Removable Expansion Joint for Concrete Slab Formwork
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Solution Overview
Problem
Existing shuttering systems for concrete slabs face challenges in renovation due to damage from shrinkage-induced stresses and improper positioning, leading to costly and labor-intensive processes for removing and replacing expansion joints.
Innovation Solution
The expansion joint system incorporates removable longitudinal segments with abradable polymer or composite materials, featuring a U-shaped cross-section and vertical offset, allowing for easy replacement and maintenance by accessing fittings such as apertures and rods for securing and unscrewing the segments, ensuring stability and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the expansion joint is made permanent and integral with the concrete slabs, then the joint stability is improved, but the ease of repair deteriorates when damage occurs
Solution Approach 1:
The expansion joint is divided into multiple segments (first longitudinal segment and second longitudinal segment) that can be independently removed and replaced. Each segment is separable from the concrete slabs through removable connections, allowing targeted repair without affecting the entire joint structure.
Solution Approach 2:
The joint transitions from a static permanent connection to a dynamic removable connection system. The segments can be securely attached during normal operation to maintain stability, and easily detached when repair is needed, providing adaptability between stability and ease of repair states.
2Stability of the object's composition
If the longitudinal segments are permanently fixed to prevent movement, then the joint stability is improved, but the ease of operation deteriorates during renovation
Solution Approach 1:
The joint is segmented into removable sections with dedicated connection points. During normal operation, the segments are fixed to provide stability. During renovation, the segmented design allows operators to easily access and remove specific segments without disturbing the entire joint or requiring complex demolition procedures.
Solution Approach 2:
The longitudinal segments can be extracted from the joint structure through removable connections. This extraction capability allows for easy operation during renovation while maintaining joint stability during normal use, as the segments can be taken out without requiring destruction of the concrete slabs or surrounding structure.
3Strength
If the expansion joint is removed completely and filler material is poured, then the structural integrity is improved, but the loss of time and loss of substance increase
Solution Approach 1:
Instead of completely removing and replacing the entire expansion joint with filler material, the damaged segments can be selectively removed and recovered for replacement. This approach maintains the functional integrity of the joint while reducing the time and material loss associated with complete removal and reconstruction.
Solution Approach 2:
The joint is divided into removable segments that can be individually replaced rather than removing the entire joint structure. This segmentation allows for minimal disruption to the surrounding concrete slabs and reduces both the time required for renovation and the material waste associated with complete removal.
4Ease of repair
If the longitudinal segments are made removable for easy replacement, then the ease of repair is improved, but the device complexity increases
Solution Approach 1:
The expansion joint is segmented into removable sections with standardized connection interfaces. This segmentation simplifies the repair process by allowing targeted removal and replacement of damaged segments. The modular design reduces device complexity compared to complete removal and replacement, as only the necessary segments need to be accessed and replaced.
Solution Approach 2:
The removable connection system allows segments to be extracted without requiring complex demolition procedures. The extraction mechanism is designed to be simple and direct, accessing fittings through openings in the concrete slabs. This approach improves ease of repair while keeping device complexity manageable by avoiding the need for complex removal and installation procedures.
Data Source
AI summary
An expansion joint (1) for a concrete slab formwork system, said joint comprising first and second longitudinal elements (2, 3), arranged side-by-side in the same horizontal plane, and intended to each form an integral part with an upper and horizontal edge of a concrete slab, the first and second longitudinal elements (2, 3) comprise arrangements (5, 6, 7) opening on their upper horizontal walls and enabling at least a portion (2a, 3a) of each of the first and second longitudinal elements (2, 3) to be withdrawn for replacement thereof. The first longitudinal element (2) comprises a stack of three layers of material (2a, 2b, 2c), with an intermediate layer (2b) having a smaller width than that of the two other layers (2a, 2c) such that the first longitudinal element (2) has a U-shaped cross-section, and the second longitudinal element (3) comprises a stack of three complementary layers of material (3a, 3b, 3c), with an intermediate layer (3b) having a larger width than that of the two other layers (3a, 3c) so as to form a transverse projection that is able to fit in the recess of the U-shape of the first longitudinal element (2).