Prestressed Concrete Sleeper Coupling Area Strength

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Solution Overview

Problem

Existing prestressed concrete sleepers face challenges in reliably absorbing loads at the coupling area of two sleeper sections due to insufficient prestressing force, which is low near the connecting device, making them prone to weakness.

Innovation Solution

Using high-strength or ultra-high-strength concrete with added fibers in the area adjacent to the connecting device, along with reinforcing steel brackets, to enhance mechanical properties and compensate for the lack of prestressing force, and employing a screw connection design for easy folding and transportation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If sleeper sections are coupled by embedded connecting devices in the sleeper heads, then rigid connection is achieved, but the coupling area becomes a potential weak point due to insufficient prestressing force

Engineering Contradiction:
Improverigid connectionVSAvoidload-bearing capacity at coupling area
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies local quality by using high-strength or ultra-high-strength concrete specifically in the coupling area adjacent to the connecting device, while the remaining sleeper sections use conventional concrete. This localized material enhancement compensates for the insufficient prestressing force in the coupling area, maintaining rigid connection while improving reliability at the critical weak point.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining high-strength or ultra-high-strength concrete with conventional concrete in a single sleeper structure. The high-strength concrete region provides enhanced load-bearing capacity where needed, while the conventional concrete is used where standard performance suffices, creating a composite structure that optimizes both rigidity and reliability.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If preassembled switches are transported to the construction site, then assembly accuracy is improved, but the switches exceed the size of available wagons

Engineering Contradiction:
Improveassembly accuracyVSAvoidswitch size
Core Design Contradiction:
Manufacturing precisionVSLength of moving object

Solution Approach 1:

The patent applies segmentation by dividing the preassembled switch into multiple sleeper sections that can be coupled together. The sleeper sections are assembled at the manufacturer's works with embedded connecting devices, ensuring high assembly accuracy. At the construction site, the sections are coupled using the embedded connecting devices, maintaining precision while enabling transport of segmented components that fit within wagon size constraints.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If conventional concrete is used in the coupling area, then manufacturing cost is reduced, but the area becomes prone to weakness due to low prestressing force

Engineering Contradiction:
Improvemanufacturing costVSAvoidmechanical properties in coupling area
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies local quality by enhancing the concrete strength specifically in the coupling area where high mechanical properties are critical, while using conventional concrete in the remaining areas where standard performance is sufficient. This selective material enhancement improves strength at the critical weak point without unnecessarily increasing manufacturing costs throughout the entire sleeper structure.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2488698B1Prestressed concrete sleeper and method for transporting and installing a switch having prestressed concrete sleepers
Publication Date: 2015.03.11 DB NETZ
  • EP2488698B1 patent drawingFigure 1
  • EP2488698B1 patent drawingFigure 2
  • EP2488698B1 patent drawingFigure 3~5

AI summary

The invention relates to a prestressed concrete sleeper, having at least two sleeper sections that can be coupled or are coupled rigidly by a connection device embedded in the sleeper heads, wherein the sleeper sections each comprise a concrete in the region adjacent to the connection device which has a higher rigidity than the concrete in the other regions.