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Splices in girder/built up beam not over vertical support posts

jar546

jar546

CBO
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Oct 16, 2009
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Not where I really want to be
Built up girders/beams with nominal lumber. Let's use a (4) 2x12 for example.

If the splices are in between vertical support posts, can you allow it?

Although it has been common building practice not to do this and common sense, the IRC does not truly cover this issue on built up girders/beams.

502.6 is pretty close to covering this but does not appear to have the correct language. There is language elsewhere (I don't have time to look it up right now) that states ".........sufficient to handle the load imposed" or something like that which is also a stretch.

What say you.....?
 
Over bearing........(is that a pun?)

We've felt that without direct bearing, then you are having to consider the shear of the fasteners, which then we consider engineering......... JMHO
 
I'm not sure I follow, are the joist abutting each other over the bearing point and not lapped 3"?
 
From AF&PA Wood Frame Construction Manual: "End joints of the nailed (girder) lumber shall occur over the supporting column or pier"
 
jeffc, no, if I understand the OP, the butting junction is not occuring over a column........
 
The girder can actually be stiffer if the splices aren't over the bearing points. In a continuous girder, the maximum negative moment is over the supports, the maximum positive moment is near midspan, and there is a point of inflection, where moment is zero, near the quarter point of the span.

You can splice all of the plies at this point, as long as you use the proper type of hanger to support the side of the girder that doesn't bear on the support. (http://www.strongtie.com/products/connectors/HCA.asp#gallery) This method is more common in steel or laminated timber construction than in light wood framing.

In a built-up girder the splices should be staggered so that only one ply is spliced at each quarter point, and each ply bears on at least 2 points. The only problem with doing it this way is that it's a bear to build up a 40 or 50 foot long girder spanning over several piers. It's usually quicker & easier to just throw in an extra ply and put the splices at the supports.
 
If you look at the equations for a beam that is supported at the center and uniformly loaded, the span and max deflection are identical to a beam simply supported at both ends.

I have no problems with the ends falling near the midpoint of a span.
 
This is not something that the code specifically allows. Thus engineering calculations are required if they do not want to try to justify what exists.
 
"This is not something that the code specifically allows. Thus engineering calculations are required if they do not want to try to justify what exists."

BINGO
 
Engineer it or.... maybe additional posts can be added to support the splices?

That might be easier than replacing part of a completed floor system.

Remember - you are not responsible for this condition. You haven't done anything wrong.
 
UPDATE:

Just got an engineered fix with a stamp from a PE on it. Called the contractor back and told him thank you and by the way, if what you did was OK why didn't the PE sign off on it as is?

We spoke for 30 minutes and have an understanding now.

All is well that ends well.
 
"

....... if what you did was OK why didn't the PE sign off on it as is?"

BINGO!

Good call Jeff, sticking by your guns...........
 
Don't have my book with me right know; but, all end joints must be supported. A splice that does not occur over a support must be corrected by an Engineer. Not occuring over support makes the splice Engineering; and, all that I have seen; the Engineer required a support below the center of the splice.

Uncle Bob
 
I'm offended by jars avatar, by the way... partially because even in my prime, I didn't look like that, and now that I'm past prime, I'm jealous..

Besides that... splices can be offset (and really should be). How stupid is it to build a beam with all splices occuring at the same point? You can build a really long, strong beam with pieces parts of different lengths.
 
peach ---

The typical girder is built up of pieces each with three points of support - the ends and the center. About 1/2 of the pieces are spliced at any support.
 
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