Title:
Piling and method of installation
United States Patent 3916635


Abstract:
A "cast-in-place" thin-walled piling, wherein the thin-walled tubular casing shell is connected to a precast reinforced concrete driving base by being outwardly expanded at its leading end so as to form a friction fit within a tapered socket formed in the base while the piling is simultaneously driven into place. An internal drop hammer compacts a charge of concrete within the casing shell to expand the shell and drive the piling into place. A precast reinforced concrete piling end cap is constructed with an internally tapered passageway extending through the cap and is similarly installed by compacting a similar charge of concrete within the trailing end of the casing shell so as to expand the trailing end wall of the shell into a friction fit with the end cap.



Inventors:
Lynch, Henry J. (Cedarhurst, NY)
Fleishman, Leonard (Oceanside, NY)
Application Number:
05/314566
Publication Date:
11/04/1975
Filing Date:
12/13/1972
Assignee:
HORN CONSTRUCTION CO., INC.
Primary Class:
Other Classes:
52/295, 405/257
International Classes:
E02D5/38; E02D5/50; E02D5/72; E02D7/28; (IPC1-7): E02D5/30; E02D5/38; E02D5/50
Field of Search:
61/53,53
View Patent Images:
US Patent References:
3751931PILING1973-08-14Merjan
3625012N/A1971-12-07Thorburn
2465557Pile and method of making the same1949-03-29Thornley
2200636Metal wall building construction1940-05-14Palmer
1971691Composite pile1934-08-28Nadel
1507138Pipe union1924-09-02Pierce
0684044N/A1901-10-08



Primary Examiner:
Shapiro, Jacob
Attorney, Agent or Firm:
Morgan, Finnegan, Pine, Foley & Lee
Claims:
What is claimed is

1. A cast-in-place, thin-walled piling, comprising:

2. A cast-in-place, thin-walled piling as claimed in claim 1, wherein said compacted means holding said leading end portion of said casing shell comprises a compacted material substantially filling said leading end portion of said casing shell located within said socket means of said pile driving base member.

3. A cast-in-place, thin-walled piling as claimed in claim 1, wherein said bearing support material substantially filling said casing shell comprises construction concrete.

4. A cast-in-place, thin-walled piling as claimed in claim 1, wherein said pile driving base member comprises a substantially solid body formed of reinforced concrete.

5. A cast-in-place, thin-walled piling as claimed in claim 1, including

6. A cast-in-place, thin-walled piling as claimed in claim 2, wherein said pile driving base member includes at least one reinforcing rod member fixedly secured therein and extending vertically into said socket means so as to engage said compacted material, whereby said at least one rod member and said compacted material form a further connection between said pile driving base member and said casing shell.

7. A cast-in-place, thin-walled piling as claimed in claim 2, wherein said compacted material comprises zero-slump concrete.

8. A cast-in-place, thin-walled piling as claimed in claim 3, wherein said reinforced concrete pile driving base member includes a plurality of vertical reinforcing bars extending over a substantial portion of the length thereof, said vertical reinforcing bars being equi-spaced circumferentially about said socket means.

9. A cast-in-place, thin-walled piling as claimed in claim 5, wherein said means expanding said trailing end portion of said casing shell comprises a compacted material substantially filling said trailing end portion of said casing shell located within said passageway of said piling end cap.

10. A cast-in-place, thin-walled piling as claimed in claim 5, wherein said piling end cap is formed of reinforced concrete.

11. A cast-in-place, thin-walled piling as claimed in claim 8, wherein said reinforced concrete pile driving base member further includes a plurality of horizontal reinforcing bars extending circumferentially about said socket means.

12. A cast-in-place, thin-walled piling as claimed in claim 9, wherein said compacted material comprises zero-slump concrete.

13. A cast-in-place, thin-walled piling as claimed in claim 10, wherein said reinforced concrete piling end cap member includes a plurality of vertical reinforcing bars extending over a substantial portion of the vertical length thereof, said vertical reinforcing bars being equi-spaced circumferentially about said passageway.

14. A cast-in-place, thin-walled piling as claimed in claim 13, wherein said reinforced concrete piling end cap member further includes a plurality of horizontal reinforcing bars extending circumferentially about said passageway.

