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Discussion Starter · #1 ·
My plan calls for three 1 3/4 x 16 " drop girder but due to height restraints in that area of basement I would like to set the girder the same height as my I-joist 11 7/8". The span is 18 ft and there is no side load only load from first floor wall and any roof braceing in that area for hips. So my question is can I use four 1 3/4"x11 7/8" lvl's in that area and be as strong as the three 16" LVL's shown on plan? Thanks for any help.
 

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KemoSabe
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My plan calls for three 1 3/4 x 16 " drop girder but due to height restraints in that area of basement I would like to set the girder the same height as my I-joist 11 7/8". The span is 18 ft and there is no side load only load from first floor wall and any roof braceing in that area for hips. So my question is can I use four 1 3/4"x11 7/8" lvl's in that area and be as strong as the three 16" LVL's shown on plan? Thanks for any help.
If there are no doors in the wall above, you can set the bottom of the beam flush to the bottom of the joists and cut the wall studs to the proper height to maintain top plate height.
Other options are a partial drop of the beam, keeping the top flush to the top of joists, or having an engineer spec a steel flitch to sandwich in between the plies of LVL.
If your engineer allows a 7x11 7/8 beam, I would order it full width to avoid laminating it on site.
You could also consider breaking the span down with a column.
In any case, give an engineer the final say in what you do.
 

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My I-Level tables (think "Weyerhaeuser," laminated-veneer-lumber, a.k.a. LVL) show that the total load capability for a triple 16 at 18'6" span is 1066 psf (pounds per foot), and the total load capability for a double 11.875 is only 299 psf. You asked whether a quad 11.875 will handle your situation, and it will, provided that your total load is 299 x 2 or 598 psf or less.

That said, it is readily apparent that a quad 11.875 has less than HALF the load-carrying ability of a triple 16 at your 18-foot span.

Why don't you get whoever figured your triple 16 to sign off on your proposed quad 11.875?

I am an engineer, but I'm not your engineer.
 

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Discussion Starter · #5 ·
Do you think I could attach the built up 16" lvls to the side of and steel I beam with a top mount hanger on one end and have a bump out on my block wall for the other end? Say if I attach it to the steel beam I could weld a plate say a ft wide to bring the web out even with the top and bottom flange and will have 2x glued and screwed on top of top flange could i mount a hanger for the girder on the side of the steel i beam that way?
 

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Fentoozler
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I think you should *send the plans and your "idea" back to engineer/archi/drafter for approval.......and get the necessary seal if required.


Lot of questions to be covered by your insurance..
 

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Curmudgeon
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Maybe we could help more
if you posted an introduction.
Fill in your profile and give
us some info about yourself
and what you do.
Right now, you are starting to
sound HO-ish.
 

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My plan calls for three 1 3/4 x 16 " drop girder but due to height restraints in that area of basement I would like to set the girder the same height as my I-joist 11 7/8". The span is 18 ft and there is no side load only load from first floor wall and any roof braceing in that area for hips. So my question is can I use four 1 3/4"x11 7/8" lvl's in that area and be as strong as the three 16" LVL's shown on plan? Thanks for any help.
No one here can answer your question. Get the Architect who drew the plans to tell you what to do.
 

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Do you think I could attach the built up 16" lvls to the side of and steel I beam with a top mount hanger on one end and have a bump out on my block wall for the other end? Say if I attach it to the steel beam I could weld a plate say a ft wide to bring the web out even with the top and bottom flange and will have 2x glued and screwed on top of top flange could i mount a hanger for the girder on the side of the steel i beam that way?

to address the original post. a quad 12" lvl sounds iffy for the span. a triple 12" lvl with (2) 5/8" steel plates sandwiched in between the plys would do the trick though. as for the connection detail to your i-beam, notch the girder into the beam, then weld a plate on either side of it, then thru-bolt into your new girder with (3) 3/4 bolts.
if you're going into a w10 then i would add a seat plate as well. but the plates and thru-bolts are crucial since you're side-loading the steel.
 

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The Duke
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to address the original post. a quad 12" lvl sounds iffy for the span. a triple 12" lvl with (2) 5/8" steel plates sandwiched in between the plys would do the trick though. as for the connection detail to your i-beam, notch the girder into the beam, then weld a plate on either side of it, then thru-bolt into your new girder with (3) 3/4 bolts.
if you're going into a w10 then i would add a seat plate as well. but the plates and thru-bolts are crucial since you're side-loading the steel.
And you personally will visit the site and sign off on the modifications to the original submitted plans to the building dept.

Another thing to think about is the MEP's. If you raise that beam and items have to go from one side to another, will you create a different mess for the client to deal with? If they are thinking a clean look of sheetrock on the ceiling and the plumber has to drop the waste line below the bottom of the joists, then you've created another issue.
 

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And you personally will visit the site and sign off on the modifications to the original submitted plans to the building dept.

Another thing to think about is the MEP's. If you raise that beam and items have to go from one side to another, will you create a different mess for the client to deal with? If they are thinking a clean look of sheetrock on the ceiling and the plumber has to drop the waste line below the bottom of the joists, then you've created another issue.
he is going perpendicular to the center girder (parallel to floor framing). i answered his question, and don't really care if there's a waste line involved or not. same for the sign off comment.
:thumbsup:
 

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Curmudgeon
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not landing much work lately?
You will notice that not many here
are willing to pass out engineering advice
to people who don't seem to be very experienced,
as we can't see their situation, and have no
idea what important details might be left out
and what they might misinterpret.
 
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Banned
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You will notice that not many here
are willing to pass out engineering advice
to people who don't seem to be very experienced,
as we can't see their situation, and have no
idea what important details might be left out
and what they might misinterpret.
seemed like he knew what he wanted to do. probably a reason why he came here to ask questions rather than go to his architect/engineer. granted he may have a w6x9 for his center girder with no columns anywhere near his t-connection, but he'll figure that out. i didn't sign anything or provide liability certificates to post on here :thumbsup:

plus i'm not trying to help the guy, i'm only contributing to a discussion about how things may get done. if we can't discuss engineering here, what are we to discuss? cellphones?
 

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The Duke
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seemed like he knew what he wanted to do. probably a reason why he came here to ask questions rather than go to his architect/engineer. granted he may have a w6x9 for his center girder with no columns anywhere near his t-connection, but he'll figure that out. i didn't sign anything or provide liability certificates to post on here :thumbsup:

plus i'm not trying to help the guy, i'm only contributing to a discussion about how things may get done. if we can't discuss engineering here, what are we to discuss? cellphones?
This is the framing forum, there's no engineering forum for a reason.
 
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