×
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

Moment Magnification - Sway Frames - ACI 318-08

Moment Magnification - Sway Frames - ACI 318-08

Moment Magnification - Sway Frames - ACI 318-08

(OP)
Hi,

The equation for moment magnification in a column in a sway frame in ACI 318-08 (same in 11) is M1 = M1ns + (deltas)(M1s), where deltas is the sway moment magnifier. My question is why does this equation not consider deltans, the nonsway moment magnifier? Shouldn't this be multiplied to M1ns, the end moment due to gravity loads?

Thanks

RE: Moment Magnification - Sway Frames - ACI 318-08

The equation is used to approximate second-order effects by doing only a first-order analysis. This is assuming that the second-order effects are small which would mean that the second-order effects from gravity loads are almost completely negligible. If the calculated magnified moment exceeds a certain limit, you will have to perform a rigorous second-order analysis which includes all of these effects.

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