SHEARWALL ANCHOR BOLTS 1

[wailuku]

when spacing anchor bolts in a shearwall should i use only the lengths of the shearwall or should i use the full length of the sill plate?

In other words, when the shear in the shearwall reaches the sill plate, doesn't the load get distributed throughtout the full length of the sill plate-thereby reducing the amount of shear per anchor bolt?

 

[DaveAtkins]

I agree with you if you are using Section 2305.3.7.2 of the IBC (perforated shear wall design) -- the entire shear wall, with openings, acts as one continuous wall. But if you are putting your shear into the individual shear wall segments, I wouldn't assume the sole plate under window openings can take some of the shear, because the sole plate is most likely not doubled up, and shear would not cross a splice in the sole plate.

DaveAtkins

 

[pthorley]

I have seen it done both ways. But I agree I would use just the sill plate under the segment. If you used the full length of the sill then it would be a cord and I am don't believe that in practice you can make that assumption.

 

[damstructural]

Another consideration: You can't assume that the sill plate will be one continuous member. The shear at the sill will not transfer (drag) across a splice unless there is a shear panel bridging it at the splice.

I use the unit shear to calc AB spacing, which is based on the length of shear wall, of course, not the length of the wall.

If you see the way sill plates are butchered in the field, you will not feel bad about adding a few extras for just a few dollars more.

Also, I usually go with 5/8" AB's (CA Zone 3 & 4) because they're usually more cost effective (larger spacings - about the same price).