Note: Descriptions are shown in the official language in which they were submitted.
I
Reinforcing steel bar mat, method for the production thereof and method for
the
laying thereof
The present invention relates to a single-axis reinforcing mat and to a method
for the
production thereof.
Reinforcements in reinforced concrete construction are often in the form of
reinforcement
mats which comprise reinforcing steel bars. Reinforcement mats of this type
have either a
single axis or two axes, i.e. have a static effect in one or in two spatial
directions. Single-
axis reinforcement mats consist of reinforcing steel bars, which are welded
onto statically
non-bearing carrying straps, they are rolled up during the production thereof
and are
therefore also referred to as roll mats. Two single-axis reinforcing steel bar
mat layers are
rolled out directly one on top of the other per reinforcement layer, the
second layer being
orthogonal to the first. The roll mats are loaded and transported to the
construction site as
rolls. There, they are unloaded from the lorry using a crane, stored in a
suitable location,
and lifted onto the resulting shell construction by the crane at the
appropriate time, where
they are rolled out by two or more workers. Machines for producing rolled-up
single-axis
reinforcing steel bar mats of this type, which also comprise reinforcing steel
bars having
individually different lengths or thicknesses within one mat, are described in
the European
patent applications EP 0 667 343 Al, EP 0 862 958 Al, EP 0 919 309 Al and EP 2
315 637
Al by the applicant.
Each concrete slab of the resulting structure comprises two reinforcement
layers at a
distance from one another, one reinforcement layer composed of the described
single-axis
reinforcing steel bar mats consisting of a plurality of rolled-out partial
mats according to the
local conditions of the structure to be erected. These must be placed in the
resulting
structure in the correct sequence according to a previously created layout
plan and rolled
out in the correct direction. It is not unusual to unroll 15, 20 or more
partial mats per
reinforcement layer. For loading onto a lorry, unloading and placement in the
resulting
building, a lot of crane time is required. At the same time, a correspondingly
large storage
space on the construction site is required. The great logistical effort
required is a
disadvantage of this prior art.
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The invention therefore addresses the problem of providing a rollable single-
axis reinforcing
steel bar mat which is logistically easier to handle.
To address this problem, the present invention provides a plurality of single-
axis reinforcing
steel bar mats, each comprising reinforcing steel bars attached to carrying
straps, which are
interconnected in a laying sequence to form a handling unit.
More particularly, in one aspect, the present invention provides a handling
unit comprising a
plurality of rollable, single-axis reinforcing steel bar mats which are
interconnected in a
laying sequence, wherein each reinforcing steel bar mat comprises reinforcing
steel bars
which are attached to carrying straps, and a visual indicator of the end of
the mat provided
between the individual reinforcing steel bar mats of the handling unit,
wherein the indicator
comprises: a reinforcing steel bar spacing of 30 cm or more, a colour marking
on the
carrying straps, a colour marking on one carrying strap, or a coupling piece
between the
carrying straps.
In another aspect, the present invention provides a method for producing a
handling unit as
defined herein, wherein a mat former, after a first reinforcing steel bar mat
has been
produced, continuously manufactures at least one additional reinforcing steel
bar mat, and
wherein a region without reinforcing steel bars is produced between the two
reinforcing
steel bar mats.
In another aspect, the present invention provides a laying method for a
handling unit as
defined herein, wherein: a) a handling unit is brought into a building to be
erected;
b) the first reinforcing steel bar mat of the handling unit is unrolled and,
when the end of the
mat is reached, this being visible on account of the visual indicator of the
end of the mat, the
connection to the following reinforcing steel bar mat is separated; c) the
next reinforcing
steel bar mat is unrolled and, when the end of the mat is reached, this being
visible on the
basis of the visual indicator of the end of the mat, the connection to the
following reinforcing
steel bar mat is separated; and d) step c) is repeated until the handling unit
has been
completely unrolled.
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Very advantageously, the invention proposes interconnecting a plurality of
reinforcing steel
bar mats to form a transportable unit, but in this case preserving the laying
sequence of the
individual mats. Accordingly, the first reinforcing steel bar mat to be
unrolled in the
production process is the last reinforcing steel bar mat to be produced, and
is therefore
located on the outside of the rolled-up handling unit. Then, the second
reinforcement mat to
be unrolled follows towards the inside, then the third and so on. The
individual reinforcing
steel bar mats are advantageously interconnected by the respective carrying
straps so that
each of the carrying straps passes through the entire handling unit. The
reinforcing steel
bars of the individual reinforcing steel bar mats are then welded onto the
continuous
carrying straps. Very advantageously, the handling of the individual
reinforcing steel bar
mats is thus simplified: now only a bundle of interconnected reinforcing steel
bar mats has
to be moved, i.e. loaded, unloaded, stored at the construction site and placed
in the
resulting structure. This reduces the required bearing surface by up to 50
(Yo, the loading
and unloading times by up to 50 %, and the required crane time by at least 25
%. The crane
only has to lift the handling unit into the resulting structure and, once
there, transport it from
one laying location to the next, and therefore there is no longer any need for
long swivelling
paths. In this case, the original unrolling layout can advantageously be
maintained. A
plurality of light reinforcing steel bar mats can advantageously be assembled
to form a
single, heavier mat, which makes good use of the loading capacity of a lorry.