15. A piling end cap member for a thin-walled piling, comprising:

16. A piling end cap member as claimed in claim 15, wherein said means expanding said casing shell comprises a compacted material.

17. A piling end cap member as claimed in claim 15, wherein said body member is formed of reinforced concrete.

18. A piling end cap member as claimed in claim 17, wherein said reinforced concrete includes a plurality of vertical reinforcing bars extending over a substantial portion of the vertical length of said body member, said vertical reinforcing bars being equi-spaced circumferentially about said passageway.

19. A piling end cap member as claimed in claim 18, wherein said reinforced concrete further includes a plurality of horizontal reinforcing bars extending circumferentially about said passageway.

20. A method of forming a cast-in-place, thin-walled piling, comprising the steps of:

21. The method as claimed in claim 20, including the steps of: precasting said pile driving base member from concrete, and reinforcing said concrete with vertical and circumferential reinforcing bars extending about said socket cavity.

22. The method as claimed in claim 20, including the steps of:

23. The method as claimed in claim 20, wherein said pile base member and said shell are driven into said load-bearing soil by the same force that serves to compact said compactable material.

24. The method as claimed in claim 20, wherein said compactable material is compacted by repeatedly raising and gravity-dropping a hammer directly onto said compactable material.

25. The method as claimed in claim 22, wherein said other end of said casing shell is expanded by the steps of:

26. The method as claimed in claim 25, wherein said compactable material is compacted by repeatedly raising and gravity-dropping a hammer directly onto said compactable material.

27. The method as claimed in claim 20, wherein said compactable material comprises zero-slump concrete.

Description:
BACKGROUND AND OBJECTS OF THE INVENTION

1. Field of the Invention

The present invention relates generally to piling of utility especially in supporting substantial unit loads in geological areas where the bearing soil would not normally support such loads using conventional piling and is overlain by one or more strata of soil which is unsatisfactory for bearing purposes, and relates more particularly to certain new and useful improvements in the construction of such pilings which are cast-in-place and in methods for installing such pilings.

2. Description of the Prior Art

In many geological areas, there are soil strata, such as loose and granular sand or dense, non-plastic clay, which will support substantial unit loads, such as are exerted by buildings and other structures, with the use of an enlarged piling base although not with conventional piling. These strata are usually overlain by one or more strata or soil which is unsatisfactory for bearing, such as fill or soft clay. It is apparent that such pilings, including the enlarged base, must penetrate the upper, unsatisfactory strata in order to be founded in a suitable bearing stratum. Furthermore, the density of the soil of the upper, unsatisfactory strata often approaches that of suitable bearing strata and, hence, offers substantial frictional resistance to penetration by the piling.

The piling must therefore be driven by a force of sufficient energy to overcome this resistance, together with the resistance of inertia provided by the piling itself. At the same time, however, it is highly desirous for economic reasons that the tubular shell of the piling be thin-walled and it is also highly desirous that the shell and base be maintained in a liquid-tight connection after the piling has been driven into place. It is also of course necessary that the base be of sufficient size to provide an adequate bearing surface.

One type of piling commonly used in the above circumstances is the so-called "cast-in-place" piling, which consists of a tubular casing or pipe shell which is driven into the soil to the desired depth and filled with suitable construction concrete. The prior constructions and/or installation techniques for such pilings, have, however, been found to suffer from one or more disadvantages or shortcomings, such as to be unsatisfactory from commercial or practical points of view.

In one such prior procedure, known in the industry as a "Franki" piling, a charge of dry concrete is placed in the leading, open end of a tubular casing or pipe shell. The concrete charge is then compacted whereupon it forms a plug which frictionally engages the inner wall surface of the shell. Further blows against the concrete plug pull the shell through the soil. Upon being driven into place, further movement of the shell is restrained while additional concrete and the original plug are driven out of the leading end of the casing shell into a balllike configuration which forms the piling base.

