Earthquake RetroFit on Wall

[RWebb]

I am messing around with a room on the corner of my house. While I have the ceiling out, I thought maybe it would be smart to do some earthquake retroFitting on it.

Here is a pic of the corner:



Both of those walls are poured concrete & the house was built in the early 1960s. My thinking is that I could get some of the metal straps that Simpson makes that have a place to nail the strap to the joist -- the strap then takes a 90 degree twist and the other end is setup to take a stud that you epoxy into a hole you blow into the concrete stem wall. This ties the joist into the wall directly instead of relying on on a few nails into the mud sill. (It turns out that my mud sill was not even properly bolted to the top of the concrete stem wall -- the nuts were sitting about 1/2" ABOVE the wood & no washers were used - but I added washers and new nuts so that is addressed now.)

Here is a pic of the strap I am thinking of using:




... not a very good pic I guess - to the right of the gun rack, you can just see the beginnings of the twist in it; the part of the strap that is bolted the wall is behind that plywood & it extends down to where that black line is drawn.

The above pic is on the other side of the house - where I tied everything together while I had the entire downstairs ceiling dropped on that side of the house (to put in hydronic heat). I tied every joist down with those straps.

My questions here are:

1. do I actually need to tie every joist into the concrete stem walls? I was told that the subfloor above this daylight basement turns the whole thing into a giant horizontal shear plate, so I only need to tie joists to the stem wall every 3 feet or so.

2. do the type of straps I am envisioning sound like the right/best thing to use?

My plan is to cut away the sheet rock you see just a tad bigger than the width and length of the straps, set them right up against the concrete stem wall and bolt them in that way - then I can mud over the strap with drywall mud or plaster and it should look pretty good.

[Zeke]

Now that you've fixed the bolts, just use A35 clips at the rim joist to sill connection and joist to rim connection. No need to double the work of the bolts. A35's can be bent to be used in a variety of configurations. Want extra strength? Use some screws along with the correct nails.

Not that your idea is bad, just labor intensive.

[RWebb]

Thx - actually that is the wall on the other side of the house that I did a couple of years ago.

do those look like the best straps to use? I've seen one that look like big hurricane ties & have flanges on each side of the joist

I am a neophyte at this so...

"sill" = "mud sill" = the horizontal 2x4 or 2x6 that sits on top of the concrete stem wall, right?

"rim joist" = ??

is the rim joist the vertical joist board that is on the outside wall of the house? and does it matter if the vertical board is parallel to the other joists? i.e. there are vertical boards on either end of the house that are parallel to all the other joists (2 of them) AND there are also vertical boards on the outsides of the house that run perpendicular to the joists - 2 of them also ---> are all 4 of these boards called rim joists, and all 4 of them need a right-angled connector to tie them to what I think is called the mud sill?

[Zeke]

You're killing me here.



A35:



You can use these in between the joists in a horizontal position to tie the rim joist to the plate.

[GWN7]

Palm nailer and the nails used to put those plates in.