Note: Descriptions are shown in the official language in which they were submitted.
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Concrete sleeper and solid carriageway
The invention relates to a concrete sleeper for a solid carriageway, with an
anchor
block, which is inserted with its upper section into an underside recess in
the
concrete sleeper and is mounted elastically by means of a ring produced from
an
elastomer and which can be inserted with its lower section into a fillable
clearance
in a top layer of the solid carriageway.
In DE 202 13 667 U1, a concrete sleeper fora solid carriageway is proposed.
The
solid carriageway comprises a lower supporting layer, a first applied asphalt
layer
and a second asphalt layer, applied as a top layer. The top layer has
clearances,
inserted in which is an anchor block, which is consequently arranged with its
lower
section in the clearance and with its upper section in the underside recess in
the
concrete sleeper. The concrete sleeper is formed as a wide sleeper, i.e. only
a
small distance is provided between two adjacent concrete sleepers. Such a
solid
carriageway is offered by the applicant under the name Getrac (registered
trademark).
A similarly constructed solid carriageway is described in DE 102 30 740 Al.
The
elastic ring arranged between the concrete sleeper and the anchor block is
conically
formed on its outer side, thereby making insertion easier. On the underside of
the
concrete sleeper there is a thin nonwoven, to compensate for any possible
unevennesses of the top layer. Since the concrete sleeper is hard-bedded
because
of the hard supporting layers, which in the case of this system are usually
produced
from asphalt, it is usually mounted with a highly elastic fastening, which can
absorb
the loads occurring when it is passed over by rail vehicles and distribute
them in the
longitudinal direction.
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Such solid carriageways with elastic intermediate layers represent a mass-
spring
system, by which tremors and structure-borne sound can be transferred to
adjacent
surface areas, buildings and structures. These waves may both cause noises in
the
audible frequency range (secondary airborne sound) and cause vibrations of the
ground or of buildings. When designing such a solid carriageway, it is
therefore
endeavored to fix the frequency range and the amplitude of the vibrations
produced
such that the tremors or the sound generated can remain restricted to certain
frequency ranges that do not represent any disturbance.
Embodiments of the invention are therefore based on the notion of providing a
concrete sleeper for a solid carriageway by which tremors are transferred to a
lesser extent to adjacent areas.
Accordingly, there is provided a concrete sleeper for a solid carriageway
comprising: an anchor block having a step with a downwardly increased diameter
with an upper section of the anchor block being insertable into an underside
recess
in the concrete sleeper, and a lower section of the anchor block being
insertable
into a fillable clearance in a top layer of the solid carriageway; an
elastomer ring
between the step of the anchor block and the underside recess of the concrete
sleeper for elastically mounting the concrete sleeper to the anchor block; a
base of
an elastic material on the underside of the concrete sleeper; wherein an outer
edge
of the step of the anchor block is rounded and the underside recess in the
concrete
sleeper has a peripheral step to engage an upper outer corner of the elastomer
ring.
The invention is therefore based on the finding that a considerable
improvement,
i.e. a reduction, in vibrational emissions can be achieved by the spring of
the mass-
spring system being chosen to be as soft as possible while compatible with the
permanent way and by the mass arranged above the spring being increased.
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In the case of conventional solid carriageways, only the highly elastic rail
fastening
has resilient properties. The concrete sleeper, which may have a considerable
mass
of 300 ¨ 1 200 kg, is however mounted hard on the top layer in the case of the
conventional solid carriageway.
By contrast, in embodiments of the present developemnt, a base of an elastic
material is arranged on the underside of the concrete sleeper, whereby the
mass
(concrete sleeper) mounted on the spring (base) is increased considerably in
comparison with an only elastically mounted rail of a conventional solid
carriageway. Tests have shown that, as a result of the concrete sleeper
according
to the invention, tremors are transferred to a lesser extent to the
surroundings in
comparison with a conventional solid carriageway.
The base of the concrete sleeper according to embodiments of the invention may
be produced from an elastomer; particularly preferred in this case is EPDM
(ethylene-propylene-diene monomer). The base may be unattached or
alternatively
connected to the concrete sleeper, for example adhesively bonded.
In the case of the concrete sleeper according to the embodimetns of the
invention,
the base is designed according to static and dynamic requirements; in
particular,
the thickness and the stiffness of the base are set such that, when it is
passed over
by a rail vehicle, a required or desired settlement that is also compatible
with regard
to the stability of the rails is achieved. The base may preferably have a
thickness of
between 6 mm and 20 mm; a base thickness of between 8 mm and 14 mm is
particularly preferred. In the case of such a base, the settlements may reach
1.5
mm to 4 mm.
