Hollow Anchor with Irregular Interior for Grout Reduction

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Solution Overview

Problem

Existing anchor arrangements for pre-stressed concrete structures face challenges in accessibility and grout retention, particularly when the anchor is not accessible after the structure is formed, and require excessive grout to secure multi-wired tendons.

Innovation Solution

A hollow anchor with multi-wired tendons featuring expanded sections that allow insertion from the opposite side of the structure, combined with an irregular internal and external surface for grout retention, reducing the need for grout and enabling efficient tendon placement and retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If tendons are inserted from the same side as the anchor location, then the anchor is easily accessible during installation, but the bellied part must be wide and can only be inserted from one side, reducing flexibility

Engineering Contradiction:
Improveanchor accessibilityVSAvoidinsertion direction flexibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The tendon is inserted from the opposite side to the anchor location, reversing the conventional approach. The expanded section is positioned at the insertion end rather than the anchor end, allowing the tendon to be fed through the structure from the far side and secured in the anchor from the near side.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of manufacture

If conventional smooth-walled anchors are used, then tendon insertion is straightforward, but excessive grout is required to secure multi-wired tendons and prevent movement

Engineering Contradiction:
Improvetendon insertion simplicityVSAvoidgrout quantity
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The anchor interior features localized irregularities and rough surfaces at specific positions rather than being uniformly rough throughout. These localized features create friction and mechanical interlocking at critical points along the tendon length, providing effective retention with reduced overall grout consumption.

Inventive Principle:
Principle #3Local quality

3Reliability

If irregularities are added to the anchor interior surface to retain grout and tendons, then tendon retention improves, but manufacturing complexity increases

Engineering Contradiction:
Improvetendon retentionVSAvoidanchor interior structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The irregularities are distributed as discrete, spaced features along the anchor interior rather than forming a continuous complex surface. This segmentation allows for simpler manufacturing processes while still providing adequate retention at multiple locations along the tendon length.

Inventive Principle:
Principle #1Segmentation

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 solution allows for efficient tendon placement and retention within the anchor, reducing grout requirements and preventing tendon movement, while enabling more tendons to be inserted through a duct, enhancing the stability and accessibility of the anchor arrangement.

Implementation Method 1

the irregularities with which, in use, the grout is arranged to cooperate to assist in retaining the tendons

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2909392B1An anchor arrangement
Publication Date: 2017.12.06 CCL STRESSING INT
  • EP2909392B1 patent drawingFigure 1~2
  • EP2909392B1 patent drawingFigure 3~4
  • EP2909392B1 patent drawingFigure 5~8

AI summary

Tendons having open sections (26) are inserted through a cylindrical surface (18) of an anchor housing ten. The tendons are secured therein by grout which cooperates with irregularities (30) formed on the interior surface of the anchor housing.