Allowable Mechanical Anchors 1

[Kkirk10]

Can anyone provide me the code reference for limitations of mechanical anchors installed in cmu? A guy in my office is claiming that only (1) mechanical anchor can be installed per masonry cell. I have never heard this statement. In the past, I have installed (2) Simpson Titen HD in one cell. The cells are always solid grouted.

 

[XR250]

I would check the manufacturer's literature. I imagine the limitations are based on actual testing.

 

[jayrod12]

Yeah I'd bet that the testing is based on a single anchor per cell.

Honestly having two anchors in a cell seems like the reduction due to the spacing factor would make it uneconomical.

 

[WARose]

Can anyone provide me the code reference for limitations of mechanical anchors installed in cmu?

Beyond the anchor manufacturer's limitations, I'd check out NCMA's TEK 12.3 (or the latest version thereof). It runs through some examples.

A guy in my office is claiming that only (1) mechanical anchor can be installed per masonry cell. I have never heard this statement.

me neither. But from a practical/economical standpoint, it would make more sense to just have a larger diameter bolt per cell than trying to cram 2 in there. (Unless you need to meet some geometric configuration.)

 

[Kkirk10]

I have a cont. angle along a cmu wall w/ 5/8" bolts @ 12" c.c. for reference. Thank you for the responses. I will continue to look around at manufacturer's specs for anything

 

[Brad805]

I would look at the minimum edge distances. 12" o/c does not work well with typical masonry.

 

[cvg]

 

[phamENG]

I think you're both right. The code doesn't restrict you to one per cell. BUT...as others have pointed out, most (if not all) post-installed anchors have that limitation in their literature.

 

[jayrod12]

By cell, they also mean 8" segments. Not each 16" block.

 

[dhengr]

Kkirk10:
Your bolt spacing should probably be multiples of 8 or 16” to match the CMU’s modules, maybe upsize the angle thk./size and the bolt dia. And, the long angles should then be detailed so they can be adjusted a few inches in length, so the holes can be centered on a grouted cell/core, but still miss any vert. rebars, and have some bond cover. This means you may have a few inch gap btwn. some long angles. For large structural bolts (threaded rods) you can hardly fit more than one bolt in a cell, without splitting, etc. during drilling, it’s just not a good idea. For smaller bolts for anchoring a light sign, or some such, a couple bolts in one cell may be acceptable. I’ve seen a single A.B. move a conc. blk. right out of a wall, either lift it out or move it laterally. Remember, the only thing holding that block in the wall is the bond strength of the bed and head mortar joints on the outer shells. Then, add tensile and/or shear strength of a grout filled core if that be the case.