×
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!
  • 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

Jobs

Web Crippling
2

Web Crippling

Web Crippling

(OP)
Will somebody please check my math?

AISC/ASD 9th Edition, Equation (K1-5)

I have a W8x24, Fy=50 ksi, bearing 6" on a solid grouted, concrete masonry bond beam.  I have approximately 4K of solid grouted concrete masonry bearing on top of the bearing end of the beam.  The allowable compressive force that I am calculating (1219 lb) seems so low, I am convinced I am misunderstanding something.  

Any comments?

Thank you!

RE: Web Crippling

Did you check out AISC, 9th Ed., page 2-31?  Use the max. end reaction condition equations.

RE: Web Crippling

Also, make sure your equation values are in the proper units.

RE: Web Crippling

(OP)
Thank you for your responses!

Yes!  AISC, 9th, page 2-31 is where I started.  My max end reaction is 66K.  But then the web crippling formula fails my design intent.  Both of the two conditions need to be considered.

I've checked my units.  Have either of you run the formula?

Please give it a try and let me know what you come up with.

Thank you!

RE: Web Crippling

Variables:
N = 6 in.
d = 7.93 in.
tw = .245 in.
tf = .4 in.
Fyw = 50 ksi

Eq K1-5 -
R = 38.5 kips

RE: Web Crippling

I ran both formulas for a W8x24 beam, 6 inch bearing length, end reaction condition.  I got an allowable load for web yielding of 66 kips and an allowable load for web crippling of 39 kips.
N = 6.0 inches bearing length
d = 7.93 inches beam depth
k = 0.875 inches
tw = 0.245 inches web thickness
tf = 0.400 inches flange thickness
Fy = 50 ksi

RE: Web Crippling

(OP)
Someone please check my math!
What am I doing wrong?

(34*(0.245)^2)*(1+3*(6/7.93)*(0.245/0.4)^1.5)*(SQRT(50000*0.4/0.245))=1217 lb

Thank you!

RE: Web Crippling

EIT2,
Maybe you have caught the error but if not, the Fyw of steel must be in ksi since the formula is the max end reaction in (kips)

RE: Web Crippling

(OP)
I did'nt catch the error until you pointed it out!
My trial is over!

Thank you!

RE: Web Crippling

EIT2,

You bring up a good point to remember, that is, when your gut gives you that "funky feeling" that something isn't right - it usually isn't.  Listen to your gut feelings!  

We all make mistakes, the key is to find them before they cause a problem.  Many times you get a feeling that something is wrong, but you can't quite put your finger on it. Listen to that feeling and look at the problem from a different angle.

RE: Web Crippling

Hi everyone,

I agree with jheidt2543, thats what these forums are for. When in doubt looking at it with other people helps.

Have a good one guys and gals

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