Anti-spalling Concrete Edging with Reinforced Corner
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Solution Overview
Problem
Concrete edges are prone to spalling due to their weakness in tension and shear, and existing anti-spalling edgings with steel strips face issues with bending and anchoring, leading to further spalling sites at the radius of curvature.
Innovation Solution
An anti-spalling edging system featuring a metal strip with a return, down-turn, and cut-outs for anchoring, reinforced with an elongate metallic member extending into the corner to stabilize the edge, and optionally using dowels and reinforcing bars to enhance structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat steel edging is used to protect concrete edges, then the concrete edge is protected from spalling, but the steel strip can become bent away from the concrete creating new spalling sites
Solution Approach 1:
The steel edging is segmented into multiple functional parts: a base strip for concrete contact, a return portion for edge protection, and a down-turn with cut-outs for anchoring. This segmentation allows each part to perform its specific function while maintaining overall structural stability.
Solution Approach 2:
The down-turn with cut-outs is designed to be embedded in the concrete before the concrete sets. This preliminary anchoring action prevents the steel strip from bending away later, ensuring long-term position stability without requiring additional reinforcement.
2Reliability
If the steel strip is reinforced with an in-turned edge or return to protect the concrete edge, then edge spalling is prevented, but the free edge of the return can lift under loading and impact
Solution Approach 1:
The return portion is further segmented by introducing cut-outs that create fingers extending into the concrete. This segmentation provides multiple anchoring points that distribute loads and prevent the return edge from lifting under impact or sustained loading.
Solution Approach 2:
The down-turn with cut-outs provides localized anchoring quality at critical points where the concrete meets the steel. The cut-outs create fingers that embed into the concrete, providing localized grip that prevents the return portion from detaching while maintaining the overall protective function.
3Strength
If the down-turn is turned down with cut-outs for anchoring in the slab, then anchoring strength is improved, but the radius of curvature at the abutment creates additional spalling sites
Solution Approach 1:
The cut-outs are strategically positioned to provide anchoring faces that extend through the return portion. These faces create localized bonding zones that distribute stresses away from the curved abutment regions, reducing stress concentration at the problematic radius of curvature locations.
Solution Approach 2:
The cut-outs create a third dimension of anchoring by extending fingers vertically into the concrete depth. This dimensional addition provides anchoring strength that compensates for the stress concentration issues at the curved abutment surfaces, effectively decoupling the anchoring function from the problematic curvature regions.
Data Source
AI summary
An anti-spalling edging comprising: a metal strip 21,31 adapted for concrete to be cast against, a return 22,32 along a top edge of the strip and forming a corner with the metal strip, a down-turn 23,33 from the edge of the return spaced from the strip and cut-outs in 26,36 the down-turn for anchoring it in the concrete and an elongate metallic member 201,202 extending in the corner, fixed to the strip and the return for reinforcement of the anti-spalling edge at the corner.