Concrete column tie requirements 1

[mjl23]

Anyone know of guidance for when cross ties are needed for concrete columns? For instance if you have a column that is 6'-0" x 12'-0" how many interior ties should be provided? My situation would be non-seismic.

 

[UcfSE]

For the ACI, provide cross ties to meet 318 7.10.5.3. Closed ties can also be used to meet this section.

 

[mjl23]

Thanks. Also found it in AASHTO LFD 8.18.2.3.4. AASHTO requires longitudinal bars be restrained every 24" instead of the 6" required by ACI.

 

[shin25]

Why can't you have the vertical reinforcing arranged in a circular pattern? This way you can provide circular ties and no cross ties will be needed per ACI 318. This may save you some money.

 

[miecz]

AASHTO LRFD 5.10.6.3 requires the 6" maximum for columns designed for plastic hinging, such as for Seismic Zones 2, 3, and 4.

 

[mjl23]

shin25 other factors (aesthetics, etc) require a rectangular column in this instance.

 

[shin25]

mjl23,

You can have a rectangular concrete section, no problem. What I was suggesting is that arrangement of the main reinforcing can be made circular.

 

[mjl23]

shin25:
Circular pattern inside a rectangular shape? Boy, that would be a lot of concrete cover, no? Given the original dimensions above of 6'x12' I don't know how feasible that is. Seems like the location of the bars relative to the c.g. of the column would not be efficiently located. Maybe I am missing your point.
I separately posted this, but do you have any thoughts if it's a given that it's 2 rectangular patterns of reinforcing, one inside the other, if the interior ties (lateral support bars) need to specifically hook the interior layer? Or is confining the outer layer and providing lateral support for the outside layer sufficiently meets the requirements?

 

[shin25]

I was suggesting a circular pattern, may be not practical for the dimesion that you are referring to, but will be applicable case by case basis. Will be effective for a smaller size column.