Pre-fabricated Anchoring Device for Prestressed Cast Wall Corrosion Protection
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Solution Overview
Problem
The manufacturing process of prestressed diaphragm walls is complex and prone to uncertain anchoring quality due to heterogeneities in concrete, which can lead to localized defects and corrosion of prestressing cables, affecting the wall's capacity and safety.
Innovation Solution
A pre-fabricated anchoring device with anti-corrosion coatings and a sealing material, such as ultra-high performance fiber mortar, is used to ensure effective anchoring and protection of prestressing reinforcements, simplifying the manufacturing process and preventing corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal sheaths forming prestressing conduits are inserted into the reinforcement cage and prestressing cables are threaded and anchored, then the diaphragm wall can be prestressed to reduce its thickness, but the manufacturing process becomes complex and the anchoring quality becomes uncertain due to concrete heterogeneities
Solution Approach 1:
The patent combines multiple functions into a single integrated anchoring device: the prestressing reinforcement, anti-corrosion coating, and sealing portion are merged into one pre-fabricated unit. This eliminates the need for separate metal sheaths, conduits, and anchoring components, thereby simplifying the manufacturing process while maintaining the prestressing function that reduces wall thickness.
Solution Approach 2:
The anchoring device is pre-fabricated with anti-corrosion coating and sealing material applied before installation. The prestressing reinforcement is pre-coated and pre-assembled, ensuring quality control is established beforehand rather than during the complex on-site installation process, thus reducing manufacturing complexity while ensuring reliable anchoring.
2Reliability
If prestressing cables are anchored in concrete, then the diaphragm wall can be prestressed, but the anchoring quality is uncertain due to localized defects such as inclusions of water, drilling mud or soil in the concrete
Solution Approach 1:
The patent introduces a sealing material as an intermediary between the prestressing reinforcement and the concrete. This sealing portion surrounds the reinforcement and creates a protective barrier that isolates the anchoring interface from concrete heterogeneities, water, drilling mud, and soil inclusions, thereby ensuring reliable anchoring quality despite adverse environmental factors.
Solution Approach 2:
The anchoring device uses composite material construction with anti-corrosion coating (such as epoxy or polyethylene) combined with sealing material (such as cement grout or specialized sealants). This composite structure provides both corrosion protection and reliable bonding to concrete, overcoming the limitations of single-material solutions and ensuring consistent anchoring quality despite concrete defects.
3Ease of manufacture
If prestressing cables are exposed during construction, then they can be installed and anchored, but they are subject to external aggressions such as corrosion which significantly impacts the capacity and safety of the wall
Solution Approach 1:
The anti-corrosion coating is applied to the prestressing reinforcement during pre-fabrication before installation. This preliminary protective action ensures that the reinforcement is already protected when installed, eliminating the need for additional corrosion protection measures during construction while maintaining ease of installation. The coating is applied under controlled conditions ensuring uniform coverage.
Solution Approach 2:
The anti-corrosion coating acts as an intermediary layer between the prestressing reinforcement and the corrosive environment. This protective barrier prevents direct contact between the metal reinforcement and corrosive agents such as water, chloride ions, and other aggressive substances, thereby protecting the structural integrity and safety of the diaphragm wall while allowing easy installation of the pre-coated device.
Data Source
Figure 1
Figure 1A~1C
Figure 2
AI summary
The invention relates to an anchor device for a prestressed cast wall (2), comprising at least one prestressing reinforcement (3) and a sleeve (5) surrounding said at least one prestressing reinforcement (3) and forming an anchor for said at least one prestressing reinforcement (3) in the cast wall (2), a length (Ld) of the anchor sleeve (5) being strictly less than a length (La) of said at least one prestressing reinforcement (3), the anchoring sleeve (5) comprising a sealing material arranged in such a way as to coat each prestressing reinforcement (3), the anchor device (1) comprising an anti-corrosion coating of each prestressing reinforcement (3).