Shear Connection Sleeve with Expanded Cross-Section
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Solution Overview
Problem
Existing shear force connection devices for reinforced concrete components often lead to crack formation due to tensile stresses, which can result in corrosion damage, especially in thinner components and when moisture penetrates through cracks, limiting the serviceability of the structural elements.
Innovation Solution
The device features an element sleeve with an inner cross-section that widens along its outer section to accommodate the shear force mandrel, allowing it to deflect without exerting pressure on the concrete above, reducing tensile stresses and crack formation, and can include multiple partial shear force mandrels for improved load distribution and serviceability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the shear force mandrel is pushed into the element sleeve with one end, then the transverse force is transmitted to the load-bearing component, but tensile stresses form in the concrete material causing cracks to form near the element sleeve
Solution Approach 1:
The element sleeve has different inner cross-sectional dimensions at different locations: a first inner cross-section at the outer section and a second inner cross-section at the inner section. This local variation in geometry allows the sleeve to accommodate the shear force mandrel while reducing tensile stresses in the concrete near the edge, thereby preventing crack formation while maintaining force transmission capability.
2Length of moving object
If the concrete layer above the element sleeve is thinner, then the panel-shaped component is thinner, but crack formation becomes more pronounced and critical
Solution Approach 1:
By providing different inner cross-sectional dimensions at different locations of the element sleeve, the design allows thinner concrete slabs to be used without excessive reinforcement. The varied geometry distributes stresses more favorably, preventing crack formation even when the concrete cover above the element sleeve is reduced.
3Object-affected harmful factors
If reinforcement is increased to absorb tensile stresses, then crack formation is reduced, but the component becomes heavier and more complex
Solution Approach 1:
The element sleeve with varying inner cross-sections prevents crack formation through its geometric design rather than relying on increased reinforcement. This approach maintains the component weight at acceptable levels while ensuring serviceability, as the sleeve geometry itself distributes stresses to avoid tensile cracking in the concrete.
Data Source
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AI summary
In a device for shear connection of a slab-shaped component (10) made of reinforced concrete, such as a platform or a flight of stairs, to a second component, such as a stairwell wall, comprising an element sleeve (30) and a shear dowel (40), wherein the element sleeve (30) is designed for flush embedding in the concrete of the slab-shaped component (10) and is made of a compression-resistant material, and wherein the shear dowel (40) can be inserted into the element sleeve (30) from the outside, it is provided according to the invention that the inner cross-section of the element sleeve (30) is wider along an outer section (a) at least in one direction than the inner cross-section along an inner section (b), and/or that the shear dowel (40) comprises several tubular partial shear dowels that can be inserted side by side into the element sleeve (30).