Anchorage Unit for Prestressed Structural Strengthening
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Solution Overview
Problem
Current methods for additional prestressing of structures face challenges such as difficulty in accessing structural components, high construction costs due to the need for machining or drilling, and limited ability to apply prestress to major sections of the structure without breaking out parts of the structure.
Innovation Solution
An anchorage unit that allows tensioning of prestressing members adjacent to a regular section, with fixing means on one side and anchoring means on the opposite side, enabling compressive stress application across a larger area without requiring additional adaptations or structural modifications, and featuring a compact cast iron design with sealing capabilities to ensure effective bonding with concrete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional anchorages are positioned at the ends of the structure to apply additional prestress over the longest possible distance, then the prestressing effect is maximized, but it becomes difficult to access structural components and position tensioning jacks near obstructions such as structural walls, columns or bracings
Solution Approach 1:
The patent inverts the conventional anchorage configuration by positioning the anchorage unit with its fixing means adjacent to the obstruction rather than away from it. The anchorage unit is designed so that the fixing means are located at one end adjacent to the obstruction, while the anchoring means are positioned at the other end to receive the prestressing member. This inversion allows the anchorage to be installed in locations previously inaccessible to conventional methods, enabling prestress application near structural walls, columns, or bracings without requiring additional openings or modifications to the structure.
2Strength
If metal bosses are fabricated with serrated bearing surfaces through machining or welding steel wires to achieve sufficient friction coefficient, then the anchorage bearing capacity is improved, but construction costs increase significantly
Solution Approach 1:
The patent employs a disposable anchorage unit designed as a complete, pre-fabricated component that eliminates the need for expensive post-fabrication modifications. Instead of machining serrated surfaces or welding steel wires to metal bosses, the anchorage unit is provided as a ready-to-install component with integrated fixing means and anchoring means. This approach replaces complex, costly manufacturing operations with a simpler, more economical solution where the anchorage unit is installed in its entirety, significantly reducing construction costs while maintaining adequate anchorage bearing capacity.
3Ease of operation
If openings or windows are created in the structure to allow bosses to be installed, then accessibility for boss installation is improved, but structural integrity is compromised and construction complexity increases
Solution Approach 1:
The patent applies preliminary action by designing the anchorage unit to be installed in its complete, pre-fabricated form without requiring any preliminary modifications to the structure such as openings or windows. The anchorage unit is provided with integrating fixing means that can be directly attached to the structural component and anchoring means that can receive the prestressing member, eliminating the need for pre-prepared openings. This approach maintains structural integrity while providing sufficient accessibility for installation by allowing the anchorage unit to be positioned and secured in its entirety without compromising the structure.
4Productivity
If the anchorage unit is designed with fixing means and anchoring means on opposite sides to enable tensioning adjacent to regular sections, then prestress can be applied to major sections without breaking out structure, but the device complexity increases
Solution Approach 1:
The patent merges the fixing means and anchoring means into a single integrated anchorage unit that functions as a complete system. The fixing means are provided at one end of the unit to attach to the structural component, while the anchoring means are positioned at the other end to receive the prestressing member. This merging of functions into a unified component simplifies the overall system compared to separate fixing and anchoring devices, while still enabling efficient prestress application to major sections of the structure without requiring structural break-out work.
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
Enables efficient application of prestress to a major section of the structural component, reducing construction costs and avoiding the need for drilling or breaking out, while maintaining effective anchorage near obstructions, allowing for better distribution of forces and ease of tensioning and retensioning.
Implementation Method 1
Additional prestressing is a known method for strengthening or repairing concrete or masonry structures and has formed the subject of standard NFP95-104. It involves generating prestressing forces by putting reinforcing members into tension
Implementation Method 2
To allow such bosses to have a surface with a sufficiently high friction coefficient bearing on a concrete structural component, this bearing surface must be serrated by machining it or by welding steel wires to it
Data Source
AI summary
The invention therefore proposes an anchorage unit for anchoring at least one prestressing member, capable of being tensioned, onto a structural component to be strengthened or repaired by additional prestressing. The anchorage unit includes means of fixing onto the structural component and means of anchoring the prestressing member located adjacent to a first side of the anchorage unit oriented towards a regular section of the prestressing member. The fixing means are located adjacent to a second side, opposite the first side, of the anchorage unit, which is so provided that it may be put into traction when the prestressing member is tensioned.