Note: Descriptions are shown in the official language in which they were submitted.
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Drive point for a pile
The invention concerns a drive point for a substantially tubular driven pile,
wherein the drive point can be fitted onto a pile end of the driven pile,
wherein at least
one first support limb with a first support surface configured to abut an end
face of the
pile end of the driven pile is arranged at an inside wall of the drive point.
Drive points of that kind are used in the construction industry for making
pile
foundations. The individual driven piles which generally comprise ductile cast
iron and
are of predetermined lengths of for example five meters are fitted one into
the other to
produce a pile foundation. To facilitate inserting driven piles one into each
other and
thus extending the length of a pile foundation the driven piles usually have a
conically
tapering first pile end and a second pile end which is shaped to provide a
socket. In
that way the pile foundation can be driven into the ground pile by pile,
whereby it is
possible to produce pile foundations of any length quickly and inexpensively.
Driven
piles of that kind are usually produced in a centrifugal casting process with
a shaping
rotating mold. That results in substantially cylindrical tubular piles which
are internally
hollow. Depending on the respective kind of use those tubular or hollow-
cylindrical
driven piles can be filled or encased with concrete or another suitable
injection material
to produce a stable foundation after having been driven into the ground.
To produce a so-called shaft-grouted pile foundation, a driven pile is fitted
on to
a drive point, the outside diameter of the drive point being greater than the
outside
diameter of the driven pile. In that way an annular space can be produced
during the
driving-in operation, and that space can be filled with the injection material
or concrete
by a pressure grouting operation.
When making pile foundations with known drive points, the worker has to place
the drive point on the ground and hold it during the mounting of the pile end
of the
driven pile into the drive point. As the driven piles to be mounted into the
drive point are
long and heavy, the holding of the drive point during the mounting is
dangerous for the
worker.
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The object of the invention is to provide an improved drive point with which
pile
foundations can be produced, while avoiding the above-described disadvantages.
According to an aspect of the invention, there is provided a drive point for a
substantially tubular driven pile, wherein the drive point can be fitted onto
a pile end
of the driven pile, wherein at least one first support limb with a first
support surface
configured to abut an end face of the pile end of the driven pile is arranged
at an
inside wall of the drive point, wherein at least one support device with a
ground
surface is arranged at an outer surface of the drive point, wherein the ground
surface
of the at least one support device supports the drive point when placed on a
ground
into which the drive point is to be driven in a driving-in direction, wherein
a
circumferential collar is arranged along the outer surface of the drive point,
said
circumferential collar projecting from said outer surface of the drive point,
wherein,
starting from a plane of the first support surface the drive point has a
cavity which
extends at least partially in the driving-in direction and into which concrete
can be
introduced through a pile core of the driven pile when the driven pile is
fitted onto the
pile end of the driven pile, wherein at least one concrete outlet passage
connects the
cavity to an upper edge of the drive point and forms a bulge in the outer
surface of
the drive point.
Advantageous configurations and embodiments of the invention are described
below.
According to an aspect of the invention, it is provided that at least one
support
device with a ground surface is arranged at an outer surface of the drive
point,
wherein the ground surface of the at least one support device supports the
drive point
when placed on a ground into which the drive point is to be driven in a
driving-in
direction.
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In that way, the drive point can be placed on the ground where it stably
stands
by itself, supported by the at least one support device. Therefore, it is no
longer
necessary for the worker to hold the drive point during the fitting of the
driven pile into
the drive end, because the drive point can stand by itself on the ground with
the
ground surface of the at least one support device. This minimized the danger
for the
worker during the fitting of the driven pile into the drive point.
In a preferred embodiment the ground surface is arranged substantially in
parallel to the first support surface. Because by this the drive point stands
straight
and stable on the ground ¨ whereby the driving-in direction is substantially
perpendicular to the surface of the ground ¨ the driven pile can easily and
exactly be
mounted to the drive point.
In a particularly preferred embodiment there is provided a plurality of
support
devices, preferably three support devices. This allows for an optimized stand
of the
drive point on the ground and an optimized stability during the driving of the
driven
pile into the ground.
In a preferred embodiment the at least one support device is in the form of a
support rib which projects from the outer surface.
A particularly advantageous embodiment of the invention is that in which three
support ribs are arranged evenly distributed in a circumferential direction at
the outer
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surface. In that case, the ground surfaces may extend linearly and may be
arranged at
angles of 1200 to each other.
