Cable Anchorage Bedding Material Design
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Solution Overview
Problem
Existing cable anchorages suffer from damage due to static and dynamic deflections, leading to fretting and reduced service life, and require larger dimensions to accommodate angular deviations, increasing costs and maintenance efforts.
Innovation Solution
A cable anchorage design featuring a flexural and/or elastic bedding material with a durometer range of 10 to 70 Shore, placed between the strand and the anchor block, to form a bedding cushion that absorbs bending stresses and reduces oscillatory movements, allowing for shorter anchorage lengths and greater deflection angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a curved deviator element is used at the anchorage exit to accommodate strand deviations, then the maximum span of cable which can be anchored is increased, but the overall dimension of the anchorage is considerably increased and supplemental costs are induced
Solution Approach 1:
The patent extracts the deviator function from a separate supplemental component and integrates it directly into the anchorage block structure. The curved surface is formed as part of the anchorage block itself, eliminating the need for additional trumpet-shaped parts while maintaining the ability to accommodate cable deviations and extend maximum cable span.
Solution Approach 2:
The patent merges the deviator element with the anchorage block into a single integrated structure. The curved surface for guiding strands is combined with the anchorage block body, reducing overall anchorage dimensions and eliminating supplemental components while preserving adaptability for various cable spans.
2Adaptability or versatility
If the anchorage is designed to accommodate greater angular deviations, then more flexible deck structures can be used, but the anchorage dimensions must be increased
Solution Approach 1:
The patent utilizes the axial dimension of the anchorage block to accommodate angular deviations. By extending the curved surface axially through the anchorage block, the design allows strands to enter at various angles without increasing the transverse dimensions of the anchorage, thus maintaining compact size while improving adaptability.
Solution Approach 2:
The patent employs a curved surface within the anchorage block that guides strands through a controlled arc. This curvature allows strands to accommodate angular deviations by following the curved path, enabling greater adaptability for flexible deck structures without requiring proportionally larger anchorage dimensions.
3Device complexity
If conventional anchorage design is used, then the structure is simple, but fretting and work-hardening occur due to repeated impacts, significantly reducing serviceable life
Solution Approach 1:
The patent incorporates a bedding material layer between the strand and the anchorage block structure. This cushioning layer is placed in advance to prevent direct contact and repeated impacts between the strand and hard surfaces, thereby eliminating fretting and work-hardening while maintaining a relatively simple anchorage structure.
Solution Approach 2:
The patent introduces a bedding material as an intermediary substance between the strand and the anchorage block. This intermediary layer absorbs impact forces and prevents direct mechanical contact, thereby protecting the strand from fretting damage and extending serviceable life without significantly complicating the anchorage design.
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 elastic bedding material effectively transfers bending stresses to the anchor block, reducing damage and allowing for more flexible cable anchoring with reduced anchorage dimensions, enabling longer cable spans and lower maintenance costs.
Implementation Method 1
a flexural and/or elastic bedding material having a durometer at 23° C. in the range 10 to 70 Shore, so as to form a bedding cushion extending substantially around the strand in the strand-channel and axially along a bedding region of the axial length of the strand-channel
Implementation Method 2
reducing localized damage which might otherwise occur as a result of persistent localized fretting of the strand against an abrupt edge
Data Source
AI summary
A cable anchorage anchors a cable, for example a stay cable having multiple strands (50), against a longitudinal tension force. The anchor block (11) of the anchorage includes multiple channels, through which the strands (50) are individually threaded. Once in position and tensioned, the space around the strands (50) in the anchor block (11) is injected with a liquid, such as a polyurethane, which subsequently sets to form a tough elastic bedding material (51) within the anchor block (11). The elastic bedding material (51) has a durometer at 23° C. in the range 10 to 70 Shore, so as to form bedding cushion extending substantially around the strand (50) in the strand-channel (6) along a bedding region (54) of strand-channel (6), the bedding cushion reducing the bending stresses in the strand (50) by absorbing bending stresses along the bedding region (54).