Percentage Loading in Lift Padeyes

• Sep 6, 2018

• #2

kingnero

Mechanical

Aug 15, 2009

1,783

BE

Perhaps a stupid question, but as this is for offshore, shouldn't you use 200% (or more) of the entire weight, per padeye?

To answer your question see attachment. Basic statics I'd say.

 

 https://files.engineering.com/getfile.aspx?folder=43b41674-1fb7-460b-b9b7-8b4390361aec&file=CG.jpg

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• Sep 10, 2018

• #3

Ussuri

Civil/Environmental

May 7, 2004

1,583

GB

You have 4 unknowns in the sling load in each leg. You can set up a system of equations, sum in x direction = 0, sum in Y direction = 0 and sum in z direction = 0. The fourth equation is the skew effect, but in answer to your question, sum of vertical loads in one pair of diagonal slings - 50% total lift weight (ie a skew factor of 1.0). You can then solve for your sling forces and then compare the %'age difference in each leg due to your offset.

 

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• Sep 10, 2018

• #4

Compositepro

Chemical

Oct 22, 2003

7,846

US

Without using load eveners (pulleys or levers) on the support cables you can easily have 100 percent of the load on only two cables. If you rig 4 cables of equal length as shown in the OP. The load will tilt when lifted so the cg is under the hook, and one cable will have zero tension. The problem is indeterminate without some extra rigging.

 

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• Sep 29, 2018

• #5

elreedyman

Structural

May 14, 2016

10

EG

i hope to return to dnv for lifting specific for padeyes design or with examples in [URL unfurl="true"]https://www.elsevier.com/books/marine-structural-design-calculations/el-reedy/978-0-08-099987-6[/url]

 

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• Oct 12, 2018

• #6

Clumpweight

Marine/Ocean

Apr 17, 2009

4

GB

Rather concerned that you are distributing 25% load on each when requirements for the design of a 4 leg sling, in accordance with EN 13414-1 : 2008, Steel wire rope slings - Safety - Part 1: Slings for general lifting service. This code is recognised as complying with the EEC Machinery Directive. This method is intended to be used for a equal leg length sling, but can be used for unequal leg length slings. see attachment.

 

 https://files.engineering.com/getfile.aspx?folder=480265e7-cf5b-4fdd-90cd-ad682843c7f4&file=SlingProVer5-1w.xls

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