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Патент USA US3060705

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Oct. 30, 1962v
Filed Oct. 29, 1958
United States Patent O?fice
Patented Oct. 30, 1962
direction. In order to facilitate removal of the lining
tube without creating voids in the concrete it will gen
erally be found highly desirable to provide ribs which
Arthur Brannam Holmes, Swanland, North Ferriby, Eng
land, assignor to Holmpress Piles Limited, Hull, Eng
. land, a British company
Filed Oct. 29, 1958, Ser. No. 770,406
Claims priority, application Great Britain Oct. 31, 1957
6 Claims. (Ci. 61-5362)
are substantially parallel to one another.
Said spacing elements may be substantially co-exten
sive with the length of any lining tube or sectioned por
tion thereof. Alternatively, the spacing elements may
be interrupted so as to provide two or more circumfer
ential groups su?icient in aggregate to keep the rein
This invention concerns reinforced concrete piles of 10 forcement in proper alignment within the bore. In this
latter event it is necessary that-the axial length of any
the type which are formed in situ.
group of spacing elements shall be slightly greater than
It is common practice to form such piles in the fol
the pitch of the hoops or spiral used in the reinforcement.
lowing manner. A bore is ‘formed in the ground by
The ribs need not necessarily be opposite to each other
driving or boring using a tube which serves as a lining
for the bore. A metal reinforcement is positioned in 15 but may be staggered.
The number of spacing elements or longitudinal ribs
the bore and the bore is ?lled with concrete. The lining
tube is then withdrawn and the concrete is expanded so
as to “key” into the earth walls of the bore by driving
using a drive feed tube of external diameter slightly less
than the internal diameter of the metal reinforcement,
which acts as a guide for the drive feed tube. The drive
feed tube is ?lled with concrete and‘ Withdrawn. If de
disposed on the inner circumferential surface of the lin
ing tube is only critical insofar as to ensure that the
reinforcement is kept in correct alignment with the lin
ing tube. Thus it will be appreciated, subject to due
regard being paid to the respective diameters of the lin
ing tube andreinforcement, that as small a number as
sired, the process of expanding the concrete is repeated,
especially if the bore has been made in soft ground.
three spacing elements may be employed if separated
lining tube has been withdrawn, spacing elements are
provided in the form of triangular or prismatic precast
ployed and the respective diameters of the lining tube
from each other around the circumference of the lining
In order to ensure that the reinforcement is maintained 25 .tube at intervals of 120°. Generally speaking, the re
lationship between the number of spacing elements em
substantially vertical and covered by concrete after the
concrete spacers having tie wires embedded therein by
and reinforcement should be such that the virtual circle
distance extending between any two adjoining spacing
proximity with the walls of the lining tube. When the
more circumferential groups, it is preferred that each
which the elements are secured to the metal reinforce 30 elements should be slightly less than the overall diameter
of the reinforcement.
ment. The spacers are secured to the outside of the
Where the spacing elements are arranged in two or
metal reinforcement so as to extend from it into close
element shall have a length not exceeding one tenth of
The use of such spacing elements suffers from a num 35 the length of the tube, a maximum depth of between one
tenth and one-twentieth of the length of the element and
ber of disadvantages. They are relatively insecure and
a thickness not exceeding one quarter of the depth of
can easily be displaced by the incoming concrete. There
the element.
is no real assurance of any permanent adhesion between
The spacing elements need not be of uniform dimen
the pre-cast concrete spacing elements and the concrete
which is poured into the bore. Moreover, there is a 4.0 sions. For example, they can consist of ribs having
tapered or chamfered end portions.
tendency for the added concrete to arch over the precast
Whilst it will generally be found more convenient to
concrete spacing elements and a void may be created be
lining tube is withdrawn, the spacers are left in situ.
provide the lining tube with spacing elements formed
neath each pre-cast concrete spacing element, thus weak—
integral therewith, the use of detachable spacing elements
ening the ?nished pile. The danger of void formation
may be reduced by increasing the mobility of the con 45 is envisaged, especially where the lining tube is com
posed of two or more inter-engaging sections which are
crete mix i.e. increasing its water content, but any in
crease in water content may militate against the strength
of the concrete. Even if the voids are avoided, the
presence of the spacing elements in the ?nished pile gives
rise to a lack of uniformity in the pile. Finally, con
siderable time is consumed in attaching the spacing ele
ments to the reinforcement and in ensuring that a proper
detached from one another during withdrawal. In such
an event, the use of spacing elements bridging the union
between two inter-engaging sections of lining tube, but
capable of being detached from the composite lining
tube before the sections of the latter are disengaged, is
The invention will now be further described by way of
number of such spacing elements are employed.
example with reference to the accompanying drawings
An object of the present invention is to provide a
method of forming a reinforced concrete pile Whereinthe 55 in which:
FIG. 1 is an elevation, mainly in section, of a driving
use of spacers attached to the reinforcement is obviated.
or lining tube,
A further object of the present invention is to provide
a method of forming a reinforced pile wherein a rein
forcement of greater simplicity can be employed with
consequential saving in cost.
Yet a further object of the present invention is to pro
vide a method of forming a reinforced concrete pile
wherein a lining tube of a novel construction is employed.
FIG. 2 is an elevation on an enlarged scale of part 0
the tube shown in FIG. 1,
‘ '
SIG. 3 is a section taken on the line III—III of FIG. 2,
FIG. 4 is a sectional elevation of a bore containing a
driving or lining tube according to the invention.
Referring firstly to FIGS. 1 to 3, a driving or lining
According to the present invention a driving or lining
tube is provided with spacing elements in the form of 65 tube 5 has a length of 27 ft., an outside diameter of 16"
and an inside diameter of 15". The tube has an en
longitudinal ribs permanently or detachably secured to
larged diameter upper end portion 5a to receive a driv
its inner surface.
mg means (not shown). Spacing elements 6, which
The invention includes a method of forming a rein
have a length of 2 ft., 21 maximum depth of 11/2", and
forced concrete pile using such a tube.
