System and method for applying stress to a reinforcement member
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Solution Overview
Problem
Carbon fiber-based reinforcing bars face challenges in bond strength with cementitious materials and shear load limitations, and there is a need for a method to uniformly apply tension during the formation of pre-cast concrete structures to enhance the mechanical integrity of the reinforcement.
Innovation Solution
A system comprising a gripping device, tension device, and tension application sub-system is used to apply and control tension in carbon fiber reinforcing bars, which includes twisting the fibers to create a non-uniform surface for increased bond strength and using a resin impregnation process to set the fibers under tension, ensuring consistent mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon fiber strands are used as reinforcing bars, then corrosion resistance is improved, but bond strength with cementitious material deteriorates
Solution Approach 1:
The patent applies local quality by creating a deformed surface pattern on specific portions of the carbon fiber rebar. The surface is selectively deformed at intervals along the length of the rebar, creating localized regions of increased bond strength while maintaining the smooth surface in other areas. This allows the rebar to achieve sufficient bond strength with cementitious material while preserving the inherent corrosion resistance of carbon fiber.
Solution Approach 2:
The patent introduces asymmetry by deforming the surface of the carbon fiber rebar to create an non-uniform surface pattern. The deformed regions create mechanical interlocking with the cementitious material, providing enhanced bond strength in those localized areas while the overall smooth surface maintains corrosion resistance.
2Ease of manufacture
If uniform surface carbon fiber rebar is used, then manufacturing simplicity is improved, but bond strength with cementitious material deteriorates
Solution Approach 1:
The deformed surface pattern is applied at regular intervals along the length of the rebar rather than uniformly across the entire surface. This approach maintains manufacturing simplicity by using a periodic pattern that can be efficiently produced through methods such as rolling or molding, while still providing sufficient bond strength through the localized deformed regions.
3Strength
If tension is applied to reinforcement member during concrete casting, then mechanical integrity is improved, but device complexity for tension application increases
Solution Approach 1:
The patent applies tension to the carbon fiber rebar before the concrete is cast, and maintains this tension throughout the casting and curing process. This preliminary application of tension ensures that the rebar is properly positioned and that the concrete develops optimal bond strength with the deformed surface pattern. The tension is applied using a tensioning device that anchors to the deformed regions of the rebar.
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 effectively enhances the bond strength and tensile load capacity of carbon fiber reinforcing bars, improving their performance in concrete structures by maintaining tension during curing and releasing it after concrete hardening, thus addressing the limitations of carbon fiber-based rebar.
Implementation Method 1
Each attachment is configured to retain a respective end of a reinforcement member with sufficient friction force based on a predetermined tension to be applied to the reinforcement member
Implementation Method 2
At least one of the first and second tension application apparatuses is further configured to create and controllably adjust a tension load within the reinforcement member
Data Source
AI summary
A system and method for applying tension to a reinforcement member is provided. The system includes a gripping device, a tension device, and a tension application sub-system. The gripping device includes first and second attachments. Each attachment retains a respective end of the reinforcement member with sufficient friction force based on a predetermined tension to be applied to the reinforcement member. The tension device includes first and second tension tubes configured to removably receive and hold the first and second attachments, respectively. The tension application sub-system has first and second tension application apparatuses and first and second coupling devices. The first and second coupling devices couple the first and second tension tubes to the first and second tension application apparatuses, respectively. At least one of the first and second tension application apparatuses creates and controllably adjusts a tension load within the reinforcement member.