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CMU missing intermediate bond beam

CMU missing intermediate bond beam

CMU missing intermediate bond beam

(OP)
On a recent project, we’re infilling an opening in an exterior wall with CMU. The opening is 18’ tall, and the wall is running bond reinforced with #5 @ 24” o.c. We typically use stack bond for the majority of our projects because of architectural preference, so the spec called for truss reinforcing at 16” o.c. vertically plus a bond beam w/ 2#5 @ 12’-0” a.f.f. and at t/wall. There is no vertical load on the wall, it only needs to withstand wind pressure (basic wind speed of 90 mph). The mason did not install the bond beam at 12’-0” but installed the bond beam at the top of wall.

My first question is, if this is designed as a one way wall, other than the fact that the mason didn’t follow the documents, is there any other concern with a running bond masonry wall spanning 18 ft vertically with only truss type horizontal reinforcing? If so, is there a way to supplement the horizontal reinforcing without making them remove the top ~6 ft of wall and putting in a bond beam?

After reading a several other threads, I’m starting to wonder if my perception of the capability of running bond may be skewed by the fact that I’ve been typically using stack bond for a while, which makes me more cautious.

RE: CMU missing intermediate bond beam

Check the minimum required horizontal reinforcing. If you're using the ACI 530, I think you will find that typical horizontal joint reinforcing (#9 wires at 16" oc) is insufficient. This would require an intermediate bond beam, so that you meet the horizontal reinforcing requirement. That's why I require intermediate bond beams. Otherwise, your running bond wall does not need it for strength.

RE: CMU missing intermediate bond beam

(OP)
Would this not fit into ACI 530-05, section 1.14.2.2.2.1- "Minimum reinforcement requirements" and be governed by "Horizontal reinfrocement shall consist of at least two longitudinal wires of W1.7 joint reinforcement spaced not more than 16" o.c..."?

Is there somewhere else in the code that is more specific on the required horizontal reinforcing? The only other areas that I found were for Walls in SDC D or not laid in running bond. It's not a shear wall, I have running bond, and I'm in SDC A.

RE: CMU missing intermediate bond beam

I'm looking, but I can't remember now where I found that. I'll post again if I find it.

RE: CMU missing intermediate bond beam

@NinerStruct: First question in your OP - Although the in-place masonry does not conform to contract documents, there is no need to remove top 6'-0" and add the missing bond beam.
Ref ACI 530-05: The code has no minimum / maximum reinforcing requirements for allowable stress design for flexural members.
Section 1.14.2.2.2.1 : Horizontal reinf shall consist of 2 wires W1.7 @ 16" or bond beam spaced not more than 120" o.c. Horizontal reinforcing could either be joint reinforcing or a bond beam.

RE: CMU missing intermediate bond beam

(OP)
@DST148: Thanks. That was how I was reading it, but it's nice to have someone else that backs it up. I wanted to confirm that by letting the wall stay that I wasn't going against code.

Thanks to both for the responses.

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