Tendon Anchor Wedge Taper Angle Configuration
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Solution Overview
Problem
Existing tendon anchoring systems in post-tension concrete reinforcing systems face issues with uneven distribution of longitudinal compressive force and stress concentration due to standard taper angles and deep penetration of gripping elements, leading to tendon failure during axial stress testing.
Innovation Solution
The anchor system features a wedge with a tapered exterior surface and a wedge receiving bore with selected taper angles, where the wedge taper angle exceeds the bore taper angle by 1° to 2°, ensuring even longitudinal distribution of lateral compressive force and reducing stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If standard taper angles are used for the wedge and wedge receiving bore, then the anchoring system is simple to manufacture and install, but the longitudinal compressive force is unevenly distributed causing stress concentration and tendon failure
Solution Approach 1:
The patent applies parameter changes by modifying the taper angles of both the wedge and wedge receiving bore from standard values to specific non-standard angles. The wedge taper angle is set between 6°-8° while the bore taper angle is set between 4°-6°, creating a controlled angular difference that transforms the stress distribution pattern and eliminates stress concentration points, thereby improving tensile strength without excessive complexity
Solution Approach 2:
The patent applies local quality by creating different taper angles at different locations within the anchoring system. The wedge has one taper angle while the wedge receiving bore has a different taper angle, allowing each component to have optimized local geometry that promotes even longitudinal distribution of compressive forces throughout the anchoring system
2Strength
If gripping elements penetrate deeply into the tendon to secure anchoring, then the anchoring grip is stronger, but stress concentration occurs leading to tendon failure
Solution Approach 1:
The patent changes the geometric parameters of the wedge-tendon interface by using shallower taper angles (wedge: 6°-8°, bore: 4°-6°) that distribute the gripping force over a longer contact length. This parameter modification reduces the penetration depth effect and eliminates stress concentration while maintaining adequate grip strength through extended surface contact
3Strength
If the wedge taper angle is significantly different from the bore taper angle, then even distribution of compressive force is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent selects specific parameter ranges (wedge taper: 6°-8°, bore taper: 4°-6°) that provide sufficient angular difference for even force distribution while remaining within practical manufacturing capabilities. These parameter values represent an optimized compromise that achieves the desired stress distribution without imposing excessive precision requirements on manufacturing processes
Solution Approach 2:
The patent applies local quality optimization by specifying taper angle ranges rather than single precise values, allowing each component to be manufactured within acceptable tolerances while maintaining the critical angular relationship. This approach ensures even compressive force distribution through local geometric optimization without requiring extreme manufacturing precision across the entire system
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 enhances the tensile strength of tendon anchoring systems by evenly distributing compressive forces along the length of the wedge, reducing the likelihood of tendon failure and improving overall structural integrity.
Implementation Method 1
The wedge has a tapered exterior surface configured to cooperate with the tapered interior surface of the wedge receiving bore to laterally compress the wedge against the tendon when the wedge is moved longitudinally into the bore
Data Source
AI summary
An anchor system for a tendon includes a load transfer device having at least one wedge receiving bore therein. The wedge receiving bore has a tapered interior surface. The anchor system also includes a wedge configured to be affixed to an exterior surface of a tendon. The wedge has a tapered exterior surface configured to cooperate with the tapered interior surface of the wedge receiving bore to laterally compress the wedge against a tendon when the wedge is moved longitudinally into the bore. Taper angle of the wedge and a taper angle of the wedge receiving bore are selected such that longitudinal compressive force exerted by the wedge is substantially evenly longitudinally distributed.