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Concrete column tie requirements

Concrete column tie requirements

Concrete column tie requirements

(OP)
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.

RE: Concrete column tie requirements

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

RE: Concrete column tie requirements

(OP)
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.

RE: Concrete column tie requirements

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.

RE: Concrete column tie requirements

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.

RE: Concrete column tie requirements

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

RE: Concrete column tie requirements

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.

RE: Concrete column tie requirements

(OP)
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?

RE: Concrete column tie requirements

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.

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