Jack-up Platform Spud Pole Damping for Deep Water Stability
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Solution Overview
Problem
Jack-up platforms are limited to shallow waters due to the maximum feasible water depth determined by spud pole length, and they struggle to operate in strong currents, leading to costly halting of operations.
Innovation Solution
The platform incorporates spud poles with a mass and damping means, such as dashpots or springs, to reduce lateral oscillating movements, allowing for longer spud poles and stable operation in deep waters and strong currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If spud pole length is increased to enable operation in greater water depths, then the platform can be utilized at greater water depths, but the spud poles become too heavy making transport difficult or uneconomic
Solution Approach 1:
The spud pole is divided into multiple segments that can be assembled in a telescopic configuration. The pole consists of an inner segment and an outer segment that can slide relative to each other, allowing the pole to extend to greater lengths when needed while maintaining a compact, transportable size. This segmentation enables the platform to reach greater water depths without requiring excessively long and heavy single-piece poles.
Solution Approach 2:
The spud pole employs a nested structure where the inner segment is positioned within the outer segment. When not in use or during transport, the segments are retracted into each other, creating a compact configuration. During operation, the segments extend outward to provide the necessary length for deep water support, effectively nesting the pole within itself to reduce transport requirements while maintaining operational length.
2Strength
If spud pole wall thickness is increased to provide structural strength, then the spud poles can support greater loads, but they become too heavy making transport more difficult
Solution Approach 1:
The spud pole is constructed using composite materials that provide high structural strength-to-weight ratio. The pole incorporates a combination of materials such as steel reinforcement within a concrete matrix, or advanced composite materials like carbon fiber reinforced polymers, which deliver the necessary load-bearing capacity without the excessive weight that would result from simply thickening solid metal poles. This allows the pole to maintain structural integrity while remaining transportable.
Solution Approach 2:
By segmenting the pole into multiple sections with varying wall thicknesses, the design optimizes material distribution. Critical sections that require higher strength (such as the base and joint areas) have thicker walls, while less critical sections have reduced wall thickness. This segmented approach provides necessary structural strength throughout the pole's length without uniformly increasing weight across the entire structure.
3Length of moving object
If spud poles are made longer to reach greater water depths, then the platform can operate in deeper waters, but lateral oscillating movements increase making the platform unstable in strong currents
Solution Approach 1:
The design accepts that longer spud poles will experience lateral oscillations from vortex formation in currents, but converts this potentially harmful effect into a beneficial one by incorporating damping mechanisms. The oscillations are allowed to occur but are then dissipated through controlled damping systems, such as viscous dampers or friction-based damping devices, which convert the oscillation energy into heat. This approach transforms the harmful lateral movements into a controlled energy dissipation process, maintaining platform stability despite the presence of long, flexible poles in deep water.
Solution Approach 2:
Damping devices are introduced as intermediary elements between the spud pole and the platform structure. These dampers act as mediators that absorb and dissipate the lateral oscillating forces generated by water currents before they can be transmitted to the platform. The damping mechanisms include viscous fluid dampers, friction dampers, or elastomeric elements positioned at strategic locations along the pole, which intercept and neutralize the oscillatory movements, protecting the platform's stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables operation at greater water depths and in strong currents, reducing platform oscillations and maintaining stability, thus preventing costly operation halts.
Implementation Method 1
damping means which connect the mass to the spud pole and which damp lateral oscillating movements of the mass
Implementation Method 2
Water flowing along the spud poles of a platform can cause vortices on the downstream side of the spud pole. This vortex formation is periodic and causes oscillating forces in the longitudinal direction of the spud pole (these forces are relatively limited) and in the lateral direction of the spud pole (substantially perpendicularly of the spud pole).
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a jack-up offshore platform (1). The platform comprises a work deck (2) supported by spud poles (3) and adjustable in height above the water surface, wherein at least one spud pole comprises means (20) for reducing lateral oscillating movements of the platform. The jack-up platform can be utilized at greater water depths than the known platform. The invention also relates to a method for operating a jack-up offshore platform in a water mass with strong current.