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Shear Strength due to Dowel Action Across Joint in Masonry CMU

Shear Strength due to Dowel Action Across Joint in Masonry CMU

Shear Strength due to Dowel Action Across Joint in Masonry CMU

(OP)
I am looking for some guidance on how to determine the design shear strength for chord horizontal bars crossing an "open" 0.375 inch wide vertical control joint in an 7.625 inch wide fully grouted CMU wall.
The mechanism is similar to shear friction with smooth surfaces, except there is actually a gap, so no interface / interlock friction at all.
I don't think ACI 530-13 discusses shear friction at all, and ACI 318-14 has some brief language in the commentary.
Existing construction - redesign is not an option.
Primary demand at joint is out-of-plane seismic per ASCE 7-10 Section 12.11.
I'm guessing the governing limit states are
1) CMU shell crushing at the vertical faces, and
2) shear stress in horiz rebars, and
3) bending stresses in horiz rebars.
Any defensible code guidance, or rational extension from published codes? I practice in California.

RE: Shear Strength due to Dowel Action Across Joint in Masonry CMU

I thought that ASCE 530 (TMS 402) has a value for bolt shear for bolts cast into masonry. Sort of similar but with rebar.

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RE: Shear Strength due to Dowel Action Across Joint in Masonry CMU

Why is there out of plane shear transfer across the vertical joint? Are you spanning the top of the wall load from a diaphragm anchor on one side of the joint to the other?

RE: Shear Strength due to Dowel Action Across Joint in Masonry CMU

(OP)
JAE - yes, I think that's all I've got for (semi) code defined action. Masonry bolt shear crushing [eq 9-7] usually governs over shear breakout, but for this case, the crushing mechanism seems overly conservative, since the horiz bar has an near-infinite backspan and does not rotate like a bolt with 5" embedment would.
Crushing capacity (phi-Bvnc) for f'm = 1,500 psi and 5/8" bolt (or rebar) = 2.44 kips

heynewp - the vertical movement joint (control joint) was aligned above one vert edge of a 10'x10' roll up door opng. The wall has 2-way behavior.

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