Glulam Drilled Hole Repair

[trossak]

Hello,
Being a geotech, I'm not entirely familar with glulam beams. A friend asked me to help him design a reinforcement for his 15.75"x5" glulam beam that has a 3" dia hole drilled through it laterally. The reinforcement would have to retain the hole opening. Thankfully, the hole is at the center height of the beam and near mid span.
I was considering epoxying a steel tube into the hole, then screwing some steel plates onto the sides of the beam. Are there any reserves about placing multiple screws into the beam?
Any suggestions would be appreciated.
Travis

 

[Taro]

The first thing to consider is whether the beam needs to be reinforced at all. The hole location is fairly benign, creating only about 1% reduction in section modulus. The beam might just be fine without any reinforcing.

 

[ERV]

Calc the load on the beam prior to doing any thing to it. Check the deflection in the beam with a string or straight edge. If it still has camber or is flat, there may not be need for concern. However, if signs of delamination (at the hole) or negative camber have occured, there may be need for concern.

 

[RustyGold]

I agree with the others - it does not appear that the location of the hole would be significant. You can contact the glulam manufacturer, or, if not available, the APA (former plywood association that has tranformed into the engineered wood authority). I have used the APA in the past - the organization has a wealth of information and is very helpful in providing the information.

 

[boo1]

The effects on the structural capacity of glued laminated timber members as a result of notching and/or drilling horizontal or vertical holes are discussed. Recommendations limiting hole sizes and locations in beams are provided at:

https://www.aitc-glulam.org/shopcart/details.asp?category=technotes&item=TN-19

Cheers