In a particularly preferred embodiment the drive point is of a substantially
rotationally symmetrical external or outside shape, the axis of rotation
extending
substantially in the driving-in direction. If an outside diameter of the drive
point
substantially continuously decreases in the driving-in direction it is then
possible for a
pile foundation to be particularly easily driven in, with the use of a
proposed drive point.
Self-evidently however it can also be provided that the outside diameter of
the drive
point is substantially constant along its extent in the driving-in direction.
A particularly advantageous embodiment of the invention is that in which the
outer surface of the drive point is at least sectionwise shaped conically.
Preferably, an
opening angle of said sectionwise conically shaped outer surface (Y) is
between 80
.. and 100 , preferably about 90 . This allows the drive point to be built
more lightweight
and with a reduced height.
When producing a shaft-grouted pile foundation, wherein the driven piles are
to
be covered with injection material or concrete, during the driving operation a
pumpable
concrete mortar which is usually of a grain size of up to 4 mm is conveyed
through the
hollow pile core of the driven pile to the foot of the pile and pressed into
the ground at
the drive point. This means that the concrete pressure grouting operation
takes place
simultaneously with the pile driving operation and is concluded upon the
attainment of
the final depth of the pile foundation. The shaft grouting operation permits a
considerable increase in the useful load of a pile foundation in particular in
gravels and
sands because a substantially higher level of shaft friction prevails in large-
grain
grounds between the pressing shaft and the ground, than between the pile tube
of an
ungrouted driven pile and the ground.
In order that the concrete mortar introduced into the pile core of a driven
pile
can issue from the driven pile and can form a pressed grouting sheathing
around the
driven pile, it is known in the state of the art for suitable openings to be
cut out of the
driven pile. That however results in a weakening of the tubular cross-section
and thus
static instabilities of a pile foundation.
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In a particularly preferred embodiment, starting from a plane of the first
support
surface the drive point has a cavity which extends at least partially in the
driving-in
direction and into which concrete can be introduced through a pile core of the
driven
pile when the driven pile is fitted onto the pile end of the driven pile,
wherein at least
one concrete outlet passage connects the cavity to an upper edge of the drive
point.
In that way, during the driving-in operation, concrete mortar or another
suitable
injection material can be introduced into the annular space between the
outside
diameter of the drive point and the outside diameter of the driven pile
without
appropriate openings or incisions having to be made for that purpose in the
casing of
the driven pile. In other words, when using a proposed drive point, the driven
pile does
not have to be manipulated at all, whereby there is also no unwanted weakening
of the
tubular cross-section of the driven pile.
In a preferred embodiment the at least one concrete outlet passage is formed
as a recess in the inside wall and/or forms a bulge in the outer surface of
the drive
point.
In a particularly preferred variant there can be provided a plurality of
concrete
outlet passages, preferably three concrete outlet passages. Preferably in that
case two
respective concrete outlet passages of the plurality of concrete outlet
passages are
arranged in the cross-section relative to the driving-in direction along the
inside wall of
the drive point substantially at equal spacings relative to each other. Self-
evidently the
concrete outlet passages can also be so arranged along the inside wall of the
drive
point that they are at irregular spacings relative to each other.
For centering the driven pile and/or for positionally stable fixing thereof at
least
one radially inwardly projecting pile-supporting device can be provided at the
inside
wall. In that case preferably the at least one radially inwardly projecting
pile-supporting
device can be in the form of a pile-supporting rib. The at least one radially
inwardly
projecting pile-supporting device provides an abutment for an outer shell
surface of the
driven pile.
In a particularly preferred embodiment at least one centering device
projecting
from the first support surface is arranged at the first support surface
configured for
CA 02934103 2016-06-27
centering the pile end of the driven pile and/or for positionally stable
fixing thereof. This
prevents the drive end of the driven pile to slip from the support surface and
block the
concrete outlet passages but rather stay stable on the support surface, even
if concrete
is pumped through the driven pile. The at least one centering device projects
from the
5 first support surface in a direction substantially opposite to the
driving-in direction and
provides an abutment for an inner surface of the driven pile.
In the mounted position, the drive end of the driven pile rests centered on
the
support surface between the pile-supporting devices and the centering devices.
