Anti-spalling Edging With Segmented Down-turn Anchors
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Concrete edges are prone to spalling due to their weakness in tension and shear, and existing anti-spalling edgings, such as flat steel edgings with returns, can fail under loading and impact, creating new spalling sites at the radius of curvature where the down-turn meets the top surface.
Innovation Solution
An anti-spalling edging system featuring a metal strip with a return and down-turn, where the down-turn has cut-outs with wide edges and narrow fingers that extend through the return, providing stabilization and anchoring in the concrete, and optionally joined at their ends for added stability during installation and curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat steel edging with return is used, then the edge of the slab is protected, but the free edge of the return can lift under loading and impact
Solution Approach 1:
The down-turn is segmented into multiple narrow fingers that extend through the return, creating multiple anchoring points in the concrete. This segmentation distributes the loads and prevents the free edge from lifting as a single unit, thereby improving resistance to loading and impact while maintaining edge protection.
2Reliability
If the free edge of the return is turned down with cut-outs for anchoring, then anchoring in the slab is improved, but a radius of curvature is created which creates new potential spalling sites
Solution Approach 1:
Instead of creating a continuous down-turn with a radius of curvature, the invention provides local anchoring quality through discrete narrow fingers with sharp edges. These fingers penetrate the concrete at specific locations without creating curved transition zones, thereby achieving secure anchoring while eliminating the radius of curvature that would create new spalling sites.
3Reliability
If narrow fingers are provided in the down-turn, then anchoring in concrete is improved, but stability during installation and casting may be reduced
Solution Approach 1:
The narrow fingers are joined at their distal ends in the vertical dimension, creating a stable three-dimensional structure. This joining at the bottom provides lateral support and prevents the fingers from bending or deforming during installation and casting, while still allowing the edges to provide effective anchoring when concrete is cast against them.
Data Source
Figure 1
Figure 2
AI summary
An anti-spalling edging comprising a metal strip (21, 31) having a return (22, 32) along a top edge and a down-turn (22, 33) from the return (22, 32), spaced from the strip. The down-turn (23, 33) is provided with cut-outs (24, 34) for anchoring the edging in concrete, with the cut- outs (24, 34) being arranged to provide faces against which the concrete abuts when cast level with the outer surface of the return (22, 32). In use the anti-spalling edging may be provided on a joint (1) between two concrete slabs (S2, S3). As such a pair on anti-spalling edgings will be provided, the two metal strips abutting with the returns (22, 32) extending in opposite directions on lay of the concrete. The joint (1) can include dowels (6) extending into the two sections of concrete for vertical load transfer in use.