×
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

TORSIONAL EFFECT IN SECOND MODE
2

TORSIONAL EFFECT IN SECOND MODE

TORSIONAL EFFECT IN SECOND MODE

(OP)
Hello guys !!!
I have modeled and analysed a single story RCC building in ETABS and I found that the building have torsional effect in second mode. Is there any remedial measure to counter this effect in designing phase or in construction phase ?

RE: TORSIONAL EFFECT IN SECOND MODE

Manipulate your lateral load resisting elements such that your centre of stiffness is in the centre of your building. This will minimise load eccentricities that exacerbate torsional problems.

Make it hard for the building to twist, distribute lateral elements towards the perimeter of the building.

RE: TORSIONAL EFFECT IN SECOND MODE

Yes. Relocate lateral load resistance elements in plan therefor reduce the distance between the center of lateral stiffness and center of the structure mass in plan.

RE: TORSIONAL EFFECT IN SECOND MODE

What's the mass participation in the 2nd mode? If it's very low, that may be okay.

Also, I'd say it is as important to increase the torsional STIFFNESS of the system as it is to have that center of stiffness match up with the center of mass. Meaning if your lateral frames are wider apart then your torsional modes should be at a higher frequency.

RE: TORSIONAL EFFECT IN SECOND MODE

(OP)
Thank you for your kind response...
Dear JoshPlum, mass participation in second mode is 20%, I think it is quite appropriate. I am planing to provide shear wall of some length around the outer far end columns, so that it can help to reduce the torsional effect.

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