Note: Descriptions are shown in the official language in which they were submitted.
CA 02484107 2004-10-07
Reinforcing Element For Concrete Construction
Description
The invention relates to a reinforcing element for concrete construction in
the
form of a set bolt which consists of a rod-shaped section with a cross-
sectional
enlargement on the end.
Set bolts of this type are primarily used to transfer compressive and
transverse forces, however, they can also transfer tractive forces. They are
predominantly used as shearing reinforcement or punching reinforcement in
structural concrete parts, moreover, as compressive or transverse stress bars
in insulating bodies which are inserted between a building ceiling and a
projecting balcony platform.
To date, these set bolts consist of structural steel or, ~nrhen there are
corrosive
influences, of high-grade steel, however, this considerably increases the
manufacturing costs.
Recently, reinforcing bars are also manufactured from glass-fibre reinforced
plastic, in particular, when it is a question of corrosion resistance or low
heat
conduction. In this case, it is duroplast which has a g9ass-fibre constituent
of
about 50% to 80~'o to obtain the desired strength. Since duroplast cannot be
subsequently shaped, to date, reinforcing elements consisting of glass-fibre
reinforced plastic have become known only in the form of bars with a constant
cross section.
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It is now the object of the present invention to produce a reinforcing element
in
the form of a set bolt in which at least the head, i.e. the cross-sectional
enlargement on the end, consists of glass-fibre reinforced plastic. The set
bolt
should thereby be distinguished by high stress absorption in direction of the
strain and stress and economical to manufacture.
According to the invention, this object is solved in that at least the cross-
sectional enlargement of the set bolt on the end consists of glass-fibre
reinforced plastic and that an axial bore is situated in its centre and that
i:his
bore and the area of the rod-shaped section surrounded by it engage in one
another in a form-locking manner.
While up to now the cross-sectional enlargement on the end is produced by
compressing a cylindrical rod, according to the invention, a separate part is
used for the cross-sectional enlargement and this separate part is engaged in
a form-locking manner with the rod-shaped section of the set bolt. This
ensures the transfer of high forces from the cross-sectional enlargement to
the
rod-shaped section even when the cross-sectional enlargement and, optionally,
also the rod-shaped section consist of plastic.
Generally, the transfer of tractive and compressive forces through the set
bolt
is in the fore, which is why it is advisable to form the form-locking
engagement
with a profiling which is primarily effective against axial forces, i.e. by
transverse ribs, bores, milled recesses or threads.
To further promote the force transfer between rod-shaped section and cross-
sectional enlargement on the end, an especially advantageous embodiment of
the invention lies in that the cross-sectional enlargement has a tubular
extension extending along its axial bore, namely in a length which corresponds
at least to three times, preferably at least four times, the diameter of the
bore.
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This results in a large form-closed contact area is obtained between the two
parts and, accordingly, a corresponding high transfer of force.
For the same purpose, it is advantageous that the tubular extension has an
increasing wall thickness in direction of the cross-sectional enlargement,
i.e. is
formed sonically, and at its end passes into the cross-sectional enlargement
at
an angle of less than 90°, in particular, of less than 60°.
If the closing shape between the rod-shaped section, on the one hand, and the
tubular extension with its cross-sectional enlargement, on the other hand, are
formed by threads, then it is possible to connect both parts to one another by
screwing and subsequent gluing or fusing. However, it is especially
advantageous if the cross-sectional enlargement, optionally with its tubular
extension, is joined with the rod-shaped section by spraying on in a molten
state. In particular, this applies even when the rod-shaped section itaelf
consists of a glass-fibre reinforced plastic.
Finally, the present invention also relates to an in:>ulating body which is
equipped with the reinforcing elements described .above and is inserted
between two structural parts to be insulated, in particular, a building
ceiling
and a balcony platform. In this case, the corrosion-resistant properties of
'the
glass-fibre reinforced plastics and its low heat conductivity are especially
advantageous. The reinforcing element according to the invention can be aced
in the insulating body for the transfer of tractive, compressive and
transverse
forces.
To absorb transverse forces, it has been customary to date in insulating
bodies
to lead the corresponding reinforcing bars diagonally through the insulating
body and to bend them back into the horizontal plane outside of said
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insulating body. Since this is rather difficult to do with reinforcing bars
made
of glass-fibre reinforced duroplast, i.e. the transverse bar must extend
diagonally into the structural concrete part adjoining the insulating part, it
is
advantageous, for the optimal introduction of force into the structural
concrete
parts, to form the outer end of the cross-sectional enlargement by a plane
which is diagonal to the axial direction of the transverse bar such that this
plane extends more or less horizontally in the adjacent structural concrete
part.
Further features and advantages of the invention can be found in the following
description of embodiments with reference to the drawings, showing
Fig. 1 a side view in the end area of a set bolt;
Fig. 2 an axial section of Fig. 1;
Fig. 3 a side view according to Fig. 1, however, in an alternative
embodiment;
Fig. 4 to Fig. 5 an insulating body with the set bolt according to the
invention in a vertical section;
Fig. 6 to Fig. 9 possible applications for the set bolt according to the
invention.
