×
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 Constant T beams

Torsional Constant T beams

Torsional Constant T beams

(OP)
Does anyone have the formula for J (Torsional Constant) for a T section beam in cm4?
or C Torsional Modulus?
Thanks
Andrew299

RE: Torsional Constant T beams

The torsional moment of inertia is "J", my Roark's gives
a general formula

     J = Ix + Iy = I1 + I2

Assuming x & y axes (or axes 1 & 2) are orthogonal.

Hopefully you have the equations for the moments of inertia for a T-section, or can derive them from rectangular equations and the offset axis theorem.  I can try and write them out, but they get a little hairy, and defining some of the terms will be difficult without a diagram.  I'm using _Roark's Formulas for Stress and Strain_, W. Young, 6th ed., McGraw-Hill, 1989; see page 63.

Ben T

RE: Torsional Constant T beams

See the thread
Thread194-92351
in the "Civil/Environmental Other" forum, where I have just placed a post.

RE: Torsional Constant T beams

The statement by btrueblood is incorrect: that formula is far from being true for open thin sections.
andrew299: look in the site below, under Beams -> Cross sections -> I beams -> Cut : by clicking onto 'Formulas' you'll see your formula.
And if you could avoid cross posting...

prex

http://www.xcalcs.com
Online tools for structural design

RE: Torsional Constant T beams

I like to direct you to an excellent document published the AISC. It is Design Guide number 9 titled Torsional Analysis of structural steel members. You can buy/view this document on their web site   www.aisc.org

If you are a member, you can download it in PDF. The design guide is an excellent source and reading on torsional analysis. It is full of charts for various boundary conditions not to mention torsional constants for various steel shapes ready for use.

Good luck

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