The "Franki" piling has been found to suffer from many serious disadvantages, the primary ones being that the bearing soundness of a particular piling is difficult to predict and the bearing capacity of any particular piling can be determined only by expensive and time-consuming load bearing or soil boring tests. The soundness of the Franki piling is unreliable because it is affected by irregularities in both the upper and the bearing strata, it is difficult to maintain a connection between the casing and base, and, particularly where several pilings are required to be placed close together, the formation of subsequent piling bases may disturb earlier formed bases, possibly even shearing earlier formed bases from their casings. Other disadvantages stem from the difficulties and expense involved in restraining further downward movement of the casing shell during the base-forming operation.

Other prior proposals for cast-in-place pilings have incorporated a base or "driving point" by initially driving the tubular casing or pipe shell onto a concrete plug, as shown, for example, in U.S. Pat. Nos. 2,465,557; 3,395,543; 3,482,409 and 3,543,524. These proposals also suffer serious deficiencies. Since the concrete plugs are forced into the leading end of the thin-walled casing or pipe shell, they do not create a reliable striking surface and in most instances require, at least initially, that a driving force be applied to the trailing end of the shell, or the application of a simultaneous driving force to both the shell and the concrete plug. Also, because of overexpansion, the leading end of the shell may be easily split, thereby destroying any liquid-tight connection between the shell and the base and impairing the overall reliability of the piling. Furthermore, the dimensions of this type of driving base or point are necessarily limited by the expansion characteristics of the thin-walled shell and therefore do not provide a significant bearing surface at the base of the installed piling. Nor do they provide a satisfactory plowing action, wherefore these pilings are also subject to buckling or collapse during driving.

In another proposal, shown in U.S. Pat. No. 1,778,925, the driving point comprises a reinforced concrete member provided with a short connecting extension for the casing imbedded therein to which the main casing is joined to form the pile. This proposal is disadvantageous because the connection of the main casing to the driving point is awkward, complicated, and unreliable. Furthermore, the base or point must be driven by an exterior tubular mandrel which is placed over the thinwalled casing shell, and hence, requires an air or steam-operated ram or mandrel drive, which is disadvantageous because of the cost and noise levels produced.

In addition, in many instances it is desirable, in order to ready the piling for supporting the desired superstructure to be constructed thereon, to provide the upper end of the piling with a cap as a finishing member. These end caps are generally intended to create a level surface upon which to work and may encompass several piles. It is of course essential that such caps be joined to the piling securely because they are subjected to a variety of forces and, in most cases, depend entirely on the piling for support. The prior art techniques have been deficient in their ability to provide an economical, yet reliable, joint between the end cap and the piling.

Objects of the Invention

It is therefore an object of this invention to provide a new and improved piling and a new and improved method for the installation of a piling.

Another object of this invention is to provide a new and improved "cast-in-place" piling and a new and improved method for the installation of such pilings.

Another object of this invention is to provide a new and improved cast-in-place piling and a new and improved method for the installation of such pilings, which fully eliminate or overcome the numerous shortcomings and disadvantages or previously known cast-in-place pilings and their methods of installation.

Another object of this invention is to provide a new and improved cast-in-place thin-walled piling which is simple and economical both in construction and in installation, and yet is durable and reliable as a bearing structure.

Another object of this invention is to provide a new and improved cast-in-place thin-walled piling which provides a positive, liquid-tight connection between the thin-walled casing or pipe shell and the driving base or "point."

Another object of this invention is to provide a new and improved cast-in-place thin-walled piling whose bearing capacity can be accurately determined without soil boring or load bearing tests.

Another object of this invention is to provide a new and improved cast-in-place thin-walled piling wherein the driving base or point provides excellent plowing action during penetration and a substantial bearing surface when driven into place.

Another object of this invention is to provide a new and improved method for the installation of a cast-in-place thin-walled piling in which the driving force is exerted near the leading end of the piling by a gravity-operated drop-hammer.

Another object of this invention is to provide a novel piling end cap, and a novel method for the installation of a piling end cap, which overcomes or eliminates the disadvantages in previously known piling end caps and their methods of installation.

Objects and advantages of the invention are set forth in part herein and in part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations, steps, processes and improvements herein shown and described.

SUMMARY OF THE INVENTION

Briefly described, the "cast-in-place" piling of the present invention comprises, in a preferred embodiment, an enlarged reinforced concrete driving base or "point," precast with a tapered socket formed therein, a thin-walled tubular casing or pipe shell having its leading end inserted in the socket of the driving base and expanded outwardly in a swaged, friction fit thereagainst by a compacted charge of concrete or the like contained in the leading end of the casing shell, regular concrete filling the remainder of the casing shell, and a precast reinforced concrete end cap.

