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RE: glulam failure

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There a couple of resources that might be helpful. One is an article that appeared in Structure Magazine a while back on post-tension repair of glulam:

 

http://www.structuremag.org/Archives/2006-9/C-Structural-Failures-ON-LINE-VERSION.pdf

 

You might also contact AITC or APA or check out their online resources:

 

http://aitc-glulam.org/shopcart/index.asp#technical

http://apawood.org/level_c.cfm?content=pub_glu_libmain

 

HTH

 

Buddy

 

John "Buddy" Showalter, P.E.
Vice President, Technology Transfer

 

American Wood Council

www.awc.org

 

The American Wood Council (AWC) develops internationally recognized standards for wood design and construction. Its efforts with building codes and standards, engineering and research, and technology transfer ensure proper application for traditional and engineered wood products.

*********************
The guidance provided herein is not a formal interpretation of any AF&PA/AWC standard.  Interpretations of AF&PA/AWC standards are only available through a formal process outlined in AF&PA's standards development procedures.

*********************

 

From: "Truitt Vance" <truitt(--nospam--at)ashleyvance.com>

To: <seaint(--nospam--at)seaint.org>

Subject: glulam failure

 

 

While we are debating the viability of this forum, how about a quick

engineering question? J =20

 

There is a 150,000 sq. ft panelized roof constructed in 1980 with =

multiple

glulams in various states of failure, all the way from =93looks fine=94 =

to =93lets

shore that one right now=94.  Due to the large spans (60=92 and 48.5=92) =

and

accessibility, I am going to recommend that we use post tension =

techniques

to fix the failed one(s) vs steel sections.  They exhibit classic =

bending

failures=85some lams are separated by 1 =BD and the cracks propogate =

cross

lamination in a shallow =93v=94 from the mid span.  I don=92t know of =

any other

technique that would be very viable for an option. =20

 

I am going to conduct a thorough observation of all the beams tomorrow =

and

my question is:  Given that all of the glue is suspect due to two =

failures

already and the time period it was constructed in, do any of you have =

any

guidance on criteria or general comments on how to determine how much

delamination is =93ok=94?  What is the best metric to use? Would you =

measure

current deflections of all of the beams? =20

 

Has anyone had experience using FRP for wood beam repair?  How did it =

go?

Cost effective?  The reps say it=92s great=85.  Since the wood is in =

great

condition, I think it would be a possibility but I would have to get

additional guidance on that.

 

Other info: based on my initial site visit, moisture has not played a =

role.

Based on my initial calcs, the beams are in the 95-98% of allowable =

bending

stress range.

 

Thanks,

 

 

Truitt