timber beam + steel plate - shear capacity? 1

[mats12]

Existing timber beam doesnt have sufficient shear capacity.

What is the best way to reinforce this? I was thinking about steel plate + epoxy glue.
As far as I understand shear force will be divided based on stiffness of both elements (timber/steel). Connection between steel plate and timber should be strong enough so it can transfer shear forces between both elements. I don't want to use screws since it makes already weak timber beam even weaker.

 

[Canuck65]

I would not rely on glue. I would use fasteners and add glue as a bonus.

When sizing the steel plate, size it for the full load. The amount of extra steel required in most cases will be a very small additional amount. The calcs are faster, the design is slightly conservative and there will be virtually no cost increase.

I would put a plate on each side, not one side as you have shown.

 

[KootK]

1) I like fasteners and glue.

2) I definitely like two sided otherwise it's a torsion nightmare.

3) I don't believe that you can transfer shear alone into the plate. You'll have to bring the companion moment along too and bring that through the fasteners. I'd anticipate plates a fair bit longer than you've shown.

4) It may be difficult to get the plates to bear upon the columns if that is your plan

5) Can you avoid shear consideration of the beam point load but virtue of it being closer than [d] to the support?

 

[jayrod12]

Can't you just put some long fasteners through the upper beam directly into the column to transfer the shear that way instead of down onto the beam below?

 

[Canuck65]

... and maybe consider putting a steel angle on the column to:

A) put angle above the existing beam, bolt into column, hide behind new beam and support new beam on angle

B) or put angle below existing beam and bolt to column to provide added shear capacity.