Said spacing elements may take the form of a series 70 a thickness of 1A", are mounted on the inner surface
of the tube 5 and are provided with tapered or cham
of “knife-like” radially disposed longitudinal ribs extend
ing along the inside of the lining tube in a generally axial
fered end portions 6a. The lower spacing elements are
a clear 5 ft. above the lower end of the tube and a clear
10 ft. below the upper spacing elements. The spacing
elements may conveniently be attached to the tube by
welding and it is important that they should be in sub
in each of said longitudinal ribs has its end portions
tapering inwardly from the inner wall of said tube.
4. The improved lining tube de?ned in claim 1 where
in each of said longitudinal ribs has a length less than
stantial alignment with the longitudinal axis of the tube.
one-tenth of the length of the tube and the distance be—
It is to be clearly understood that the drawings are
tween the end of the tube and the nearest circumferen
tial group of ribs is less than the distance between the
not to scale.
The dimensions have been included to
show the relative proportions and location of the spac
ing elements on a typical driving tube. They have been
two circumferential groups of ribs.
5. An assembly of pile forming elements comprising a
given as a guide only and must not be interpreted in 10 retractable lining tube located in a bore in the ground,
any limiting sense. If a 45 ft. driving or lining tube
said tube having spacing elements in the form of longi
were used, three or more sets of spacing elements could
tudinal ribs secured to its inner surface in at least two
conveniently be used in place of the two sets shown in
circumferential groups, each group comprising at least
the drawings. _
three spacing elements and a reinforcement for said pile
In FIG. 4, a tube 5 is shown positioned in a bore 7, 15 centrally located within said tube by means of said
in which a reinforced concrete pile is to be formed. A
spacing elements, said reinforcement comprising a uni
metal reinforcement 8 is maintained in a substantially
form skeletal structure of generally longitudinal rod and
vertical position within the bore by means of the spac
circumferential hoop configuration, the axial length of
ing elements 6 of the tube 5 While concrete is poured
any circumferential group of spacing elements being
into the bore 7. Since the spacing elements are “knife 20 greater than the distance between adjoining hoops in
like,” the amount of disturbance suffered by the concrete
said skeletal structure, and the virtual circle distance be
when the tube 5 is subsequently withdrawn from the
tween any two adjacent spacing elements being less than
bore is reduced to a minimum. The length of each
the overall diameter of the reinforcement.
spacing element 6 exceeds the distance between adjacent
6. In apparatus for use in the construction of a rein
hoops 8a of the metal reinforcement 8.
forced concrete pile comprising at least two interengage
The spacing elements of the present invention form
able sections of a retractable cylindrical lining tube to
an integral part of the driving or lining tube and are in
be driven into a bore in the ground and a skeletal rein
consequence withdrawn with the tube. Hence, the pos
forcement of longitudinal rods and circumferential hoops
sibility of any void being established beneath the spac
vertically disposed within and equally spaced from the
ing elements is substantially eliminated and the 11/2” 30 inner surface of said tube, wherein said tube is there
concrete cover of the reinforcement normally demanded
after ?lled with concrete and withdrawn from said bore
in concrete work can be achieved with much greater cer
leaving said skeletal reinforcement embedded in concrete
tainty than when using the aforementioned tie-on pre
within said bore to form the ?nished pile, the improve
cast concrete spacing elements. In particular, this cover
ment whereby any radial movement of said skeletal metal
may be achieved before the concrete exudes from the
reinforcement relative to the inner surface of said tube
lining tube.
In addition to facilitating correct align~
is obviated during the ?lling of said tube and the with
ment of the metal reinforcement in the bore and per
drawal of said tube sections from said bore and said
mitting good concrete cover of the metal reinforcement,
reinforcement is evenly embedded in said concrete, com
the use of the “knife-like” spacing elements of the pres
prising a ?rst group of spacing elements in the form of
ent invention enables a high degree of uniformity to be 40 longitudinal ribs secured to and circumferentially spaced
achieved in the ?nished pile since these elements do not
about the inner wall of each of said interengageable
remain in the ?nished pile.
sections adjacent the free end thereof to engage the hoops‘
I claim:
and centrally locate the reinforcement in the tube; and
II. An assembly of pile forming elements comprising
a second group of spacing elements in the form of lon
a retractable lining tube temporarily located in a bore 45 gitudinal ribs bridging the junction between the inner
in the ground, said tube having at least two vertically
surface of each pair of interengageable sections and se
spaced separate groups of spacing elements in the form
cured thereto, said second group of spacing elements
of longitudinal ribs secured to its inner surface, each of
being detachable from at least one of said inner tube
said groups comprising at least three spacing elements
surfaces before said sections are disengaged.
and a reinforcement of longitudinal rods and vertically 50
References Cited in the ?le of this patent
spaced circumferential hoops for said pile centrally lo
cated within said tube, said spacing elements engaging
the hoops to centrally locate the reinforcement in the
Lally ________________ __ Feb. 5, 1907
2. The improved retractable cylindrical lining tube de 5
?ned in claim 1 wherein each of said longitudinal ribs
has a length less than one-tenth of the length of the
tube, a maximum depth of between one-tenth and one
twentieth of the length of the rib and a thickness of
less than one-quarter of the depth of the rib.
3. The improved lining tube de?ned in claim 1 where
Moran _______________ __ July
Kenny _______________ __ Dec.
Prankignoul __________ __ Nov.
Newman _____________ __ Feb.
Germany ____________ __ Jan. 19, 1938
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