In a preferred embodiment the end face of the pile end of the driven pile is
located at a circumferential edge of the driven pile and the at least one
first support
limb is configured to extend from the circumferential edge of the driven pile
such that
the at least one first support limb is offset from a central axis of the
driven pile.
To be able to provide a universally useable drive point for a plurality of
driven
piles of different outside diameters it can be provided in a preferred variant
that
arranged at the inside wall of the drive point is at least one second support
limb with a
second support surface for an end face of a pile end, wherein the spacing of
the
second support surface from the edge of the drive point in the driving-in
direction is
greater than the spacing of the first support surface from the edge of the
drive point. It
is however also possible for the first and second support surfaces to be in
the same
plane. Generally the first and second support surfaces can preferably be in a
plane
parallel to a cross-sectional plane transversely relative to the driving-in
direction.
As generally hollow-cylindrical driven piles are used, an advantageous
development of the invention provides that the at least one first support limb
and/or the
at least one second support limb in the cross-section relative to the driving-
in direction
is/are in the form of a segment of a circle or a segment of a circular ring.
It is desirable
in that respect if a circular arc of the segment of the circle or circular
ring extends over
less than 340 , preferably over between 40 and 120 , particularly preferably
over
between 70 and 90 .
In a preferred embodiment the drive point at least partially and preferably
completely comprises cast iron.
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A particularly advantageous embodiment of the invention is that in which the
drive point is in one piece. It will be appreciated however that it is also
possible for
the drive point to be of a multi-part configuration.
In a particularly preferred embodiment a circumferential collar is arranged
along the outer surface of the drive point, said circumferential collar
projecting from
said outer surface of the drive point. Preferably, the circumferential collar
is arranged
along the upper edge of the drive point. The circumferential collar provides a
cutting
effect and reduces or prevents the breaking off of soil around the driven pile
during
the driving of the driven pile.
Protection is also sought for an arrangement comprising a drive point
according to an aspect or any of the embodiments of the invention described
above,
and a cylindrical elongated sleeve, wherein said drive point is arranged
inside said
cylindrical elongated sleeve, wherein a circumferential support collar
projecting
radially inwards is arranged on a sleeve end of said cylindrical elongated
sleeve
configured to abut the circumferential collar of said drive point.
In this case, the circumferential collar of the drive point functions as a
holder or
support for the cylindrical elongated sleeve which provides an additional
protection
against the breaking off of soil around the driven pile during the driving of
the driven
pile, in particular when driving the driven point into soft ground.
In a preferred embodiment the cylindrical elongated sleeve at least partially
and preferably completely consists of cast iron or sheet steel. The
cylindrical
elongated sleeve can also consist of a flexible geotextile with the
circumferential
support collar consisting of steel.
Further details and advantages of some embodiments of the present invention
are described by means of the specific description hereinafter. In the
drawings:
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Figure 1 shows a proposed drive point in a perspective top view,
Figure 2 shows the drive point of Figure 1 in a bottom view,
Figure 3a shows the drive point of Figure 1 in a top view,
Figure 3b shows a cross-section taken along section plane B-B through the
drive point of Figure 3a,
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Figure 4a shows the drive point of Figure 1 in a top view,
Figure 4b shows a cross-section taken along section plane C-C through the
drive point of Figure 4a,
Figure 5 shows a longitudinal section through a proposed drive point along the
driving-in direction with a driven pile fitted theron,
Figure 6 shows a longitudinal section through an arrangement comprising a
proposed drive point and a cylindrical elongated sleeve,
Figure 7 shows the arrangement of Figure 6 in a different operating condition,
Figure 8a shows a front view of a cylindrical elongated sleeve, and
Figure 8b shows a cross-section taken along section plane A-A through the
cylindrical elongated sleeve of Figure 8a.
Figure 1 shows a proposed drive point 1 in a perspective top view. In this
example the drive point 1 is of a one-part structure and comprises ductile
cast iron.
The external shape of the drive point 1 is substantially rotationally
symmetrical in
relation to the axis of rotation R (see Figure 4b). The outer surface 16 of
the drive point
1 is at least sectionwise shaped conically, wherein an opening angle of said
sectionwise conically shaped outer surface 16 is about 90 .
