Environmental limitations in suction bucket based jacket foundation installation, using vertical lift-off from a jack-up vessel

Title

Environmental limitations in suction bucket based jacket foundation installation, using vertical lift-off from a jack-up vessel

 Author

van Doorn, N.T.

Contributor

Metrikine, A. (mentor)

Faculty

Civil Engineering and Geosciences

 Department

Offshore and Dredging Engineering

 Date

2016-07-27

 Abstract

In order to gain insight in maximum wave conditions in which installation of a four-legged suction bucket based jacket foundation could safely take place, a 2D time domain MATLAB model has been created, containing the most important features of a heavy lifting jack-up crane vessel and its appropriate rigging elements. The model is used to calculate the forces in the crane cable, as a result of the jacket’s behaviour through its interaction with the water. The environmental forces that act upon the jacket during the installation are based on an irregular wave field. 2000 Seeds were required her in, to find out that the maximum DAF values of the crane cable has a Weibull distribution. In order to reduce computational time, only 50 simulations per wave condition of interest are done, from which an insight is gained into which wave combinations should be handled with extra care. Those with a wave period of 4 to 5 seconds showed resonant behaviour with the waves, resulting in un-acceptable slack and causing the load cable DAF values to exceed the maximum allowable value of 1.3. For significant wave heights of 2 meters, wave periods longer than 8 seconds showed tolerable DAF values. Synchronization of the jacket’s vertical oscillation with the waves showed to be an important initiator of high DAF. Since the initial oscillations are caused by slamming and the jacket's eigen-period is affected by the heave added mass, these two phenomena are very important.

 Subject

jacket slamming
Offshore installation
suction bucket
time domain
MATLAB

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http://resolver.tudelft.nl/uuid:3e9c27be-9a25-444d-8e71-d948d1210e19

 Part of collection

Student theses

 Document type

master thesis

 Rights

(c) 2016 N.T. van Doorn
Files
PDF Thesis_NTvanDoorn_1513893.pdf 15.42 MB
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