Anchorage Assembly for Concrete Structures
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Solution Overview
Problem
Existing anchorage systems for concrete structures with pre-stressed tendons require extra free length outside the structure for tensioning, which complicates maintenance and inspection, and lacks efficient protection for unsheathed strands during de-tensioning.
Innovation Solution
An anchorage assembly with a two-part design where the tendon's end portion passes through individual perforations of an anchor head and an intermediate portion is placed within a tubular member, allowing for a removable locking system and a filler compound to seal and protect the strands, enabling de-tensioning and re-stressing without bulky protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If extra free length of tendon is placed outside the concrete structure for tensioning, then the tendon can be properly tensioned, but it requires bulky protection and complicates maintenance operations
Solution Approach 1:
The anchor head is designed to be inserted within the tubular member, creating a nested configuration where the anchorage components are housed inside the structure rather than extending outside. This eliminates the need for bulky external protection while maintaining full tensioning functionality.
Solution Approach 2:
The invention changes the spatial arrangement by moving the anchorage from an external configuration to an internal one, utilizing the three-dimensional space within the tubular member. This dimensional repositioning allows the anchor head to be accessed and operated on from the interior of the structure.
2Reliability
If anchor head has larger diameter than opening in bearing plate, then anchorage is secure, but de-tensioning requires removing the anchor head from the structure
Solution Approach 1:
The locking system is designed to be removable and reversible, allowing the anchorage to transition between locked (secure) and unlocked (accessible) states. This dynamic capability enables both secure anchoring during tensioning and easy access during maintenance operations without compromising structural integrity.
Solution Approach 2:
The locking system can be temporarily removed to allow anchor head extraction for maintenance, then reinstalled to restore security. This temporary discarding and subsequent recovery of the locking mechanism enables maintenance operations while maintaining long-term anchorage security.
3Ease of operation
If strands are exposed outside the structure, then tensioning is accessible, but corrosion protection is compromised
Solution Approach 1:
The strands are nested within the tubular member throughout their length, with only the anchor head portion accessible for tensioning operations. This nested configuration provides continuous corrosion protection through the tubular enclosure while maintaining operational accessibility through the removable locking system.
Solution Approach 2:
The tubular member acts as an intermediary protective barrier between the strands and the external environment. It provides corrosion protection while allowing the anchor head to be accessed and operated on through the removable locking mechanism, thus mediating between protection and accessibility requirements.
Data Source
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AI summary
The invention relates to anchorage assembly (20), comprising a tendon (10) made of strands (12), a first part (C) with the strands (12) passed through individual perforations of an anchor head (30), a second part (B) with an intermediate portion of the tendon (10) placed within a first tubular member (24) able to receive a removable protective product (38). The strands (12) have said end portion passed through on one hand an opening (27) formed in a bearing plate (26) disposed within the structure (42), and on the other hand said individual perforations of said anchor head (30) which is placed outside of the front face (40) of the structure (42), wherein the anchor head (30) has an outside diameter (D5) smaller than the diameter (D4) of said opening (27) of the bearing plate (26), wherein it further comprises a removable locking system (32) interposed between said anchor head (30) and said bearing plate (26), the presence of the locking system (32) preventing thereby the anchor head (30) to enter said opening (27) and said second tubular member (24) outlet.