Validation of Analysis Methods for Padeye Attachment Under Dynamic Loading through Destructive Testing (2014-423)
- General Dynamics NASSCO
- San Diego State University
NSRP ASE Investment: $139K
Rigging is an essential part of ship construction and the application of padeye attachments as lifting points is common practice. Although essential, the application and removal of these padeye attachments, and any number of additional stiffening components, strictly for rigging operations, represents a substantial non-value-added shipbuilding activity. In an attempt to reduce this substantial non-value-added cost and associated risk, ship yards have designed lifts that push the limits of crane capacity, opting to lift and turn larger and increasingly heavier blocks. Workers and assets vital to daily shipyard operations are exposed to an increased risk with every lift. The rigging engineers responsible for padeye design and the development of lifting arrangements are ultimately responsible for ensuring the safety of those involved in the lift itself.
This project expanded upon work completed during the 2012 NSRP Panel Project Validation of Analysis Methods for Padeyes through Destructive Testing ATI Agreement No. 2005-333 and continued the investigation of the padeye to ship structure interface in order to provide rigging engineers with more design aid references. This investigation utilized scenarios and information gathered during the 2010 RA and attempted to combine both analytical methods with destructive testing in an effort to provide further insight into the understanding of effective analysis methods for padeye attachment gained during the 2012 Panel Project. The greater demand placed on lifting attachments to accommodate shipyard operations has increased the importance of their design more than ever. The sheer number of lifting padeyes used per ship warrants the efficiency of their design. The rigging engineers responsible for padeye design and the development of lifting arrangements are ultimately responsible for ensuring the safety of those involved in the lift itself. With this research, rigging engineers now have several new references to assist with the development of block lifting arrangements. The methods described in this report to calculate block loading and padeye weld capacity will help rigging engineers produce a more optimized design, enhance and maintain safe rigging practices, and reduce non-value added cost by optimizing the level of padeye attachment required.
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