Acceptable to lay CMU column ties in bed joint? 1

[StrEng007]

I came across this detail online for constructing a built up masonry column.

Is it normal to lay the column ties in the bed joint? I'm not sure where else they would go if you're using solid blocks as shown.

 

[phamENG]

It really doesn't work well in practice. You have a 3/8" tie, and a 3/8" bed joint. That doesn't work, so you have to increase your bed joint thickness to something closer to 3/4". Now your column coursing doesn't match your wall coursing. If I specify masonry columns that require ties, I specify open blocks for the purpose.

 

[jayrod12]

It really doesn't work well in practice. You have a 3/8" tie, and a 3/8" bed joint. That doesn't work, so you have to increase your bed joint thickness to something closer to 3/4". Now your column coursing doesn't match your wall coursing. If I specify masonry columns that require ties, I specify open blocks for the purpose.

Do you really need the mortar above and below the tie for the small area that it's going to impact? My argument would be no, and therefore the coursing stays pretty well the same.

 

[StrEng007]

Notch the CMU to accept the dept of the tie?

 

[bIockhead]

Don't forget that the mortar joint is also what eats all your other variations in tolerances. If you jam a bar in there that occupies the idealized thickness, the mason loses one direction in one of the "levers" at their disposal to gauge up their coursing as PhanENG alluded to. Is it the end of the world? Probably not? Is it fair for that poor mason to be held to the same expectations of workmanship and appearances as the sample panel? I'd argue not.

 

[Greenalleycat]

This is why they make specific open column blocks
I think it is a poor detail

 

[SE2607]

I recommend using a 16"x16" column block (open in the center) and put your ties within the grouted cells.

 

[bIockhead]

I think notching the webs or face shells is fine, but is a pain for whoever on site drew the short end of the straw. A lot of masons would probably opt to switch to a pier block or open unit to save the hassle, but since it's fully grouted anyways then I don't think the means and methods in this regard will have any measurable impact on the final result, unless the mortar joints end up being too fat (which reduces compression performance - not idea for a column)

 

[NC-ENG]

From a practical standpoint, we would just notch the webs. It isnt really that big of a deal from a labor perspective (you wouldnt really see any upcharge per unit). Plus the idea of a special shape may be impacted if the column has to have bull nose corners. If BN corners are required, then you may be forced to notch webs.

You wouldnt see the tie attempted to be placed within the CMU headjoint in practice.

 

[StrEng007]

Thanks everyone. I think I agree most with notching the webs if open block is not used.

 

[EngDM]

It really doesn't work well in practice. You have a 3/8" tie, and a 3/8" bed joint. That doesn't work, so you have to increase your bed joint thickness to something closer to 3/4". Now your column coursing doesn't match your wall coursing. If I specify masonry columns that require ties, I specify open blocks for the purpose.

Is there any difference in strength? You have a little less web to deal with so less of the block takes compression, more goes to the mortar. Is this significant?