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In order to improve the mechanical strength of the base of the concrete
sleeper
according to the invention, the base may be provided with a nonwoven mat on
one
or both sides.
A development of the invention may provide that the base has a clearance in
the
region of the underside recess for the anchor block. If appropriate, this
clearance
may also be provided at the ends of the sleeper. This clearance may be
circular or
square, so that the anchor block can be mounted without any problem. The
anchor
block does not necessarily have to be round or cylindrical, it may furthermore
also
be rectangular or hexagonal. Alternatively, the base may be formed as two
parts, in
that a first base section is arranged under one sleeper block and a second
base
section is arranged under the second, opposite sleeper block. Depending on the
respective design, it may also be provided that the base is not formed with
its full
surface area under a sleeper block or a rail bed; instead, it may for example
be
formed as a strip that is made narrower than the rail bed.
The rounded step prevents the ring produced from the elastomer from being
damaged by settling movements that occur millions of times during operation.
Since, unlike in the prior art, there is no sharp edge at this location,
damage to the
elastomer ring is avoided.
The width of the step of the anchor block may in this case be set such that
the ring
lies approximately with half its radial width on the step of the anchor block.
The ring preferably lies approximately over half its radial width against the
step of
the concrete sleeper. This means that the ring, which has a rectangular or
approximately rectangular cross section, lies with contact at two diagonally
opposite
corner points, so that when subjected to loading it undergoes a shearing
deformation and deforms in a way similar to a parallelogram. The cause of this
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deformation is that it lies on the one hand with its upper, outer corner
against the
step of the concrete sleeper and on the other hand with its lower, inner
corner
against the step of the anchor block. If the concrete sleeper is subjected to
vertical
loading when it is passed over by a rail vehicle, first the base of the
concrete
5 sleeper and at the same time the ring undergo a vertical spring
deflection; horizontal
forces occurring are introduced into the supporting layer via the anchor
block. The
ring is preferably circularly formed; also conceivable furthermore are other
configurations that are adapted to the cross section of the anchor block, for
example
the ring may be formed as a rectangular, square or hexagonal surround.
In the case of the concrete sleeper according to the invention, the ring is
consequently clamped at the top and bottom, since it lies at the top against
or on
the step of the clearance in the concrete sleeper and lies at the bottom
against or
on the step of the anchor block. In a preferred embodiment, the ring is
mounted or
supported at the top on its outer side and at the bottom on its inner side.
This
results in the previously explained parallelogram-like shearing deformation,
which
allows a certain vertical movement of the mounted concrete sleeper. This
shearing
deformation has the advantage that the ring is only subjected to moderate
loading
thereby, as a result of which a long service life can be expected.
The invention relates furthermore to a solid carriageway, comprising a number
of
concrete sleepers of the type described above, which are embedded in a top
layer
or a supporting layer, the top layer or the supporting layer having on its
upper side
clearances for the anchor blocks that are filled with a casting compound.
Further advantages and details of the invention are explained below on the
basis of
an exemplary embodiment with reference to the drawings. The drawings are
schematic representations in which:
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Fig. 1 shows a side view of a concrete sleeper according to the
invention;
Fig. 2 shows a plan view of the concrete sleeper from Fig. 1;
Fig. 3 shows a sectional view taken in the transverse direction of a
sleeper
embedded in a solid carriageway; and
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Fig. 4 shows a longitudinal section of the concrete sleeper according
to the
invention embedded in a solid carriageway.
The concrete sleeper 1 shown in Figs. 1 and 2 in a side view and a plan view
is
formed as a wide sleeper and comprises two sleeper blocks 2, 3, on the upper
side
of which rail beds 4, 5 are formed. The two sleeper blocks 2, 3 are connected
to one
another by a middle section 6, which ¨ as can be seen in Fig. 2 ¨ has a
smaller
width than the sleeper blocks 2, 3. The wide sleeper that is described in this
exemplary embodiment should not be understood as a restriction, since the
concrete sleeper may also be of some other form, for example a cuboidal form.
With
the rail beds 4, 5 and the middle section 6, the sleeper blocks 2, 3 form an
integral,
monolithic component. Respectively arranged under the sleeper blocks 2, 3 is a
base 7, 8 of an elastic material. In the exemplary embodiment represented, the
base consists of EPDM (ethylene-propylene-diene monomer) and has a thickness
of 14 mm. However, the thickness indicated should not be understood as a
restriction; rather, the thickness of the base may typically be between 6 and
20 mm;
the base thickness used is set within the limits of the stiffness and the
tuning
frequency of the concrete sleeper.
