Flat slab punching shear link layout

[hetgen]

Hi All,

ACI 318 11.12.3.3 reads ....The spacing between adjacent stirrup legs in the first line of shear reinforcement shall not exceed 2d measured in a direction parallel to the column face. However, other building codes such as the Eurocode recommend a further limitation on the spacing of shear reinforcement measured along perimeter around the column on successive lines of shear reinforcement.

Noting the above,according to Eurocode and many other building codes, the orthogonal arrangement of stirrup shear reinforcement shown on ACI commentary is not acceptable . And to satisfy the Euro codes requirement one has to reinforce as shown on attached, which is very difficult to monitor on site.

Why is the requirement of these building codes different? Could you please shed some light on this.

Thanks.

 

[KootK]

It sounds as though you know more about this than most folks, me included. I'll show my bias for North American practice here:

1) I think that research supports the notion that a radial (Euro) layout of shear reinforcement performs the best.
2) Although orthogonal (North American) shear reinforcing layouts perform less well, they perform adequately.
3) Orthogonal layouts are more constructible in my opinion.

1 + 2 + 3 = I like orthogonal layouts. Of course, you'll have to pay homage to whatever code governs for your project.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[rowingengineer]

thread507-306324

this thread is probably worth a read.

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."

 

[KootK]

Thanks for posting (reposting) this Rowing. I wasn't abreast of the original thread. I'm trying to dig up the referenced articles this morning. I'm particularly interested in this statement by you:

"This statement would support the theory that to much reinforcement has been used to justify the punching values. Punching shear is effected by the amount of reinforcement, this isn't stated in this particular code, but is covered in a few other codes, and punching shear articles."

Could you point me to a particular code or article?

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[hetgen]

Thank you Kootk and Rowing, i will read through the thread.

Kootk... the link below summaries and explain the effect of flexural reinforcement and other factor on punching shear, it could answer your question.

http://infoscience.epfl.ch/record/116123/files/Muttoni08a.pdf

 

[KootK]

Upon quick inspection, that probably does answer my question. Thanks hetgen.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.