Cable Head Ring Assembly for Wind Tower Foundation Joints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for connecting a tubular steel wind turbine tower to a tubular concrete foundation, such as a spar buoy, are challenging due to high precision requirements, lengthy installation processes, structural weaknesses, and manufacturing difficulties, especially for large components, which are exacerbated by the large moments and forces experienced by floating wind turbines.
Innovation Solution
A cable head ring with concentric inner and outer tubular webs and aligned holes is used to secure the wind turbine tower to the concrete foundation, eliminating the need for a T-flange and utilizing tensioning tendons and anchors for a robust connection, with passages for tendons outside the annular gap for easier handling and inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a T-flange with multiple bolts is used to secure the wind turbine tower to the concrete foundation, then the connection strength is improved, but the installation time and complexity increase significantly
Solution Approach 1:
The connection system is segmented into distinct functional components: the cable head ring integrated with the concrete foundation, and the tower flange attached to the wind turbine tower. This segmentation allows parallel preparation of components and simplifies the final assembly process, reducing installation time while maintaining connection strength through dedicated bonding and mechanical fastening elements.
Solution Approach 2:
A cable head ring serves as an intermediary element between the concrete foundation and the tower flange. This intermediary component provides integrated attachment points for both chemical bonding (via bonding agents applied to the concrete surface) and mechanical fastening (via anchors and bolts), enabling simultaneous achievement of strong connection and simplified installation procedure.
2Reliability
If a thick layer of grout is used to adhere the levelling ring to the anchor ring, then the structural weakness is reduced, but the installation time increases
Solution Approach 1:
The levelling ring function is extracted and integrated directly into the cable head ring structure. The cable head ring incorporates built-in levelling features and positioning elements that eliminate the need for a separate levelling ring component and its associated thick grout layer, thereby reducing installation time while maintaining structural reliability through the integrated design.
Solution Approach 2:
Multiple functions (anchoring, levelling, and structural connection) are merged into the single cable head ring component. This consolidation eliminates the need for separate levelling ring and anchor ring components that required thick grout layers for assembly, reducing both installation time and potential structural weaknesses associated with multiple grout joints.
3Reliability
If bolt holes are fabricated through the T-flange, anchor ring and levelling plate, then the connection reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The cable head ring is pre-assembled with anchors and positioning elements in their correct locations before being installed on the concrete foundation. This preliminary assembly ensures precise alignment of all connection points, eliminating the need for high-precision hole fabrication through multiple separate components during the main installation process, while still achieving reliable mechanical fastening.
4Adaptability or versatility
If a T-flange is used for large diameter components, then the connection capability is improved, but the manufacturing difficulty increases
Solution Approach 1:
The connection system is divided into the cable head ring (attached to concrete foundation) and the tower flange (attached to wind turbine tower). This segmentation allows each component to be manufactured independently using appropriate techniques for their respective sizes and materials, avoiding the manufacturing difficulties of fabricating and handling extremely large T-flanges as single pieces, while maintaining the ability to connect large diameter towers through the modular assembly process.
Data Source
AI summary
A cable head ring for use in connecting a wind turbine tower to a concrete foundation. The cable head ring includes an annular plate for connecting to the upper end of the concrete foundation, an inner tubular web extending axially from the annular plate and an outer tubular web extending axially from the annular plate. An annular gap is formed between the inner and outer tubular webs for receiving a tubular wind turbine component. The annular plate has a plurality of passages extending axially therethrough for receiving tensioning tendons of the concrete foundation. The inner and outer tubular webs include holes extending radially therethrough. The positions of the holes in the inner tubular web correspond to the positions of the holes in the outer tubular web such that a fastener can extend radially through a hole in the inner tubular web and a hole in the outer tubular web.