stairs - concreting section - where is stop?

[Adistruct]

Hi guys

I got suspeect few times when i saw the concreting sections on the site. See here on of the photos. Can this be right?
The new section will basicaly act only as share fors on the bars. This doesn't look to correct?

What is the right way to do it?
i attached some samples sketches maybe you could give a comment on it.

buy

Adi

 

[Adistruct]

here the sampels

 

[JAE]

I can possibly work alright if you cast new concrete onto existing concrete with reinforcement extending across the shear plane. This would be a shear friction method with a smooth plane of concrete at the interface. Probably not the best detail but can work.

One thing you can do is roughen the surface of the concrete with a chipping hammer to get a higher friction across the joint.

I get the impression you are not from the US (from the language on the photo) so the ACI 318 code may not be applicable (its Chapter 11 Shear Friction provisions are the applicable section).

 

[ron9876]

A or B. Not D and no reason for C. Like JAE said shear friction should easily carry the shear.

 

[hokie66]

I prefer B or C. I regard shear friction as black magic, and never allow A.

 

[JAE]

Hmm...I'd go with A.

The others just don't look right if the right hand landing is hanging from the left hand stair structure.

 

[rowingengineer]

I'm with hokie B or C, maybe an alternative E where you us shear dowel across the joint.

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[hokie66]

JAE,

I took it that the stair was bearing on the landing/floor, not the other way around. The landing and flights are normally cast between previously built floors.

 

[ishvaaag]

In any case, in part due to being folded plates, reinforced concrete stair slabs are between the noblest friends of structural designers, considering the treatment they have to stand.
Fortunately.