Bar Coupling Sleeve With Deformed Inner Surface
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Solution Overview
Problem
In reinforced concrete construction, existing methods for splicing reinforcing steel bars and terminating bars at structure ends often fail to achieve the required design strength, particularly in transferring forces effectively without discontinuities or special provisions, leading to inadequate strength distribution.
Innovation Solution
A high-strength steel sleeve with deformations on its inner surface, allowing for the insertion of reinforcing bars and an adhesive, which enhances bonding and mechanical anchorage, enabling effective force transfer through wedging action without the need for special tools or heat application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If lap splicing is used to connect reinforcing bars, then the bars can be joined end-to-end, but the splice length is excessive and does not achieve adequate force transfer efficiency
Solution Approach 1:
The sleeve is segmented into multiple chambers separated by barriers, with each chamber containing deformations that create localized anchorage zones. This segmentation allows force transfer to occur in discrete stages along the bar length, achieving adequate strength over a compact splice length rather than requiring a long continuous overlap.
Solution Approach 2:
The sleeve acts as an intermediary device between two reinforcing bars, providing a mechanism for force transfer through its internal deformations and adhesive material. The sleeve mediates the connection by converting direct bar-to-bar contact into a multi-zone anchorage system that achieves superior force transfer efficiency.
2Strength
If mechanical anchors or hooks are added to terminate bars at structure ends, then the development length is reduced and full bar strength is achieved, but the device complexity and construction effort increase
Solution Approach 1:
The sleeve is designed to perform multiple functions: it can connect two bars end-to-end for splicing, or terminate a single bar at a structure end by filling only one chamber. This multi-functionality eliminates the need for separate anchorage devices like hooks or mechanical anchors, reducing overall device complexity while maintaining full bar strength capability.
Solution Approach 2:
The deformations within the sleeve chambers create self-anchoring action that automatically develops full bar strength without requiring additional external anchorage devices. The adhesive material flows into the deformations and cures to create a self-sustaining anchorage system that eliminates the need for hooks or mechanical anchors.
3Reliability
If traditional splicing methods are used, then construction is simple, but the splice cannot withstand 125% of the yield strength as required by code
Solution Approach 1:
The sleeve changes the physical parameters of the splice zone by introducing deformations that create localized anchorage points and using adhesive material to enhance bond strength. These parameter changes allow the splice to achieve 125% of yield strength capability while maintaining simple installation procedures similar to traditional lap splicing.
4Strength
If the sleeve chambers are completely filled with adhesive, then adequate bond strength is achieved, but excess adhesive creates waste and increases cost
Solution Approach 1:
The sleeve chambers are designed to be partially filled with adhesive rather than completely filled. The deformations within each chamber create sufficient anchorage action with only partial adhesive coverage, eliminating the need to fill the entire chamber volume. This partial action approach achieves adequate bond strength while significantly reducing adhesive waste and cost.
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 solution provides a design strength capable of withstanding 125% of the yield strength of the reinforcing bar, ensuring continuous force transfer and adequate strength distribution at splices and terminal locations without discontinuities or special provisions.
Implementation Method 1
the deformations provide a mechanical anchorage for the adhesive. The deformations mechanically engage the adhesive to resist the tendency of the adhesive to be withdrawn from the device when a tension force is applied to the reinforcing bar
Implementation Method 2
An adhesive (a non-cementitious material) may be placed into one of the holes and, thereafter, the reinforcing bar may be inserted into the hole, thereby forcing the adhesive into the valleys formed by the deformations of the device
Data Source
AI summary
Particular embodiments of the inventive technology relate to a device for connecting the ends of two concrete reinforcing bars in which a metal sleeve has chambers at each end to accommodate the end of one reinforcing bar. Forces may be transferred from one bar to the other through, the use of, inter alia, an adhesive established within the space between the outside of the reinforcing bars and the deformed inner surface of the sleeve. The chambers are, preferably, separated by a fluid impervious barrier. One port associated with each chamber may be established to allow fluid such as air to escape, preventing air voids in the adhesive. Another configuration of the inventive device would be intended for the retention (under load, of course) of only one reinforcing bar, with an enlarged flange for anchoring the end of one reinforcing bar, perhaps at and outer surface of, e.g., a concrete slab.