Repair 7"x14" parallam beam that has been notched on the tension side? 4

[rand00]

Is it possible to repair a 7"x14" (20-24 feet long) parallam beam that has been notched on the bottom (tension side) by a contractor to run electrical wiring? The notch is 0.5-1.0" deep (leaving 13.0-13.5" of the beam untouched), spans the 7" width, and is approximately 9' from one end of the beam. The beam is one of two beams that support a 2-story family room above. Can attach pictures if it helps.

If so, what is the appropriate repair method? Thanks in advance!

 

[msquared48]

Does it need to be repaired? Run the calculations and see whether or not the remaining section will do the job. If you are not a structural engineer and do not know how to do this, hire one.

In the meanwhile, scare the bejesus out of the contractor so he doesn't do this type of thing again - have a little fun.

Mike McCann
MMC Engineering

 

[4thorns]

The manufacturers web site should have the info you need regarding holes, notches etc. If not then contact them. They usually have engineers more than willing to answer questions regarding their product.

 

[jaypartain]

As Mike stated, I would first run the analysis with the reduced section to determine if the beam needs reinforced. Make sure you account for any overcut when determining the depth of the member. If it needs to be reinforced, check with the supplier or manufacturer as stated by 4thorns. I don't know your situation, but if you had the engineered lumber package submitted to you then that engineer may be responsible. Outside of this, I would check to see if a heavy gage Simpson flat strap could be installed across the notch to carry the tension. You could possibly use (2) 3" wide straps.

Jason A. Partain, P.E.

http://www.myconstructionfinds.blogspot.com

 

[Ron]

Agree with Mike...do the math. Jay's repair method is probably acceptable to the manufacturer. Watch out for the contractor...he appears to ask forgiveness rather than permission.

 

[woodman88]

I would repair or replace it.
To repair it, I would add additional member to one face to increase the total (the additional member plus the notched member) I and S back to the original non-notched member requirements. Also if repairing it, I would require the notch to be radial cut (no square or bevel cut corners) at each end. Be sure to have the beam jack up to relieve stresses before connecting the additional members.
As for using metal straps, unless you can pretension them, the critical slip requirements of the nails make them useless for this application.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[Lion06]

Jay-

Just to be clear (if this is a homeowner and not an engineer), the flat strap should be installed on the bottom of the beam, not the sides, and would have to have the fasteners designed to carry that tensile force across the joint.

I've looked into this briefly before (for LVL's, not PSL's, but I have to imagine it's a similar situation), and the manufacturer told me that they do their QA/QC process after the beams are ripped to height. For this reason, they strongly suggest no modifcations be made to the top or bottom of the beam (including small notches at bearing, which is all too common in residential construction). They also have requirements for where holes can be drilled, but I, personally, feel comfortable taking a little more liberty with holes that fall within the cross-section than I do messing with the tension face near mid-span.

1" out of a 14" section is a reduction in capacity of almost 15%. Not huge, but not insignificant.

 

[rand00]

All, thanks very much for the very helpful replies--much better than for-pay sites out there. Indeed, I'm merely a homeowner (software engineer by trade) who is baffled by a contractor cutting into a support beam. Intuitively, this did not seem proper. I have a structural engineer coming out today and will update this post once I get results of the analysis. Thanks to all the replies here I have a much better grasp of the issues.

PS-I've been told here and elsewhere that this improper activity is all-too common, which is comforting (misery loves company) and disheartening at the same time.

 

[RFreund]

Lion -

You say they do their QC after they have been ripped to height - so this means ripping down say a 14" LVL to say 11.25" is not technically the same as a 11.25" LVL? I guess I haven't looked in the process of how levels are made but I wouldn't have guess that x-section material properties varied in height the way glulams do.

EIT

 

[Lion06]

RFreund-

The manufacturing process is to build very deep beams and rip them to the proper depth. After they rip them to height is when they do the QA/QC to make sure that ripping the beam didn't cause any problems along the cut (maybe causing the beam to start separating through the width. I didn't ask about all the things they check for, that's one that seems to make sense to me).

So, ripping a 14" LVL to 11.25" is the same as an 11.25" LVL, but now that you've ripped it instead of the factory, it can't undergo their QA/QC and they won't warrant it.

With that being said, we had to do this on a job not long ago. I had them rip it to height and put the cut side on the top.

If a plumber is getting in there with some kind of hand saw, going to town on the bottom of the beam........... that's not a clean cut like a table saw ripping it down and that would cause me some concern.

 

[woodman88]

Lion06
The ICC Report ESR-1387 section 5.6 (page 4 of 12) states "...Parallam PSL and Microllam LVL may be cut to size for required application." Also that they "...may be notched, drilled, or tapered end cut provided design is by a design professional."
So I find it hard to believe that they won't warrant it done in the field if they are making them per this ICC Report.
See the attached report

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[Lion06]

Woodman-

That's good to know. I'll keep that in my back pocket for next time.

This report is for a specific Manufacturer, though, correct (Weyerhauser)? That is not the manufacturer I spoke with previously, but what I would still note is that the ilevel Specifier's Guide (attached) says on page 36 to "NOT cut, notch, or drill holes in headers or beams except as indicated in the illustrations and tables". Additionally, the actual warranty language says that it does not cover delamination, perceived inadequacy of design, or perceived defects due to "Any alterations to the PSL after the original installation". It's the 5th bullet item in this link -

http://www.ilevel.com/literature/TJ-1007.pdf

I guess one could make the case that Anything done to the PSL during the course of the project on which it is used is part of the orginal installation, otherwise all plumbing and electrical holes would need to be cut on the ground. It's not real clear, though, and I, personally, would still stay away from notching the tension face near mid-span of such a heavy member supporting two stories.

If the member ever actually failed at the notch (and the damage would be significant), I have a hard time believing that they would cover the loss. My very first question to any design professional in that situation would be to if depth needed at the most critical location on the beam (for bending, of course) was adequate with 1" less than specified, why not specify a member that is 1" more shallow and preclude the notch? There are reasonable responses to this, but could quickly lead to an answer (like the plumber cut it and I checked it) that could void the warranty since it was done after the "original installation". Again, the original installation is never clearly defined, but my first thought is that once the member is set and supported, then the "original installation" of it is complete. I may be mistaken with that thought process, though. Any thoughts?

 

[woodman88]

Lion06
This report (ESR-1387) is called out as being the "Code Evaluations" of the LVL's in the iLevel guide. See page 3.
How this applies to warranties/original installations, since they are exceeding the requirements stated in the report in their warranty, I guess the courts will have to decide.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[Lion06]

Thanks very much for the info. It does seem odd that the two documents seem to give slightly conflicting guidance on the use of cuts and notches, and even holes (thouch not as conflicting for holes).

 

[RFreund]

Good info, thanks guys.

EIT