Pad-eye Xtra – Padeye, Shackle and Sling Checks

Description

Purpose
TNApadeyeXtraV1.xls is a macro-assisted Excel workbook file available to assist in the design of lift padeyes of various sizes and shapes. Its basic capabilities are:
1. Build up a padeye model out of basic building block components (Main Plate with optional cheek plates, side plates and Main Plate Edge stiffeners)
2. Draw scaled elevation and section views and present them together with a summary of the input data and the design utilization results.
3. Perform a number of design strength checks. (See list in Reported Results section below.)
4. Perform dimensional checks with Rigging components selected from built-in DataBases of Shackles and wire rope
5. Print the visible worksheets in PDF format.
This App is geared toward evaluating structural designs of padeyes/lugs utilized in lifting applications but is also applicable to structural pin connectons subjected to tension loads.
It has been developed over a 30 year period in projects connected with offshore and onshore faciities construction and subsea installation design.
Selected spot input and output checks are included to alert user to inconsistencies in the data.
Approximately 20 strength and dimensional checks are performed. Ideal for occasional use, preliminary designs, and quick QC checks of padeye designs by others.

Instructions
1 All user input is entered in Worksheet “Inputs” in the cells highlighted in blue ie
2 Supplementary nomenclature/notes/ input instructions are provided and highlighted in yellow ie
3 Required user input consists of basic padeye dimensional data, Design Guideline selection, Shackle and Wire Rope catalogue reference selection
Detailed description of the parameters is provided below and in Worksheet “Input”.
4 See also the “Example Inputs” workbook that is supplied with this App.
5 To set up the header and footer content on the printed output, fill in the admin information in the Inputs worksheet upper right and click the macro
button labelled “Set up Print Pages”.
6 Initially the workbook calculations are executed by clicking the macro button at the top of worksheet “Inputs” that is labelled
“Calculate Workbook and Re-draw Padeye”. After execution, the active worksheet is “Outputs” where summary results are presented
plus a scaled sketch of the padeye under consideration.
7 In the present version of this App, the contents of visible worksheets can be copied to external Excel workbook for manual formatting in reporting applications.

Reported Results
1 All results are presented on Worksheet “Outputs” with supplementary details presented in worksheet “CalculationsSI”.
2 Results for the following design checks are provided accompanied by a scaled elevation view and section sketches of thepadeye/lug being evaluated:
a Shackle pin bearing in way of the Pin Hole.
b Shackle pin pull through shear (double shear)
c Combined normal and shear stress in Main Plate at horizontal section in way of pin hole
d Combined tension, bending and shear (including torsion) stress in Main Plate at interface with main structure
e Cheek plate fillet welds based on User specified sling load split assumption.
f Weld group at Main structure interface (includes welds to side plates and edge plates if applicable)
g Block tear-out behind cheek plate (Russo 1992)
h Recommended shackle based on minimum WLL (unless specific shackle is specified or pin hole diameter is specified)
i Estimated wire rope sling dimensional parameters
j Dimensional Checks – pin hole, padeye/shackle and shackle/wire rope

Results for the following less common checks are also reported
k Combined tension and bending stress in Main Plate at top-of-side plates
l Tear through net section (Optional Chevron 1993 req’t)

Limitations
Validity of calculation is restricted to padeyes/lugs satisfying the following characteristics:
a. Must exhibit mirror-symmetry about the plane of the Main Plate
b. Loaded in tension only
c. Main Plate stiffening does not extend past the plane through the Pin Hole that is parallel with the Main Plate/Structure interface
d. Strength calculations are applicable to the padeye only. Shackle and wire rope selections are utilized in dimensional clearance checks are or guidance only.
e. Availablity of wire rope choices in the larger diameters limits sling loads to about 1000 MT for full strength and dimensional checks.

References
1. Noble Denton Lift Guidelines (ND/0027 now included in DNVGL-ST-N-001)
2. AISC WSD 9th ed, Ch D3 (Pin ends of tension members)
3. Document EM/039, Rev 3, Dec 1991 ,Guidelines for Design, Fabrication and Inspection of Lift Points by Shell UK E&P
4. Chevron Document, “Padeye Program Version 2.1, Description and User Manual”, June 16, 1993
5. Russo et al, “PAD EYE DESIGN AND ANALYSIS”, ISOPE June 1992
6 .Orner W. Blodgett, “Design of Welded Structures”, Lincoln Arc Welding Foundation, 1966
7 .Shackle Catalogues (Crosby and Van Beest)
8. KTL Offshore Pte Ltd Catalogue, “Wire Rope, Rigging and Mooring For Off shore Construction”
9. Various additional Industry Lift Point design guidelines (eg Petronas PTS, TOTAL GS)