Just gotta vent for a moment here.
I didn,t think it looked quite right when I framed it in a few weeks ago but a call to the eng. confirmed the beam sizes and the hardware, so I carried on.
Then while doing some backframing yesterday I held a string on the beam and found about 3/8″ deflection in a 4ply x 14″ x 1 3/4″ LVL . The beam spans 11 and a half feet and is point loaded in the center.The load it’s carring is the 3rd floor and roof.
There is no drywall loaded yet and the stucco is going on next week.
I spazzed at the eng. on the phone yesterday and he showed up this morn to make sure I had put it together according to his specs. and he took some measurments and said he’d have to run the numbers again and get back to me in aday or two.
Then as a piece of freindly advice he said that this size of beam when fully loaded could easily DEFLECT UP TO 3/4″!!!!!!!!!!!
So I calmly asked if he could give me a stud cut list to get a level floor and how much would I have to curve my gutters to get them to flow after the house settles? HA!
This engineer is supplied by the lumber yard and is part of their material package . I told the yard that Ide be getting a second opinion and they said are willing to pay for it.
I expect to be putting in a metal ‘C’ channel to stiffen it up but I’ll wait and see what the brainiacs come up with.
On the pics the long 3ply beam being carried is directly under the front wall of the top floor.
There goes my planned break xmas to newyears. This is NOT what I wanted for christmas and now I’m going to have to go out and buy some tools to make myself feel better.I’m thinking one of those PC recips with the twisty noses, maybe a new coil gun too.
AARGHH …………Rik………..(oops sorry fer the pic size the house is 52′ wideI’ll fix it later gotta surf for tools now)
Edited 12/17/2003 10:23:45 PM ET by RTACOMA
Edited 12/17/2003 10:25:07 PM ET by RTACOMA
Replies
Sad too hear your upset by the deflection but it is normal for these beams to "sag" but its well within the limits of the beam. (How ever double checking is a good idea) What you want is stiffer. I guess your main problem is the floor and above is dropping in the beam area and for new construction is looking bad. Engineer would have helped things if he had warned you in advance as you could have built in the expected deflection.
Just took another look at the pictures. Could you add another 4 plys to stiffen the beam? Might reduce the deflection to 3/16"
Had very much the same problem a few years back. Did not see the deflection until a half ton 12-foot wide picture window unit was hanging in the air ready to go into the opening. Would not fit. Luckily it was 2x6 exterior wall and we had some other LVL we could rip. Went to the truck, got my big hydraulic floor jack. While helpers held up the window, laid cribbing, had to jack the floor joists, pull the beam, knock out the spacers. Ripped extra stock and tripled the beam. Got deflection down to a quarter inch and installed the window. Its solid beam so no space for insulation, but better than having second story and loadbearing ridge post crush the window.
He's not right in saying the beam could have up to 3/4" deflection - That would be L/180. It appears the beam carries floor load, so it would be limited to L/240. That's about 9/16".
Whether or not code allowed deflection is O.K. is kinda subjective. I'm pretty sure I would have let that one go.
Looks like adding anything to the sides of the beam would be difficult at this point. But that may be your best bet if you can't live with the deflection.
In retrospect, that's a pretty poor basic design. (IMHO) I-joists hanging on beams that hang on other beams is just asking for problems. I'd like to think I would have looked for a better solution that that if I were designing the floor system.
BTW - It's hard to tell in the pictures, but it looks like not all the nail holes are filled in those beam hangers. They need to all be there, since the beam is carrying so much load.
Why are they called apartments when they are all stuck together?
>I-joists hanging on beams that hang on other beams is just asking for problems.
That was my first thought, too. That's a lot of weight concentrating on a small area.
As an aside, one of the things I love about designing what I do is that for something like floors, if you don't wanna support it from below, you can hang it from above. Use thick threaded rod, with appropriate brackets, nuts, etc. Gives a lot of flexibility, and lets you see buildings from a whole new perspective.
Edit: Oh, I forgot that I'm not speaking to you no more....Celine?!?!?!?!?!? Good Grief! :)
Edited 12/18/2003 9:11:33 AM ET by Cloud Hidden
"Oh, I forgot that I'm not speaking to you no more....Celine?!?!?!?!?!? Good Grief! :)"
I like SOME of her music in LIMITED quantity. And I don't like HER - Just her singing.
She has an incredible voice. Just wish she wouldn't SCREAM so much.When your pet bird sees you reading the newspaper, does he wonder why you're just sitting there, staring at carpeting?
>I like SOME of her music in LIMITED quantity. And I don't like HER - Just her singing.
That's like saying to your high school date's father, "We were just fooling around, we didn't go all the way. And I don't like HER--just her......" Ahhh, never mind. Ha ha ha!
I was wondering since I can't tell from the pics, are the doubled up LVL's nailed per the manufacturers specs? I saw a few bolts but i can't imagine that they are all that were called for. This could be a big part of your problem if they are not there. My structural eng. always designs with LVL posts when we are placing LVL beams with big loads.
Just some thoughts,
Curly
Restoring the past for the future.
A couple of years ago, while framing a series of four-plexes, I experienced some really tremendous sag in some psl's that were cantilevered four feet to pick up two stories of exterior wall above that were thirty feet long, plus the roof above. I think we had about 3/4" sag in four feet, before the roof went on. Didn't notice it until I was standing the sheeted gable on top of the wall, and the doggone truss was up in the air at each end. The engineer (architect) came out and looked, looked, scratched his head. The builder grilled me three or four times about my installation.
After much freaking out on all sides, they decided to build some steel corbels, and bolt them underneath the deflecting beams. I don't remember being too impressed with the results, as I was the one trying to lift the beams with a high-reach fork...they didn't want to go back up!
What's the point of all this? I think the beams deflected for two reasons. First, they were undersized. Second, they came out wet, and then got wetter, during an awfully wet spell. I don't think saturating manufactured beam helps them at all, and loading them up while soaked couldn't help...I mean, if your going to bend wood, the first thing you try to do is get moisture in the wood, right? Were these LVL's saturated when installed?
If the beams continue to fall, or if the current sag just won't work, could you put a column under the intersecting points of the two beams, down the ground?
Lastly, in the past year I've decided to just build things like the architects and engineers draw them...and let the results land on their shoulders. Build it as drawn, and trust other professionals to do their job. You can spend a lot of time worrying about something you don't have responsibility for, even though you may be thinking you're seeing problems that you can't live with yourself...
Yes all the holes are filled and every thing is laminated to specs.Architecturally a wider beam is unacceptable because the beams are dropped 6 inches and will (?) create a feature on the ceiling, also I only have one inch available for bearing to the side of the beam because of a window.
So if I find that I'm likely to see more deflection Ithink I will have to remove a ply and replace it with something stiffer, but I'm not going to speculate on that until I hear back from the engineers.
My major concern is that if a beam is going to deflect that much on this house it will create serious out of level conditions on the floor/ doors / roof(flat) /cieling/ cabinets.Major deflection has to be designed in , I once formed a 48 ft long slab band under a gym floor with 2'' of camber; after removing shoring post cure the slab was perfectly staight.
Gotta get to work now .......theres a tool store on the way. I'll post when the eng.s get back to me .
Cheers all ..........Rik........
If you're limited by the width you can make the beam, you could add a piece of steel between two of the LVL's. This would strengthen and stiffen it quite a lot.
Good luck,
Andy
CAn we say Flitch plate? I hope not for your sake.