In this example, three support devices 14 with a ground surface 15 are
arranged at the outer surface 16 of the drive point 1, wherein the ground
surfaces 15 of
the support devices 14 support the drive point 1 when placed on a ground 24
into
which the drive point 1 is to be driven in a driving-in direction E (see
Figure 5). The
support devices 14 are in the form of support ribs which project radially
outwards from
the outer surface 16. The support devices 14 have beveled edges 22. As the
support
devices 14 are in the form of relatively slim ribs and have beveled edges 22,
they do
not cause much resistance during the driving in of the driven pile 2 into the
ground 24.
Therefore, the support devices 14 provide the advantage that the drive point 1
can be
stably placed on the ground 24 without hindering the driving in of the driven
pile 2 into
the ground 24.
Starting from the plane of the first support surfaces 7 provided in the drive
point
1 is a cavity 9 extending in the driving-in direction E. In this example three
concrete
outlet passages 10 are provided between the cavity 9 and the upper edge 11 of
the
drive point 1. That makes it possible for concrete mortar which is introduced
through
the pile core 3 of the driven pile 2 and which penetrates into the cavity 9 by
way of the
end face 8 to pass in production of a pile foundation by way of the concrete
outlet
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passages 10 to the outside wall of the driven pile 2, thus permitting the
production of a
shaft pressure grouting (see Figure 5).
In this example, the concrete outlet passages 10 are formed as recesses in the
inside wall 5 and they form bulges in the outer surface 16 of the drive point
1.
Projecting from the inside wall 5 of the drive point 1 in opposite
relationship to
the driving-in direction E are a plurality of first support limbs 6 which each
have a first
support surface 7. The first support surfaces 7 of the first support limbs 6
are disposed
in this case in one plane and in total form a defined abutment for the end
face 8 of a
pile end 4 of a fitted-on driven pile 2 (see Figure 5). That defined abutment
provides
that the driven pile 2 can be fitted on to the drive point 1 in the driving-in
direction E to
such an extent until the end face 8 of the driven pile 2 bears against the
first support
surfaces 7 of the first support limbs 6. The maximum depth of insertion
engagement of
the driven pile 2 in the driving-in direction E is afforded by the spacing T
from the upper
edge 11 of the drive point 1 to the plane of the first support surfaces 7 (see
Figure 4b).
Each concrete outlet passage 10 is arranged between two respective first
support limbs 6. In this case the concrete outlet passages 10 are arranged
substantially
at equal spacings relative to each other along the inside wall 5 of the drive
point 1 in a
circumferential direction.
A plurality of pile-supporting devices 13 in the form of pile-supporting ribs
are
arranged at the inside wall 5 for centering the driven pile 2 and/or for
positionally stable
fixing thereof.
In this example, centering devices 18 projecting from the first support
surface 7
are arranged at the first support surfaces 7 configured for centering the pile
end 4 of
the driven pile 2 and/or for positionally stable fixing thereof (see Figure
5).
Besides first support limbs 6 for a first driven pile 2 this embodiment
additionally
has second support limbs 6' for a second driven pile of a different outside
diameter
relative to the driven pile 2. Each second support limb 6' has a second
support surface
7', wherein the total of the second support surfaces 7' forms a defined
abutment for the
end face of the second driven pile. In the driving-in direction E the spacing
T' of the
second support surfaces 7' from the edge 11 of the drive point 1 is greater
than the
spacing T of the first support surfaces 7 from the edge 11 of the drive point
1 (see
Figure 4b). It will be appreciated that it will also be possible for both
support surfaces
7, 7' to be in the same plane. In that case it would only be necessary for the
width of a
support surface 7, 7' in the radial direction to be selected to be of such a
size that it is
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suitable for the entire band width of the outside diameters Dp of the driven
piles 2 to be
employed.
Centering devices 18' projecting from the second support surfaces 7' are
arranged at the second support surfaces 7' configured for centering the pile
end of a
driven pile and/or for positionally stable fixing thereof. Further, radially
inwardly
projecting pile-supporting devices 13' in the form of pile-supporting ribs are
arranged at
the first support limbs 6 for centering the driven pile and/or for
positionally stable fixing
thereof.
In this example, a circumferential collar 17 is arranged along the outer
surface
16 of the drive point 1, said circumferential collar 17 projecting from said
outer surface
16 of the drive point 1 along the upper edge 11 of the drive point 1.
