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!

*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.

Jobs

Sample problems 1, 2 & 3 of part 2 AISC 8th ed.

Sample problems 1, 2 & 3 of part 2 AISC 8th ed.

(OP)
I need help.  On sample problems #1 of AISC Manual, 8th ed. Part 2, I am clear up to the part where it talks about Fy' - " A check of the Fy' column shows a dash, indicating that Fy' is greater than 65 ksi. Therefore, the shape is compact and the assumed allowable stress of Fb=0.66Fy is correct."  I get Fy'= 88ksi which is > 65ksi, but where did 65ksi come from?  

On sample problem 2 why did they use the formula Fb=0.60Fy?

On sample problem 3 I am clear up to the part where it says "Since Fy' is less than 50 ksi, the shape is non-compact due to flange criteria.  Therefore, the allowable stress is less than 0.66Fy and must be determined from formula(1.5-5a)..."  Where did 50ksi come from and why does that make the shape non-compact?

RE: Sample problems 1, 2 & 3 of part 2 AISC 8th ed.

fxp
This is the way I understand it.
AISC ASD limits plastic design to steels with yield strength up to 65ksi.
Example #1(36ksi material) had a f'y greater than 65 which is wht the column had a dash (-) instead of a number. You will notice there is no number greater than 65.
If the f'y had been less than 36, the member would have been non-compact.
Example #3 (50ksi material) had a f'y less then 50ksi so the member is non-compact.

Warren

RE: Sample problems 1, 2 & 3 of part 2 AISC 8th ed.

On example #2 the compression flange is now braced at 9ft which is too far for the member to be consider compact.
Lc = 7.4ft < 9.0ft.

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


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