Notched Beam Solution with Nailed-on Sister

[RM87]

Hello all,

Here's the story:

The plumber thought it would be a good idea to notch a 5"X5" square directly at the bottom of a 1.75"X14" LVL 2.0E joist, about 1/3 of the distance in on a 20' +/- total span. The contractor on site has asked me to run a calculation evaluating a 3.5X9.25 PSL 2.0E sister spanning 6'-0" directly centered over this notch, with 2 rows of 16d nailing @ 4" O.C fastening the PSL to the LVL. My question is if anyone has any reference materials they can point me towards to run the analysis for this condition. I would need to evaluate the bending in the PSL as forces are passed through the nails. Anyone have any suggestions?

Thanks a lot folks,
R

 

[KootK]

Some recommendations:

1) Remember that, if you don't jack the beam to relieve stress, you'll need to account for those stresses at the notch that will be baked into the cake.

2) With only about 3' of reinforcement either side of the notch, I wouldn't bother trying to enforce flexural compatibility between the LVL and PSL. I'd just treat the PSL as a tension strap resisting a conservatively estimated tension.

3) I'd use angled screws rather nails to improve stiffness.

4) I'd use a member on either side just to improve symmetry.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Ron]

There are several things you can do for this. Sistering is bulky, but if the beam is hidden is doesn't matter.

Some other methods to consider:
Use a repair flitch plate in the same shape as the notch, made of 1/8" to 1/4" thick steel plate on both sides. Thru-bolt the plates.

Use threaded rod on the bottom of the beam to take the tension.

One major goal of any of these repair methods is to prevent migration of cracks that eminate from the corners of the notch.

As KootK noted, jack the beam up to take out deflection before doing any repair.