1979 Wood I-Joist Capacity
1979 Wood I-Joist Capacity
(OP)
Hi,
I was inspecting a 1979 condo unit (in Canada) that has original Wood I-Joists with no clear identification on the drawings or on the product.
Does anyone know how I can detemine the capacity of such a product? Currently the joists appear to be under-designed based on deflection and we are anticipating having to cut down the span. I was hoping to find span tables on the joist but I am worried this will come back to first principles. Any advise on either way. I don't even know where to start for designing an I-Joist from first principles.
The joist appears to be douglas fir top and bottom chord. 1.5" deep by 1.75" wide. The web is 3/8" thick fir plywood that is embedded in the fir chords 5/8". The joist is a total of 11-7/8" deep.
There was only one stamp on a single joist (on the plywood) that indicated:
B0131
COFI Exterior Canada
CSA 0121-1X
DFP
--
Any Help Would Be AWSOME!! Thanks!
I was inspecting a 1979 condo unit (in Canada) that has original Wood I-Joists with no clear identification on the drawings or on the product.
Does anyone know how I can detemine the capacity of such a product? Currently the joists appear to be under-designed based on deflection and we are anticipating having to cut down the span. I was hoping to find span tables on the joist but I am worried this will come back to first principles. Any advise on either way. I don't even know where to start for designing an I-Joist from first principles.
The joist appears to be douglas fir top and bottom chord. 1.5" deep by 1.75" wide. The web is 3/8" thick fir plywood that is embedded in the fir chords 5/8". The joist is a total of 11-7/8" deep.
There was only one stamp on a single joist (on the plywood) that indicated:
B0131
COFI Exterior Canada
CSA 0121-1X
DFP
--
Any Help Would Be AWSOME!! Thanks!






RE: 1979 Wood I-Joist Capacity
The chords take the moment, the plywood takes the shear.
Check deflection using the E of the chords. I would probably neglect the contribution of the plywood web in the calculation of I.
RE: 1979 Wood I-Joist Capacity
http://i-joist.org/links.asp
RE: 1979 Wood I-Joist Capacity
RE: 1979 Wood I-Joist Capacity
Mike McCann
MMC Engineering
RE: 1979 Wood I-Joist Capacity
Can anyone post a simple example for I-joist design? or point me in the right direction?
RE: 1979 Wood I-Joist Capacity
RE: 1979 Wood I-Joist Capacity
The shear flow between the chords and the plywood web won't affect the capacity of the member in bending. The connection needs to be able to take the shear flow but it doesn't affect the moment capacity (unless it can't take the shear flow, but then you don't have a composite section anymore and your plywood web is doing a lot of work in bending).
RE: 1979 Wood I-Joist Capacity
http://w
Here is Jager Engineered Wood Products a company that has apparently been in the business since 1980. They might be able to give you some information about the early I-joists. There is a lot of info at this site.
I might add their construction details are outstanding.
h
RE: 1979 Wood I-Joist Capacity