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


Weld Fatigue

Weld Fatigue

Weld Fatigue

I do not get into AASHTO much and I want to see if I am interpreting something correctly with respect to welding and fatigue.  It isn't a bridge, but it is supposed to be designed per AASHTO.

I have a wide flange that is to be hung via a vertical knife plate located over and parallel to the web.  I believe the weld of the knife plate to the wide flange falls under the condition shown in 5.4 of Table  Am I correct in assuming that the live load stress range in the weld metal needs to be less than or equal to 10ksi?  I ask because it makes a fillet weld virtually impossible to use in this situation.  

RE: Weld Fatigue

A graphic would be helpful.

"Structural engineering is the art of modelling materials we do not wholly understand into shapes we cannot..."...ah...screw it, we don't know what the heck we are doing.

RE: Weld Fatigue

The threshold is 10 ksi meaning if your stress range is less than or equal to 10 ksi your detail will have infinite life. Otherwise, you can compute the mean life and the safe fatigue life.


RE: Weld Fatigue

I agree with bridgebuster.  If you are looking for infinte life then yes, you are limited to 10ksi.  In bridge design, you typically would not have a connection detail as you are describing or at least it would tend to not be heavily loaded so that this would not be an issue.  Incidentally, this is pretty much the same requirement that you would fine in AISC Table A-3.1.

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