Shear connection from existing plywood diaphragm to new shear wall
Shear connection from existing plywood diaphragm to new shear wall
(OP)
I have a scenario as follows: I have a project where we are raising up an existing single story wood framed house and building a new lower level. The owner was planning/hoping to leave the existing finishes as-is.
My question: I am detailing an interior lower plywood shearwall to the existing floor diaphragm. Ideally I would install a line of plywood edge nailing from the top of the floor diaphragm down to solid 2x blocking between to floor joists then use framing angles from joist to top plate. The edge nailing in the floor diaphragm obviously goes against the owners wishes of leaving the existing finishes as-is. Does anyone have a creative suggestion to acheive the floor diaphragm to blocking connection from the underside of the diaphragm?
My question: I am detailing an interior lower plywood shearwall to the existing floor diaphragm. Ideally I would install a line of plywood edge nailing from the top of the floor diaphragm down to solid 2x blocking between to floor joists then use framing angles from joist to top plate. The edge nailing in the floor diaphragm obviously goes against the owners wishes of leaving the existing finishes as-is. Does anyone have a creative suggestion to acheive the floor diaphragm to blocking connection from the underside of the diaphragm?






RE: Shear connection from existing plywood diaphragm to new shear wall
The load path would be floor diaphragm to two joist lines, two joist lines to blocking, blocking to shear wall.
DaveAtkins
RE: Shear connection from existing plywood diaphragm to new shear wall
1. Use glue at the top of the blocking to the underside of the plywood diaphragm.
2. I would also use Simpson LPT4 clips applied flat to the blocking and shear wall double top plate. And, finally,
3. I would go back and infill the joist spaces without the blocking with blocking, glued on top and with LPT4,s. This set of blocking could be installed flush with the other side of the plate so they could still be end nailed.
This is about as good of a connection as you will be able to get without nailing the floor diaphragm to the top of the blocking. If you want to, just alternate the blocking flush to one side of the top plate, then flush with the opposite, for the length of the wall.
Lots of options here, depending on the capacity your wall needs.
Mike McCann
McCann Engineering
RE: Shear connection from existing plywood diaphragm to new shear wall
MSQUARRED48: Regarding the glue, I know that it would provide some connection, but is that accepted by City plan checkers? I guess I should mention that this project is in Oakland CA, Zone 4, 5 km to Type A Hayward Fault
RE: Shear connection from existing plywood diaphragm to new shear wall
RE: Shear connection from existing plywood diaphragm to new shear wall
RE: Shear connection from existing plywood diaphragm to new shear wall
RE: Shear connection from existing plywood diaphragm to new shear wall
No, glue is not recognized as transferring any force when applied like this, I just think that it is good practice, plus it can't hurt.
It's structural contributions can be considered though when in a tested system, as one that is ICBO tested and rated. If you note, TJI has span tables for their floor joists that are load rated both with and without glue.
Mike McCann
McCann Engineering