Development of flexural reinforcement in footings and pile caps

[TomNally]

Hi, Friends:

Say that we have a 6'x6' isolated footing, 24" deep, with a single layer of rebars on the bottom. Is there any code requirement that the rebar at the edges of the footing be developed by hooks?

Followup and related question:

Say that we have a 6'x6' concrete pile cap, 24" deep, supported by 4 piles. Is there any code requirement that the rebar at the edges of the pile cap be developed by hooks?

To me, a plain reading of 12.10.3 suggests not, but there may be provisions which override that.

Thanks! I appreciate it.

---Tom Nally

 

[rowingengineer]

I have to agree with hokie66 (theoretically) given the size of the footing, it will act like a deep beam thus; the bars need to be developed past the nodes.

However if the footing was to oversize the footing by the development length (appropriate to the stress level in the bars), then we have a different question all together. Taking this info and assuming:
most geotechnical engineer are quite conservative (no insult intended) and often use safety factors in the range of 3-10, which is normally base on conservative assumptions.

I would say practically this isn’t going to be a situation where I would not expect a failure from the detailing of straight bars.

Saying that is this was a cantilever in a building (of significance), i may loose sleep, if the shear force was high enough near the end of the cantilever, thus i always detail with hooked bars on cantilevers and sometimes on foundations.


When in doubt, just take the next small step.

 

[dik]

It likely depends on the size of the rebar, if a hook is required.

Dik