Post-Tensioning Wedge Assembly With Retention 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 dropping wedges, limited ability to thread wedges onto strands due to bending, and misalignment issues which can damage the strand or result in insufficient anchoring.

Innovation Solution

A wedge assembly featuring a circumferential groove on the wedge's outer surface and a wedge ring that fits into the groove, allowing perpendicular installation and retention, with a gap for expansion to secure the wedge to the strand, and optional guides for separation and elastic expansion to facilitate easy installation and maintain a clearance fit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If wedges are threaded onto the end of the strand, then the wedge can be secured to the strand, but the ability to thread the wedge is limited due to strand bending and misalignment risks

Engineering Contradiction:

Improveease of wedge installationVSAvoidrisk of wedge dropping and strand damage

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The wedge assembly is divided into separate components: the wedge body and the wedge ring. The wedge ring can be independently installed onto the strand using a tool, and then the wedge is placed into the ring. This segmentation allows the wedge to be secured without threading it directly onto the strand end, eliminating the threading limitation while maintaining secure attachment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The wedge ring acts as an intermediary component between the wedge and the strand. Instead of directly threading the wedge onto the strand (which is difficult and risky), the wedge ring serves as a mediator that can be easily installed onto the strand and then receives the wedge, facilitating secure attachment without direct threading.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If wedges are made to engage the strand through threading, then secure anchoring is achieved, but misalignment during installation can damage the strand or result in insufficient anchoring

Engineering Contradiction:

Improvealignment precision between wedge and strandVSAvoidstrand damage from misalignment

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

By separating the wedge and wedge ring into independent components, the system eliminates the alignment sensitivity inherent in threading operations. The wedge ring can be installed independently with minimal alignment requirements, and the wedge is then placed into the ring without requiring precise alignment with the strand, thereby preventing strand damage from misalignment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The wedge ring serves as an intermediary that decouples the alignment requirements from the final anchoring function. It can be installed onto the strand with minimal precision requirements, and the wedge is then secured within the ring without requiring precise alignment with the strand axis, thereby eliminating misalignment-related strand damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If a traditional wedge design without groove and ring is used, then the structure is simpler, but the wedge cannot be easily retained to the strand and may drop

Engineering Contradiction:

Improvewedge assembly structureVSAvoidwedge retention to strand

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The wedge assembly is segmented into the wedge body and wedge ring components. The wedge ring provides a retention mechanism that prevents the wedge from dropping off the strand end. This segmentation adds minimal complexity while significantly improving reliability, as the wedge ring can be easily installed and securely holds the wedge in position.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The wedge ring acts as an intermediary retention component between the wedge and the strand. It provides a mechanical interface that secures the wedge to the strand without requiring complex threading or attachment mechanisms, thereby preventing wedge drop with minimal added complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 solution enhances the ease and accuracy of wedge installation, reduces the risk of damage, and ensures a secure anchor by allowing wedges to be positioned and retained on the strand without threading, addressing the limitations of existing systems.

Implementation Method 1

expanding the gap of the wedge ring such that the wedge passes through the gap of the wedge ring

Methodology Applied

Scientific EffectElastic expansion: Elasticity

Data Source

PatentUS10106983B2Wedge for post tensioning tendon

Publication Date: 2018.10.23 SORKIN FELIX

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.