×
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

Does bracing requirement change with end conditions?

Does bracing requirement change with end conditions?

Does bracing requirement change with end conditions?

(OP)
I have a cantiliver beam loaded at the end.  According to AISC Allowable Steel Design, (Lb < Lu).  My question is, is the effective unbraced length of a cantilever beam double the actual unbraced length.

I would assume that its ability to twist is greater than if it was a pin-support of the same length subject to the same load.

RE: Does bracing requirement change with end conditions?

  No, you can use the actual length for the unbraced length for a cantilever beam.
  Cantilever columns are a different story.

RE: Does bracing requirement change with end conditions?

In Australian practice (AS4100) the effective length of an unbraced cantilver is:
- the actual length, for load height position at the shear centre
- twice the actual length, for load height position at the top flange

This is to account for the "de-stabilising" effect a load positioned at the top flange, which will increase the twist and lateral deflection.

RE: Does bracing requirement change with end conditions?

The ASD 9th clearly states that you can use 1.0 x the length as the effective length. However, there is more to it than either 1.0 or 2.0 times the length. Stability Design Criteria for Metal Structures presents a table regarding this topic. There is also a discussion at http://www.seaint.org/sealist1.asp search the archive for "cantilever beam".

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