Pre-fabricated Threaded Bar Assemblies with 3D Cage Frames
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Solution Overview
Problem
Conventional prefabricated reinforcement cages for concrete structures using threaded reinforcing bars face issues such as impeded concrete flow, stress discontinuity, and the development of shrinkage cracks due to flat, two-dimensional templates, and require workers to climb the cage for hoisting lead release.
Innovation Solution
Three-dimensional prefabricated assemblies of threaded bars held by cage frames with axially extending steel plates and internally threaded sleeves, allowing minimal interference with concrete flow and providing rigidity while enabling free rotation of bars for easy installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flat, two-dimensional templates are used to hold reinforcing bars in formation, then the bars can be positioned with accurate spatial relation and the module gains rigidity for lifting, but the template occupies significant sectional area that impedes concrete flow and causes stress discontinuity leading to shrinkage cracks
Solution Approach 1:
The invention transitions from using flat two-dimensional templates to three-dimensional cage frames. The cage frames extend axially parallel to the reinforcing bars, creating a volumetric structure that supports the bars without occupying significant cross-sectional area. This dimensional change allows concrete to flow freely around the reinforcement while maintaining accurate bar positioning and eliminating the stress discontinuities caused by flat templates.
Solution Approach 2:
The cage frames are constructed with thin-walled structural elements that provide the necessary rigidity for lifting and bar positioning while occupying minimal space. The axially extending frame plates and longitudinal internally threaded sleeves create a lightweight yet rigid structure that does not impede concrete flow.
2Stability of the object's composition
If conventional prefabricated cages are used with rigid structure for installation, then the assembly gains stability and rigidity, but the free rotation of threaded bars is impeded, requiring complex locking mechanisms
Solution Approach 1:
The cage frames are designed with axially extending internally threaded sleeves that allow the threaded reinforcing bars to rotate freely during installation. The sleeves provide a controlled environment for bar rotation while maintaining the overall rigidity of the cage structure. This dynamic design eliminates the need for complex locking mechanisms, as the bars can be rotated and coupled in place within the flexible sleeve structures.
3Productivity
If rigging is attached to the permanent cage at the top for hoisting, then the cage can be lifted efficiently, but a worker must climb up the cage to release the hoisting leads, creating safety risks
Solution Approach 1:
The hoisting leads are extracted from the permanent cage structure and made detachable. The cage frames are equipped with detachable hoisting leads that can be easily attached and removed without requiring workers to climb the structure. This separation of the hoisting function from the permanent cage structure eliminates the safety hazard while maintaining efficient lifting capability.
Data Source
AI summary
A pre-fabricated reinforcement cage is constructed of at least two cage frames spaced apart from each other. The cage frames include preferably axially extending steel plates and axially extending sleeves preferably having an internal threading pattern that is complimentary to the external threading pattern of a plurality of longitudinal reinforcing bars. The cage frames are optionally also provided with lifting bar guide collars to receive a lifting apparatus comprised of one or more lifting bars. The cage frame plates, sleeves and lifting bar guide collars are fastened together. The longitudinal reinforcing bars, having continuous, external thread-like deformations along their length are installed into the internally threaded sleeves or into threads of locking nuts holding the bars within optional smooth sleeves during the fabrication.