Notched LVL beam configuration problem
Notched LVL beam configuration problem
(OP)
I need some fun opinions on this one. I have an architect situation which requires some out of the box thinking and blah blah blah. Anyway, it has been proposed to design a series of beams shaped like the attachment. The beams would get cut out of large LVL stock (about 20" deep members) and be shaped with a "tray". I know the limits of notching are vastly exceeded here but on one hand this doesn't seem so crazy. I am sure it can hold some load but how much? Obviously not simple beam theory going on and it is wood...
So I propose it to the consortium: Any experience with this, tips, tricks, analysis theory here would be appreciated. I don't need a bunch of "why are you doing that?" etc. It is what it is and I am trying to either refute it completely or work with it with some attempt at engineering principles. My personal opinion is to drop it out the window but I am trying to entertain the possibility.
Thank you in advance
So I propose it to the consortium: Any experience with this, tips, tricks, analysis theory here would be appreciated. I don't need a bunch of "why are you doing that?" etc. It is what it is and I am trying to either refute it completely or work with it with some attempt at engineering principles. My personal opinion is to drop it out the window but I am trying to entertain the possibility.
Thank you in advance
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MAP





RE: Notched LVL beam configuration problem
Mike McCann
MMC Engineering
RE: Notched LVL beam configuration problem
RE: Notched LVL beam configuration problem
Mike McCann
MMC Engineering
RE: Notched LVL beam configuration problem
RE: Notched LVL beam configuration problem
I'd also recommend contacting iLevel. They could probably give you some suggestions for stress concentrations etc if you need to go this route.
RE: Notched LVL beam configuration problem
Fabricated steel beam is not an option.
Some of my ideas:
Treat it like a standard beam & reduce the section some to some arbitrary amount at the ends? +Safety factor of say 1.5?
Model is as a 12" beam with reduced section on ends, sitting on corbel/haunches? Maybe the steel plate gussets have merit for this analogy so if it splits a little, so what.
I haven't even got loading on this yet as it is still conceptual.
Ultimately I guess it will come down to some guesswork and the only way to really know is testing but it seems like there is still an inherent amount of strength in this just waiting to be tapped. After stewing on this more I'd really want to make this work just to shove it in my Arch's backside. I just need a rational approach/model to thinking about this. If not then I go a different route after yelling at everyone who doesn't know, to show me how it is supposed to calc out.
______________
MAP
RE: Notched LVL beam configuration problem
Personally, if iLevel won't sanction it (and they do allow bigger notches / holes with further analysis) I probably wouldn't go with it unless the loading is really light. You'd be on your own if anything were to fail.
RE: Notched LVL beam configuration problem
What about using a trapezoidal shaped beam with 14'1" unnotched bottom, bearing on two haunches with a concealed connection. Still some tricky design, but... Again, if loads are relatively small...
RE: Notched LVL beam configuration problem
The key for me is to come up with a reasonable model that is defensible with some engineering methodology and then play it safe a little after that. I am just brainstorming here as I know it will carry some load but can't quite design (prove) it.
______________
MAP
RE: Notched LVL beam configuration problem
and yes, doing the brainstorming thing only here too....
so as you said (second one ) above, then you have a 12" beam with tapered ends, granted rather radically tapered, but some tried and true design methodologies exist for these, although perhaps not this radically tapered, i haven't walked through it in awhile.....AITC Timber Construction Manual 4th edition starting page 5-216, and perhaps the architect could adjust the geometry a little to provide a nicer heel if needed.
the corbel wants to rotate inward with a moment of approximately P ft-lbs (guessing moment arm as 12"). so either need to a) secure the corbel to the wall with a moment connection (difficult with moment arm somewhere around 1 3/4"
just my 2 cents, hope i didn't make a dumb error, but at least those aren't usually as bad as my smart errors....