Since the
laying sequence is not changed during the assembly ("pooling") of the
reinforcing steel bar
mats into a single handling unit, no problems result for the processors on the
construction
site. It can follow the usual predefined unrolling pattern.
In one embodiment of the invention, it is provided that the interconnected
reinforcing steel
bar mats are interconnected in descending order of mat width. Accordingly, the
widest mat
to be unrolled is located on the outside of the handling unit, the narrower
reinforcing steel
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bar mats are rolled up inside the handling unit and follow the first in the
unrolling sequence.
This results in a particularly advantageous centre of gravity for the handling
unit.
In one embodiment of the invention, it is provided that the interconnected
reinforcing steel
bar mats of a handling unit are arranged symmetrically about the longitudinal
axis of the
handling unit This also leads to a particularly advantageous centre of
gravity. A crane driver
would not be surprised by eccentric centres of gravity which cannot be seen
from the
outside of a rolled-up handling unit.
According to the invention, it is further provided that a visual indicator of
the end of the mat,
in particular in the form of a reinforcing steel bar spacing of 30 cm or more,
is provided
between the individual reinforcing steel bar mats of a handling unit. In order
to mark each
end and each start of the interconnected reinforcing steel bar mats, an
indicator is provided
according to the invention. This may consist for example of a colour marking
on the carrying
straps or on one carrying strap. However, a reinforcing steel bar spacing of
30 cm or more
is preferred. Since such a large reinforcing steel bar spacing is not
permissible according to
the relevant DIN standards, an operator on the construction site would notice
such a
spacing immediately. Said operator would recognise from the oversized
reinforcing steel bar
spacing that one reinforcing steel bar mat was ending and the next was
starting. He can
therefore readily cut through the thin carrying straps using a simple pair of
tin-snips and
then either immediately unroll the next reinforcing steel bar mat or, as will
be described
further below, place the rest of the handling unit in another location in the
resulting
reinforcement layer.
As a result of the fact that the first reinforcing steel bars of a reinforcing
steel bar mat which
is first when viewed in the unrolling direction, and/or the last reinforcing
steel bars of a
reinforcing steel bar mat which is also last when viewed in the unrolling
direction of the
handling unit comprise shorter, in particular eccentrically arranged,
reinforcing steel bars,
advantageously supports, entrances or the like can be avoided without any
problems at the
start and at the end of the unrolling process.
In one embodiment of the invention, it is provided that a plurality of
handling units are
interconnected in a laying sequence to form a complete handling unit. This
development of
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the inventive concept of pooling individual reinforcing steel bar mats has the
advantage of
making the handling units even bigger, if this is desirable for transportation
purposes. This
is the case in particular when many smaller reinforcing steel bar mats form
part of one
reinforcement layer.
The invention also includes a method for producing a handling unit according
to what has
been described previously, in which a mat former, after a first reinforcing
steel bar mat has
been produced, continuously produces at least one additional reinforcing steel
bar mat, a
region without reinforcing steel bars being produced between the two
reinforcing steel bar
mats. In other words, the mat former continuously produces reinforcing steel
bar mats which
are not separated from one another. The conventional cutting through of the
carrying straps
is no longer required during the individual production of the mats.
Lastly, the invention also includes a laying method of a handling unit, as has
been
described previously. In this laying method, a handling unit is placed in a
structure to be
created, the first reinforcing steel bar mat of which is unrolled and, when
the end of the mat
is reached, the connection to the following reinforcing steel bar mat is cut
through, the next
reinforcing steel bar mat is rolled out and, when the end of the mat is
reached, the
connection to the now following reinforcing steel bar mat is separated, the
previously
mentioned steps are repeated until the handling unit is rolled out and thus
dismantled.
In one embodiment of this method, it is provided that the rest of the handling
unit which
remains after unrolling one or more reinforcing steel bar mats is placed at a
second laying
location inside the structure to be created by means of a crane. This means
that a handling
unit may also contain a plurality of reinforcing steel bar mats which are not
to be laid
immediately one after the other spatially. Merely the temporal sequence of the
unrolling is to
be maintained, not necessarily the local sequence.
