Retrofitting Screw Anchorage With Grout After Temporary Release
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Solution Overview
Problem
The temporary release and re-establishment of tapping screw anchorage in mineral substrates often results in a decrease in anchorage performance due to substrate dust relocation, which is not adequately addressed by existing methods.
Innovation Solution
A method involving the removal of a primary screw, filling the annular gap between the screw and substrate with hardenable grout, and re-installing a retrofitting screw to emulate the effect of substrate dust, thereby maintaining or improving anchorage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tapping screw is unscrewed and subsequently screwed back into the hole, then the anchorage is temporarily released and re-established, but the anchorage performance decreases due to substrate dust relocation
Solution Approach 1:
A lubricant composition is introduced as an intermediary substance between the screw thread and the substrate hole wall. This lubricant fills the annular gap and replaces the function of substrate dust, providing continuous lubrication during screw rotation and preventing direct metal-to-concrete contact that would generate harmful dust and heat
Solution Approach 2:
The chemical composition of the annular gap is changed by introducing a lubricant composition with specific tribological properties. This changes the friction characteristics and prevents the generation of substrate dust, thereby maintaining anchorage performance during re-installation
2Reliability
If hardenable grout is applied during initial installation, then anchorage performance is improved, but the process becomes more complex and time-consuming
Solution Approach 1:
The invention uses a disposable lubricant composition that is applied only during re-installation operations. This eliminates the need for permanent grout application during initial installation, simplifying the original installation process while providing the anchorage performance benefits when needed
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 use of hardenable grout in the annular gap between the retrofitting screw and the substrate compensates for the loss in anchorage performance caused by substrate dust relocation, ensuring reliable and continuous anchor performance during re-installation.
Implementation Method 1
hardenable grout is placed in the annular gap, and the hardenable grout is hardened in the annular gap
Data Source
AI summary
A method for temporarily releasing a screw anchorage includes unscrewing and removing a primary screw having a thread that is tappingly engaged in a mating thread in an ungrouted hole in a mineral substrate from the ungrouted hole. Subsequently to the unscrewing and removing, a retrofitting screw is screwed into the hole to form an annular gap between the retrofitting screw and the mineral substrate. A hardenable grout is placed in the annular gap and the hardenable grout is hardened in the annular gap.