Threaded Sleeve Prestressing for Crack-Resistant Concrete Joints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for joining and reinforcing concrete components are inadequate in distributing loads uniformly and preventing cracks, as they only become effective after a crack occurs, limiting their ability to absorb forces before significant damage.
Innovation Solution
A system comprising first and second threaded sleeves with external threads, a power drive, and an elongate clamping element that axially tensions the sleeves to create bond stresses in opposite directions, allowing for pre-tensioned reinforcement and uniform load distribution, thereby preventing crack development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional joining methods (screws, anchors) are used to connect concrete components, then the components can be joined together, but the load distribution is non-uniform and crack prevention is ineffective
Solution Approach 1:
The system applies preliminary action by pre-tensioning the threaded sleeves together with the clamping element before any crack occurs. This creates compressive bond stresses in the concrete that counteract tensile forces, preventing crack initiation. The pre-tensioned state is established during installation, transforming the reinforcement from reactive (after cracking) to proactive (before cracking).
Solution Approach 2:
The system changes the stress state parameter in the concrete from pure compression (conventional reinforcement) to a combination of compression and bond stress. The clamping element creates axial tension in the threaded sleeves, which generates bond stresses in the concrete that distribute loads uniformly. This parameter change enables crack prevention while maintaining load-bearing capacity.
2Strength
If conventional reinforcement (steel bars) is used to absorb tensile forces, then tensile strength is improved, but the reinforcement only becomes effective after a crack occurs
Solution Approach 1:
The threaded sleeves and clamping element are pre-assembled and pre-tensioned during installation, creating bond stresses in the concrete before any crack occurs. This preliminary action eliminates the time delay inherent in conventional reinforcement, where steel bars only engage after cracking. The system is immediately effective upon installation, providing both compression and bond stress reinforcement simultaneously.
3Reliability
If the clamping element axially tensions the threaded sleeves to create bond stresses, then load distribution becomes uniform and cracks are prevented, but the device complexity increases
Solution Approach 1:
The system merges multiple functions into integrated components: the threaded sleeves serve both as anchoring elements and as tensioning members, while the clamping element provides both compression force and bond stress generation. This merging reduces the number of separate components needed compared to conventional systems that require separate anchors, reinforcement bars, and tensioning devices, thereby reducing overall system complexity despite the advanced functionality.
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 increases the load-bearing capacity of concrete components by generating composite stresses before cracks form, providing enhanced stability and preventing crack occurrence in concrete structures.
Implementation Method 1
an external thread with which the threaded sleeve can be screwed into the respective component and which is suitable to form a connection with the respective component
Implementation Method 2
an elongate clamping element that axially tensions the sleeves to create bond stresses in opposite directions
Implementation Method 3
create bond stresses in opposite directions, allowing for pre-tensioned reinforcement and uniform load distribution
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The invention relates to a system (18) for joining two components (10, 12) or for reinforcing a component, comprising a first and a second threaded sleeve (20, 22) which each comprise the following: an outer thread (31), with the aid of which the threaded sleeve (20, 22) can be screwed into the respective component (10, 12) and which is suitable to form a composite with the respective component (10, 12), and a power drive, by which a torque for screwing the threaded sleeve (20, 22) into the respective component can be transmitted to the threaded sleeve. The system (18) further comprises an elongate clamping element (24) which is suitable to be guided through the second threaded sleeve (22) and introduced into or guided through the first threaded sleeve (20), and which is suitable to axially clamp the first and the second threaded sleeve (20, 22) in such a manner that the first and the second threaded sleeve (20, 22) form opposed composite stresses in the respective component (10, 12).