Does CMU Wall Brace Concrete Tie Column?

[dengebre]

I have a project with numerous concrete columns that are cast within the plane of concrete masonry walls (a/k/a concrete “tie columns”). The walls and columns are supported only at the floors above and below. The column and walls are 7-5/8” thick and the column widths range from 16”-32”. Does the CMU wall brace the column for buckling about the weak axis of the column (out-of-plane bending)?

The conservative approach would be to say “no” arguing that the wall cannot brace the column if the wall itself is unbraced between supports. The counter argument is that the wall can support the column if: the column and wall are mechanically tied together; and the wall is designed to withstand a brace force applied to the wall (say 2% of the compressive force on the column).

I am curious as to how others have approached this. Thank you in advance for your insight.

 

[jayrod12]

If the walls aren't part of the lateral system, I tend to not account for their contribution to the columns. Even if they are part of the lateral system, I still may ignore their contribution. In reality they will most definitely brace the columns, however I see so many renovations that include removing walls that I'd be hesitant to count on that wall being there for the life of the building.

 

[bones206]

I’m actually working on my first structure of this construction type in Florida. While I do not have any previous experience to draw from, I can tell you that I am not considering the CMU infill to have any bracing effect on the tie column’s weak axis. I consider the tie column to have the same unbraced length as the wall.