In various alternate embodiments, the outer surface of the driving base is slightly outwardly tapered from the leading end to the trailing end thereof and the leading end extremity is preferably conically shaped to present a pointed surface to aid penetration. Also preferably, the driving base is reinforced both vertically and radially and reinforcing dowels extend vertically into the socket, serving to further connect the casing shell to the driving base.

The piling end cap is preferably formed of reinforced concrete precast with an open central passageway which is adapted to receive the trailing end of the casing shell of the piling therethrough and further is slightly tapered from both open ends towards an intermediate central point. The cap is connected to the casing shell by compacting a charge of concrete or the like within the casing so as to expand the walls thereof outwardly into a swaged friction fit with the internally tapered cap passageway. A single cap may be formed with one or more passageways to thereby interconnect a plurality of pilings together.

The method of the present invention for installing a "cast-in-place" piling comprises, in the preferred embodiment, precasting a reinforced concrete driving base or point with a socket formed therein tapering slightly outwardly from the opening to the base thereof; inserting a thin-walled tubular casing or pipe shell into the socket formed in the base; pouring a charge of concrete into the shell; and compacting the concrete charge to thereby expand the shell wall into a positive, liquidtight friction fit against the tapered socket surface and simultaneously drive the base and casing shell to the desired bearing position. The thin-walled shell is thereafter filled with suitable construction concrete and preferably capped in the manner described immediately hereinabove.

It will be apparent from the foregoing general description that the objects of the invention specifically enumerated herein are accomplished by the invention as here embodied.

Thus, by providing a precast reinforced concrete base with an internal socket having outwardly tapered walls from the opening thereof to the socket base, and by expanding the leading end of a thin-walled tubular casing shell into a swaged friction fit with the socket by compacting a charge of concrete or the like within the casing shell, a positive, liquid-tight connection between the casing shell and the driving base is simply and economically formed and is both durable and reliable.

While expanding the casing shell into a positive connection with the base, the shell and base are simultaneously driven to the desired bearing depth, and the strength of the connection between the shell and base is continuously enhanced during the driving operation, rather than being weakened or destroyed, as in prior procedures.

The present invention also permits the piling base and shell to be driven by means of a gravity-operated drop hammer and provides a ramming surface for the hammer, i.e., the concrete charge within the base socket, which is near the bottom or leading end of the pile. These features are highly advantageous in facilitating an effective and economical driving process.

Thus, aside from the other provisions which must be made where a thin-walled casing is involved, much greater forces are required where the driving force strikes the trailing end of the piling because the force must be transmitted down the piling to the driving point, and is thereby significantly dissipated. In addition, when a striking surface is provided at the lower or leading end of the piling, more accurate control is provided and the associated calculations with respect to bearing load and the like are substantially less complicated. Further, the provision of a piling that can be driven by a gravity-operated drop hammer is highly advantageous, because much greater forces can be achieved, with less equipment and less manpower, at much lower noise levels, than with the alternative of air or steam-operated ram devices.

A further advantage of the present invention is that the bearing capacity of a particular piling can be accurately and readily determined by the use of simple calculations based on the height and weight of the hammer and the penetration distance per blow, or by correlation to a single load test piling, and does not require further load or soil boring tests.

It will be understood that the foregoing general description and the following detailed description as well are exemplary and explanatory of the invention but are not restrictive thereof.

The accompanying drawings, referred to herein and constituting a part hereof, illustrate preferred embodiments of the invention, and together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, cross-sectional view, partly in elevation, of the bottom, leading end of a piling constructed in accordance with the invention, the view illustrating a reinforced concrete pile driving base or "point" precast with an internal tapered socket and a thin-walled, tubular casing or pipe shell inserted into the socket of the driving point prior to being swage fitted therein;

FIG. 2 is a fragmentary, cross-sectional view, partly in elevation, similar to FIG. 1, illustrating a compacted concrete charge within the casing shell and the wall of the shell expanded outwardly in accordance with the method of the invention into a liquid-tight, positive friction fit with the internal tapered socket wall of the driving point;

