×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• 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.

Round HSS design for torsion: Member length 'L' in section H3 of AISC 360-102

Round HSS design for torsion: Member length 'L' in section H3 of AISC 360-10

(OP)
Hello,

Please refer to the attached image which shows a round HSS spanning 20" with a nodal moment of 100 kip-in acting at beam center. As per section H3 of AISC 360-10, I have to use the length of member to calculate Fcr value. Does this 'length of member' mean only that portion of the beam which has an internal torsion due to the applied moment or does it mean the whole member length between supports irrespective of the internal forces?

Regards,
Su

RE: Round HSS design for torsion: Member length 'L' in section H3 of AISC 360-10

Is your acting torsion force also fixed translationally? If so I'd say L = 10 inches.
If not I'd think 20 inches.

Check out Eng-Tips Forum's Policies here:
FAQ731-376: Eng-Tips.com Forum Policies

RE: Round HSS design for torsion: Member length 'L' in section H3 of AISC 360-10

I'd think it would be 20". That equation, as I understand it, is meant to account for how local buckling issues can be affected by end conditions. So, unless there is some kind of significant rotational restraint provided at mid-point of the HSS, I'd have to believe L would be 20" for that equation.

RE: Round HSS design for torsion: Member length 'L' in section H3 of AISC 360-10

(OP)
Thanks to both of you for replying!

I asked AISC and they confirmed that L is always the span length no matter where the torsion is applied.

Regards,
Su

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.

Resources

eBook â€“ How to Choose the Correct Corrosion Testing Method
When designing a metal component, engineers have to consider how susceptible certain alloys are to corrosion in the final productâ€™s operating environment. In a recent study by NACE (National Association of Corrosion Engineers), it was estimated that the direct and indirect costs of corrosion in the United States is approximately 6.2% of the GDP. In 2016, that cost exceeded \$1 trillion dollars for the first time. Download Now

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:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!