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Slide presentation from "Spenncon" explain how to design concrete sleepers.
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[BS en 13230-6] -- Railway Applications. Track. Concrete Sleepers and Bearers. Part 6. DesignDeskripsi lengkap
[BS en 13230-6] -- Railway Applications. Track. Concrete Sleepers and Bearers. Part 6. Design
what is concrete? its constitution, stages, properties, different test etcFull description
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Chapter 23
Concrete & Other Artificial Ties
Types of ties
Timber Timber
Concrete
Plastic (and composite) composite)
Steel
2
Types of ties
Timber Timber
Concrete
Plastic (and composite) composite)
Steel
2
•
Concrete –
Early Use •
–
Problems (not pre-stressed)
After World War II •
Pre-stressed Pre-stressed Designs
•
Revised Specs
Concrete Cross Ties (Monoblock)
• • • •
•
Precast, pre-stressed concrete Effective for high tonnage or high speed track Elastic fastener systems of various designs Vulnerable to mechanical damage, rail seat abrasion, effects of poor subgrade Must insulate in track circuit territory
Typical Concrete Tie
~ 2 1/2 times heavier than wood ties, More expensive than wood ties Pre-cast, Pre-Stressed, elastic fastenings embedded
Tie Manufacturer
Highway Crossing Surface
Turnout
•
Fastenings
•
Recent Experience
•
Economics ???
Some Problems with Concrete Ties
Epoxy Repair of Concrete Tie Rail Seat Deterioration
Wear and Abrasion
Pumping Track (stiffer track compared to wood tie track, need quality support for concrete tie track)
Concrete Tie Pads
•
Recent Experiences with Concrete Ties –
–
–
–
Need high-quality subgrade for support Pressures on ballast are higher under concrete ties compared to wood ties
Concrete tie track produces stiffer(higher modulus) track compared to wood tie track Rail-Seat abrasion and insert problems
AREMA Manual •
Performance Specifications
•
Tie Spacing – wider than wood ties
•
Tie Dimensions – slightly larger than wood ties
•
Load Distribution – higher ballast pressure
•
Impact Factor – higher than for wood ties
•
≈55%
For 27-inch tie spacing
•
Ballast Pressure
•
Subgrade Pressure
•
Lateral & Longitudinal Loads
•
Rail Flexure
•
Concrete Properties – very high strength
•
Pre-tensioning Tendons – typically 270 kip
•
Tie Pads -- important
•
Steel
•
Two-Block Concrete/Steel
•
Plastic
Steel Ties
•
•
•
•
•
Rolled channel shape with downturned ends Elastic fastener systems of various designs Track stiffness comparable to timber ties Poor for wet or corrosive environments May abrade soft ballast materials
Alternate Concrete Tie Two-Block or Bi-Block With Steel Beam
•
Reconstituted/Laminated Wood
•
Slab Track
•
Azobe & Mora Wood
•
Plastic
Concrete Slab Track Direct Fixation Ballastless Track
Azobe Hardwood Ties
Plastic Ties •
Attractive in areas where timber is decay prone
•
In-track behavior similar to timber
•
Compatible with timber tie handling and installation equipment
•
Compatible with fasteners used for timber
•
Pre-drill fastener holes to avoid splitting tie
First Steel Reinforced Plastic Bridge Ties installed in American railroading. Bridge P 424.8 Leeds, AL May, 2005 Manufactured by Plastic Pilings. An additional 1000 ties will be installed in 2006 30