FIG. 3 is a fragmentary, cross-sectional view, partly in elevation, illustrating a piling end cap constructed in accordance with the invention and connected by a positive friction fit in accordance with the method of the invention to the upper, trailing end of the casing shell shown in FIGS. 1 and 2;

FIG. 4 is a fragmentary, schematic view of exemplary soil strata having an upper soil stratum unsuitable for bearing support and a lower suitable bearing stratum, illustrating a piling constructed as shown in FIGS. 1 and 2 being installed according to the method of the invention;

FIG. 5 is a view, similar to FIG. 4, illustrating two pilings driven into place in the bearing stratum and capped by a single piling end cap in accordance with the invention;

FIG. 6 is a schematic view of an alternative configuration for the precast pile driving base or point illustrated in FIGS. 1 and 2; and

FIG. 7 is a schematic view of a second alternative configuration for the precast pile driving base or point illustrated in FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now more particularly to the embodiments of the apparatus of the invention shown in the accompanying drawings, there is illustrated in FIGS. 1 and 2 a pile driving base or "point" 1, having a precast reinforced concrete body 2 and an internal, open-ended socket 3, a thin-walled tubular casing or pipe shell 4 extending into socket 3, and a compacted charge of concrete 5 within shell 4 serving to outwardly expand the bottom, or leading end wall of shell 4 into a positive, liquid-tight, swaged friction fit with socket 3.

As used herein, and in the preceding descriptions, the term "thin-walled" refers to steel plate material such as that designated by the American Society of Testing and Materials as ASTM A-252, Grades 1-3, which is the standard material for steel encased pilings, and equivalents thereto, on the order of 1/4 - 1/16 inch thick.

Advantageously, and as here preferably embodied, the body 2 of driving base 1 is slightly inwardly tapered from its upper surface 6 to its bottom surface 7 and the bottom surface 7 is preferably formed in the shape of a cone so as to present a pointed end 7a, facilitating penetration of the piling through the soil strata.

Socket 3 is cast in body 2 so as to have a base 9 in the interior of body 2 and an opening 8 preferably centrally located in the top surface 6 of body 2. The shape and size of the opening 8 of socket 3 is the same as, and slightly larger than that of the thin-walled casing shell 4, and the dimensions of the base 9 of the socket 3 are slightly larger than the corresponding dimensions of opening 8, so that socket 3 is formed with an outwardly tapered wall surface 10. Advantageously, and as here preferably embodied, shell 4 is a tubular cylinder and socket 3 approximates a frustum of a cone whose upper diameter 8 is slightly larger than the outer diameter of shell 4 and whose base 9 has a diameter slightly larger than that of opening 8.

It will be seen from the foregoing, and as illustrated in FIG. 2, that when the concrete charge 5 is compacted in the leading end 12 of the casing shell 4, the casing wall expands to form a swaged friction fit with the tapered wall 10 of the socket, thereby positively and liquid-sealingly connecting shell 4 and base 1.

As the concrete charge 5 is compacted, a radially outwardly directed force is exerted on the wall of the shell 4 and the socket 3. Since this force is substantial, the concrete body 2 is advantageously constructed with a plurality of vertical reinforcing bars 20 and helical compression reinforcing bars 22 encompassing socket 3, thereby insuring against possible fracture of the base during the driving operation.

Also advantageously, and as preferbly embodied, in order to further insure the integrity of the connection between the shell 4 and socket 3, additional reinforcing bars 24 are suitably tied to vertical bars 20 and are formed so as to have a portion 24a extending vertically into socket 3 to thereby engage the compacted concrete charge 5.

As here preferably embodied, concrete charge 5 is a concrete mixture which is known in the industry as "zero-slump" concrete - i.e., the mixture does not significantly settle or "slump" when external support is removed. Such a mixture preferably comprises about one part cement, two parts sand and four parts gravel or other aggregate. Water is added to the mixture in an amount sufficient to cause hydration. It will, of course, be understood that other compactable materials equivalent to zero-slump concrete may be used with equally satisfactory results, if desired.

