UHPFRC Hollow Transition Piece for Lighter Jacket Installation

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Solution Overview

Problem

Transition pieces for wind turbines made of thick steel sheets are costly, complex to manufacture, require heavy maintenance, and result in increased project delays due to corrosion and fatigue, while reinforced concrete alternatives are too heavy and costly to lift and require oversized substructures.

Innovation Solution

A transition piece with a hollow structure made of ultra-high performance fiber-reinforced concrete (UHPFRC) and pretension members, featuring a top part to support the wind turbine and distal supports on a jacket substructure, allowing for prefabrication and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thick steel sheets are used to manufacture transition pieces, then structural strength is improved, but manufacturing cost and complexity increase

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies composite materials by combining ultra-high performance fiber-reinforced concrete (UHPFRC) with pretensioned steel elements. The UHPFRC provides compressive strength and durability, while the pretensioned steel members provide tensile strength and structural rigidity. This composite approach replaces the need for thick steel sheets while maintaining structural integrity and reducing manufacturing complexity.

Inventive Principle:
Principle #40Composite materials

2Strength

If thick steel sheets are used to manufacture transition pieces, then structural strength is improved, but manufacturing time increases

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent applies preliminary action through pretensioning of steel members before concrete placement. The steel reinforcement elements are pre-tensioned to the required stress level, and anchorages are pre-installed in the UHPFRC structure. This allows for faster assembly and reduces on-site construction time while ensuring proper structural strength development.

Inventive Principle:
Principle #10Preliminary action

3Quantity of substance

If traditional reinforced concrete is used to manufacture transition pieces, then material cost is reduced, but weight increases significantly

Engineering Contradiction:
Improvematerial costVSAvoidstructure weight
Core Design Contradiction:
Quantity of substanceVSWeight of moving object

Solution Approach 1:

The patent applies parameter changes by using ultra-high performance fiber-reinforced concrete (UHPFRC) instead of traditional reinforced concrete. UHPFRC has significantly higher compressive strength (typically 150-300 MPa) compared to conventional concrete (20-40 MPa), allowing for reduced section dimensions and lower weight while maintaining the same load-bearing capacity. The fiber reinforcement also eliminates the need for traditional steel rebar, further reducing weight.

Inventive Principle:
Principle #35Parameter changes

4Quantity of substance

If traditional reinforced concrete is used to manufacture transition pieces, then material cost is reduced, but lifting and installation difficulty increases

Engineering Contradiction:
Improvematerial costVSAvoidlifting and installation ease
Core Design Contradiction:
Quantity of substanceVSEase of operation

Solution Approach 1:

The patent applies parameter changes by using UHPFRC with superior strength-to-weight ratio. The elevated compressive strength and tensile properties of UHPFRC enable the creation of lighter, more compact structural sections that are easier to lift and install. The material's high early strength development also allows for faster formwork removal and earlier installation, improving construction efficiency.

Inventive Principle:
Principle #35Parameter changes

5Strength

If steel structure is used for transition pieces, then structural strength is maintained, but maintenance requirements increase

Engineering Contradiction:
Improvestructural strengthVSAvoidmaintenance requirements
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The patent applies composite materials where UHPFRC serves as the primary structural material, replacing most steel components. UHPFRC exhibits excellent corrosion resistance, fatigue performance, and durability in harsh marine environments. The fiber reinforcement provides ductility and crack control, reducing maintenance needs. Only minor steel elements (anchorages, connections) remain, significantly reducing corrosion and maintenance requirements compared to all-steel structures.

Inventive Principle:
Principle #40Composite materials

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

The UHPFRC structure reduces manufacturing costs and complexity, minimizes maintenance needs, and facilitates installation with reduced weight and crane requirements, while maintaining structural integrity.

Implementation Method 1

a plurality of pretension members at least partly extending within the hollow structure

Methodology Applied
Scientific EffectPretension: Tension

Data Source

PatentEP4621220A1Transition piece having a hollow structure intended to support a wind turbine and comprising ultra-high performance fiber-reinforced concrete
Publication Date: 2025.09.24 TOTALENERGIES ONETECH
  • EP4621220A1 patent drawingFigure 1
  • EP4621220A1 patent drawingFigure 2
  • EP4621220A1 patent drawingFigure 3

AI summary

Transition piece (16) comprising a hollow structure (32), and pretension members (36) within the structure. The structure defines an interior volume (34) and has a top part (40) for supporting a wind turbine. The structure comprises ultra-high performance fiber-reinforced concrete and forming feet (42, 44, 46) forming supports intended to rest on a jacket. The feet comprise an upper wall (54), the structure having side walls (56) extending between the top part and a base (58) defining the supports. The side walls extend between the upper wall of two successive feet, each of the feet having two lateral walls in a horizontal transverse direction respectively formed by two successive side walls. The interior volume is delimited by the top part, the upper wall of each of the feet, the side walls and the base.