Figures 1 to 3 each show only the one end of a reinforcing element in the form
of a head. The other end can look exactly the same, however, it can also be
shaped differently or end as a normal reinforcing bar. The reinforcing bar or
its illustrated rod-shaped section is designated with 1, the cross-sectional
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enlargement on the end with 2. As can be seen, the cross-sectional
enlargement 2 is a self-contained part. It no longer has the conventional form
but a tubular extension 2a with which it surrounds the rod-shaped section l..
An axial bore 3 runs in the centre of the cross-sectional enlargement 2 and
its
extension 2a. In the embodiment, said axial bore 3 is continuous, however, it
can also be in the form of a blic~d-end bore. The essential point is that, on
the
one hand, the outer side of the rod-shaped section 1 has a profiling 4 at
least
in the area inserted in the bore 3 and that the bore 3 has a profiling 5
corresponding thereto, so that both parts engage with one another in a form-
locking manner.
This form-closing in combination with the tubular extension 2a ensures an
intimate connection and, accordingly, a high transfer c~f force between the
two
parts. As a result, both the reinforcing bar 1 and the cross-sectional
enlargement 2 with its tubular extension 2a can be made of a glass-fibre
reinforced plastic.
In the embodiment, the profiling 4 and 5 is formed by threads. Thus, it would
be possible to screw the cross-sectional enlargement 2 with its tubular
extension 2a onto the rod-shaped section 1 and to then connect both parts
with one another. However, in most cases, it is more advantageous to insert
the end of the rod-shaped section 1 into an injection-molding tool and to
spray
the cross-sectional enlargement 2 with its tubular extension 2a on in a molten
state.
Preferably, the tubular extension 2a also has a certain profiling on its outer
side to promote its later connection with the concrete. To this end, its has
several successive sections 6 or 7, stepped in their diameter, the diameter of
which increases gradually in direction of the cross-sectional enlargement 2 in
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order to then pass into the cross-sectional enlargement 2 at an angle of less
than 60°.
In Fig. l, the sections 6 are separated from one another by a step extending
peripherally in a screw-thread type manner, while the sections 7 in Figs. 2
and
3 are separated by several steps extending peripherally in a circular manner.
Of course, any other profilings desired are also possible in this case. The
important point is only that the outer cross section of the extension 2a
increases, whether it be stepped or continuous. At the end, the extension 2a
then passes over into the substantially steeper cross-sectional enlargement 2,
preferably with a thread angle of 30° to 60°.
Figs. 4 and 5 show the use of the set bolt described above in insulating
bodies.
These insulating bodies are inserted between a building ceiling and a
projecting balcony platform to minimize the heat flow between two structural
parts. They are generally equipped with reinforcing elements for the transfer
of tractive, compressive and transverse forces.
In the embodiments shown, one can see an insulating body 10 which is
situated between a balcony platform 11 and a building ceiling 12. 'rhe
insulating body 10 contains h~rizontally continuous tensile bars 13 as usual
in
its upper area, diagonally extending transverse bars 14 in ifs central area
and
horizontally continuous compressive bars 15 in its lower area.
it is now important that the aforementioned bars can consist entirely or
partially of glass~fibre reinforced plastic due to the set bolts according to
the
invention, as can be seen in Fig. 4 for the preferred application for
transverse
and compressive bars.
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Fig. 4 shows an alternative for the design of the set k~olt. In the case of
the
transverse bars 14, they do not: have any end faces extending at a right angle
to the longitudinal axis of the bars, but diagonally extending end faces 14a.
Their diagonal position is selected such that both end faces 14a lie in a
horizontal plane. As a result, they can better absorb forces in vertical
direction.
Fig. 5 shows the transverse bars with normal ends extending at a right angle
to
the axis of the bar.
In the case of the rod-shaped section 1, the plastic used for the present
application consists of approx. 50% to approx. X30% glass fibres, the
remainder of duroplast. in the case of the sprayed on head part, i.e. the
cross-
sectional enlargement 2 on the end and its tubular extension 2a, it consists
of
approx. 20% to 60°~o glass fibres, the remainder of thermoplastic
material.
Fig. 6 shows the vertical section through a concrete balcony 21 in which the
four set bolts 22, each extending at a right angle to one another and parallel
to
the outer sides of the beam 21, serve to bind the statistically measured
bending reinforcement which extends in horizontal direction in the beam, as
replacement for a bracket encasement.
In the embodiment of Fig. 7 which shows a vertical section through a
horizontally protruding console 32 attached to a column 31, the set bolts 33
serve to absorb the bending forces of the console 32 and to transfer theme to
the column 31 or its reinforcement 34, wherein the set bolts replace the
structural parts usually designated as anchors which are loaded for tension in
the upper console area and for pressure in the lower console area.
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In Fig. 8, a bending-resistant frame corner 41 is also shown in a vertical
section in which the set bolts 42 of the invention are used to replace
brackets
which are usually used at this point for reinforcement.
The embodiment shown in Fig. 9 shows set bolts 5.1, 52 according to the
invention which are arranged vertically in a ceiling 54 situated on a suppori~
53
and hereby extend between an upper grid reinforcement layer 55 and a lower
grid reinforcement layer 56. The set bolts 51, 52 here serve as shearing
reinforcement or punching reinforcement elements and carry the forces
between ceiling and support away from the support toward the outside in a
truss-like manner, so that the support is prevented from punching through the
ceiling. In this case, the diameter enlargements on the end heads of the set
bolts 51, 52 promote the transfer of force onto the re spective grid
reinforcing
layers.
