Pullout Capacity of Pipe Piles in a Concrete Cap

[TLHS]

Has anyone seen work on the bond strength of a steel pipe pile into a concrete pile cap? For significant uplift you would want nelson studs or rebar to develop the strength of the pile, but that's a lot of labour if you're just looking at a nominal load. There's obviously some frictional or bond strength between the concrete and the steel, but I don't know how to quantify it. A brief search of the internet and my literature doesn't seem to come up with anything directly applicable.

 

[JAE]

I would worry that the piling might have petroleum/oil residue on them and have a high variability in bond with the concrete.

I stood under a pile hammer counting blows for about 400 pipe piling at a grain terminal project on the Mississippi River many years ago and remember being covered in oil/grease at the end of the day.

Perhaps today's hammers are cleaner but I'd still wonder.

 

[BliMan]

We used pipe plugs, rebar L dowels and spiral cage, then poured the embedded length of pipe pile with the pile cap, since pipe inside is generally clean and the top generally crowned in from the pile driving shoe. For some reason 10-feet of plugged pipe filled with concrete + Ls was 'magic', but this was 16" cans, it would obviously correlate to pile diameter and uplift load per piling.
Might want to 180 hook the Ls if you're tight packed and deep capped.

 

[BAretired]

I would not rely on bond strength between a steel pipe and concrete. Not even for a small force. Provide a base plate on the pipe or adequate fasteners attached to the pipe wall and extend into the concrete.

BA