• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

The J-L Bolt Debate

Joe.B said:
What kind of issues? Issues with installation or design? Or real-world failures?

I've only ever seen them on a few jobs, always new construction and part of an engineered design. They look like they make construction easier and listing wise they're supposed to be stronger than basic anchor bolts.

Typically, we see the basic anchor bolts and SSTB's with HDU's.
Click to expand...
Not one for one with anchor bolts....
 
I've seen anchor bolt failure under two different situations.
  1. Flooding
  2. Winds
In one instance, the house had a built-in two-car garage on the left front of the house. The garage door was left open, and a thunderstorm was brewing, causing some straight-line winds to hit, which was the perfect storm because the wind went right into the garage door, creating a positive pressure, blowing out the gable exterior wall on the outside of the property, ripping it off the block, and the common roof was damaged from uplift.
 
ICE said:
R403.1.6 Foundation anchorage. Wood sill plates and woodwalls supported directly on continuous foundations shall be anchored to the foundation in accordance with this section.
......The bolts shall be located in the middle third of the width of the plate. A nut and washer shall be tightened on each anchor bolt. There shall be not fewer than two bolts per plate section with one bolt located not more than 12 inches or less than seven bolt diameters from each end of the plate section.....

As to an engineer approving the anchor bolts. Engineers do not approve anything and "within accepted tolerances" is engineer speak for Blah, Blah, Blah. The middle third is a tolerance. The plate washers will be sticking out of the wall.

I did ask what do you see wrong. Since one can't see a missing anchor bolt I suppose that doesn't count.

What is not clear in the picture is the amount of the anchor bolt above the concrete that is not threaded. If I an seeing what I think that I'm seeing is correct, those are really long bolts and the plate will be stacked with washers.
Click to expand...
That's a good citation, and exactly why I started asking questions. This was a multi-family building, therefore a CBC design outside the scope of the CRC. Chapter 18 (foundations) of the CBC doesn't have an equivalent citation. It basically requires an engineered design. Also, nothing equivalent in chapter 23, or anywhere else for that matter.

Closest I could find was references to forces in ASCE 7. So that's what I discussed with the engineer. The hold downs don't rely on the nut and washer to anchor the wall, they use the bracket that is connected to the framing which has a lot of leeway in how they're designed, and during the rough framing inspections those were all installed correctly.

Around here walls that are sitting on concrete use two bottom plates, one P/T and the other not, and the bolts go through both. Like this:
1761162864649.png
 
jar546 said:
So the real question is how the CMU is grouted when the J or L bolts are installed. I've seen them just fill the cell below with pieces of the empty lime bags and then set the anchor in mortar. Like that is going to do anything.
Click to expand...
I once failed a contractor for missing anchor bolts on a portal frame. The trimmers and kings were installed on a sill plate and I could just see the crack of the un-grouted cells underneath. The next day I was back for the reinspection. It was a miracle, brand new anchor bolts, in fully grouted masonry that was not new, with nice big plate washers, on a wider sill plate. Also in plain view was a little slop poking out around the plate washer from some expandable foam cans that weren't there the day before. Because I am the @#$ I gave it a little tug. Out slid the bolt. Turns out expandable foam is not good in tension.
 
MtnArch said:
Why the double plate? For shear boundary nailing? Why not use a 4x PT plate?

Just curious ...
Click to expand...
That's a great question and I don't have an answer for you. It's not always done here, but it is by far the prevailing method here. I can think of several advantages, but not sure of the origin.
 
jar546 said:
I've seen anchor bolt failure under two different situations.
  1. Flooding
  2. Winds
In one instance, the house had a built-in two-car garage on the left front of the house. The garage door was left open, and a thunderstorm was brewing, causing some straight-line winds to hit, which was the perfect storm because the wind went right into the garage door, creating a positive pressure, blowing out the gable exterior wall on the outside of the property, ripping it off the block, and the common roof was damaged from uplift.
Click to expand...

jar546 said:
I've seen anchor bolt failure under two different situations.
  1. Flooding
  2. Winds
In one instance, the house had a built-in two-car garage on the left front of the house. The garage door was left open, and a thunderstorm was brewing, causing some straight-line winds to hit, which was the perfect storm because the wind went right into the garage door, creating a positive pressure, blowing out the gable exterior wall on the outside of the property, ripping it off the block, and the common roof was damaged from uplift.
Click to expand...
The anchor bolts didn't fail - despite poor placement, but the wind ripped the studs right off the plate. The roof ended up in a parking lot about a block away.
 

Attachments

  • 20250715_095549[1].jpg
    20250715_095549[1].jpg
    2.7 MB · Views: 5
BuildingOfficial89 said:
The anchor bolts didn't fail - despite poor placement, but the wind ripped the studs right off the plate. The roof ended up in a parking lot about a block away.
Click to expand...
I had a similar result from a case where the guy turned his attached residential garage into a paint booth. He had just stepped out the man door when it blew. The man door hit him and he ended up ten feet away. There was parts of the garage scattered in the neighborhood.
 
OK. Tell me why I don't buy this guy's argument? The little threaded bolt is gonna have way less uplift resistance than the l-bolt. And the expansion bolt - again same sort of issue.

In short, I find this video really suspect.
 
jar546 said:
It is a bit controversial and I have spoken to different P.E.'s who agree and some that disagree. The proof is in the testing.
Click to expand...

Until there's an apples-vs-apples-vs-apples test of the three types of bolts in the video, it's one-sided performance art, nothing more.

And I ain't no engineer, but I'd wager a thread on a bolt is going to give way less surface area and uplift resistance than an l-bolt.
 
You must log in or register to reply here.
Back
Top