Longitudinal Reo Effect on Punching Shear

[handex]

Firstly I would like to note that this question is purely academic and for interests sake. For punching shear calcs I follow the formulas in AS3600, which dont have any terms that account for longitudinal reinforcement passing through the critical shear plane. This leads me to believe to that the longitudinal reinforcing has negligible effect, which goes against my common sense. I would have thought that the bars in tension say over a column that pass through the critical shear plane would significantly increase the shear-friction capacity of the shear plane, going by the logic used in the shear-friction formula used also in AS3600 for longitudinal shear?

If anyone could shed some light on how I am seeing this wrong it would be much appreciated.

Thanks

 

[rowingengineer]

As3600 does have a requirement that 25% oflong steel of the column strip located within some distance of the support.

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]

The bars on the tension side have to be there, otherwise you don't have a "d" to plug in the formula. The way we design for punching shear is largely based on testing, and the method is deliberately simplified in the number of variables. The KISS principle.

 

[Michel60]

Good morning handex,

I have seen some testing for this condition and as I recall the absence of reinforcing has the larger effect, i.e. once reinforcing is present (within some minimum amount) the differences with having more are limited. Also it's benefit tends to be when it all has already gone very wrong. The cracks have become large and the horizontal reinforcing is just tying things together. So as a result no real reason to be plugging this one into the design equation, just be sure you have the reinforcing in place.

regards,
Michel