Punching shear 1

[perfectaccess]

if i have free end cantilever in slab how much length (limit) i will consider in punching area?
i mean limit is d/2 but may be the whole cantilever side will not punch,but what is the limit?

 

[jayrod12]

The entire length of cantilever could fail in one way shear.

Punching shear checks only happen at columns (and point loads from above).

 

[DaveHolder]

Normally basic control perimeter of column is set at 2d

 

[KootK]

It depends on your local code. Typically a cantilever past a column in excess of 4d-5d will allow you to assume a four sided shear perimeter.

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.

 

[joncle10]

The ACI doesn't address this point. Generally, I consider the edge of the cantilever as a large opening. so I use a distance of 10d. I know that it is conservative but I found no clause in the ACI which details this point.
According to which code it is 4 to 5d KootK ?

 

[KootK]

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.

 

[rapt]

Calculate the perimeter

1 as 4 sided
2 as 3 sided and extending to the ends of the cantilever.

Use the smallest perimeter, or in ACI methodology the one that gives the smaller shear capacity.

 

[hokie66]

And don't forget to factor in the effect that bending has on the shear. The stress is not constant.

 

[perfectaccess]

Thanks guys, really helpfull