The invention is described in a preferred embodiment by way of example with
reference to
drawings in which further advantageous details can be found in the figures.
Functionally like
parts are provided with the same reference numerals.
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The figures of the drawings show in each case unrolled partial views of
embodiments of a
handling unit.
Fig. 1: a first embodiment,
Fig. 2: a second embodiment,
Fig. 3: a third embodiment, and
Fig. 4: a fourth embodiment.
Fig. 1 is a partial view of the simplest form of an unrolled handling unit 1
comprising the first
three of a plurality of reinforcing steel bar mats 2. The carrying straps 3
and the individual
reinforcing steel bar mats 4 can easily be seen. The indicator 5 can also
easily be seen, in
this case being a region without reinforcing steel bars 2 which is
approximately 30 cm big.
According to the invention, greater spacings than 30 cm would also be
possible, but the
spacing must not be clearly less than this value, in order to safely mark the
end of the mat.
Likewise, the individual mats 2 separated by regions 5 can easily be seen. The
handling
unit 1 shown in Fig. 1 comprises reinforcing steel bar mats 2 which have a
uniform
reinforcing steel bar length and mat length. The unrolling direction 8 is
indicated by an
arrow, the remaining, still rolled-up part of the handling unit 1 is not
shown, but it is joined
below the indicated fourth mat 2. The length of the reinforcing steel bars 2
here defines the
overall width of the handling unit 1. According to the invention, the bars 2
could also consist
of a material other than reinforcing steel, for example steel bars having a
smooth surface.
They could also vary in terms of diameter from mat to mat or within one mat,
and also in
terms of bar length and edge orientation. Variation in edge orientation means
that not all the
bars have to start flush on one side. The invention can be applied to all
rollable mats. By
means of the invention shown, for example 4-6 partial mats of a reinforcement
layer can be
assembled and thus easily transported. According to the invention, it would
also be possible
to provide no continuous carrying straps during the production process, but
rather to
detachably fasten said straps to one another for example using a coupling
piece. After the
corresponding mat has been unrolled, the coupling piece would then be detached
so that
the second mat is released. Lastly, it would also be conceivable to loosely
roll up the
individual mats to form a handling unit, i.e. comprising separated carrying
straps, and to
provide a different type of transport securing means, wherein it is to be
assumed that the
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inner layers of the handling unit are held by the pressure of the outer layers
at least during
transportation. This would result in a particularly simple handling unit.
Fig. 2 shows an unrolled handling unit in which the successive reinforcing
steel bar mats 2
are assembled in descending order of width, wherein the decrease does not have
to be
large. At the same time, in this embodiment, all of the mats 2 are arranged
symmetrically
about the longitudinal axis 6.
Fig. 3 shows a handling unit 1 in which two smaller mats 2, which have to be
rolled out side-
by-side, since they are intended to receive a concrete pillar therebetween,
are arranged
side-by-side. It is likewise shown that the first two reinforcing steel bars 4
of a first
reinforcing steel bar mat 2 to be unrolled turn out shorter than the following
bars of the
same mat. This advantageously makes it possible to avoid a pillar or the like
in that the still
rolled-up handling unit 1 is put down by the crane at a slight distance from
the edge of the
reinforcement layer, opened, and the topmost centimetres of the mat towards
the edge are
rolled out, as is shown at the side of Fig. 3. The rest of the mat is then
rolled out in the
opposite direction.
Fig. 4 lastly shows a complete handling unit 7 composed of two handling units
1, wherein
the inner handling unit 1 which is to be laid second is shown as a dashed
line, and wherein
for the sake of clarity, in each case only the topmost layer of the rolled-up
reinforcing steel
bar mats 2 of a handling unit are shown.
When assembling the individual mats 2 to form a handling unit 1, the maximum
weight of
the handling unit must be adhered to, which is restricted less by the loading
capacity of a
lorry or the bearing capacity of a crane than by the bearing capacity of the
spacers for the
specific reinforcement layer. Conventionally, such spacers cannot withstand
burdens
greater than 100 kg/m. Therefore, when rolled up, the complete handling unit
must not
exceed this amount, unless spacers having correspondingly large dimensions are
provided
on the construction site.
By means of assembling individual reinforcing steel bar mats to form a common
handling
unit according to the invention, production is very advantageously simplified,
the required
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bearing surface is considerably reduced, the loading/unloading time is greatly
decreased
and the required crane time is considerably reduced. This invention therefore
very
advantageously complements the very fast output of roll mats to form an
economically very
cost-effective overall system with respect to laying times and labour costs.
List of reference numerals
1 handling unit
2 reinforcing steel bar mat
3 carrying strap
4 reinforcing steel bar
mat width
6 longitudinal axis
7 complete handling unit
8 unrolling direction
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