Wind Tower Flange Connection Using Unbonded Tendons
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Solution Overview
Problem
The existing connection systems between wind tower shafts and support surfaces require precise installation, are sensitive to geometrical errors, and can weaken the bearing capacity of the shaft, increasing costs and maintenance needs.
Innovation Solution
A connection system utilizing a post with paired bolts and unbonded post-stressed tendons, where the tendons are distributed uniformly around the perimeter, embedded in a concrete foundation cage, allowing for flexible adjustment and reduced sensitivity to installation errors, with a flange that does not have through holes for enhanced bearing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If steel bars or pins are used as active reinforcement embedded in the foundation, then the connection between shaft and support surface is achieved, but the mounting precision requirement increases and mounting time increases
Solution Approach 1:
The invention changes the connection mechanism from mechanical interlocking (requiring precise hole alignment) to friction-based connection through surface compression. By compressing the flange surfaces together, the connection becomes less sensitive to positioning errors, allowing broader mounting tolerances while maintaining connection reliability.
Solution Approach 2:
The invention replaces the traditional mechanical connection system (steel bars/pins requiring precise hole alignment) with a friction-based compression system. The tendons apply compressive force to press the flange surfaces together, creating a reliable connection without requiring precise hole positioning.
2Reliability
If steel bars or pins are used as active reinforcement, then the connection is achieved, but the mounting time increases and auxiliary means are required
Solution Approach 1:
The invention extracts and eliminates the need for complex auxiliary mounting systems (annular templates) required for traditional bar/pin installation. The tendon-based compression system can be installed directly without requiring specialized positioning equipment, significantly reducing mounting time and simplifying the installation process.
Solution Approach 2:
The invention replaces the complex mechanical installation process of traditional reinforcement systems with a simpler tendon tensioning and compression system. This substitution eliminates the need for time-consuming auxiliary means and direct mounting operations.
3Reliability
If mounting holes are drilled in the flange, then the active reinforcement can be installed, but the bearing capacity of the flange is weakened and price increases
Solution Approach 1:
The invention extracts and eliminates the need for mounting holes in the flange by using a hole-free tendon anchoring system. The tendons are anchored to the flange surface without requiring penetration, thereby preserving the flange's bearing capacity and structural integrity while achieving reliable connection.
4Adaptability or versatility
If non-adherent strands are used instead of steel bars, then the flexibility for position adjustment is improved, but the position consistency deteriorates and auxiliary systems are still required
Solution Approach 1:
The invention enables the tendon system to self-adjust and self-position through the compression mechanism. The tendons automatically distribute the compressive force evenly across the flange surfaces, eliminating the need for precise pre-positioning or auxiliary positioning systems while maintaining position consistency through the self-equilibrating nature of the compression connection.
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 system provides a robust, reliable, and cost-effective connection that is less sensitive to installation tolerances, increases the service life of the connection, and maintains the structural integrity of the wind tower shaft.
Implementation Method 1
A connection system of a shaft of a wind tower to a support surface comprising a foundation, the shaft comprising: a post with a first face and a second face, and a fixing end, the post being configured to be placed vertically on the support surface, a plurality of bolts distributed in pairs on both first and second faces of the post such that each bolt of each pair of bolts is fixed on either the first face or second face of the post, a flange located in the fixing end of the post and adapted for being fixed on the support surface, a plurality of pairs of tendons, each tendon comprising: a lower anchoring embedded in the foundation, an upper anchoring, at least one strand with a first end and a second end, the strand extending from the upper anchoring to the lower anchoring
Data Source
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AI summary
The invention introduces a connection system for connecting a shaft of a wind tower to a support surface (1), by means of a shaft, a foundation cage (13) and a plurality of pairs of tendons (7) wherein each tendon comprises a lower anchoring (8) adapted for the placement thereof inside the foundation, an upper anchoring (8'), at least one strand with a first end and a second end, the strand extending from the upper anchoring to the lower anchoring, a pair of sleeves for each strand, a sleeve fixed to the upper anchoring and a sleeve fixed to the lower anchoring, each sleeve housing a segment of the strand. Additionally, the system introduces a method for connecting a shaft of a wind tower to a support surface.