Optimization of the shear tool deployment system for removal of steel piled jackets

It is estimated that there are more than 200 steel piled platform installations in the North Sea which have reached the end of their life and have to be cut and removed. In comparison with other cutting methods, the shear tool cutting method offers the greatest potential regarding optimizing the tim...

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Bibliographic Details
Published in:Proceedings of the Institution of Mechanical Engineers. Part M, Journal of engineering for the maritime environment Journal of engineering for the maritime environment, 2016-05, Vol.230 (2), p.354-363
Main Authors: Godjevac, Milinko, Huijsmans, R HM, van der Eijk, Hidde M, de Grave, Louis
Format: Article
Language:English
Subjects:
Comparative analysis
Cutting tools
Design analysis
Design engineering
Environmental conditions
Heave
Mathematical analysis
North Sea
Optimization
Shear
Steel
Workability
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Summary:It is estimated that there are more than 200 steel piled platform installations in the North Sea which have reached the end of their life and have to be cut and removed. In comparison with other cutting methods, the shear tool cutting method offers the greatest potential regarding optimizing the time of the operation. However, the existing shear tool is susceptible to blade bending–related failures caused by heave motions of the heavy lift vessel to which the tool is attached. While there are many studies related to the operability and workability of sea surface structures, this study focuses on the operability and workability of an underwater structure, the shear tool system. In order to improve the performance of the existing shear tool, the new shear tool system has been designed as an equalizer with additional counter weights; thus, this system acts as a passive heave compensator. In total, six different design concepts have been assessed using a multicriteria sensitivity analysis, and the most promising concept has been selected. Afterwards, the performance of the new design was compared with the performance of the existing tool by calculating their operability and workability for the removal of the benchmark (Northern North Sea jacket) structure. The workability calculation was based on 15 years of environmental conditions and results indicate that the new design leads to 50% workability increase.
ISSN:1475-0902
2041-3084
DOI:10.1177/1475090215571378