Self-Tapping Anchor for Concrete Shear Reinforcement

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Solution Overview

Problem

Existing methods for reinforcing concrete structures to withstand increased load situations and changed standards are inadequate, particularly in terms of complexity, accessibility, and durability, as they require extensive preparation and may lose strength at high temperatures.

Innovation Solution

A connection arrangement featuring a rod-shaped anchor element with a self-tapping external thread for direct insertion into concrete, coupled with a clamping nut for adjustable force distribution, which increases the shear strength of concrete slabs by forming a three-dimensional framework of pressure and tension struts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If adhesive anchor rods are used to increase shear capacity, then the punching shear resistance is improved, but the insertion and centering process becomes complex and requires careful hole preparation with limited service life

Engineering Contradiction:
Improvepunching shear resistanceVSAvoidinsertion and centering complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent replaces the chemical adhesive bonding system with a mechanical threaded connection system. The anchor rod features a self-tapping thread that directly engages with the concrete substrate, eliminating the need for adhesive materials and complex preparation procedures. This mechanical substitution simplifies the installation process while maintaining structural integrity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The anchor rod incorporates a self-tapping thread design that automatically creates its own threading in the concrete substrate during insertion. This self-service mechanism eliminates the need for pre-drilled holes with precise tolerances or complex centering procedures, allowing for straightforward direct insertion and significantly reducing installation complexity.

Inventive Principle:
Principle #25Self-service

2Strength

If adhesive compounds are used for anchoring, then the initial bond strength is achieved, but the strength decreases sharply at temperatures above 60°C reducing fire resistance

Engineering Contradiction:
Improveanchor bond strengthVSAvoidtemperature resistance
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent replaces the temperature-sensitive adhesive bonding system with a temperature-resistant mechanical threaded connection. The metal thread and concrete engagement maintain their structural properties at high temperatures, eliminating the sharp strength degradation that occurs with adhesive compounds above 60°C and significantly improving fire resistance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the fundamental bonding mechanism from chemical adhesion to mechanical interlocking. This parameter change in the connection method transforms the temperature-dependent adhesive bond into a temperature-stable mechanical connection, where the threaded engagement geometry maintains its load-bearing capacity across a wide temperature range including fire conditions.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If self-tapping threads are used for direct concrete anchoring, then the ease of installation is improved, but the load-bearing capacity must be sufficient for reinforcement applications

Engineering Contradiction:
Improveinstallation easeVSAvoidload-bearing capacity
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The self-tapping thread design performs the hole creation and thread formation actions simultaneously during a single insertion operation. This preliminary action of creating the engagement geometry before load application ensures both installation simplicity and adequate load-bearing capacity, as the threaded connection is fully formed and engaged with the concrete substrate before any service loads are applied.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The anchor rod utilizes a composite construction combining a self-tapping threaded section for concrete engagement with a smooth shaft section for coupling device attachment. This composite design allows the threaded portion to provide secure mechanical anchoring in concrete while the smooth portion enables easy coupling with reinforcement elements, achieving both ease of installation and high load-bearing capacity.

Inventive Principle:
Principle #40Composite materials

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

This solution allows for efficient reinforcement of concrete structures without pre-threading, maintains strength under high temperatures, and significantly enhances the shear resistance of concrete slabs by distributing loads effectively across the concrete matrix.

Implementation Method 1

screwed at its front end into a bore extending through the first region (and penetrating the second region) by means of a self-tapping external thread

Methodology Applied
Scientific EffectMechanical forcing / Self-tapping thread mechanism: Mechanical Force

Implementation Method 2

The coupling device engages the second region and, if necessary, exerts a force on it, thus connecting the second region to the first region via a shaft section

Methodology Applied
Scientific EffectMechanical compression: Compression

Data Source

PatentEP2715013B1Connecting arrangement and method for producing a punching shear reinforcement, a subsequent lateral-force reinforcement and/or a reinforcement connection
Publication Date: 2019.01.09 PROF FEIX RES & DEV
  • EP2715013B1 patent drawingFigure 1~2
  • EP2715013B1 patent drawingFigure 3~4
  • EP2715013B1 patent drawingFigure 5~6

AI summary

The present invention relates to a connecting arrangement for coupling a first and second region (9, 11; 109, 111; 209, 211) made of porous material, in particular concrete, having an anchor element (13; 113; 213) with a threaded portion (107; 117) at a front end, this threaded portion being screwed into a bore (27; 127) running in the first region (9; 109; 209), and with a connection portion (23; 123) at a rear end. Also provided here is a coupling device (29; 129), which can be fixed on the connection portion (23; 123), acts on the second region (11; 111; 211) and couples the latter to the first region (9; 109; 209) via a shank portion (25; 125) running between the threaded portion (17; 117) and the connection portion (23; 123), wherein the threaded portion (17; 117) runs entirely within the bore (27; 127) in the first region (9, 109; 209). The present invention also relates to a method for producing a punching shear reinforcement, a lateral-force reinforcement and/or a reinforcement connection using a connecting arrangement according to the invention.