Sheathing-Retaining Wedge Assembly for Post-Tension Anchorage
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Solution Overview
Problem
Conventional dead-end anchorage systems in post-tension systems face challenges in preventing sheathing shrinkage and liquid intrusion, requiring additional corrosion-protection tubes that increase costs and installation complexity.
Innovation Solution
A wedge assembly with a tendon-retaining portion and a sheathing-retaining portion, featuring a barbed rim or similar hook means, is designed to securely engage and retain the sheathed portion of the tendon within the anchor cavity, preventing shrinkage and liquid intrusion without the need for additional tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dead-end anchorage systems are used, then the tendon can be anchored, but the sheathing shrinks and liquid intrusion occurs, requiring additional corrosion-protection tubes
Solution Approach 1:
The patent combines the tendon-retaining function and sheathing-retaining function into a single integrated wedge assembly. The wedge includes a tendon-retaining portion with a channel for the tendon and a sheathing-retaining portion with a barbed rim that engages the sheathing, eliminating the need for separate corrosion-protection tubes while maintaining both anchorage and shrinkage prevention functions
Solution Approach 2:
The wedge assembly serves multiple functions simultaneously: it anchors the tendon through friction engagement, prevents sheathing shrinkage through the barbed rim engagement, and provides liquid-tight sealing by retaining the sheathing end within the anchor cavity. This multi-functional design replaces the conventional multi-component system with a single unified component
2Object-affected harmful factors
If additional corrosion-protection tubes are installed, then liquid intrusion is prevented, but installation complexity and costs increase
Solution Approach 1:
The liquid-tight sealing function is integrated into the wedge assembly itself through the sheathing-retaining portion that engages the sheathing with a barbed rim and retains it within the cavity. This eliminates the need for separate corrosion-protection tubes, simplifying installation to a single component while maintaining liquid intrusion prevention
3Stability of the object's composition
If the sheathing is retained within the anchor cavity, then shrinkage is prevented, but the wedge assembly design becomes more complex
Solution Approach 1:
The wedge assembly is segmented into distinct functional portions: a tendon-retaining portion with a channel and tapering outer surface for tendon anchorage, and a sheathing-retaining portion with a barbed rim for sheathing engagement. This segmentation allows each portion to be optimized for its specific function while maintaining overall design efficiency
Solution Approach 2:
Different portions of the wedge assembly have different structural characteristics tailored to their specific functions: the tendon-retaining portion has a tapering outer surface for friction-based anchorage, while the sheathing-retaining portion has a barbed rim with enhanced engagement features for positive mechanical retention of the sheathing
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 wedge assembly effectively retains the sheathing within the anchor cavity, eliminating the need for additional corrosion-protection tubes, simplifying installation, reducing costs, and ensuring a liquid-tight seal, thus addressing the issues of sheathing shrinkage and liquid intrusion.
Implementation Method 1
A hook means is formed at an end of the sheathing-retaining portion opposite the tendon-retaining portion. The hook means is suitable for engaging a sheathing of a tendon extending through the channel of the sheathing-retaining portion and the tendon-retaining portion
Implementation Method 2
The outer surfaces of the wedges are juxtaposed against the tapered portion of the cavity. The sheathing-retaining portions are juxtaposed against a wall of the passageway
Data Source
AI summary
A sheathing-retaining article for use with a post-tension anchorage system has a wedge with a tendon-retaining portion and a sheathing-retaining portion. The tendon-retaining portion has a channel extending longitudinally therealong. The channel is suitable for retaining the tendon therein. The tendon-retaining portion has a tapering outer surface with a wide end at one end of the wedge and a narrow end spaced therefrom. The sheathing-retaining portion extends outwardly from the narrow end of the tendon-retaining portion. The sheathing-retaining portion engages a sheathing of a tendon extending through the channel of the wedge.