare, with a crimp splice in the middle. Presumably this was a manufacturing splice that should have been cut out at the factory but wasn't.I continue to be amazed that I just happened to strip that specific 5-foot length, and that it didn't instead end up in a wall in my house.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Wayne,
If I am not mistaken shear stress in a simple beam with a uniform load goes to zero at the 1/4 and 3/4 span points as well and reverses direction there.
Ron
Wayne is correct on this one, shear for a simple beam is zero at the center.
A simple demo is to take 2 thin boards or sticks, load at the center - the ends of the sticks move the most relative to each other, meaning that is location of max shear.
"shear for a simple beam is zero at the center."
That's true, but only if the load is uniform all the way across a beam.
But in reality, that's rarely the case. How often does the floor of a house have a uniform load all the way across it?
There are going to be all sorts of unbalanced loads in a typical residential situation. There may be mulitple spans of an I-joists, which moves the zero-shear point. There will be a fridge on one side of the span but not the other. Or maybe a piano. Or a rather large Mother-in-law. (-:
So while shear may be lower at the center of a span, I don't buy into the "zero shear" stuff too much.
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I've never seen one like that either. Looks defective to me.
Dave
I believe the hole is less than the max allowable hole size.
If you actually had the brains to successfully blow your nose, you'd realize that this is not a typical "hole" at all, but a gap in the OSB. Big difference.I'd explain it to you, but I don't see any reason to teach you engineering.
Your kid may be an honor student, but YOU are still an idiot.
Last time you were abusive I believed you were spoken to by our hosts.I hope they do not need to speak to you again.
I was never abusive to you - You just can't take the heat without whining to the moderators. Go ahead and talk to them again, if it makes ya feel better. You'll have to come up with a better threat than that to scare me.
Your village just called. They're missing their idiot.
Hey, Ron, insults aren't your style, either. I thought GHR was making a joke, and a pretty good one at that.Okay, i'm safely out of range now...carry on.
GHR has never made any attempt at humor before. All he's done is make obnovious posts that pat himself on the back and give bad advice. To the best of my knowledge, he's never made the slightest effort to post anything helpful to anyone. So yeah, I stomped on him pretty hard. But he deserves it, IMHO.
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I can't figure out if you're calling me a pig, or offering to buy me some slop.
(-:
BTW - No email from GP yet.
If a pig loses its voice, is it disgruntled?
Ok, back on track ... Do they use special 40' long osb pieces for 40' joists? If not, then there's gonna be a splice in the web anyway.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
The OSB (or plywood) has always been spliced in I-joists to the best of my knowledge.
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Do they use special 40' long osb pieces for 40' joists? If not, then there's gonna be a splice in the web anyway.
Well I'm sometimes a little sloppy, but I think even I could get the splices a little closer together. ;)
In theory I would think you could make a continuous piece of OSB, but in reality, you're probably right, they're probably splicing.jt8
"Success is not the key to happiness. Happiness is the key to success." --Albert Schweitzer
I don't remember any splices in I-joist webs I've ever seen. Just butt joints.
That would mean there is a vertical "gap" each 8'.
Comparing the amount of wood in an I-joist to a truss joist, splitting a 2x4 into 1/2 thick slices only give a bit more than 14" or 15" width (gotta consider their longer diagonal length) and on a truss joist the web ends are about 2' OC.
That's the equivant of 10" "gaps" 2'OC if we're just considering the amount of wood in the web.
Considering the main purpose of the web, holding the two flanges apart, that little 2" space won't let them move.
I don't think there is a structural problem in that piece.
I'ld still send it back.SamT
That was my point. What's the difference in a 1/4" gap and a 4" gap? It's still a discontinuous web.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Dont feed the troll.
Tim Memphest 2006
November 18th
Boss or GHR? <G>
Hey now - Don't MAKE me come up there.
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Your village just called. They're missing their idiot.
at times I think his tags are more enticing than his posts<g>
sometimes your tag lines are more appropriate then others... like this time for example *G*
Your village just called. They're missing their idiot.
Just happened to come up in rotation, or did it seem appropiate?
Terry
"Just happened to come up in rotation, or did it seem appropiate?"
Some tag lines I save for special occasions/people.
(-:
Here's one I've been saving for when I was posting to a woman. Just haven't had the chance lately:
You're hard to put a finger on.
So if you don't mind, I'll use my whole hand.
Any word back from GP?
jt8
"Success is not the key to happiness. Happiness is the key to success." --Albert Schweitzer
Nothing yet. If I don't hear back today I may email 'em again.
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ah... did the little baby get his little ego hurt....
you're an idiot for making the statement you did above, it was incorrect and false, had or if someone read what you wrote and believed you, they could have been screwed when they went to cut "hole" as you called it in their I joist in the same manner..
now, since you seem to like to act like a damn 3 year old, why don't you take your ball, run home to mommy crying, and never come back.
and don't let the door hit you in asz on the way out.
I've seen a number of them like that out here on the left coast.
Normally I'd not have a problem with that even at the center span;
EXCEPT - look at the bottom chord, there is a big knot there, would be unsuitable for center of span even with a continuous osb web.
That puppy needs a couple hydraulic press applied truss plates across the knots <G>
Edit: Was the web purposely left out on that piece to show where to cut it during production and it got missed???
Edited 9/21/2006 11:15 am ET by junkhound
"I've seen a number of them like that out here on the left coast."
I'm surprised to hear that.
"there is a big knot there, would be unsuitable for center of span even with a continuous osb web. "
The knot doesn't go all the way through. Doesn't look like that big of a deal to me.
"Was the web purposely left out on that piece to show where to cut it during production and it got missed???"
I don't really know, as I don't know much about how they're assembled.
I was under the impression that they're produced in one continuous length, and just cut off to the desired length as they come out of the machine. If that's the case, then the OSB web should be continuous.
But I don't know for a fact that they're made like that.
It is when we forget ourselves that we do things that are most likely to be remembered.
For a few seconds I thought maybe you were spoofin about this, and maybe it was attacked by "plumber ants" (distant cousin to carpenter ants)!
Nope - No bull. I did get an email from GP asking me to send them the picture of the I-joist. I just sent it off, so I haven't gotten a response yet. I'll post back with whatever they say....
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Nothing to do with the thread, but your last tag-line put me on the floor...Phat
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Someone was asleep at the Q.C. department the day that rolled off the line. I'd call the manufacturer.