Figure 2 shows the drive point 1 of Figure 1 in a bottom view. As can be seen,
in this example three support devices 14 in the form of support ribs are
arranged
evenly distributed in a circumferential direction at the outer surface 16 of
the driven pile
1. The ground surfaces 15 of the support devices 14 extend linearly and are
arranged
at angles of 1200 to each other. Three concrete outlet passages 10 form bulges
in the
outer surface 16 of the drive point 1. The three concrete outlet passages 10
are
arranged at angles of 1200 to each other, and they are offset from the support
devices
14 in a circumferential direction.
Figure 3a shows the drive point 1 of Figure 1 in a top view, and Figure 3b
shows a cross-section taken along section plane B-B through the drive point 1
of
Figure 3a. The drive point 1 comprises three first support limbs 6, each
having a first
support surface 7 configured to abut an end face of a pile end of a pile with
an an
outside diameter Dp (see Figure 5). The drive point 1 further comprises three
second
support limbs 6', each having a second support surface 7' configured to abut
an end
face of a pile end of a pile with an outside diameter smaller than D. The
ground
surfaces 15 of the support devices 14 define a support plane which is arranged
substantially in parallel to the first support surfaces 7 and the second
support surfaces
7'.
In this example each of the three first support limbs 6 and each of the three
second support limbs 6' is in the form of a segment of a circular ring in a
cross-section
relative to the driving-in direction E, wherein the segments with respect to
the first
support limbs 6 have a larger radius than the segments with respect to the
second
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support limbs 6'. In this case the circular arc of each segment of the
circular ring
extends over a respective angular range of about 90 and the three circular
arcs are
arranged distributed uniformly along a notional circle.
5 Figure 4a shows
the drive point 1 of Figure 1 in a top view, and Figure 4b
shows a cross-section taken along section plane C-C through the drive point 1
of
Figure 4a. The three first support surfaces 7 of the first support limbs 6 are
arranged
with a spacing T from the edge 11 of the drive point 1 in the driving-in
direction E. The
three second support surfaces 7' of the second support limbs 6' are arranged
with a
10 spacing T' from
the edge 11 of the drive point 1 in the driving-in direction E, wherein
the spacing T' of the second support surfaces 7' is greater than the spacing T
of the
first support surfaces 7.
Figure 5 shows a longitudinal section through a proposed drive point 1 along
the driving-in direction E with a driven pile 2 fitted theron. The drive point
1 stands
stably by itself on a ground 24, supported by the ground surfaces 15 of the
support
devices 14 projecting radially outwards from the outer surface 16 of the drive
point 1.
At an upper edge lithe drive point 1 is of an outside diameter D greater than
an outside diameter Dp of a fitted-on driven pile 2. In the driving-in
direction E the
outside diameter D of the drive point 1 decreases in a frustoconical
configuration in the
direction of its end, thereby making it easier to drive in a pile foundation
with fitted drive
point 1.
The abutment for the end face 8 of the driven pile 2, which is arranged at the
spacing T from the upper edge 11 of the drive point 1 in the driving-in
direction E, is
formed by a total of three first support surfaces 7 (see Figures 4a and 4b).
In the
mounted position, the drive end 4 of the driven pile 2 rests centered on the
support
surfaces 7 between the pile-supporting devices 13 which project radially
inwardly from
the inside wall 5 and the centering devices 18 which project from the first
support
surfaces 7 in a direction opposite to the driving-in direction E.
Figure 6 shows a longitudinal section through an arrangement comprising a
proposed drive point 1 and a cylindrical elongated sleeve 19, and Figure 7
shows the
arrangement of Figure 6 in a different operating condition. The drive point 1
is arranged
inside the cylindrical elongated sleeve 19. A circumferential support collar
20 projecting
radially inwards is arranged on a sleeve end 21 of the cylindrical elongated
sleeve 19
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and is configured to abut the circumferential collar 17 of the drive point 1.
Figure 7
shows the operating condition when the driven pile (not shown) is driven into
a ground
24 in the driving-in direction E. As can be seen, the support collar 20 of the
cylindrical
elongated sleeve 19 abuts the circumferential collar 17 of the drive point 1.
Figure 8a shows a front view of a cylindrical elongated sleeve 19, and Figure
8b
shows a cross-section taken along section plane A-A through the cylindrical
elongated
sleeve 19 of Figure 8a. In this example, the inner sleeve wall 23 is inclined
in the
direction towards the sleeve end 21 of the cylindrical elongated sleeve 19.
