×
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

Anchor Bolt Tension in Circular Pattern (For Vessels)

Anchor Bolt Tension in Circular Pattern (For Vessels)

Anchor Bolt Tension in Circular Pattern (For Vessels)

(OP)
Hi!

In ASCE Wind Loads and Anchor Bolt Design for Petrochemical Facilities, the anchor bolt maximum tension is calculated by the formula below:

Tension = 4*M / (N*BC) - W / N

Where:
M = maximum moment on vessel
N = number of anchor bolts
BC = bolt circle diameter
W = minimum weight of vessel

It is stated there that it was calculated by assuming an elastic distribution of forces and moments, which is based on the moment inertia of the bolt group.

I'm just curious on how did they arrive on this formula. How was it derived?
Can anyone show me the formulas used? Thanks :)

RE: Anchor Bolt Tension in Circular Pattern (For Vessels)

For a thin cylindrical beam, bending stress is equal to Mc/I +/- P/A.
Set c = R, I is pi*R^3*t, and A is 2*pi*R*t, where t is the thickness, R is the radius.
Then stress is equal to M/(pi*R^2*t) +/- P/A.
This is a varying stress, but the equivalent axial load that would give that same stress is A*stress or
(M/(pi*R^2*t) +/- P/A) * 2pi*R*t = 2M/R +/- P
And, assuming this total force is divided amongst N bolt, the load per bolt is 2M/(RN) +/- P/N or 4M/(ND) +/- P/N

There may be more elegant ways to show that, but it's still based on the Mc/I +/- P/A.

People have tried to complicate this by considering the composite steel/concrete area in the foundation. However, the stress in the cylindrical shell is assumed to be of this load distribution, so there's not much motivation to assume a different load distribution above the concrete surface than below.

RE: Anchor Bolt Tension in Circular Pattern (For Vessels)

(OP)
Thanks for your fast response. Your answer did enlighten me. :)

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