×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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.

Students Click Here

Partial Penetration and Full Penetration Joints on Lift Padeyes

Partial Penetration and Full Penetration Joints on Lift Padeyes

Partial Penetration and Full Penetration Joints on Lift Padeyes

(OP)
Hi All,

I am currently working on a offshore structure with beams which have lifting padeyes welded to them. As per DNV requirements all lifting padeyes need to be welded with a full penetration joint. What I have is a padeye 35mm thick and I-beam flange 10mm thick. If we bevel the padeye with a root of 3mm, we are left with a bevel of 16mm on each side. Doing a 16mm bevel weld on a 10mm flange will practically distort the flange.

1. My question is, whether a Complete Joint Penetration is practical here? Otherwise a 10mm bevel on either side of the padeye will be practical to weld on a 10mm flange (base metal).

2. I have done calculations and the 10mm weld are sufficient for the loads. But I want the criteria of DNV to be fulfilled, that is the padeye joint has to be full penetration. Any way out here? Any suggestions?

Thanks in advance.

Regards,

HungryDinosaur

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

Which DNV code?

2.7-1 doesn't mandate full pen. But its a good idea from an NDT perspective. Can you modify the design to set in the pad eye?

Nick

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

(OP)
Nick,

Its difficult to modify the design. What do you mean "set in the padeye"?

Regards,

HD

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

Quote (NickClark)

2.7-1 doesn't mandate full pen
And how to interpret 4.3.1 Welding of padeyes
All main welds between pad eyes and the primary frame structure
shall always be full penetration welds.

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

Thanks for the correction ak762. I am thinking of 2.7-3 which allows fillet welds in shear if I read correctly. If you can't modify the design but need to meet the dnv then your a bit stuck. I still don't know the code you need to meet or the eye design but I was speculating that you could insert the eye into the flange and prep the flange instead. Its up to you to come up with a solution and it will be difficult to provide more without details

Regards

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

(OP)
Nick,

Yeah looks like I am stuck here. The code is DNV 2.7-1.

Regards,

HD

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

Can you use a doubler plate? Would that be acceptable?

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

(OP)
Ussuri,

I never thought about that. But is it normal to do so?

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

In accordance with DNV 2.7-1? I don't know. I have never designed to it. It was just a thought so I would guess you would need to investigate.

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

Can you design the pad-eye to be slotted into the I beam? Search for the following TCM153-474863, shows different ways to mount pad-eyes.

Petrotrim Services
www.petrotrim.com

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

Dear Ussuri,

please provide your thoughts on the double plate.


Thank You

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes


Hi

Below is a copy of an extract from the DNV, the last sentence talks about transferring the lifting load through a plate and its thickness must be adequate, how does your 10mm thick plate and your pad eye compare with this statement.
It suggests to me that if your plate isn't thick enough, then using a doubler might be an option. See another extract further down.


The thickness of the pad eye at the hole shall not be less than 75% of the inside width of the joining shackle.

Guidance note:

When the pad eye thickness is below the 75% limit, it can be increased by welding on cheek plates or by inserting a

thick walled pipe or drilled out boss through the pad eye. See Appendix D for strength calculations of such structures.

Pad eyes shall be welded to the frame with full penetration welds. If the lifting force is transferred through the

thickness of a plate (the z-direction), plates with specified through thickness properties must be used.



---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---








The thickness of the pad eye at the hole shall not be less than 75% of the inside width of the joining shackle.

Guidance note:

When the pad eye thickness is below the 75% limit, it can be increased by welding on cheek plates or by inserting a

thick walled pipe or drilled out boss through the pad eye. See Appendix D for strength calculations of such structures.

Pad eyes shall be welded to the frame with full penetration welds. If the lifting force is transferred through the

thickness of a plate (the z-direction), plates with specified through thickness properties must be used.



---e-n-d---of---G-u-i-d-a-n-c-e---n-o-t-e---

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

A doubler plate is a thicker section of plate welded onto a thinner plate. It acts as an interface between the one structural element and another. Sometimes used when you have to put some high loads into a thin plate. The doubler is thicker and designed to take the loads and then distribute them over a wider area on the thin plate.

RE: Partial Penetration and Full Penetration Joints on Lift Padeyes

So, the most reasonable solution for this is to use higher strength steel for padeye (to reduce a thicknes, probably cheek plates shall be provided to ensure mentioned 75% of shackle clearance), or / and (when not requirements are not fullfiled) insert an I-beam with thicked web(s) in region when the padye to be installed.
You can also ask DNV Advisory (DNV GL since few moths) whether another solution is acceptable.

Naval Architect/ Structural Engineer
Poland

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! Already a Member? Login


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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