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
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
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
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
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
Regards
RE: Partial Penetration and Full Penetration Joints on Lift Padeyes
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
RE: Partial Penetration and Full Penetration Joints on Lift Padeyes
I never thought about that. But is it normal to do so?
RE: Partial Penetration and Full Penetration Joints on Lift Padeyes
RE: Partial Penetration and Full Penetration Joints on Lift Padeyes
Petrotrim Services
www.petrotrim.com
RE: Partial Penetration and Full Penetration Joints on Lift Padeyes
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
RE: Partial Penetration and Full Penetration Joints on Lift Padeyes
You can also ask DNV Advisory (DNV GL since few moths) whether another solution is acceptable.
Naval Architect/ Structural Engineer
Poland