Hello!
I'm wondering what gluing adds if you glue and screw together, for example, two 45x120 pieces to form one 90x120 piece?
It's clear that the joint becomes stronger if you’re pulling the planks apart (if used as a post, i.e., the glue counteracts buckling), but what does the glue add if used as a beam? In that case, the joint will be vertical in the direction of the load. Does gluing make any difference at all in load-bearing capacity, or does it increase torsional rigidity or counteract shearing?
I imagine that gluing allows for a continuous beam splice, meaning you don't need to splice over a support.
It would be great to get an answer to clear this up with my brother-in-law... (so he doesn’t end up being right
)
/Henjen
I'm wondering what gluing adds if you glue and screw together, for example, two 45x120 pieces to form one 90x120 piece?
It's clear that the joint becomes stronger if you’re pulling the planks apart (if used as a post, i.e., the glue counteracts buckling), but what does the glue add if used as a beam? In that case, the joint will be vertical in the direction of the load. Does gluing make any difference at all in load-bearing capacity, or does it increase torsional rigidity or counteract shearing?
I imagine that gluing allows for a continuous beam splice, meaning you don't need to splice over a support.
It would be great to get an answer to clear this up with my brother-in-law... (so he doesn’t end up being right
)/Henjen
If I have understood it correctly, a glued beam becomes stronger than a sawn one in the same dimension.
Apparently, it is the number of joints that creates the strength, compare plywood.
Apparently, it is the number of joints that creates the strength, compare plywood.
I would think that the beam you're talking about, 120x90, and 120 in height then, doesn't become significantly stronger when glued. But probably a bit more resistant to twisting.
In the other direction, however, gluing helps.
Without glue, the strength is about twice the strength of such a beam. With glue, the beam behaves like a homogeneous beam twice as high, and then the strength becomes... let's see now... if I remember correctly 4 times as strong.
That's what I believe anyway.
In the other direction, however, gluing helps.
Without glue, the strength is about twice the strength of such a beam. With glue, the beam behaves like a homogeneous beam twice as high, and then the strength becomes... let's see now... if I remember correctly 4 times as strong.
That's what I believe anyway.