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motions significantly affect the structural requirements is efficient.
This group includes the moored floating structures, tethered
platforms, articulated towers, guyed towers, and single point
moorings.
The main factors influencing the selection of the platform
types and especially the structural configuration are the utility
requirements, the water depth, the lateral and vertical loads
resulting from the environmental factors and the lateral and
vertical resistance of the fluid-structure-soil system (restoring
forces, soil resistance).
Furthermore, the fabrication techniques, the towing and
installation methods and last but not least the aspects of
maintenance and reliability can affect essentially the selection of a
structural system.
The utility requirement is reflected in the size of the
superstructure needed to support the necessary equipment for
drilling and production. Therefore, the most important factor
affecting the size of the deck structure is the number of and the
productivity of the wells.
Interaction Structure-Environment
A rigorous analysis of the fluid-structure-soil interaction is
extremely complex and expensive. For design purposes, the
acceptable simplifications concerning the interaction modes as
well as the mathematical models for idealization are necessary.
Environmental Conditions
An accurate knowledge of the environmental parameters is
fundamental to the sound design of marine structures. In order to
calculate the loads likely to be imposed by the natural phenomena
and to predict the resulting motion and structural response
characteristics under normal and extreme conditions various
meteorological and oceanographical parameters (metocean
parameters) have to be established. Metocean parameters
important for the design analysis of marine structures are:
Wind: Mean Wind Speed
Mean Wind Direction
Wind Power Spectral Density Function
Variation of Wind Speed above the Sea level
Wave: Significant Wave Height
Mean Wave Period
Wave Amplitude Spectral Density Function
Mean Wave Direction

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