Anchoring Rod Conical Profile for Cracked Concrete Fastening
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Solution Overview
Problem
Existing anchor rods for chemical fastening in boreholes are limited by high expansion forces, requiring complex cleaning and being unsuitable for edge fastenings and cracked concrete, with potential load value reductions and contamination issues.
Innovation Solution
An anchor rod with a conically profiled anchoring area, featuring specific ratios of outer to core diameter and cone angle, allowing for uniform load introduction and high load values without cleaning, suitable for uncleaned and cracked boreholes, and edge fastenings, through optimized geometry and non-adhesive surface coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If composite expansion anchors are used to achieve secure anchoring in cracked concrete and tensile zones, then high load values and expansion capability are improved, but complex cleaning of the borehole is required and expansion forces become too high for edge fastenings
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric parameters of the anchoring area, specifically the ratio of outer diameter to core diameter (dA/dK = 1.35-1.55) and the ratio of distance between conical extensions to average borehole diameter (p/dcut,med = 0.40-0.60). These parameter optimizations enable the anchor rod to achieve high load values without requiring complex cleaning procedures, as the optimized geometry allows effective load introduction even in uncleaned boreholes
Solution Approach 2:
The patent implements preliminary action through the conical profiling of the anchoring area, which is designed to automatically distribute and uniformize load introduction during the insertion process. The conical shape with specific angles (22.5° to 27.5°) prepares the mortar compound and borehole interface in advance, creating optimal bonding conditions without requiring preliminary cleaning actions
2Strength
If the outside diameter of the anchoring area is increased to improve load values, then load capacity is improved, but the mortar shell becomes too thick to break open and expand against the borehole wall
Solution Approach 1:
The patent resolves this contradiction through precise parameter optimization, specifically setting the ratio of outer diameter to core diameter (dA/dK) within the range of 1.35-1.55. This parameter range is critical as it ensures the anchoring area has sufficient outer diameter to provide high load capacity while maintaining a core diameter that allows the mortar shell to remain thin enough to break open and expand effectively against the borehole wall
3Force
If the cone angle of extension sections is decreased to reduce expansion forces for edge fastenings, then expansion pressure is reduced, but load values decrease
Solution Approach 1:
The patent applies parameter changes by optimizing the cone angle of the extension sections within a specific range (22.5° to 27.5°). This optimized angle range achieves the right balance between converting normal forces into radial spreading forces (requiring smaller angles) and maintaining sufficient load introduction capability (requiring larger angles). The specific angle range ensures expansion forces are low enough for edge fastenings while load values remain high
4Ease of operation
If drilling dust remains between the borehole wall and hardened mortar compound to avoid cleaning, then installation simplicity is improved, but the anchor rod can be pulled out under load
Solution Approach 1:
The patent applies parameter changes by optimizing the surface area and geometry parameters of the anchoring area, specifically the ratios dA/dK = 1.35-1.55 and p/dcut,med = 0.40-0.60. These parameter optimizations create sufficient bonding surface area and optimal stress distribution that enable the anchor to achieve high reliability and load capacity even in uncleaned boreholes with drilling dust present, eliminating the need for cleaning while maintaining anchoring reliability
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 anchor rod achieves high load values with low expansion pressure, enabling use in uncleaned and cracked boreholes and near-edge applications, while eliminating the need for complex cleaning and ensuring secure fastening without material failure.
Implementation Method 1
the force transmission takes place on the one hand through the cohesive effect of the composite mortar between the borehole wall and the mortar mass, but on the other hand also via a spreading effect through the spreading sections. Due to the spreading effect, the normal forces (tensile forces) acting on the anchor rod are converted into radially acting spreading forces when the anchor rod is loaded
Implementation Method 2
an anchor rod or other fastening element is embedded in a mortar compound filled hole is inserted and is fixed after the mortar has hardened
Data Source
AI summary
An anchoring rod for anchoring in a borehole of a component by means of a curable organic and/or inorganic mortar composition has an attachment region (14) and an anchoring region (12) with a profiled section (16) that interacts with a curable organic and/or inorganic mortar composition which is filled into the receiving bore. The profiled section consists of wider portions that are conically shaped and the diameter of each of which increases in the direction of the free front end of the anchoring rod. The anchoring region is characterized in that the proportion of the separation (p) of the wider portions to the central borehole diameter (dcut, med) is 0.40 to 0.60, the proportion of the outer diameter (dA) to the core diameter (dK) of the wider portions is 1.35 to 1.55, and the cone angle of the wider portions (alpha) is 22.5° to 27.5°.