U.S. patent number 3,628,337 [Application Number 04/861,368] was granted by the patent office on 1971-12-21 for anchorable pile.
Invention is credited to Thomas L. Adams, Fred C. Stepanich.
United States Patent |
3,628,337 |
Stepanich , et al. |
December 21, 1971 |
ANCHORABLE PILE
Abstract
A piling consisting of a main, elongated pile member which has
within its body, a plurality of retracted anchors which after the
pile is inserted into the ground, are capable of being
independently moved laterally of the piling member to provide
anchors for the piling member without movement of the piling
member.
Inventors: |
Stepanich; Fred C. (Bangkok,
TH), Adams; Thomas L. (APO San Francisco, CA) |
Family
ID: |
25335606 |
Appl.
No.: |
04/861,368 |
Filed: |
September 26, 1969 |
Current U.S.
Class: |
405/253; 52/161;
254/41; 405/244; 405/252.1 |
Current CPC
Class: |
E02D
5/54 (20130101) |
Current International
Class: |
E02D
5/22 (20060101); E02D 5/54 (20060101); E02d
005/54 (); E02d 005/80 () |
Field of
Search: |
;61/53.68,53.6
;52/161,155,160,162 ;254/41 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Shapiro; Jacob
Claims
We claim:
1. An anchorable pile comprising a generally hollow elongated pile
member having a penetrating point at one end and being open at the
opposite end; there being a plurality of openings in said pile
member spaced at different positions along the axis thereof; a
plurality of shear plates telescoped in said pile member with one
at each said opening; removable means including a tapered member
extendable along the axis of said pile member, said tapered member
having a threaded portion and said shear plates interfit between
the threads of said tapered member, for wedgedly moving said shear
plates normally of the longitudinal axis of said pile member by
rotating said tapered member, and means extending through said open
end for actuating said means for moving said shear plates.
2. An anchorable pile according to claim 1 wherein said plurality
of openings are each elongated in a direction transverse to the
longitudinal axis of said pile member.
3. An anchorable pile according to claim 1 wherein said shear
plates have an outer end surface which conforms to the
configuration of the exterior surface of said pile member.
4. An anchorable pile according to claim 2 wherein said extending
means includes a shaft.
5. An anchorable pile according to claim 1 wherein the exterior
configuration of said pile member is a hexagon.
6. An anchorable pile according to claim 1 wherein the exterior
configuration of said pile member is circular.
7. An anchorable pile according to claim 1 wherein the exterior
configuration of said pile is square.
8. An anchorable pile according to claim 1 wherein sufficient of
said shear plates are present to substantially provide a complete
circumferential surface projection around said pile member.
9. An anchorable pile according to claim 1 wherein said tapered
member is withdrawable after said shear plates are moved
normally.
10. An anchorable pile comprising a generally hollow elongated pile
member having a penetrating point at one end and being open at the
opposite end; there being a plurality of transverse openings in
said pile member spaced at different positions along the axis
thereof; a plurality of generally flat shear plates telescoped in
said pile member with one at each said opening; removable means
telescoped in said pile member having a tapered end extendable
along the axis of said pile member, said tapered end arranged to
contact said shear plates and move them normal to the axis of said
pile member on downward movement of said removable means, and means
extending through said open end for moving said removable means
downwardly for moving said shear plates and upwardly for removal of
said removable means.
Description
A structural piling derives its supporting value from either and/or
both the bearing on its embedded end and cohesive friction of the
surrounding earth on the pile surface area. In areas characterized
by cohesive, low-strength soils which are excessively deep, piling
economy and size is determined by utilizing piling members whose
maximum supporting value is governed by the friction or shear
strength of the soil media. In such cases where pile end bearing
cannot be relied on, the economical pile size and hence the rated
supporting value of each pile is significantly minimized to values
well below that of which the pile itself is capable of sustaining.
