Radially Compressible Bushing for Dowel Alignment in Concrete
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Solution Overview
Problem
Existing dowel placement methods for concrete construction are labor-intensive and costly, often resulting in non-parallel positioning of slip dowels due to the need for expensive equipment and complex installation processes, which impede the desired slippage and lead to buckling or unevenness in cold joints.
Innovation Solution
A dowel placement system featuring a radially compressible bushing and a flange-less dowel sleeve that creates a friction force to maintain alignment during concrete pouring, reducing material costs and simplifying installation by eliminating the need for direct support from the concrete form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If drilling method is used to place slip dowels, then dowel positioning can be achieved, but the process becomes extremely labor intensive and expensive
Solution Approach 1:
The dowel placement system performs preliminary actions by pre-positioning the dowel rod within the form before concrete pouring. The form itself is designed with features that guide and constrain the dowel rod to the correct position and orientation, eliminating the need for post-pouring drilling and adjustment operations.
Solution Approach 2:
The form acts as an intermediary tool that facilitates accurate dowel placement. The form includes specific structural features such as guides and constraints that mediate between the dowel rod and the final positioned state, ensuring proper alignment without requiring complex drilling equipment or highly skilled labor.
2Manufacturing precision
If drilling equipment and trained laborers are used, then parallel dowel alignment can be achieved, but equipment costs and labor training requirements increase
Solution Approach 1:
The form is designed to be self-servicing for dowel placement. It includes built-in guides and constraints that automatically align the dowel rod to the correct parallel orientation during installation, eliminating the need for expensive drilling equipment or highly trained laborers to achieve proper alignment.
Solution Approach 2:
The system replaces expensive, complex drilling equipment and highly trained laborers with a simpler, more affordable form design. The form itself becomes the tool that provides the necessary precision through its structural features, reducing overall project costs while maintaining dowel alignment quality.
3Adaptability or versatility
If smooth steel dowel rods are inserted to allow slippage, then longitudinal expansion and contraction can occur, but non-parallel positioning prevents desired slippage
Solution Approach 1:
The form is designed in advance with specific geometric features that pre-align the dowel rod to the correct parallel orientation before concrete pouring. This preliminary positioning ensures that when the concrete sets, the dowel rod maintains the proper parallel alignment with adjacent slabs, enabling the desired slippage for thermal expansion and contraction.
Solution Approach 2:
The form acts as an intermediary that transfers the parallel alignment requirement to the dowel rod placement. The form's structural features guide the dowel rod into the correct orientation, ensuring that the dowel rod and adjacent slabs are properly aligned to facilitate longitudinal movement while maintaining common plane.
4Stability of the object's composition
If dowel rods are placed to maintain common plane, then buckling prevention is achieved, but accurate positioning requires complex installation procedures
Solution Approach 1:
The form provides self-service positioning for the dowel rod through its built-in guides and constraints. These features automatically ensure that the dowel rod is positioned at the correct height and parallel orientation, maintaining the common plane between slabs and preventing buckling without requiring complex installation procedures or highly skilled labor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system ensures accurate and cost-effective placement of dowels, allowing for efficient longitudinal movement of concrete slabs while preventing buckling, with reduced material usage and simplified installation procedures.
Implementation Method 1
the bushing and dowel sleeve are configured such that insertion of the bushing within the dowel sleeve causes the outer diameter of the bushing to compress and conform to the inner diameter of the dowel sleeve and to create a friction force between the bushing and the dowel sleeve to mitigate movement of the dowel sleeve relative to the bushing
Data Source
AI summary
A dowel placement system including a fastener configured to be engageable with a form, and a radially compressible bushing coupled to the fastener and defining an adjustable outer diameter. The system further includes an elongate dowel sleeve having opposed proximal and distal end portions, and an axial opening having an inner diameter and extending into the dowel sleeve from the proximal end portion to the distal end portion. The bushing is insertable within the axial opening of the dowel sleeve, and the bushing and dowel sleeve are configured such that insertion of the bushing within the dowel sleeve causes the outer diameter of the bushing to compress and conform to the inner diameter of the dowel sleeve and to create a friction force between the bushing and the dowel sleeve to mitigate movement of the dowel sleeve relative to the bushing during formation of the concrete structure.