Contact US

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!

*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

Plate yeild line theory

Plate yeild line theory

Plate yeild line theory

HI everyone,
I'm struggling to design cross braced frame connections. I would highly appreciate if someone could explain the design steps and how to determine the plate thickness using plate yield line theory.
The brace members are SHS square hollow section and the collector is 250PFC channel beam.

Each brace is subjected to 60kN tension force.


Thank you

RE: Plate yeild line theory

1. Yield line theory is fine for some things, but you don't need it here. You indicate a 15mm plate but you don't indicate a width. Make sure you allow room for the fillet weld.

2. An all round weld is not possible because the angle is too small.

3. The iron workers will not appreciate having a common plate for two braces above and below the beam. Makes them awkward to handle on site, more so if the braces are long. Better to use separate base plates. If you do use a common plate, put a bolt between the two braces. It reduces the moment.

4. Braces above and below the beam do not align. Much better to make them align, even if they don't intersect at the exact center of the beam.

5. Draw a section through the connection to demonstrate how the SHS and channel align. The flange of the channel is 90mm wide, which is almost identical to the SHS. If the 15mm plate is centered over the channel flange, the load will be eccentric to the channel, causing a bending moment in the flange and web. The web of a 250PFC is only 8mm thick. Why use a channel? A wide flange would be better. You may need to add some stiffeners. The stiffeners you have are not well placed.

6. For the design, resolve your 60 kN force into a vertical and horizontal component. Design the 15x? plate for the bending moment resulting from the vertical force. The horizontal force is resisted by shear in the bolts.


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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. 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