×
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

Reviewing Older Calcs (AISC 9th ED) question

Reviewing Older Calcs (AISC 9th ED) question

Reviewing Older Calcs (AISC 9th ED) question

(OP)
I have a copy of some calculations done by another engineer.
Anytime I can get calculations to look and learn from I try to get most I can from it.
I have a lot of respect for this engineer, and sadly he has passed away since the calculations were done so I can't ask him about this.
So I hope some one here can answer a question I have.

The calculation was using AISC 9the Ed Table J3.3 for Allowable Tension Stress Ft.
Here is what I am confused about.

for A325 from the table.
The calcs I am looking at show this;
Ft = [sqrt((44000^2)-4.39fv^2)]*area

The area is of the bolt.
fv is the shear stress on the bolt (psi).

I thought that the 44000 was psi, and (fv) was in psi so if you multiply by the area of the bolt you were getting a force.
The calcs then compare Ft to actual tension stress(ft) which is a psi.
So was multiplying by the area a mistake or am I missing something?

Thanks

RE: Reviewing Older Calcs (AISC 9th ED) question

I don't have the calculation in front of me, but it looks like a minor typo by the original engineer. Sometimes, at about 3:30 in the afterrnoon, things start to blur. If he multiplied a stress times an area, it's a force.
If that was the worse mistake I ever made, I would be very satisfied with myself.

RE: Reviewing Older Calcs (AISC 9th ED) question

If the calculations did indeed multiply the equation from Table J3.3 by the bolt area and then compare the allowable tensile stress, Ft, to the actual tensile stress, ft, then that is a mistake. You are correct that multiplying Ft by the bolt area results in the allowable tensile force, not stress. Note that the AISC 9th edition steel manual, and all previous editions, was based on allowable STRESSES so it would have been likely that the engineer intended to compare bolt stresses (Ft versus ft) rather than bolt forces.

Interestingly, the equation you quoted uses psi whereas the AISC Specification in the 9th edition manual uses ksi. I am guessing this engineer practiced before AISC switched from using psi to ksi in the Specification and preferred to work in psi rather than ksi.

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