Countersinking J-Bolt in a wooden sole plate in residential construction allowed?

[SparksRfun]

We have a situation where we are installing a modular building system on 2x4 wooden sole plates attached to a concrete foundation. Residential Construction. In this case, if it were a standard framed wall the code in our case would require a J-bolt with a 3" washer plate every so many inches. It would be fine if that bolt interfered with a stud, the stud could be notched.

However the system we are using involves bringing modules in by a crane. It would be awkward to notch the bottom of one of these modules. Previously this has been solved by using Titan HD anchors with flat heads - but it required a LOT of them - they are installed on 12" centers in the sole plate before the modules are dropped in. We are trying to find alternatives to using so many drilled anchors that may be less costly in labor.

I've looked for anything in the code that allows or prohibits countersinking the J-Bolt washer and nut below the top of the 2x4 wooden sole plate, without result. Is there a specific prohibition against such a practice?



SparksRfun

"The truth will set you free, but first it will make you madder than a wet bobcat"

 

[phamENG]

In a single 2x plate? No, you can't. There nothing left of it to do the job. You could potentially double the plate and recess it in the top plate, but there are other considerations. Also, even in normal site built construction, you couldn't notch the studs like that. You just have to coordinate the locations of the anchors and the location of the studs. The same can be done here. The shop should be able to tell you where they start pulling their stud dimensions, and maybe even shop drawings showing scavenger locations. Then have the foundation contractor set anchors accordingly.

If you want a unique anchorage solution that lets you skip the coordination step, you'll need to hire a local structural engineer to evaluate it and give you a bespoke design.

 

[jayrod12]

I'm anticipating that the pre-fabricated modules are coming with a wall bottom plate already installed? Or is it platform framing on the floor?

If platform framed, you should be able to coordinate anchor locations with floor joist locations to avoid a conflict.

If not platform framed, i.e. you just have the wall bottom plate sitting on your sill plate, in the vein of pham's recommendation, could they drill the bottom plate of the wall at the anchor locations so there's no conflict? After coordinating stud locations of course.