Wood Frame Shear Wall Hold Down at Masonry Wall
Wood Frame Shear Wall Hold Down at Masonry Wall
(OP)
I've got some wood shear walls coming down on parallel masonry basement walls. I have the following questions:
1) What are some good tie-down connector options for this scenario?
2) Is there anything unusual to be worried about with masonry? I kinda have this picture in my head of the tie down yanking the upper courses of the block away from the rest.
1) What are some good tie-down connector options for this scenario?
2) Is there anything unusual to be worried about with masonry? I kinda have this picture in my head of the tie down yanking the upper courses of the block away from the rest.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.






RE: Wood Frame Shear Wall Hold Down at Masonry Wall
Existing masonry or new? If existing then your concern would be definitely justified. If new, then grout and reinforce the cores with the hold-down anchors, and perhaps one each side of that one. A long anchor bolt would slso help, the issue would be room in the core. You could thread the top of the reinforcing i guess and use that as your anchor bolt.
But that's just me spit-balling.
Option: Blocking the chord out to match the wall width, and then long coil straps with concrete screws into the masonry wall. Likely a bit messy but it has the advantage of grabbing multiple courses of blocks.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
I guess that my main concern was the presence of the face shells. The face shells would mean that some of the embed solutions would be infeasible. Although, I suppose that there really isn't much difference in an anchor bolt scenario so long as one takes account of the material properties and proximity to edges etc.
It's new but my odds of getting anything fancy done are pretty remote. I misspoke with regard to the basement wall. It's more accurately masonry grade beams.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
You mean an all concrete grade beam as opposed to a masonry bond beam, right? I'd love that but I won't be able to negotiate it here.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
What kind of masonry grade beam thickness are we talking? 8" or 10" blocks?
What's the size of the wall above? would there be any openness to matching the beam thickness?
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
Can your anchor rod splice to a footing dowel?
How deep is you masonry "grade beam" - I don't know that I've ever seen a "masonry" grade beam.
Is there a concrete footing?
Do you have a detail? You usually do!
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
Like I'd say no to that. Hit me. Detail below. Outside of stud = outside of block.
It can be.
Side mounted as in attached to the side of the block rather than embedded into it?
I could. I'll just make the whole darn thing a bond beam.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
Also, check out the PB holddown from Simpson Strong-tie, might be exactly what you're looking for in a sense.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
Don't quite know yet. Relatively small. I was hoping to get a handle on the detail and a rough capacity and then work backwards from there to determine how many panels I want.
LOL. As long as they actually sheath between the sill plate and wall bottom plate.
Thanks so much. My only concern is what jd mentioned: do the straps need to stay inside of the building envelope?
My chords are going to land nicely upon trusses. I wonder if I could use a similar approach to tie down the trusses.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
If this for warm or cold climate? If cold, I assume they'd be doing something to slow the heat loss through the masonry. Insulated floors never work as intended, you really should be heating the crawlspace.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
I would restrict the concrete strength to 2000 psi unless you can specify better...
Mike McCann, PE, SE (WA)
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
NCMA has a spreadsheet for masonry anchor bolts at http://ncma-br.org/pdfs/68/TEK%2012-03C%20-%20MSJC... . If the link doesn't work try https://www.masoncontractors.org/tech-notes/ and scroll down to NCMA TEK 12-03
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
I have been running into this monthly on my residential jobs now that they are cracking down on lateral stability in our area. Also, 75% of our foundations are 8" CMU.
As has been suggested, I run the rod all the way into the footing. I give them the option of not grouting the cells that contain the rod. This gives them some flexibility in the rod while framing. I usually show a double band in the area of the shearwall so the chord compression loads can easily span over the un-grouted cell column.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
Yes, yes they are.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
Probably. Currently, I'm digging XR's idea of running the anchor rod all the way down.
Poor terminology on my part. Let's call it a stem wall.
There is. 16"W X 12"H
Yeah, I'm a sketch-a-holic. It's funny. I seem to have oodles of time to post sketches in other peoples threads. Then, when it's my thread, I'm in a hurry for an answer and I just go bare bones. I posted a partial above. If you feel that anything is missing from your mental picture, let me know.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
One thing worth noting. if you bring your threaded rod into the stem wall and through the top grade beam so you are transferring tension loads into the rebar... make sure you put 90-degree bent bars from the vertical cells into the bond beam. try to only use one bar per cell this way at the laps you only have 2 bar diameters. I've done this numerous times and it works... as far as numbers and construct ability but only for residential so i have never inspected it during construction, TBD.
If you are using straps, you also should consider this. it will keep the bond beam from pulling off due to inadequate laps.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
You could just give them the expected tensile load at each location and let them figure it out. Show an intended connection but otherwise stay hands off and cover the details in CYA statements about coordinating connection details. Is this project north or south of the 49?
RE: Wood Frame Shear Wall Hold Down at Masonry Wall
Close. Pre-fab.
South.
Honestly, I'm not sure that there really will be great competence at that end. If I ask them to figure it out, I suspect that they'll either screw it up or just come back and ask me to figure it out later.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Wood Frame Shear Wall Hold Down at Masonry Wall