Bolts subject to bending - Ledger board fastened through brick veneer

[Dvdt18]

Good Day All,

Just curious to see if anyone has come across design resources for for bolts subject to bending.

BVLZ are not approved in Canada and therefore not available.

Thank you in advance.

 

[phamENG]

Then make your own and prove it with calculations.

The issue with the 'bolt in bending' is that you'll need to have a nut/head on the inside of the wall and one on the outside of the wall at the sheathing. This will clamp the bolt to the structural support and allow you to consider it cantilevered. Managing the bearing stresses and connections and preventing cross grain tension and torsion while also keeping that bolt hidden can be a challenge.

Then you need to make sure the bolt can't bear on the brick, since if it can that WILL be the stiffest load path and that IS where the bolt will be supported.

Then there's flashing. Now you have a bunch of big holes in the brick - how do you flash those and keep water out of the wall?

I've had the contractor remove sections of brick at an interval, mount a bracket to the back up, patch the brick, and then mount the ledger to the bracket. I think there's a company in Vermont that patented a similar system.

 

[Dvdt18]

Thanks phamENG. Agreed, it's not easy, just looking for re-assurance that it isn't easy to verify bolts in bending. Stiffness is a whole other issue. Bearing stresses and cross grain tension and torsion further complicates things. Just curious if there actually is any literature out there specifically discussing this with supportive calculations. We all know the principles, but has someone actually done it code compliant. No doubt the clients wont like it as they've been doing it "for 30 years".

Those brackets are handy, I'll look into them.

Thanks phamENG.

 

[dik]

Building officials in Winnipeg don't like people to attach decks, etc. to veneer. It's probably not a good idea. pham's comment about the treatment of the building envelop is a good one. I often have designs connecting ladders to masonry walls. If veneer, then the ladder must be supported at the base with the veneer only supporting lateral loads. I have a comment that in the event of a 'windstorm' condition that the ladder should not be used. I'm relying on the existing lateral strength to resist loads on the ladder.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[XR250]

The bolt will bear on the brick regardless and it generally has the capacity for that. No way you will get enough torsional stiffness at the band. The only issue I run into is when this occurs over existing lintels with unknown size.

Then there's flashing. Now you have a bunch of big holes in the brick - how do you flash those and keep water out of the wall?

You can flash under the first deck board to keep the majority of the water out. Brick is not intended to be watertight anyway - hence weepholes.
Can also add some caulk to the bolts for some extra resistance.

 

[Dvdt18]

To all future folks reading this. Here's a helpful article.

https://seblog.strongtie.com/2017/06/spanning-the-gap/

AWC Technical Report 12 was very helpful.

Thanks.

 

[WARose]

Just curious to see if anyone has come across design resources for for bolts subject to bending.

Forgetting about the masonry for a second.....IIRC, AISC has a combined shear & tension capacity equation for bolts/rounds. Generally, I've combined the bending & tension stress under the f_t portion of that equation.

 

[XR250]

I have a comment that in the event of a 'windstorm' condition that the ladder should not be used. I'm relying on the existing lateral strength to resist loads on the ladder.

I think if you have to add this note, you should re-think your design.

 

[SE2607]

I'm not sure I see the problem. Are you talking about bending in the ledger due to shear on the anchor or something else?

 

[dik]

Nope... design is OK. I'm using the veneer for lateral resistance of the ladder only... same loading or less than it would be in a windstorm. I'm happy with it; I don't like loading veneers.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik