Repair to delaminating glulam

Question

Repair to delaminating glulam

dik (Structural)

(OP)

16 Feb 07 14:51

I just returned from a church where the main roof beams are constructed using glulam and there is some serious delamination.  I've provided them with 'emergency' information about shoring the existing structure; existing condition is dangerous.  Glulam has 'gapped' approx 1/2" in places and split follows the tapered splicing of the 2x members.

I suspect the delamination has occurred because of high humidity and possibly a non waterproof adhesive.  I'm in the process of trying to obtain construction documents.

Any suggestions about repairing delaminations?  reconstruction may be an issue and repair costs could be several hundred thousand dollars.

Dik

MiketheEngineer (Structural) · Answer 1 · 2007-02-16 15:00:07

Get back to the manufacturer if possible - no matter how old..

dik (Structural) · Answer 2 · 2007-02-16 15:08:24

Thanks, Mike, I'm in the process of obtaining drawings.

Dik

structuralaggie (Structural) · Answer 3 · 2007-02-16 15:32:52

The only experience I had with delaminaion of glulams was when a contractor tried to have some glulams pressure treated after they were fabricated. Its not something I speced, just something the homeowner wanted the contractor to do and nobody asked me. Half of them just fell apart. I hope they didn't use the others, but again, nobody asked me. At anyrate, my guess is that is was the moisture, but could have had something to do with the preservative as well.

JAE (Structural) · Answer 4 · 2007-02-16 15:44:37

dik,

I had my church in the same situation - these were exterior gluelams holding up a "drive-under" canopy. Horizontal splits along the lams.

What we did was drill long lag screws from the bottom up to cross over the split lams. We used lag screw shear capacities and calculated the horizontal shear at the lam to ensure that we had enough grip.

You can also inject epoxy as an added help but I'm not sure of the epoxy-wood applicability...you'd have to check with local epoxy injection folks to see about that.

We counter sunk the lag screws and plugged the holes with wood dowels to hide and protect the lag screw heads.

AUCE98 (Structural) · Answer 5 · 2007-02-16 17:09:47

dik,

Our company has pressure injected gluelams and applied FRP to add strenght to overloaded members. It is a viable solution.
Regards,

AUCE98

LPPE (Structural) · Answer 6 · 2007-02-16 17:53:02

I had a site with a few tapered gluelam columns that had started to delaminate. We did exactly what JAE did with the lag screws. The columns were to be boxed out, so we didn't go the extra step and use the wood dowels to hide the bolts. Nice touch, though...

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Repair to delaminating glulam