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

25% Rule for Dual System with SMF

25% Rule for Dual System with SMF

25% Rule for Dual System with SMF

Please help me to comprehend ASCE7-05 section 12.2, "Dual System with Special Moment Frames capable of resisting at least 25% of prescribled seismic forces". It's unclear that each floor of SMF shall resist 25% of base shear or story shear forces. How to define the "prescribled seismic forces"?
BTW, for dual system with special RC shear wall and RC frame, how to achieve this in ETABS?
Thanks in advance!

One conference proceeding paper, Earthquake-Resisting Dual Systems and the 25% Rule by Jon D. Magnusson maybe helpful. But I can't download it. Can anybody help me?  
Replies continue below

Recommended for you

RE: 25% Rule for Dual System with SMF

25% of the story forces.

RE: 25% Rule for Dual System with SMF

Older codes simply required 100% of the story shear taken by the concrete walls and 25% of that into the moment frames.  Newer codes require the story shear be distributed to the shear walls and moment frames in proportion to their relative rigidities, but still moment frames shall be designed to no less than 25%.

RE: 25% Rule for Dual System with SMF

Hi, slickdeals.
Thanks for your answer. Do you have any papers or books to prove the "25% of the story forces"?

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