Cable Anchorage Seal Element and Prestressing System
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Solution Overview
Problem
Existing cable anchorages for tensioned cables, such as those used in bridges and buildings, face challenges in easy installation and replacement due to the need for precise control of cable length and the difficulty in achieving a safe and reliable sealing effect, particularly when replacing individual strands, which often requires significant anchorage length and complex procedures.
Innovation Solution
The cable anchorage design incorporates a recessed region with a stop element that deforms the sheath end to form a radially protruding bulge, allowing for a compressed seal and mechanical anchoring, which simplifies the installation and tensioning process by ensuring precise positioning and enhancing sealing properties, thereby reducing the required anchorage length and facilitating easier replacement of strands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional cable anchorage design is used with individual seal elements held in recessed regions, then sealing is provided for each strand, but the anchorage length must be sufficient to ensure the sheathed portion protrudes beyond the seal element after locking, which makes the anchorages larger and heavier
Solution Approach 1:
Instead of having the seal element protrude beyond the sheathed portion as in conventional designs, the patent inverts the arrangement by having the sheathed portion protrude beyond the seal element. The seal element is positioned to seal around the sheathed portion at a location where the sheathed portion extends beyond the anchorage, eliminating the need for excessive anchorage length while maintaining reliable sealing.
Solution Approach 2:
The patent changes the spatial arrangement by positioning the seal element to act on the sheathed portion in a different dimensional configuration. The seal element is arranged to seal around the sheathed portion at its exit from the anchorage, utilizing the dimensional space more efficiently to reduce the overall anchorage length while maintaining sealing effectiveness.
2Reliability
If a conventional cable anchorage design is used, then strands can be anchored, but replacement of individual strands requires precise control of cable length and complex procedures, reducing ease of operation
Solution Approach 1:
The patent applies segmentation by providing individual seal elements for each strand channel, allowing independent replacement of individual strands without affecting other strands. Each seal element can be independently removed and reinstalled, simplifying the replacement procedure and eliminating the need for complex precise length control across the entire cable assembly.
Solution Approach 2:
The patent incorporates preliminary action by pre-positioning the seal elements in the anchorage body such that they are ready to seal around the sheathed portions of strands as they are inserted. This preliminary arrangement of seal elements eliminates the need for complex post-installation sealing procedures and precise length control during replacement operations.
3Reliability
If adequate anchorage length is provided to ensure sheathed portion protrusion, then sealing reliability is maintained, but the anchorages become larger and heavier, increasing weight of stationary object
Solution Approach 1:
The patent inverts the conventional arrangement where the seal element protruded beyond the sheathed portion. Instead, the sheathed portion is designed to protrude beyond the seal element at the anchorage exit, allowing the seal element to be smaller and positioned more compactly within the anchorage body, thereby reducing the overall weight of the stationary anchorage structure.
Solution Approach 2:
The patent changes the critical parameter from seal element protrusion distance to sheathed portion protrusion distance. By changing which component protrudes and by how much, the anchorage dimensions and weight can be optimized while maintaining the necessary sealing reliability through the repositioned seal element.
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 a shorter anchorage length, reducing installation complexity and costs, while ensuring reliable sealing and mechanical stability, even under thermal variations and creep, thus enabling the use of cable anchorages in structures with limited space and improving maintenance accessibility.
Implementation Method 1
the sheath end deformed so as to form an outwardly radially protrusion
Implementation Method 2
which is thereby outwardly radially compressed by said deformed sheath end
Data Source
Figure 1~2
Figure 3
Figure 4~6
AI summary
The present invention concerns a cable anchorage comprising at least one axial channel (6) for accommodating an elongated element (5) with a sheathed portion (5a) and an unsheathed end portion (5b), wherein the channel (6) between a first channel end (3), proximal to a running part of the elongated element, and a second channel end (1) equipped with immobilising device (12), a seal element (26) in the channel (6), a stop element (9) having an end facing said seal element (26) which defines a shoulder (9a), so that an axial displacement of the of the elongated element (5) with respect to the stop element (9) in said channel (6) is possible up to the abutment of the end of the sheathed portion (5a) against the shoulder (9a), creating thereby an abutment position of the elongated element (5) in said channel (6).