Various means of attempting to insure maximum mobilization of all
available soil shear resistance are in use ranging from a "Y"
cross-sectional pile area to a corrugated pile shell. A variety of
means are also in use that attempt to maximize the positive pile
bearing or "mechanical locking" or "keying" effect of the pile to
its surrounding soil. They include, among others, the widely used
step tapered shell pile, the Franki-type caisson (wherein the tip
area is excavated to permit concrete placement of a larger area
bulb at the pile base), etc.
The methods stated above attempt to make maximum use of or increase
(1) the effective cross-sectional area of the pile which can be
used in pile tip bearing, and (2) the frictional (shear) resistance
between the exterior surface of the pile and the surrounding soil
media. All methods used to date require special pile sections
and/or construction methods and procedures.
Pilings of all sorts are commonly used to support structures,
retaining walls, resist uplift and prevent earth movement. Such
pilings are driven essentially vertical into the ground by pile
drivers or the like. While it is the intent to have the pilings
generally immobile at full penetration in the earth, the weight of
the structures on the pilings, earth movement, settlement,
consolidation, etc., tends to loosen the pilings permitting further
penetration of the pilings with resultant distortion of the
structure. The loosening may be lateral but it is in most cases
almost always vertical. A number of different types of earth
anchors have been proposed, but in all of the known types, the
laterally expending anchor members are extended by pivoting from a
point near the head of the elongated earth penetrating member.
These expanding anchor members are expanded away from the elongated
shaft by pulling the shaft backwardly out of the hole into which it
has penetrated which reduces end bearings, or by pivoting the
anchors mechanically which leaves a void above the anchors. This
type of anchor is intended to anchor against pulls or tension
directed out of the hole, and such anchors do not prevent inward
movement of the piling shaft. In fact, inward movement of this type
of anchor tends to collapse the anchor system.
Included among the objects and advantages of the invention is a
piling arranged with extendable anchors which are laterally
extended from the pile axis after the piling has reached its
desired penetration in the earth and without movement of the
piling.
Another object of the invention is to provide laterally extending
anchors for piling members, which anchors may be independently
extended normally to the axis of the piling by a simple mechanism
which may be later withdrawn and reused.
Still another object of the invention is to provide a piling with
greatly increased ability to resist not only bearing loads but in
resisting uplift forces such as those created by hydrostatic
forces. By providing a "locked key" near the pile tip to act
against the increased "shear resistance cone" and weight of earth
will minimize the necessity for mass foundations and battered
piling.
These and other objects and advantages of the invention may be
readily ascertained by referring to the following description and
appended illustration in which:
FIG. 1 is a side elevational view of one form of the invention, in
partial section, illustrating one means of extending anchor members
of a piling;
FIG. 2 is a schematic cross section of a piling along line 2--2 of
FIG. 1;
FIG. 3 is a schematic cross-sectional view of the piling of FIG. 1
taken along section line 3--3 with the lateral anchors in retracted
position;
FIG. 4 is a schematic cross-sectional view of the piling of FIG. 1
similar to FIG. 3 along section line 3--3 with the anchors in
partially extended position;
FIG. 5 is a schematic cross-sectional view of the piling of FIG. 1
taken along section line 3--3 illustrating the full extension of
the anchors;
FIG. 6 is a cross-sectional detailed view of one end of an anchor
according to the invention showing a modified piling
configuration;
FIG. 7 is a top plan view of the modified form of piling of FIG. 6
with its anchor members in full extended position; and
FIG. 8 is a top plan view of another modified form of piling
according to the invention with its anchor members fully
extended.
In general, the invention includes a hollow, elongated piling
member having a penetrating point which is arranged to be driven
into the earth by any suitable means. A plurality of anchor members
or shear plates are telescoped in the piling member at different
elevations preferably, but not necessarily, near the penetrating
point of the shaft. These shear plates are completely retracted
while the piling is being driven into the ground. When the piling
has reached its desired penetration a mechanism is inserted through
the hollow core of the piling member and used to move the shear
plates normal to the axis of the piling into the surrounding earth,
thus providing a means of anchoring the piling against vertical
deflection .
