LVL side load

[SteelPE]

I have only dabbled in wood design so my question may be relatively simple. Location USA code IRC 2003.

I recently visited a house were I was responsible for the design of some steel beams and columns. While on site, I noticed an extremely large LVL that was extremely long. The house was still under construction and there were no supports visible but there were a few uninstalled columns present at the site.

The LVL was made of of 4 individual LVK's laminated together. I noticed no bolts only nails and screws. The floor joists framed into each side of the LVL using face mounted hangers.

Question, in my dabelings with wood design I seem to remember that side loading a LVL made up of four members was not allowed per the mfr. (I was using BC at the time). Is this standard for all mfr?

 

[MiketheEngineer]

The old rule of thumb was 3 members.

One could make the case that since it is being framed from BOTH sides then only two plies carry each of those loads and this would be acceptable.

I allow that - assuming everything else falls in line - but I do reduce capacity (increase of SF) a bit. Just so I feel comfortable.

 

[woodman88]

If the load was coming from one side there would be two main concerns. 1) Can ¼ of the load be actually transmitted to the fourth ply given the possibility of beam rotation. 2) How to verify the connection of the center two ply’s.
As the load is coming from both sides. You could look at them as two doubled beams or a single and triple beam depending on the load distribution. In this case the center connections would need to transfer enough load the keep the deflection of all four ply's the same. Be sure to check the unbalanced condition for the load transfer.
As for the connection if the ply's are 2” or less wide you can use the Simpson SDS25600 (STRONG-DRIVE SCREWS) which are 6” long from each face to insure that the center ply's are properly connected.

Garth Dreger PE
AZ Phoenix area

 

[boo1]

Microllam LVL beams design guide shows four 1-1/2" member build up (see pages 38-39), but not with nails. Note nailing required adjacent to the hanger page 39.

Consider asking the LVL manufacture or reviewing there guide.

 

[jeffhed]

We allow LVL members with up to 4 plies, but require through bolting to tie the multiple plies together. This is a standard requirement on our house plans. We always fasten all plies of a multiple ply member together to keep the deflection the same for all plies of the member. If it weren't tied together, you could have one "member" with a lesser deflection than the adjacent "member". If there is enough difference in deflection, it could cause cracking in sheet rock or tile grout.