Wind Turbine Tower Reinforcing Elements Shear Strength

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Solution Overview

Problem

The assembly of wind turbine towers faces challenges in achieving sufficient shear strength in vertical joints due to the limitations of concrete shear strength, leading to issues with mortar leakage, increased costs, and temperature control requirements during the grouting process, which can affect the mechanical properties of the mortar.

Innovation Solution

The use of reinforcing elements with varying diameters and spacings along the height of the tower, providing different shear strengths in upper and lower regions, optimizes shear force distribution and reduces material usage, while avoiding the need for extensive formwork and temperature control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If mortar is poured by gravity in vertical joints, then the filling process is facilitated, but hydrostatic pressure causes leakages and irregular surfaces

Engineering Contradiction:
Improvemortar filling processVSAvoidjoint surface regularity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A formwork system acts as an intermediary between the mortar and the joint, controlling mortar flow and containing hydrostatic pressure. The formwork includes retention elements that prevent leakage while allowing controlled filling, and release elements that enable clean removal without damaging the joint surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The viscosity and flow characteristics of the mortar are modified through chemical additives and mixing parameters. This controlled parameter change allows the mortar to fill the joint adequately under gravity while reducing hydrostatic pressure effects that cause leakage and surface irregularities.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If formworks are used to retain mortar, then mortar leakage is prevented, but auxiliary elements and fastening operations increase cost and complexity

Engineering Contradiction:
Improvemortar retentionVSAvoidformwork system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The retention function is extracted from a complex fastened formwork system and integrated directly into the precast segments through embedded retention elements. This eliminates the need for separate formwork assembly and fastening operations, reducing complexity while maintaining reliable mortar retention.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The precast segments are designed with self-contained retention and release mechanisms that automatically perform the formwork function. The retention elements are built-in to the segment geometry, and release elements enable automatic formwork removal without manual fastening or complex operations.

Inventive Principle:
Principle #25Self-service

3Reliability

If temperature control is maintained during mortar curing, then mechanical properties are ensured, but process complexity and cost increase

Engineering Contradiction:
Improvemortar mechanical propertiesVSAvoidtemperature control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Temperature control measures are implemented preliminarily during mortar mixing and initial placement. Insulated formworks and heated mixing equipment are used in advance to ensure the mortar reaches optimal curing temperature, eliminating the need for complex continuous temperature control systems during the entire curing process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The curing process parameters are optimized by adjusting mortar composition (additives, aggregates) and initial curing conditions. This parameter change allows standard ambient temperature curing to achieve the same mechanical properties that would otherwise require controlled temperature systems.

Inventive Principle:
Principle #35Parameter changes

4Strength

If reinforcing elements are embedded in vertical joints, then shear strength is sufficient, but material usage and construction time increase

Engineering Contradiction:
Improvevertical joint shear strengthVSAvoidassembly time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The reinforcing function is segmented and distributed as discrete elements embedded at specific intervals in the vertical joints, rather than using continuous reinforcement. This segmentation reduces total material usage and allows faster installation by placing only the necessary number of elements at critical locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Reinforcing elements are strategically placed only in locations where shear strength is critically needed, based on structural analysis of stress distribution. This local quality approach concentrates reinforcement where necessary while minimizing material usage and installation time in less critical 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

This configuration enhances the shear strength of vertical joints, minimizes material usage, and simplifies the assembly process by ensuring adequate shear resistance without mortar leakage, thereby reducing costs and improving the mechanical integrity of the tower.

Implementation Method 1

The reinforcing elements provide at least a first shear strength and a second shear strength along the height of the at least a section of the tower

Methodology Applied
Scientific EffectShear strength: Shear Stress

Implementation Method 2

Traditionally mortar is poured by gravity in the vertical joints taking advantage of the gravitational action which facilitates the filling of this type of joint

Methodology Applied
Scientific EffectGravitation: Gravitation

Implementation Method 3

because of the high hydrostatic pressure generated by the column of mortar, leakages can appear

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Increase

Data Source

PatentEP3502466B1Wind turbine tower with reinforcing elements
Publication Date: 2021.10.13 NORDEX ENERGY SPAIN SAU
  • EP3502466B1 patent drawingFigure 1
  • EP3502466B1 patent drawingFigure 2~3
  • EP3502466B1 patent drawingFigure 4~5

AI summary

Wind turbine tower with reinforcing elements. The wind turbine tower comprises at least a first section (1) comprising at least two segments (2) defining at least two vertical joints (3) disposed between the at least two segments (2), at least two reinforcing elements (4) placed in each vertical joint (3), and at least an upper region (5) disposed above at least a lower region (6). The reinforcing elements (4) are configured to provide a first shear strength (1ss) in the at least upper region (5) and a second shear strength (2ss) in the at least lower region (6), the first shear strength and the second shear strength having different values and being enough to bear a maximum expected shear force in the vertical joint s (3).