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Horizontal Cold Joint - Footings

Horizontal Cold Joint - Footings

Horizontal Cold Joint - Footings

(OP)
All - are they are any issues with punching shear if a footing gets poured with a horizontal cold joint.

For example, if there was a 4' thick footing that got poured in 2 lifts of 2' thickness. I have checked the interface shear and vertical reinforcement provided to cater to the horizontal shear to ensure they are composite for flexure.

I could not find any literature that talks about this being acceptable for punching shear and I don't feel comfortable doing it.

Thoughts?

RE: Horizontal Cold Joint - Footings

I don't have any issues with the punching shear in that circumstance, only the flexural capacity, which you have already checked.

Mike McCann, PE, SE (WA)


RE: Horizontal Cold Joint - Footings

I also think that you're okay. With horizontal shear and overall flexure restored, you're back to the same shear cracks. My only concern would be second pour restraint cracking in the upper concrete possibly interacting with the shear cracks . Got any top steel?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Horizontal Cold Joint - Footings

For what it's worth, many of the big raft foundations beneath taller buildings get poured in more than one layer.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Horizontal Cold Joint - Footings

Koot,

I guess they also abandon the tower crane pieces that they appear to be casting into the slab as well?

RE: Horizontal Cold Joint - Footings

Heck of an anchorage slab for the tower crane.

Mike McCann, PE, SE (WA)


RE: Horizontal Cold Joint - Footings

Quote (jayrod12)

I guess they also abandon the tower crane pieces that they appear to be casting into the slab as well?

Embarrassingly, I don't know. The plans show two cranes in the area, one on top of the raft and one on a footing below the raft (pic). That's all it says. Would one ever abandon a crane chunk like that? Maybe there was some sequencing voodoo that eliminated that necessity.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: Horizontal Cold Joint - Footings

It does seem expensive to leave it behind. But the pic appears to show it already cast in to the raft that's been poured.

RE: Horizontal Cold Joint - Footings

(OP)
Is there any research or testing that shows the cold joint is not detrimental to punching shear?

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