glulam repair
glulam repair
(OP)
I have some glulam beams that have suffered checking as a result of severe fluctuations in moisture content over 30 years. I have evaluated the checks based on AITC Technical Note 18, and have determined that some of the checks have decreased the shear capacity of the beams. Does anyone have any thoughts on how to repair these checks? I read in some other AITC literature that repair of checks by epoxy injection is not the best solution when your goal is to fix the shear capacity. My thought is to put some thru-bolts in the beam with top and bottom plates. I would design the bolts based on transering the shear flow, similar in theory to bolting cap plates to a steel beam. I might also inject some epoxy anyway, as some insurance.





RE: glulam repair
Calculate the actual shear on the beams and see if it exceeds the reduced allowables. Shear may not be the critical factor.
Check to see if the reduced cross-sectional area resulting from the through bolts doesnt become critical...the beam width will now be reduced by the diameter of the bolt hole.
If shear is critical, look into lag-bolting some thin steel plates onto the sides of the lam. This may be easier to access than trying to get at the top of the beam.
RE: glulam repair
Cheers
RE: glulam repair
RE: glulam repair
Horizontal Shear Stress, Fv, shall be modified by Shear Factor, CH;
0.69<=CH=KLx[850/(b x L)]0.2<=1.0
where:
KL=loading coefficient (1.0 for uniformly distributed),
b=width of beam, in.,
L=span of beam, in.,
APA has an article Evaluation of Check Size in Glued Laminated Timber Beams:
http://www.apawood.org/pdfs/managed/EWS-R465E.pdf