Adhesive Anchor Bolt Sleeve Structure for Shallow Embedment Strength
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Solution Overview
Problem
Conventional adhesive anchors exhibit poorer construction performance and deeper embedding depths compared to metal expansion anchors, often resulting in mushroom-shaped superposed failure and inadequate tensile strength, especially at shallower embedding depths.
Innovation Solution
An anchor bolt configuration featuring a head part, a shank part with a smaller diameter, and a sleeve part that extends into the anchor hole, where the sleeve part is secured by adhesive, creating a wedge effect to enhance tensile strength without directly contacting the adhesive, allowing for substantial tensile strength at a shallower embedding depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the embedding depth of adhesive anchor is increased to 10 times or more of anchor diameter to obtain substantial tensile strength, then the tensile strength is improved, but the construction performance deteriorates and the embedding depth becomes excessively deep
Solution Approach 1:
The anchor bolt is divided into three distinct parts: head part, shank part, and sleeve part. The sleeve part (length: 0.5-2.0 times anchor diameter) is segmented from the shank part and positioned at the embedding portion, allowing it to be secured by adhesive while the shank part maintains its toughness. This segmentation enables substantial tensile strength at reduced embedding depths (5-8 times anchor diameter) without requiring the conventional 10 times or more embedding depth.
2Ease of operation
If the embedding depth is reduced to match metal expansion anchors (4-5 times anchor diameter), then the construction performance improves, but mushroom-shaped superposed failure occurs in concrete
Solution Approach 1:
The sleeve part acts as an intermediary element between the shank part and the adhesive/concrete interface. It is specifically designed to be secured by adhesive in the embedding hole, creating a transition zone that distributes stresses and prevents direct stress concentration at the concrete surface. This intermediary structure eliminates mushroom-shaped superposed failure while enabling reduced embedding depths (5-8 times anchor diameter) that match metal expansion anchor performance.
3Strength
If the shank part directly contacts the adhesive to improve bonding, then the tensile strength increases, but the toughness of the anchor bolt is impaired
Solution Approach 1:
The anchor bolt is segmented into shank part and sleeve part with distinct functions. The shank part (diameter: smaller than head part) maintains full toughness and is not directly contacted by adhesive, while the sleeve part (extending from opening part to hole back part) is specifically designed to be secured by adhesive. This segmentation allows the shank part to retain its ductile properties and toughness while the sleeve part provides the adhesive bonding interface for tensile strength.
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 enables substantial tensile strength to be achieved at a shallower embedding depth than conventional adhesive anchors, while maintaining the toughness of the anchor bolt and improving construction performance by preventing mushroom-shaped superposed failure.
Implementation Method 1
an outer peripheral surface of the sleeve part is secured by the adhesive to contribute to tensile strength
Implementation Method 2
the anchor bolt exerts a wedge effect on the fixed body at the head part
Implementation Method 3
a tensile force (pulling force) acts on the sleeve part as a compressive force via the head part when the tensile force acts on the shank part
Data Source
Figure 1'
Figure 2
Figure 3
AI summary
[Object] Provided is an anchor bolt for an adhesive anchor or the like that can be caused to exert substantial tensile strength at a relatively shallow embedding depth. [Solution Means] An anchor bolt 11A for an adhesive anchor that is fixed via adhesive to an anchor hole AH formed in a fixed body C includes: a head part 14 that is inserted into a hole back part of the anchor hole AH; a shank part 15 that is continuous with the head part 14 and formed to have a diameter smaller than the diameter of the head part 14; and a sleeve part 16 into which the shank part 15 is inserted, the sleeve part extending from an opening part Ha to the hole back part of the anchor hole AH and having a tip end thereof abutted onto the head part 14.