Composite Anchoring Element with Prestressed Cables

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Solution Overview

Problem

Existing anchoring elements, particularly self-perforating bars, are limited by their cost-effectiveness and ductility, as their resistance and cost increase proportionally with cross-sectional area, and they do not fully exploit the synergy between tensioning elements and tubular elements, leading to suboptimal load resistance and higher construction costs.

Innovation Solution

An anchoring element comprising a tubular bar with prestressed steel cables constrained by cement grout, where the cables are either fully or partially buried within the grout, allowing for enhanced resistance and ductility by leveraging the synergy between structural steel and prestressed steel, and enabling adjustable ductility during installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the cross section of self-perforating bars is increased to develop greater counteracting force, then the resistance capability is improved, but the cost increases proportionally

Engineering Contradiction:
Improvecounteracting forceVSAvoidcost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent combines structural steel tubular elements with prestressed steel cables to create a composite anchoring system. The structural steel provides tensile strength and ductility, while the prestressed cables provide additional anchoring force. This composite approach allows achieving greater counteracting force without proportionally increasing the cross-sectional area of single bars, thereby reducing material costs while maintaining or improving resistance capability.

Inventive Principle:
Principle #40Composite materials

2Strength

If more anchoring elements are installed to increase total thrust resistance, then the overall resistance is improved, but the construction cost increases linearly

Engineering Contradiction:
Improvetotal thrust resistanceVSAvoidconstruction cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

By creating a composite system that combines the strengths of structural steel (ductility and tensile resistance) with prestressed cables (high anchoring force), the patent achieves higher total thrust resistance per anchoring element. This reduces the number of elements needed for a given resistance requirement, thereby lowering overall construction costs while maintaining or improving total thrust resistance.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the tubular element occupies only one section of its length, then the installation is simplified, but the synergy between tensioning elements and tubular element is not fully exploited

Engineering Contradiction:
Improveinstallation simplicityVSAvoidconstraining action
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies local quality by concentrating the cement grout and tensioning elements in specific zones where they are most effective. The tubular element can have varying properties along its length, with reinforced sections at critical locations (such as the anchored end in the ground) and simpler sections elsewhere. This allows the system to achieve maximum constraining action where needed while maintaining installation simplicity in other areas.

Inventive Principle:
Principle #3Local quality

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 anchoring element achieves higher resistance and lower construction costs per ton, with a significant reduction in the number of anchoring elements required, while offering improved ductility and safety, especially in seismic conditions, through the synergy of structural steel and prestressed steel cables.

Implementation Method 1

a tubular bar (2) with mainly longitudinal development driven in the ground (S) where it is constrained by means of a cement mix (C); one or more cables (5) or prestressed steel strands arranged inside the bar (2) and constrained by means of the cement mix (C) present inside said bar (2)

Methodology Applied
Scientific EffectCement grout bonding: Adhesive

Implementation Method 2

one or more cables (5) or prestressed steel strands arranged inside the bar (2)

Methodology Applied
Scientific EffectPrestress: Elasticity

Data Source

PatentEP2634313B1Improved anchoring element for ground consolidation
Publication Date: 2015.11.18 DALLA GASSA
  • EP2634313B1 patent drawingFigure 1
  • EP2634313B1 patent drawingFigure 2
  • EP2634313B1 patent drawingFigure 3

AI summary

The invention is an anchoring element (1; 30) for making ground (S) containment and consolidation structures, comprising: a tubular bar (2) with mainly longitudinal development driven into the ground (S), in which it is constrained by means of a cement mix; one or more cables (5) arranged inside the bar (2) and constrained in the cement mix (C) present inside the bar (2); and a fixing unit (6) suited to fix the anchoring element (1; 30) to the ground (S). The fixing unit (6) is connected to the ends (5a, 2a) of the cables (5) and of the bar (2) projecting from the ground (S). The cement mix (C) fills the bar (2) completely and the cables (5) are buried in the cement mix (C) for their entire length. According to a variant embodiment, the cement mix (C) fills the bar (2) partially, for a section of its length (Cb) in which the ends of the cables (5) are immersed.