Bundle Prestressing Control for Concrete Casting

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Solution Overview

Problem

Existing methods for prestressing reinforcement strands in bundle-type slipform casting fail to ensure uniform stressing, affecting the load-bearing capacity and quality of cast concrete slabs, as they do not effectively detect deviations or correct issues in real-time.

Innovation Solution

Implementing an automatic control system that measures and compares the behavior of measurable variables like force and elongation during the stressing process, using Hooke's law to predict expected behavior, and issuing alerts or releasing stress when deviations occur, ensuring accurate and uniform prestressing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If bundle-type stressing is used to prestress reinforcement strands, then the casting process can proceed efficiently, but uniform stressing of all strands cannot be guaranteed

Engineering Contradiction:
Improvecasting efficiencyVSAvoidstressing uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback control system that continuously monitors the stressing force applied to reinforcement strands during bundle-type prestressing. Sensors measure the actual force applied, and this information is fed back to a control unit that compares it against target values. When deviations are detected, the system automatically adjusts the stressing force to maintain uniform prestressing across all strands in the bundle, thereby resolving the contradiction between casting efficiency and stressing uniformity.

Inventive Principle:
Principle #23Feedback

2Device complexity

If traditional bundle stressing is used without monitoring, then the process is simple and fast, but deviations in stressing cannot be detected early

Engineering Contradiction:
Improvestressing process simplicityVSAvoidstressing accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a monitoring and feedback system that tracks the stressing force in real-time during bundle prestressing. The control unit receives data from sensors and compares actual stressing values against predetermined target values. When deviations exceed acceptable thresholds, the system generates alerts and can automatically adjust the stressing process. This feedback mechanism maintains high reliability while preserving the simplicity and speed of bundle-type stressing through automated control.

Inventive Principle:
Principle #23Feedback

3Device complexity

If reinforcement strands are stressed without real-time monitoring, then the equipment is simpler, but quality issues cannot be detected until after casting

Engineering Contradiction:
Improveequipment simplicityVSAvoidproduct quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements real-time feedback monitoring during the bundle stressing process, where sensors continuously measure the force applied to reinforcement strands and feed this information to a control unit. The control unit compares measured values against target values and automatically adjusts the stressing process to maintain precision. This ensures high product quality while keeping the equipment relatively simple through automated control, rather than requiring complex mechanical adjustment mechanisms.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical adjustment mechanisms with an automated control system that uses sensors and feedback loops to monitor and adjust stressing forces. Instead of relying on intricate mechanical systems to maintain precision, the invention uses electronic sensing and control to achieve the same goal, thereby maintaining equipment simplicity while dramatically improving manufacturing precision and product quality.

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

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 approach guarantees correct stressing of reinforcement strands, detects deviations early, and allows for process restarts without strand replacement, enhancing the quality and consistency of cast concrete products.

Implementation Method 1

The predetermination of the expected behavior of the at least one measurable variable affecting strand stressing process may be carried out by implementing Hooke's law, for example. Thereby the at least one measurable variable is advantageously a force exerted in the strand stressing process, an elongation of the reinforcement strand bundle

Methodology Applied
Scientific EffectHooke's law: Hooke's Law

Data Source

PatentEP2993007B1Method and apparatus for casting prefabricated prestressed concrete products
Publication Date: 2021.02.17 ELEMATIC OY AB
  • EP2993007B1 patent drawingFigure 1
  • EP2993007B1 patent drawingFigure 2
  • EP2993007B1 patent drawingFigure 3A~3B

AI summary

A method and an apparatus for casting prefabricated prestressed concrete products with a substantially horizontal slipform casting process, in which method reinforcement strands are stressed in a bundle on a casting bed (2) before the slipform casting is started, wherein the expected behavior of at least one measurable variable affecting the strand stressing process during the strand stressing process is predetermined, and the behavior of the at least one measurable variable is measured and compared to its predetermined expected behavior during the strand stressing process.