Hooked bar in compression

[LH85]

When we calculate the capacity of column in pure compression, ACI allows us to use the compression force in rebars together with concrete. But at the connection between that column and the footing, ACI states that hooks can not be used to develop compression. So how the compression force in the rebars transfer to the footing ? The load will disperse from face of the rebar to the footing via bonding ? Does ACI mean that within the column, the rebars contribute to the total resistance, but at the footing, suddenly all the compression will be resisted by the concrete only ? So where the compression in the rebars goes ? It cannot be equal to Fy x As in the column and then becomes zero at the footing suddenly.

 

[JAE]

I think the concept is that the compression is simply taken by the concrete and any portion of the compression in the rebar on the compression side is simply transferred out from the bars into the concrete bearing area.

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[rapt]

The footing must be deep enough to allow the compression to transfer to the concrete through bond over the straight length. The only use for the hook/cog at the bottom is for tieing to the bottom footing reinforcement. It cannot be assumed to transfer any force to the concrete.

 

[KootK]

The footing must be deep enough to allow the compression to transfer to the concrete through bond over the straight length.

This. Basically, what you have is a straight bar development that just happens to have a hook on it for construction convenience.

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