×
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.

# Unequal Leg Angle Bending - Symmetry Parameter Bw (CSA S16-19)3

## Unequal Leg Angle Bending - Symmetry Parameter Bw (CSA S16-19)

(OP)
Hi Everyone,

I am trying to evaluate the bending capacity of an unequal length angle (L 127x89x9.5.
The CSA design equation requires you to calculate the symmetry parameter of the section and that involves the evaluation of an area integral. Please see the attached screenshot.

Does anyone know of a solved example or reference for the evaluation of this variable?

Thank you

### RE: Unequal Leg Angle Bending - Symmetry Parameter Bw (CSA S16-19)

to do the actual integral convert the problem to a sum of line integrals for each segment defining the perimeter of the angle.
Green's Theorem for line integrals
you'll need to find functions for P and Q such that the difference of the partial derivates = z(w^2+z^2)

z and w can the be written in parametric form for each edge vertices as, each (z,w) pair is a transformation of the (x,y) coordinates to the principal axis angle:
w(t) = w1+t(w2-w1)
z(t) = z1+t(z2-z1)

and then back substituted into P and Q so the integral is from 0 to 1 dt instead of dz or dw.

My Personal Open Source Structural Applications:
https://github.com/buddyd16/Structural-Engineering

Open Source Structural GitHub Group:
https://github.com/open-struct-engineer

### RE: Unequal Leg Angle Bending - Symmetry Parameter Bw (CSA S16-19)

Thanks for the reference Celt! Where is that from anyway?

### RE: Unequal Leg Angle Bending - Symmetry Parameter Bw (CSA S16-19)

I honestly don't remember was the result of some late night googling a few years ago, have always had it earmarked to do a spreadsheet then I got sidetracked with other stuff.

My Personal Open Source Structural Applications:
https://github.com/buddyd16/Structural-Engineering

Open Source Structural GitHub Group:
https://github.com/open-struct-engineer

### RE: Unequal Leg Angle Bending - Symmetry Parameter Bw (CSA S16-19)

2
The Commentary for AISC 360 also includes values of Beta_w for most typical angle sizes. You can find it for free online here - page 404 in the PDF.

-Laurent

### RE: Unequal Leg Angle Bending - Symmetry Parameter Bw (CSA S16-19)

(OP)
Amazing references! To be honest, I changed the design to use equal leg angles as it made for an easier calculation.
I will have to find time and go through the calculations in the references shown!

Much appreciated :)

### RE: Unequal Leg Angle Bending - Symmetry Parameter Bw (CSA S16-19)

L8x4:

L4x3 1/2:

L2 1/2 x 1 1/2: (This one is actually sensitive to the thickness)

Equal Leg: (Numerical precision -- 1.33 E -15 is pretty much 0)

Formula for Each linear edge of the angle defined by start point (w1,z1) and end point (w2,z2):
For Green's Theorem assume P=0, so need to integrate the function with respect to w. Then perform the parametric substitutions and change of variable to dt.

The sheet models the fillets with several straight line segments.

My Personal Open Source Structural Applications:
https://github.com/buddyd16/Structural-Engineering

Open Source Structural GitHub Group:
https://github.com/open-struct-engineer

#### 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

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
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™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:

• 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!