Sinusoidal Formwork Expansion Joint for Concrete Slab Stress Distribution
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Solution Overview
Problem
Existing concrete slab formwork systems with non-linear expansion joints fail to distribute stresses uniformly across the slab thickness, leading to disorders such as cracks and damage near the joints due to uneven concrete pouring and vehicle impacts.
Innovation Solution
A formwork system with sinusoidal expansion joints that maintain continuity over the entire height of the joint, ensuring that vehicle wheels remain supported on the slab surface and preventing concrete from extending unevenly, thus distributing stresses uniformly across the slab thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a non-linear expansion joint is used to limit shocks from vehicle wheels, then vehicle impact resistance is improved, but stress distribution uniformity deteriorates
Solution Approach 1:
The patent applies a sinusoidal (curved) profile to the expansion joint instead of a straight line. This curvature allows the joint to maintain continuity over the entire height while following the natural sinusoidal shape of vehicle wheel passages, thereby reducing impacts and improving stress distribution uniformity across the slab thickness.
2Adaptability or versatility
If a groove-shaped separation between slabs is created, then expansion joint functionality is improved, but concrete slab durability deteriorates due to cracks and damage
Solution Approach 1:
The groove-shaped separation is transformed into a sinusoidal profile that follows the natural path of vehicle wheel passages. This curved design maintains the expansion joint's ability to accommodate slab movement while eliminating the sharp edges that cause concrete cracking and damage, thereby improving durability.
Solution Approach 2:
The patent converts the harmful effect of vehicle wheel impacts on straight joints into a beneficial design feature by shaping the joint to follow the sinusoidal path of wheel passages. This transforms the source of damage into a design element that reduces impacts and improves overall performance.
3Stability of the object's composition
If metal joints are positioned at the separation between slabs, then formwork system stability is improved, but concrete slab integrity deteriorates due to wheel impacts on metal joints
Solution Approach 1:
The metal joints are positioned along a sinusoidal profile rather than a straight line, allowing them to follow the natural path of vehicle wheel passages. This curved positioning maintains the structural stability of the formwork system while preventing wheels from directly impacting the metal joints, thereby preserving concrete slab integrity.
Data Source
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AI summary
A formwork system comprising an expansion joint in the form of two longitudinal elements (10a, 10b) having identical sinusoidal profiles, with the lower face of the first sinusoidal element (10a) fixed to a separating element (5) arranged along its length and extending orthogonally to said lower face, and intended to create a vertical separation between two adjacent concrete slabs, and the second sinusoidal element (10b) being connected to the separating element (5) or to the first sinusoidal element (10a) by fastening means (12) capable of breaking under a horizontal contraction force of at least one concrete slab, so that the two sinusoidal elements (10a, 10b) move away from each other with the first element (10a) remaining fixed to the separating element (5), the amplitudes and widths of the sinusoidal elements being such that the external sinusoidal profiles of the elements sinusoidal (10a,10b) do not cross the longitudinal plane defined by the separating element (5).