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

Unbraced Length

Unbraced Length

Unbraced Length

I have an Unbraced WF beam Pinned at both ends and a post at mid-span which places segments of both the top & bottom flanges under compression. Is it accurate to use the location of the infections points as the unbraced length (where the moment switches from + to -) or the total length of the whole beam?

Thank you

RE: Unbraced Length

It is inappropriate to use the inflection points as a brace point.

You would use the full span length but use a Cb factor (per AISC) on the moment capacity.
Or you could add a positive brace at the inflection point, or anywhere for that matter, to limit the Lb.

RE: Unbraced Length

Search "rafter without fly brace" in this forum smile

RE: Unbraced Length

Do not use inflection points as braces. I believe this is even written in most codes. Inflection points aren’t 100% accurate.

RE: Unbraced Length

Is the post above or below the beam? Is the post braced laterally? There might be more to evaluating the stability of this system than just a standard unbraced length check on the beam. All I know right now is you have a pin-pin (torsionally restrained at ends?) beam that is unbraced and is supporting a post - doesn't sound too stable to me.

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


Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. Download Now
eBook - Managing the Context of Product Complexity Using the Digital Twin
Keeping track of changes to complex products is difficult—think Aerospace & Defense equipment, new generations of commercial aircraft, and software-based automobiles. A new way to managing the digital context of the physical product is required and the answer is the Digital Twin. This ebook explores the opportunity available for Operations and Maintenance for the Digital Twin. Download Now
White Paper - Trends in Industrial Filtration
Substantial progress has been made in filtration technologies in recent years. New filter media materials, designs and processes have led to filters that are more efficient, reliable, compact and longer lasting. This white paper will discuss the various trends that are impacting operational responsibilities of MROs today and the resources that are available for staying up-to-date on the latest filtration solutions. 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:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close