Flat Dowel Groove Alignment for Cast-in-Place Concrete Slabs
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Solution Overview
Problem
Existing methods for maintaining alignment and accommodating expansion and contraction between cast-in-place concrete slabs require special forming apparatus and do not effectively manage lateral movement without secure adhesion, which complicates the process.
Innovation Solution
A flat planar dowel is slidably received within a groove cut in one slab and embedded in the adjacent slab, with a gasket to seal against fluid intrusion and allow limited lateral movement, eliminating the need for special forming apparatus and ensuring horizontal alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art dowels and load transferring devices are cast-in-place during slab formation, then alignment maintenance is achieved, but special forming apparatus and support mechanisms are required
Solution Approach 1:
The dowel is pre-installed in the groove of the first slab before the second slab is formed. This preliminary placement eliminates the need for special forming apparatus to support dowels during concrete pouring, as the dowel is already positioned and secured by the gasket before the second slab is placed
Solution Approach 2:
The dowel and gasket assembly is extracted from the concrete mixture and installed as a separate pre-assembled unit. This removes the complexity of embedding dowels during forming, as the dowel is placed in a pre-formed groove and secured with a gasket before the second slab is formed against it
2Adaptability or versatility
If cast-in-place dowels with sheaths are used to accommodate lateral movement, then movement accommodation is achieved, but support mechanisms during formation are still required
Solution Approach 1:
The gasket is pre-installed around the dowel before the second slab is formed. This preliminary action secures the dowel in position and provides the necessary support during formation, eliminating the need for additional support mechanisms while still allowing lateral movement through the gasket's flexible design
Solution Approach 2:
The gasket acts as an intermediary between the dowel and the concrete slabs. It provides the necessary support and positioning during formation, while its flexible nature allows lateral movement of the slabs relative to the dowel without requiring complex support mechanisms
3Strength
If biscuit dowels are glued into grooves for secure adhesion, then strong bonding is achieved, but lateral movement is restricted
Solution Approach 1:
The gasket serves as an intermediary between the dowel and the concrete, providing secure anchorage through friction and mechanical interlocking while its flexible material allows lateral movement. This replaces the glued connection with a mechanical connection that maintains both strength and movement capability
Solution Approach 2:
The gasket's material properties are selected to provide high friction and mechanical interlocking for strong bonding, while its elastic properties allow it to deform and accommodate lateral movement. This combination of parameters achieves both strong anchorage and movement accommodation
Data Source
AI summary
First and second cast-in-place concrete slabs are maintained in alignment by cutting a semi-circular groove in an edge surface of the first formed slab, positioning a flat rectangular dowel within the groove so that the dowel extends outwardly from the edge surface, and then casting the second slab against the edge surface to embed the dowel within the second slab. A gasket is engaged with the dowel to seal the groove against the intrusion of fluid concrete as the second cast-in-place. The gasket also serves to space the dowel from the groove to accommodate limited lateral movement of the dowel and groove relative to one another.