×
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.

# Seismic Design Manual Braced Frame Problem2

## Seismic Design Manual Braced Frame Problem

(OP)
I am currently trying to work through an OCBF Design Example and am confused with Example 3.4 on page 3-17.

1. On the "Gusset to Beam Weld Design" I don't see where "fpeak" and "favg" come from. I looked all over and can't find those equations so if somebody could point me to them that would be great.

2. On page 3-16 I'm a little hazy on how exactly they come up with alpha and beta. I understand what those variables theoretically are, but the numbers they put to it don't match what I think it should be in my head. Why subtract 1 from 9 if the gusset plate is directly to the beam? Thanks for any advice.

### RE: Seismic Design Manual Braced Frame Problem

1.  It is simple statics.  You are trying to determine the actual stresses on the weld lines and these are based on a P/A +/- My/I type calculation.  Once you have the x and y stresses, you then use a square-root-of-sum-of-square (SRSS) calc to get the resultant maximum stress on the weld line.

2.  They are calculating the length of weld (9" - 1" cope at the corner), then dividing that by 2 to get the center of the weld, then adding back the 1" cope to get the distance from the beam-column corner to the center of the weld line.

### RE: Seismic Design Manual Braced Frame Problem

(OP)
Great, that helps out a lot JAE.  Now do you also happen to know where the provision for designing for the greater of "fpeak" or "1.25favg" is called out?  I seem to be missing that.

### RE: Seismic Design Manual Braced Frame Problem

The 1.25 factor accounts for the uneven stress distribution along the weld length.  It was 1.4 in previous AISC manuals.  Look in the 13th edition manual, page 13-11.

### RE: Seismic Design Manual Braced Frame Problem

(OP)
Now I have a new question on the same problem.  On pg. 3-18 it checks the gusset plate for rupture and yielding at the beam weld.  How come they are able to get away with only checking shear rupture, and then saying that tensile rupture and yielding as well shear yielding will not govern.  If I check this out through the equations J4-1 through J4-2 on pg. 16.1-112 of the steel manual I get that shear yielding actually controls the gusset thickness.  Any insight?

#### 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.

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!