Concrete Dowel Placement Using Embedded Baseplates
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Solution Overview
Problem
Existing methods for installing slip dowels in concrete construction are time-consuming, prone to misalignment, and require expensive and heavy inserts, leading to increased costs and potential cracking at cold joints due to improper placement.
Innovation Solution
A system using thin polymer baseplates with tubular projections and fasteners is employed, where the baseplates are attached to concrete forms and remain embedded in the concrete, allowing slip dowels to be inserted and embedded in the second concrete slab, ensuring proper alignment and reducing installation time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional methods of drilling holes or forming cavities for slip dowels are used, then slip dowels can be installed to prevent buckling and displacement at cold joints, but the installation process becomes time-consuming and labor-intensive
Solution Approach 1:
The patent applies preliminary action by pre-attaching baseplates with integrated tubular projections to the concrete forms before pouring the concrete. This allows the slip dowel holes to be prepared in advance as part of the formwork system, eliminating the need for post-pour drilling or cavity formation. The baseplates remain embedded in the concrete after form removal, providing ready-made receptacles for slip dowel insertion.
Solution Approach 2:
The patent merges multiple functions into a single integrated component: the baseplate serves as both the mounting substrate and the structural element that remains embedded in the concrete, while the tubular projection integrated into the baseplate provides both structural support and the receptacle for the slip dowel. This consolidation eliminates separate operations for creating dowel holes and reduces the number of components needed.
2Reliability
If slip dowels are installed using traditional methods, then cold joints can be reinforced, but misalignment and improper positioning of dowels occur leading to cracking and faulting
Solution Approach 1:
The baseplates are attached to the forms at precisely positioned locations before concrete pouring, establishing accurate alignment references in advance. The tubular projections extend from the baseplates in predetermined orientations, ensuring that when slip dowels are inserted, they achieve proper parallel alignment automatically without requiring post-installation adjustment or measurement.
Solution Approach 2:
The baseplates act as intermediary elements that mediate between the concrete formwork system and the slip dowels. They provide a stable, pre-positioned platform that ensures accurate placement of slip dowels while remaining embedded in the concrete to maintain alignment. The tubular projections serve as intermediaries that guide and constrain the slip dowels to achieve proper orientation.
3Manufacturing precision
If heavy and expensive inserts are used to form cavities for slip dowels, then proper dowel placement can be achieved, but installation costs increase significantly
Solution Approach 1:
The baseplates are designed as economical, lightweight components made from materials such as plywood or metal that are much less expensive than traditional heavy inserts. They serve their purpose during concrete pouring and form removal, then remain as thin embedded plates that provide sufficient support for slip dowel alignment without requiring the mass and cost of traditional cavity-forming inserts.
Solution Approach 2:
The baseplates are designed as thin plate structures rather than bulky three-dimensional inserts. This thin-film approach provides sufficient structural function for alignment and support while dramatically reducing material quantity and cost compared to traditional heavy inserts. The thin profile allows easy attachment to forms and minimal interference with concrete pouring operations.
Data Source
AI summary
A concrete surface with a cold joint, dowel slip system and method for forming that surface are provided. Baseplates having tubular projections are fastened to at least one first form using fasteners extending part way into the first form, with the first form forming part of a periphery of a first concrete slab. When the first form is removed, the baseplates, projections and fasteners remain embedded in the first concrete slab. Slip dowels are inserted into the tubular projections and a second concrete is poured adjoining the first concrete slab, with the second concrete embedding the slip dowels, backplates and projecting distal ends of the fasteners and forming a cold joint.