Column Reinforcement Using Fiber Anchors Through Blocking Structures
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Solution Overview
Problem
Older reinforced concrete structures without lateral reinforcement are at risk of catastrophic failure during earthquakes due to inadequate shear capacity, and traditional retrofitting methods are costly and disruptive, especially when blocking structures prevent complete wrapping of columns with fibrous sheets.
Innovation Solution
A method involving the creation of strategically located openings in columns and blocking structures to allow insertion of fiber anchors and application of fibrous sheets, which confine the column perimeter without requiring extensive demolition, enhancing shear capacity and ductility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional retrofitting methods are used to reinforce columns, then shear capacity is improved, but construction cost and structural disruption increase significantly
Solution Approach 1:
The retrofitting process is segmented into discrete steps: creating openings at specific locations, inserting fiber anchors at predetermined intervals, and applying fibrous sheets in sections. This segmentation allows the work to be performed in manageable portions without requiring complete demolition or prolonged structural disruption.
Solution Approach 2:
The reinforcement is applied locally at critical areas where openings are created and fiber anchors are inserted. The fibrous sheets are wrapped around specific portions of the column perimeter that are most vulnerable to shear failure, concentrating the reinforcement where it is most needed rather than requiring complete column replacement.
2Reliability
If complete wrapping of columns with fibrous sheets is performed, then reinforcement effectiveness is maximized, but blocking structures must be removed which increases cost and disruption
Solution Approach 1:
Instead of requiring complete wrapping around the entire column perimeter, the method applies partial wrapping where fibrous sheets are secured to the accessible exterior perimeter surface portion. The fiber anchors inserted through openings in the blocking structure provide the necessary anchorage to achieve effective reinforcement without removing the blocking structures.
Solution Approach 2:
Fiber anchors serve as intermediaries that connect the fibrous sheets to the column through the blocking structure. These anchors are inserted through openings in the blocking structure and secured to the column, allowing the fibrous sheets to be effectively attached without requiring removal of the blocking structures that would otherwise prevent complete wrapping.
3Ease of manufacture
If blocking structures are removed to access the entire column perimeter, then complete wrapping is enabled, but structural integrity during demolition is compromised and cost increases
Solution Approach 1:
Openings are created in the blocking structures at predetermined locations before applying the fibrous sheets. These openings are positioned to provide access to the column perimeter at critical locations while maintaining the overall integrity of the blocking structures. The fiber anchors are then inserted through these pre-created openings to secure the reinforcement.
Data Source
AI summary
A method of reinforcing a column positioned proximate a blocking structure that prevents wrapping a sheet material completely about the column. The column includes an exterior perimeter surface portion extending between first and second intersections with the blocking structure so that the exterior perimeter surface portion is accessible from one side of the blocking structure. A first opening is formed in the column and/or the blocking structure. The first opening is located proximate the first intersection of the exterior perimeter surface portion of the column and the blocking structure. A portion of the first fiber anchor is inserted through the first opening. The first fiber anchor has at least a first end. The first end of the first fiber anchor is secured to the exterior perimeter surface portion of the column. An outer fibrous sheet is applied to the exterior perimeter surface portion.