In the embodiment shown in FIG. 1, a hexagonal, hollow core pile 10
is provided with a penetrating point 12 at its lower end and open
at the upper end 14. Extended inside of the pile void is a circular
shaft 16 having the mechanism assembly 18 and 20 at the lower end.
The assembly consists of a tapered screw thread 20 terminating in a
tapered drift pin 22 at its lower end. A plurality of shear plates
or anchor plates are mounted in slots in the piling shaft. As shown
in FIG. 1, the shear plate 25 is extended through an aperture 25a
in the shaft. Shear plate 28 extends through its aperture 28a at a
different elevation from that of aperture 25a. By forming the
apertures at different heights, six shear plates may be telescoped
from the shaft. As shown in FIG. 4, plates 25 through 30,
inclusive, are arranged through their own apertures telescoped
inside the piling 10. Each plate at its inner end is provided with
an arcuate cutout. The notches are indicated in FIG. 4 as 25n, 26n,
etc. With all of the plates retracted, shown in FIG. 3, the notches
form a central opening 35 which permits the drift pin to pass
centerwise of the plates and start the plates moving outwardly
under the influence of the screw 20.
In using the device of FIGS. 1 through 5, the shear plates remain
completely retracted within the body of the pile 10 during the pile
driving operation. When the piling has penetrated the earth to its
desired depth, the circular shaft 16 and mechanism assembly 18 and
20 are inserted into the pile void and torque is applied to the
shaft 16. The shaft is, in turn, forced downwardly engaging the
plates one after the other from the uppermost one to the lowermost.
Engagement is initially with the drift pin follower by the screw
thread 20. Initially, the tapered drift pin 22 enters the opening
35 and permits the thread on the tapered screw 20 to engage the
shear plates one after the other. When the screw thread 20 is moved
fully to the bottom, all the plates are fully extended, shown in
FIG. 5, and forces into the earth around the shaft of the piling.
The extended shear plates increase the effective resistive
cross-sectional area of the pile.
The plates are designed for each pile section and adapted so that
in retracted position, their outer edges will be flush with the
outside face of the pile. The limiting horizontal dimension to
which the plates may be extended is governed by the size of the
pile and the size of the central void. Generally, the larger the
size of the pile and available void, the greater will be the
effective area available in the extruded plates. As pointed out
above, to maintain the structural integrity of the pile, the
openings through the pile wall are staggered along the axis of the
pile. Maximum effectiveness is achieved with the plates near the
pile tip, however, they may be placed at any position along the
pile's length.
As shown in Fig. 1, the plates are pushed outwardly into the
surrounding soil by means of a tapered thread. This device makes
use of the extremely high mechanical advantage of the tapered
screw. Thus, as the tapered thread is advanced, the plates are
extended through the openings in the pile and full protrusion is
ensured by the guide or head 18 above the screw. While
substantially any number of shear plates may be used with a single
tapered thread, one single series of plates which substantially
covers the periphery of the pile will in most cases be adequate.
The plates, of course, are positioned and spaced along the pile
axis so as to coincide with the screw pitch. The use of the screw
permits the plate extension, and will also permit removal, salvage
and reuse of the screw thread mechanism and the drive shaft.
The use of a hexagonal pile permits the use of six plates which
will be adequate for increasing the effective cross-sectional area
of the pile. Other cross-sectional configurations, however, may be
useful to provide a pile capable of housing a series of extendable
plates. As shown in FIG. 7, a circular pile 40 is provided with a
series of extendable plates 42 each of which has an outer arcuate
edge 43 approximately matching the exterior surface of the pile.
These plates are staggered axially along the piling, as explained
above.
In the configuration of FIG. 8, a square piling 50 is provided with
a series of four shear plates 52, each of which has an outer edge
53 which is squared to mate with the outside surface of the piling
50. These shear plates are staggered along the piling.
Other means may be provided for extending the shear plates
laterally from the axis of the pile. A conical wedge with out screw
threads may be driven between the plates to force the plates
outwardly into the soil. For large cross-sectional piles, a
hydraulic unit acting like a jack may be used to force each of the
plates outwardly, progressively down the pile.
* * * * *