Designing Jamb Bars for an Opening in a CMU Wall

[Philip.screw]

When designing an opening in a CMU wall, do you need to design rebar members to resist out-of-plane forces similarly to a jamb stud with wood construction? The attached image is a generic CMU wall detail I found on Google. The detail calls for bars at the opening jambs, which I assume helps resist the out-of-plane forces. I'm trying to find information in the TMS (TMS402-13 / TMS602-13, these are the versions my office has) and the Masonry Designers' Guide 2016, but I cannot find any design examples or mention of jamb reinforcement around openings.

Is there a design guide or code section that covers this? How do other engineers design jamb bars?

My current method to design jamb bars is to design an 8" wall strip in our software (Enercalc) and use that to determine the minimum required area of steel. Is this method reasonable / similar to what other engineers use?

 

[driftLimiter]

8" Strip adjacent to the opening feels pretty small to me.
A reasonable strip width in my view could be defined by the lintel extension length beyond the opening.

** Edit I suppose a caveat to my above statement is that the wall is fully grouted. I don't do any partially grouted stuff so I'm not sure how you all deal with that.

 

[PMR06]

For out of plane loading, I would design the jamb reinforcing for a tributary width equal to 1/2 the door width + 1/2 the distance to your next vertical reinforcing.

Looking at your wall elevation, I would also explore the idea of moving the mid-height bond beam up 2 courses to coincide with the lintel.

 

[lexpatrie]

Hang on......

Well, I can't find it now, but there used to be a structural calculation package for the New Stafford Police Department by Grenier Engineering out on the internet that had jamb calculations. I couldn't quite independently verify everything in there, but it's a starting point, provided you can find it. Seal date is 4-14-20, it's a mix of Tedds calculations, hand calculations, and Excel, as well as some Red-Spec I joist calcs. It's a strange little package because some of it is direct (color) output from Tedds, and some of it they printed it out and scanned it back in so those pages are B&W and skewed. and the direct PDF color output from Tedds is in the middle, suggests two designers to me, and then again at the end.

I'll just skip discussing EnerCalc. Maybe it's gotten some quality bolted on in the last twenty years. I gave up on it in 2005.