descripcion del sistema lvt
DESCRIPTION
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Doc No: DPD079.GN
Revision: June-09
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LOW VIBRATION TRACK (LVT)
System description
SONNEVILLE INTERNATIONAL CORPORATION
8109 Tis Well Drive, Suite 513
Alexandria, VA 22306, USA
Tel. +1 703 619 1530
Fax +1 703 619 1534
E-mail [email protected]
www.sonneville.com
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Contents
1. General information
2. Technical description
3. Installation
4. Drainage
5. Transition zones
6. Homologations
7. System behaviour during use
8. References
9. Stages of development
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1. General information
TRIBETON®, the trademark for railway products by CREABETON MATERIAUX AG, has been the
licensee of the twin-block sleeper system by Roger Sonneville for Switzerland since 1953 and
since its further development also for the single-block system for use in the slab track by Bernard
Sonneville. Thanks to the successful and close collaboration with Sonneville International
Corporation, TRIBETON® is marketing the single-block system known as Low Vibration Track
(LVT) in Europe.
2. Technical description
The LVT-system consists of reinforced concrete blocks that are separated from the concrete slab
by a rubber boot specially developed for this purpose. This boot contains an resilient block pad
below the concrete block.
Individual concrete block
Resilient block pad
Rubber boot
This elastic support of the concrete block by means of a pad, which is individually designed for
each project, allows improved load distribution. Regardless of the type of fastening system used,
an elastic rail pad is used as this is decisive for one of the characteristics of this system - two-
stage elasticity.
LVT Standard
Longitudinal and cross section
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LVT High Attenuation (HA)
The LVT HA modification was developed to fulfil the high requirements with regard to vibration
attenuation in urban centres.
Due to its wider block (additional mass) as well as its softer pad, this system has a lower natural
frequency. It therefore bridges the gap between the LVT Standard and a floating slab.
With a view to reducing the application of an expensive floating slab to a minimum and
maintaining constant rail track rigidity for the entire project, LVT HA can replace floating slabs in
a certain frequency range.
LVT Standard LVT HA
Low Profile (LP) for LVT Standard and LVT HA
Depending on the conditions on site, LVT Standard or LVT HA supports with a lower profile can
be used.
280 mm
50 mm
For normal profile LVT Standard and LVT HA, the minimum distance from the bottom edge
of the rail foot (with a 10 mm rail pad) to the top edge of the 1st stage concrete is 280 mm.
240 mm
50 mm
For the low profile variant for LVT Standard and LVT HA, the cross-section can be reduced by
40 mm. The minimum distance from the bottom edge of the rail foot (with a 10 mm rail pad) to
the top edge of the 1st stage concrete is 240 mm.
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LVT for switches and crossings (S&C)
To achieve homogenous behaviour on the
entire track, the LVT S&C system was
developed with elastically mounted single
blocks. Any turnout or crossing geometry can
be reproduced with a combination of only five
different blocks. The exact S&C layout with
proper placement of the blocks is created in
close collaboration with the special trackwork
manufacturer.
Double crossover in Hong Kong, China
Fastening system
The LVT system can be set up with all customary fastening systems. It must be kept in mind that
a rail pad of cdyn = 150 kN/mm is required to achieve the desired two-stage elasticity.
3. Installation
"Top-down“ installation procedure guarantees excellent track geometry by placing the track
(with the pre-mounted LVT blocks) in its end position prior to embedding it in concrete.
Installation and production tolerances for individual blocks are therefore not critical.
Rhomberg Bahntechnik AG’s installation procedure Installation procedure using iron horses
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4. Drainage
Efficient surface drainage can be installed depending on the slope of the slab or specific
ground conditions in the middle or along the side. Drainage gutters can also be installed in
the turnout area up to the turnout's interior.
St. Louis open-air station, USA
5. Transition zones
LVT Standard – ballasted track
Transition zones from the slab track to the ballasted track are designed specifically for each
project respectively. The transition can be designed using a variety of approaches to the
problem, such as varying distances between support points, adjustments of block pad rigidity,
ballast mats, ballast bonding, additional mounted rails, etc.
The suitable procedure is selected in close collaboration with the customer and according to
country-specific regulations. Depending on the project, combinations of various solution variants
can also get a chance.
LVT Standard – LVT HA
To ensure a fluid transition of deflection from the LVT Standard to the LVT HA system, the
distances between supporting points can be modified, and the rigidity of the pads can be
adjusted in a stepwise manner.
6. Homologations
The LVT-system is registered in the following countries:
- Germany Federal Railway Authority (EBA)
- Switzerland Federal Railway Authority (BAV)
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7. System behaviour during use
The LVT-system has been used in Switzerland for more than 15 years without any maintenance
required. The precursor system had been installed in the Bözberg tunnel (Switzerland) as one of
the first slab track systems in the world and can thus show more than 40 years of maintenance-
free use. The SBB considers its experiences with the LVT-system to be very positive.
Even outdoors, the LVT-system displays very good performance when subjected to various
environmental influences. A variety of letters of reference can be obtained on request.
Copenhagen Metro, Denmark Porto Alegre, Brazil
8. References
The LVT-system is being used on more than 730 km of track throughout the world and
references are available regarding its performance in tunnels, at grade, and on bridges.
The list of references, which is available on demand, contains both metro lines as well as lines
that are used with an increased axle load of 36 tons (Pueblo, CO High Tonnage Loop). For this
purpose, the system is adapted to the operator's requirements by utilising a variety of pads.
Apart from the Eurotunnel, at 120 million gross tons per year the busiest tunnel in Europe, the
LVT-system can produce even further important references, all over the world: In addition to the
projects in tunnels and at grade the system is installed successfully on bridges and viaducts
especially in Asia (Honk Kong), Brazil (Porto Alegre, Rio de Janeiro) and England (London).
In Switzerland the Lötschberg base tunnel (max. speed permitted 250 km/h) was equipped with
LVT. The start of installation of the LVT-system in the Gotthard base tunnel (which is worldwide
the longest railway tunnel) is scheduled for 2010.
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Rubber boot depth = 100 mm
Rubber boot depth = 153 mm
9. Stages of development
The origins of LVT can be traced to the twin-block concrete sleepers developed in the 40s by
Roger Sonneville for ballasted track. Then in the 60s, a twin block sleeper with tie-bar was
developed for the ballast less track.
Twin block sleeper with tie-bar
The tie-bars would interfere in many projects and was therefore removed in a subsequent
development step which resulted in the development of the single block system LVT. By
dispensing with the tie-bar, it was possible to increase the rubber boot depth and therefore also
the embedment of the block by more than 50 %. This has positive effects on the track geometry
and the behaviour of the track.
Single block system LVT
Furthermore, leaving out the tie-bar effects improved behaviour for electrical insulation and
simplifies track cleaning. In addition, the track centre can be used as an escape route.