Design Values for Glulam Beam from 1979?

[calpolyholley]

Does anyone know of a good reference for design values for glulam beams around 1979? Do the beams produced back then have similar design values to the beams produced today? I am trying to determine the feasibility of converting a floor beam from an office live load (40 psf) to a storage live load (125 psf). The building was constructed in 1979. We are focsuing only on gravity loads at the moment; we will be considering the lateral effects on the walls later. Thanks

 

[dik]

You might check with CITC. Typically flexural strength was 24f (2400 psi flexural tension) and 18c (1800 psi for compression. I think that shear was 175 psi... but, been a long time <G>.

Dik

 

[samdamon]

1977 edition of "National Design Specification for Wood Construction" gives allowable stress values for both hardwood and softwood glulam members, in tables 5A and 5B of the supplement "Design Values for Wood Construction". Regret I do not have time to compare the allowable values published then to those now, but try to get your hands on a copy of this particular year of the NDS, it will probably help. It has a light green cover. You might also want to review a contemporary design text when interpreting those tables, believe design methods have changed slightly over time.

 

[RARWOOD]

Chaecking a copy of the second addition of the AITC Manual, it appears design values were similair. The 2005 NDS shear values are higher than in earlier editions.

I believe dlk meant to refer you to AITC. You should give them a call.

 

[dik]

Sorry... could be either Canadian/American... forgot about the AITC.

Dik

 

[RARWOOD]

dlk

My apologies, as an US designer, I tend to forget about the research that has been conduct on wood in Canada and other parts of the world.

I have a copy of the "Wood Design Manual" published by the Canadian Wood Council. It has a lot of useful information which I refer to occasionally.