Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a thrust stud,
particularly for joining concrete floor elements to
each other and to concrete wall elements, such that an
expansion gap remains between the individual floor ele-
ments or between the floor element and the wall element.
Structures comprised o walls and floor elements
always present the problem of positioning the floor ele-
ments between or against the walls in such a way that
no damage occurs from natural expansion. Customarily,
for each orthogonal, horizontal direction the floor
element is caused to abut on at least one of its sides
against bearing elements, rather than being rigidly and
permanently affixed to the wall itself. Under this
arrangement, sliding bearing means are provided between
the bearing elements and the floor, in order to avoid
thrust damage to the bearing elements and thus to the
wall.
'rhis technique has proven feasible, but has the
disadvantage that the wall structures must be overly
thick, due to the bearing elements which are required.
Also, the sliding bearing means must be carefully in-
stalled in order to ensure that they function correctly.
'rO avoid these disadvantages, thrust studs have
been developed in which a steel bar extends on one end
into a sleeve, such that, when the bar is fixedly cast
into the wall or into an end face of a floor element,
and the sleeve is cast into the opposing element, -
which is a floor element, the said opposing element
can glide over the free end of the bar. This avoids
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the combination of bearing elements and sliding bearing
means, yet still relieves the floor from having to
accommodate the expansion play.
These known thrust studs, however, have their own
disadvantages. The concrete surrounding them is sub-
jected to enormous stresses. The entire weight of the
floor elements which abut the wall is borne in very
small regions of the wall.
This leads to the development of cracks and
locally excessive compression of the concrete, with
direct consequences to the safety of the structure. The
only remedial measure available is to employ a large
number of such thrust studs, which becomes expensive.
Accordingly, the object of the invention is to
devise a thrust stud which h'as the advantages of the
known elements of the general type and does not have
the disadvantages of the said known elements, in par-
ticular being improved in the areas of safety and
economy.
A construction in accordance with the present
invention comprises a thrust stud located within an
expansion gap between two concrete elements and in-
cludes at least two steel bars extending between the
concrete elements which are joined together in
parallel orientation by at least one steel plate. The
thrust stud further comprises at least two sleeves
mounted in one of the concrete elements and re-
spectively slidably receiving respective ends of the
steel bars. The sleeves are jointed together in
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parallel orientation by at least one other steel plate
in one of the concrete elements. The longitudinal axis
of the axes of the sleeves is oriented parallel to the
longitudinal axes of the steel bars wherein the steel
bars are fixedly mounted to the other of the concrete
elements and are slidable within the sleeves to thereby
enable expansion and contraction of the gap.
Two advantageous embodiments of the inventive
thrust stud are described hereinafter, with reference
to the drawings.
Fig. 1 shows a partial longitudinal cross
section, side view, of the first embodiment of an in-
ventive thrust stud;
Fig. 2 is a partial longitudinal cross section,
top view, of the same thrust stud;
Fig. 3 is a transverse cross section of the same
thrust stud;
Fig. 4 is a side view of the element with the
bars, of a second embodiment of an inventive thrust
stud;
and
Fig. 5 is a front view of the element of Fig. 4,
with the force exertion plate indicated by the dashed
line.
In Fig. 1 the dot-dashed lines represent a
concrete floor element 1 which is joined, by means of
an inventive thrust stud 4, to a wall 2 in which a ~
second concrete floor element 3 has been incorporated.
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The thrust stud, as seen best from Fig. 2, is comprised
of two steel bars 5 and two sleeves 6. The two steel
bars 5 are joined together on the top and bottom by
respective steel plates 7, and in the same way the two
sleeves 6 are joined together by two steel plates 8.
Advantageously, the steel plates are joined to the
respective members, bars or sleeves, by welding,
whereby the longitudinal axes M of the steel bars 5
coincide with the longitudinal axes _ of the sleeves 6.
Thereby it is assured that the sleeves 6can slide
freely over the steel bars 5 without problems, i.e.
seizing.
The sleeves 6 joined by the steel plates 8 are
also joined to a front plate 9 which promotes easy
mounting of the thrust stud.4 in the concrete form
used in producing the concrete floor element 1 before
the concrete is poured, since the front plate can be
nailed to the form planks on the end face of the floor
element 1, via spikes or nails run from the inside of
the floor element, (floor element cavity in the form)
through the holes 10 (Fig. 3) provided therefor.
Figs 4 and 5 illustrate a second advantageous
embodiment of the inventive thrust stud, wherein the
two steel bars 5' are joined together by a single steel
plate 7'. The element, with the sleeves, not shown,
also has only a single joining plate. Since this
embodiment of the thrust stud is particularly suited
for vertical construction, it comprises compressive
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reinforcing means 11 in the form of steel reinforcing
bars which fixedly anchor the two elements (the steel
bars 5' and the sleeves) in the concrete, against
movement along the longitudinal axes M and m of the
said steel bars 5' and sleeves, and which reinforcing
bars transmit to the concrete the forces borne by the
said two elements, said transmission being in an
improved manner and over an increased surface.
In order to be able to more easily position the
assembly with the two steel bars 5' in the concrete
floor element 3, and in particular to improve the
transmission, into the surrounding concrete, of the
forces borne by said bars, the steel bars 5' are
advantageously provided with a force transmission
plate 12 which in the completed structure comes to rest
against the end face of the concrete floor element.
If the material used for the inventive thrust
stud 4 is exclusively high strength material which is
also corrosion resistant, it may beemployed without
20 problems in all applications. Because both the steel
bars 5 and the sleeves 6 are joined by plates 7 and 8,
respectively, to form assemblies which are rigid to
bending, the inventive thrust stud when installed
horizontally can bear very large lateral thrusts without
suffering damage.
If floor elements having extremely high weights
or loads are to be inserted between walls, inventive
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thrust studs according to the first embodiment may be
installed also in a vertical orientation. In such
cases, Leonhard's law is no longer followed with regard
to the section modulus and moment of inertia. Rather,
the thrust stud is the equivalent of a solid, vertical
support. In such installation configurations the two
steel bars 5 no longer operate as individual bars. In
any event a precondition is that the steel plates bind
the bars and the sleeves, respectively, together in
such a way as to produce an assembly which is rigid to
bending.
Some of the features of the inventive thrust stud
may be varied from those of the above-described
advantageous embodiments without experiencing loss of
the advantages afforded. Thu's, it is possible that the
material of the sleeves 6, the plates 8 joining them,
and the front plate 9 may be high strength plastic
rather than corrosion-resistant steel, and that the
assembly comprising the sleeves 6, plates 8, and front
plate 9 may have a unitary structure. Further, more
than two bars and two sleeves, respectively, may be
~oined by connecting plates to form rigid assemblies of
a plurality of bars, and a plurality of sleeves,
respectively.
