Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Confilct between AS3600 and ACI318 (Punching reinforcement)

Confilct between AS3600 and ACI318 (Punching reinforcement)

Confilct between AS3600 and ACI318 (Punching reinforcement)

There seem to be a clear confident between the way AS3600 distribute the punching shear reinforcement and what ACI318 thing reinforcement should be spaced.

first AS3600 chapter 9 c.9.2.6 states that maximum spacing of punching shear reo ( ties) should not exceed 300 or Depth of slab.
ACI on the other hand R8.7.6d shows that stirrups spacing shall not exceed effective depth/2 half what AS3600 allows for.

one more thing, AS3600 c.9.2.6 states that the width of the stirrups should be as big as possible within a, a being the with of the critical punching shear area.
ACI however limits the width of the stirrups to 2d which might be much less than the previously mentioned a.

has anybody else came across this conflict and knows the logic behind both codes.

Thanks in advance, and looking forward to hear your responses.

RE: Confilct between AS3600 and ACI318 (Punching reinforcement)

If you read the commentaries to both codes you will discover the difference.

AS3600 currently only considers torsion reinforcement as increasing shear capacity.

RE: Confilct between AS3600 and ACI318 (Punching reinforcement)

Rapt, can you please elaborate. I have read both commentaries still can't seem to get an answer

RE: Confilct between AS3600 and ACI318 (Punching reinforcement)

C9.2.4 in the AS3600 commentary explains it much better than I can!

RE: Confilct between AS3600 and ACI318 (Punching reinforcement)

Dear Rapt, I am only discussing torsion reinforcement and how AS3600 and ACI specify different spacing for it. I have a basic understanding of the punching shear model.
The issue for me is, how come AS3600 specify spacing of ties to be max of D or 300 while ACI limits it to d/2.
same goes for the allowable width of the tie.

RE: Confilct between AS3600 and ACI318 (Punching reinforcement)

There is a fundamental difference in how the reinforcement is considered in AS3600 compared to ACI which you still do not seem to understand.

In ACI the reinforcement is basically contributing to a shear head and can be used to resist vertical shear without torsion (no moment transfer).

In AS3600, the reinforcement can only be used to increase the capacity due to torsion (moment transfer). There is no way in the AS3600 formulae to design shear reinforcement to resist vertical shear only.

The AS3600 model defines a torsion strip, and that controls the dimensions of the ties (width). Obviously the AS3600 committee at the time thought that a maximum spacing of 300 or D was sufficient for torsion reinforcement.

Eventually AS3600 will change to another punching shear model, but that will not happen until at least 2022 based on the current development schedule.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close