Min rebar requirement for stair

[Jandra11]

Guys can someone show me how to do detail the rebar of the stair.The stair will not be suspended (see attached)

so can someone tell me what is the minimum requirement of rebar except for the temp bar at the bottom part of the stair and 10mm bar @ the nosing of every step. Im confuse on how to put the zigzag like rebar. Do I still need to include that? Thank you in advance

 

[hokie66]

I think the "zigzag" bars, as well as the nosing bars, are superfluous for stairs on the ground. They do nothing structurally, and just provide a corrosion source.

 

[Jandra11]

@hookie thank you. so ill only provide temp bars at the bottom part for both ways?

 

[hokie66]

I would. Centrally located between the throat and the ground.

 

[Jandra11]

@hookie one more question. if the the stair is suspended is it required to put those zigzag rebar and nosing bars?

 

[dik]

Don't use nosing bars... cause more problems than they solve.

Dik

 

[Jandra11]

@dik thank you for the advice

 

[JAE]

Agree with the others - just use a mat of rebar (indicated by your letters "H" and "I" in your image.

Check out Eng-Tips Forum's Policies here:
faq731-376

 

[hokie66]

Jandra,
If you are building a suspended stair, it will likely need both top and bottom reinforcement in the slab section, but forget putting bars in the treads. They are just mass concrete. One exception to this might be some application where your stairs are spanning side to side.

 

[dik]

Hokie... bot reinforcing still works. Have seen countless stairs with 'nosing bars' exposed due to corrosion... large surface area around nosing bar leads to excessive carbonation, corrosion sets in, and concrete spalls off.

Dik

 

[hokie66]

dik,
We are on the same page with that. I hope nothing I said gave the wrong impression.

 

[Jandra11]

thank you all for all the comments and advices

 

[dik]

Hokie... not at all. I think the reason for the nosing bars was to accommodate any point load at the edge... not realising that the bar was a stress riser... also subject to corrosion. Seen too many stairs where the concrete has spalled off at the nosing bar.

Dik

 

[NorthCivil]

Learn something new everyday. I don't do much big concrete, just little stuff, and have always spec'd a nose bar. I'll kill it from my standard detail and stop asking for it. I'm sure contractors won't complain.

stuff like this is why I list eng-tips as PDH's

 

[dik]

First one I saw, the concrete had spalled off... I asked Arnold why it was there and he said that if a heavy load were applied to the nosing that it kept it from breaking off. He didn't say it wasn't required.

Dik