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!

*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

ACI 318-02 Versus ACI 318-05 - 2 way PT Slabs

ACI 318-02 Versus ACI 318-05 - 2 way PT Slabs

ACI 318-02 Versus ACI 318-05 - 2 way PT Slabs

In ACI 318-02, section 18.3.3, it defines the different classifications of PT Slabs, with type U being the typical uncracked PT slab with the tension stress limit equal to 7.5 (f'c^0.5) (which is increased from the 1999 and earlier codes which put the limit at 6 (f'c^0.5)).  At the bottom of that section of the code, it says that all two way slabs should be designed to Class U.

In the new ACI 318-05, they still have class U with a tension limit of 7.5, but the words at the bottom of section 18.3.3 says that all 2 way slabs should be designed as Class U with tension stresses limited to 6.

The problem I have is that I am using software that is tailored to the ACI 318-02 code, but we don't want to go to the 7.5 limit since it seems like a mistake in the 02 code.  Anybody run across this code issue?  Is the 02 code a mistake that has been corrected with some erratta?  Or did they just rethink the tension stress limits?

RE: ACI 318-02 Versus ACI 318-05 - 2 way PT Slabs

To the top.  Has anybody run across this?

RE: ACI 318-02 Versus ACI 318-05 - 2 way PT Slabs


I was told by someone close to the ACI committee several months after the release of the 02 code that the committee had admitted they had made a mistake and there was an amendment released limiting the tension stress in 2way slabs to .6f'c^.5. I do not think I have ever actually seen a copy of the amendment.

Actually, in negative moment regions of 2way slabs this limit is still very unconservative as it does not recognise the stress concentration near the column compared to the average stress that ACI designers actually calculate.

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! Already a Member? Login


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