Contact US

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

AS3600-2018 Bending factors?

AS3600-2018 Bending factors?

AS3600-2018 Bending factors?

I notice the phi factors for bending have changed, as have the rectangular stress block factors.

What's the background to these changes?

RE: AS3600-2018 Bending factors?

The old rectangular stress block was fairly inaccurate for concrete strengths over about 40MPa and gave some very misleading results, especially around decompression on column interaction diagrams.

RE the phi factors, some people thought that the old ones were too conservative given the improvements in materials technology etc. I cannot comment further or I could get in trouble.

RE: AS3600-2018 Bending factors?

Thank you rapt

Are the new phi factors in any way related to the change in stress block shape? Or are the two changes unrelated coincidence?

RE: AS3600-2018 Bending factors?

I'd guess that the new phi factors bring us closer to eurocode's partial factor results. No idea whether that's the basis though.

RE: AS3600-2018 Bending factors?


No relationship to the stress block changes. The stress block is now similar to the Canadian code stress block. There was a problem with the old stress block in that it did not predict the centroid of the force well in some situations. The only relationship to Eurocode is the addition of a reduction factor to allow for the concrete width reducing towards the compression face as the stress block derivation assumed a constant width. I had been requesting this for many years.

A "statistical" review of the phi factors was done and apparently showed they were low.

Nothing to do with Eurocode material factors either.

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