Post-Tensioning Wedge Assembly with Elastic Ring
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Solution Overview
Problem
In post-tensioned concrete construction, existing wedge systems for anchors face challenges such as the risk of wedges being dropped, limited accessibility due to strand extension and bending, and misalignment issues which can damage the strand or result in an insufficient anchor.
Innovation Solution
A wedge assembly that includes a wedge ring capable of elastic deformation, allowing it to be installed from the side of the strand without threading, and featuring expansion features and guides to facilitate easy coupling and retention, ensuring secure engagement with the strand even when misaligned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wedges are threaded onto the end of the strand after positioning, then secure anchoring is achieved, but the risk of dropping wedges and misalignment damage increases
Solution Approach 1:
The wedge is pre-assembled with the anchor assembly before the strand is positioned in the concrete member. This preliminary assembly ensures proper alignment and prevents wedge dropping during installation, as the wedge is already secured to the anchor rather than being threaded onto the strand end after positioning.
Solution Approach 2:
The wedge and anchor assembly are combined into a single integrated unit before strand installation. This merging eliminates the separate step of threading the wedge onto the strand, reducing the risk of misalignment and damage while maintaining secure anchoring functionality.
2Adaptability or versatility
If the strand extends far from the end of the structure, then the anchor can reach distant reinforcement, but the ability to thread the wedge onto the strand end is limited
Solution Approach 1:
The wedge is pre-assembled with the anchor assembly at a convenient location before the strand is positioned. This eliminates the need to access the far end of the structure for wedge installation, as the wedge is already attached to the anchor which remains accessible at the structure end.
Solution Approach 2:
The wedge assembly approach shifts the installation point from the strand end (far from structure) to the anchor assembly (at structure end). This dimensional change in installation location improves accessibility while maintaining the ability to anchor distant strands.
3Strength
If traditional metal wedges are used, then strong anchoring is achieved, but the installation process is complex and time-consuming
Solution Approach 1:
The wedge and anchor are merged into a pre-assembled unit, eliminating the time-consuming separate operations of positioning the anchor and then threading the wedge onto the strand. This single integrated assembly reduces installation steps while maintaining anchoring strength through the preserved wedge-strand engagement mechanism.
Solution Approach 2:
The wedge-anchor assembly is prepared in advance, converting a multi-step installation process into a single installation action. This preliminary preparation significantly improves installation productivity without compromising the strength of the final anchor 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 wedge assembly provides a secure and efficient method for anchoring strands in post-tensioned concrete, reducing the risk of damage and misalignment, and enabling easier installation by allowing the wedges to be positioned around the strand before tensioning, thus enhancing the stability and reliability of the anchor system.
Implementation Method 1
A wedge assembly that includes a wedge ring capable of elastic deformation, allowing it to be installed from the side of the strand without threading
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A wedge assembly for post tensioning concrete includes one or more wedges and a wedge ring. Each wedge includes an outer surface having a circumferential groove formed thereon. The wedge ring is adapted to fit into the groove of the wedges and retain the wedges to a strand. The wedge ring including a gap adapted to allow the wedge ring to be installed from the side of the wedges. When installed to the strand, the wedges may form a clearance fit maintained by the wedge ring. At least one wedge may include a guide adapted to assist with the separation of the wedges when installed to the strand.