×
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

Strength of pinned connection

Strength of pinned connection

Strength of pinned connection

(OP)
Looking for guidance on how to calculate the strength of say a lifting lug and a shackle. Assume 3/4" plate with a 13/16 hole one diameter from the edge. How do you calculate the "pull out" strength of the lug, is it the projected are of the pin. Hope this is not confusing, I am a mechanical engineer not structural.

Regards

RE: Strength of pinned connection

Why bother making you own when you can buy these items from reliable distributors such as Crosby; it will be cheaper and more reliable than making your own. The lifting capacity will be embossed on the shackles so don't mismatch the pins sizes and manufacturers, and be wary of any shackle made in China particularly if you do critical lifts.

RE: Strength of pinned connection

The ASME BTH-1 has the design checks for a pin connected plate in Chapter 3-3.3.1. The equations check for tension in the net section, splitting beyond the hole, double plane shear, dishing, and a bearing check.

RE: Strength of pinned connection

ASME Standard BTH-1 addresses lifting components. There is a double shear plane from the top and bottom of the hole to the edge of the plate. The plate thickness x this length is the shear area. I think BTH-1 uses a factor of safety of 5.

RE: Strength of pinned connection

(OP)
So I calculate the projected double shear area i.e. .75X.81X2 If using a 36 assume 36ksi/5 and rate the load?

RE: Strength of pinned connection

No, that's not how it's done. Specifically for the case of the double plane shear strength, the equation is:

0.70*Fu/(1.20*Nd)*A
where Fu is the ultimate tensile strength of the steel and Nd is the design factor

The design factor is determined by the Design Category of the lug, which is based on a service class, which is based on the number of load cycles.
In addition to that, there's still 4 other failure modes that need to be checked for the pinned connection.

My recommendation is to get a copy of the BTH-1 and become familiar with it, especially if you're going to be designing these lugs on a consistent basis.

RE: Strength of pinned connection

(OP)
Sorry, I used a bad example this has nothing to do with below the hook rigging, just a simple pinned joint as in two pcs of tubing telescoped together connected via 3/4" pin (i.e. 4 in sq tubing connected to 3 1/2" tubing).

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