On its underside, the concrete sleeper 1 has in its middle section 6 an
annular
recess 9, into which an anchor block with an elastomer ring can be inserted.
In the
fitted state, the concrete sleeper 1 is coupled via the anchor block to the
supporting
layer of a solid carriageway, so that horizontal forces can be transferred
into the
underlying ground. Vertical forces are introduced from the concrete sleeper 1
into
the supporting layer via the base 7, 8. In the case of a solid carriageway, at
least
every second or third concrete sleeper is provided with an anchor block.
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Fig. 3 shows the concrete sleeper 1 in a section taken in the transverse
direction in
the region of its recess, after it has been fitted into a solid carriageway.
The
concrete sleeper 1 has a number of reinforcing rods 10, 11, which may be
untensioned or pretensioned. Arranged under the concrete sleeper 1 is an
anchor
block 12, which is secured by a mounting band 13. Between the anchor block 12
and the concrete sleeper 1 there is an elastic ring 14, which is produced from
an
elastomer. In Fig. 3 it can be seen that the anchor block 12 has a step 15.
The
anchor block 12 has a greater diameter under the step 15 than above the step
15.
The outer edge formed by the anchor block 15, on which a corner of the ring 14
lies,
is rounded. In Fig. 3 it can also be seen that the ring 14 lies approximately
with half
its width on the rounded step 15; the outer corner of the ring 14 is in
contact with a
side face 16 of the recess 9. The outer corner of the ring 14 is not
vertically
mounted, so that the ring 14 can at least slightly move vertically. A clear
space is
formed between the upper side of the anchor block 12 and the underside of the
recess 9.
The recess 9 in the concrete sleeper 1 has a peripheral step 17 with an
outwardly
increased diameter; the ring 14 lies with its upper outer corner against this
step 17.
Like the step 15, the step 17 is rounded, thereby avoiding damage to the ring
14
when it undergoes deformation under load. In Fig. 3 it is shown that the ring
14 lies
approximately over half its radial width against the step 17 of the recess 9
in the
concrete sleeper 1.
In the production of a solid carriageway, an asphalt supporting layer 18 is
provided
with clearances 19 for the anchor blocks 12. The clearances 19 are
cylindrically
formed and adapted to the size of the anchor blocks 12; the depth of the
clearances
19 is chosen such that a clear space 20 remains under the anchor block
inserted
together with the concrete sleeper and is subsequently cast with a casting
compound or a casting mortar 21 after the positioning and alignment of the
concrete
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sleeper 1. Casting slits 22, through which the casting compound 21 is
introduced,
extend laterally from the clearance 19.
The concrete sleepers 1 have rail fastenings, which ¨ unlike in the case of
conventional solid carriageways ¨ are not highly elastic rail fastenings. The
rail
fastenings used allow compensation in the vertical and lateral directions. The
vertical compensation is made possible by shims of varying thickness, the
lateral
compensation by angled guiding plates of varying width. In addition, there is
a hard
intermediate layer, which is arranged between the rail and the surface of the
concrete sleeper and consists of EVA (ethylene vinyl acetate).
Fig. 4 shows a solid carriageway 23 comprising the concrete sleeper 1, mounted
on
which are rails 24, which are held by rail fastenings 25. The concrete sleeper
1 is
connected via the anchor block 12 to an asphalt top layer 26, which is located
above an asphalt supporting layer 27. The asphalt supporting layer, produced
in
multiple layers, is mounted on a frost protection layer 28. The loads
occurring when
the solid carriageway 23 is passed over are substantially introduced via the
bases
7, 8 arranged under the concrete sleeper 1 into the asphalt top layer 26.
Settlements of typically 1.5 ¨ 4 mm occur thereby. This produces the advantage
that the entire mass of the concrete sleeper 1 is elastically mounted, whereby
the
tuning frequency of transferred vibrations is lowered. On the other hand, the
spring
stiffness of the base 7, 8, which has the function of a spring in the spring-
mass
system, is of a soft design, which similarly has a positive effect on the
tuning
frequency.
When it is passed over by rail vehicles, the sleeper is moved vertically down
and
subsequently up again. The ring 14 can absorb these movements with almost no
wear, since it lies at two diagonally opposite corners against the anchor
block 12 on
the one hand and against the recess 9 in the concrete sleeper 1 on the other
hand.
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In the case of another configuration, the solid carriageway is produced in a
concrete
type of construction. In this case, the concrete sleepers are mounted on a
concrete
supporting layer by means of the anchor block.
