Tie columns in masonry shear walls

[StrEng007]

Does placing tie columns at the end of a masonry shear wall reduce the depth of the shear wall?

Take a 8" CMU shear wall that is 10'-0" long and you place an 8x12 tie column at each end. The CMU portion is now reduced to (10ft - 2ft). In theory, I'd like to keep the shear wall 10FT long. The tie columns would then take place of the chord steel that you'd typically placed in the filled cells at each wall end.

 

[haynewp]

If the horizontal bars correctly terminate in the concrete tie columns then I would consider the shear wall length still to be 10 ft.

 

[StrEng007]

Wall doesn't require horizontal steel other than the 2x W1.7 wires that will be achieved through horizontal ladder reinforcing (ie, no bond beam steel).

So as long at the ladder reinforcing makes it way across the full tie-column depth, that would constitute continuity there?

 

[KootK]

I assume that we're talking about the setup shown below. Similar to haynewp, I think that it comes down to this:

1) If you don't need horizontal reinforcement as designated shear reinforcement, you can use the full 10' regardless of what you do with the ladders. The concrete becomes, effectively, just some improved masonry.

2) If your horizontal reinforcement -- no matter its form -- is shear reinforcement then it probably ought to carry across the tie columns as connecting the wall chords in this way is usually thought to be mechanically correct.

3) If you have designated shear reinforcement AND the tie columns are meant to be your chords, them I'm not sure that you have any choice but to run the shear reinforcement into the tie columns. As with beams, however, it's always been a bit nebulous as to whether or not shear reinforcement is truly neutered just because it doesn't fully connect the tension reinforcing to the compression block. To some extent, I'm sure that it's not.