×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Jobs

ACI318-08 Appendix D, attachment ductile yielding

ACI318-08 Appendix D, attachment ductile yielding

ACI318-08 Appendix D, attachment ductile yielding

(OP)
I don't see the chance of D.3.3.4 will happen for most of post-installed anchors. Then the choice will be to use either D.3.3.5 or D.3.3.6. I'm a little bit confused about the attachment ductile yielding if I use D.3.3.5. What's the definition of that?

The attachment, not the anchor bolt, not the structure, will yield in ductile way at the force level of 0.75*phi*Nn & 0.75*phi*Vn? Could anyone please give me a example? How often do we use this kind of situation? For any kind of MEP seismic brace, can I assume D.3.3.5 will happen?

RE: ACI318-08 Appendix D, attachment ductile yielding

I think 3.3.5 and 3.36 are in the intent of that either you warrant trough the attachment that the connection fails without destroying the anchor assembly itself or if you don't worry to prove it you stay limited to 0.4 (or 0.5) times the nominal strength of the assembly.

Hence, if you want to approach the nominal strength of an anchor assembly outside the scope of 3.3.4, you need to include a yield fuse between the connected part and the base anchor assembly.

For example, assuming you were only to transmit shear, you would include a receiving shear tab or weld where the weld or plate thickness itself lead to yield prior to overstraining the base anchor assembly over its nominal strength in shear.

If we were sayomg "prior to for every case overstraining", quite likely we would have to include a overstrength factor for the strength of the yield fuse, in more than retiring the fi factors.

RE: ACI318-08 Appendix D, attachment ductile yielding

In the last paragraph, errata, "saying".

The intent of such paragraph is that the base assembly must be sized in that case for any forces (shear in the example) that could potentially be transmitted by the "fuse", overstrength of the same included.

RE: ACI318-08 Appendix D, attachment ductile yielding

(OP)
Thanks a lot ishvaaag. The yield fuse concept is really helpful.

RE: ACI318-08 Appendix D, attachment ductile yielding

D3.3.4 can happen in a properly designed anchor.  The requirement is that a ductile portion of the anchor yield before a brittle/fracture failure mode is reached in the anchor.  I think this will be even more common with the new adhesive anchor rules.

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!


Resources