It will be apparent from the foregoing that the charge 5 is poured into the thin-walled shell 4 after the leading end 12 of the shell is inserted in the socket 3 of the driving base. The charge 5 settles to the leading end 12 of shell 4 and is of a predetermined amount so that, upon compaction, it will substantially fill that portion of shell 4 which is within socket 3, as illustrated in FIG. 2. Since the concrete charge 5 at this point has not yet set up, or hardened, it will compact under the force of a suitable driving means. It will be seen from FIG. 2 that as the charge 5 is compacted it comes into secure engagement with the reinforcing bars 24 and the interior walls of the leading end 12 of shell 4. As the charge 5 continues to be compacted, it exerts a force radially outwardly against the wall of shell 4 which deforms the wall so that it extends to the full dimensions of the tapered wall 10 of socket 3. This action creates a swaged, friction fit between the shell 4 and driving base 1, thereby positively and liquid-sealingly connecting the shell with the base.

In accordance with the invention, driving means are provided for compacting charge 5 and for driving the piling base 1 and shell 4 to the desired bearing position. To this end, as preferably embodied, there is provided a drop-hammer 30 which serves to drive base 1 and shell 4 into the soil by being raised and dropped repeatedly, striking the concrete charge 5 within the base socket 3. Thus, the force of hammer 30 is applied near the leading end of the piling base 1 and therefore does not damage the casing shell and is not dissipated by the use of any intermediate driving member. Advantageously, hammer 30 has an enlarged head 32 which is sized to provide about two inches of clearance between it and the wall of shell 4. Hammer 30 may suitably weigh on the order of 10,000 lbs. and is dropped from a height sufficient to provide the desired force.

It will of course be understood that the driving means for the piling of the present invention may, alternatively, comprise a pneumatically operated ram or mandrel (not shown). While the use of such a device is subject to the disadvantages of cost and noise previously mentioned, and is therefore not preferred, it may nevertheless be used satisfactorily where these disadvantages are not prohibitive.

It will be apparent from the foregoing that, in operation, the thin-walled casing shell 4 is placed in the socket 3 of driving base 1. The concrete charge 5 is then poured into the shell followed by the pile driving hammer 30. The pile is placed in the desired position and the hammer 30 is then repeatedly raised and dropped onto concrete charge 5 until the desired bearing position is reached. It will be apparent that as the pile is driven into the ground, the concrete charge 5 continues to be compacted, thereby creating a permanent leak proof bond between the driving base 1 and the shell 4. Thereafter, the casing shell is filled with a construction concrete or other suitable bearing support material to complete the piling unit.

Referring now more particularly to FIG. 3 of the accompanying drawings, in accordance with the invention there is provided a piling end cap 40 which is positively connected to the trailing end 42 of casing shell 4 by means of a swaged, friction fit, in a manner similar to that described for connecting shell 4 to the pile base 1.

To this end, as here preferably embodied, cap 40 is comprised of a reinforced concrete body 44 precast with an open central passageway 45 adapted to receive the trailing end 42 of the casing shell 4 therethrough. Passageway 45 is slightly tapered from each of the open ends towards an intermediate central point 46 having a diameter slightly larger than the diameter of the open ends thereof. It will be understood that the size and shape of passageway 45 is consistent with that of shell 4 and, in the preferred embodiment, is therefore circular in crosssection.

The body 44 of end cap 40 is also preferably reinforced with a plurality of vertical reinforcing bars 47 and helical compression reinforcing bars 48 encompassing passageway 45 in order to prevent fracture during the connection of the cap to the piling shell, as described immediately hereinafter.

Thus, cap 40 is placed over the thin-walled, tubular casing or shell 4 which has been previously driven into place and filled with construction concrete, as previously described and illustrated at 49. However, shell 4 is filled with concrete only to a level which corresponds to the approximate lower surface of cap 40 when the latter is installed about the trailing end 42 of shell 4. A charge of preferably zero-slump concrete 5 is then poured into the trailing end 42 of shell 4 above the hardened construction concrete 49 and is compacted therewithin by drop-hammer 30, also as previously described, thereby creating radial, outwardly directed forces on the shell wall, expanding the latter to the full dimensions of passageway 45. Thus, a swaged, friction fit is provided between the cap 40 and the shell 4, which resists forces exerted in both the upward and downward vertical directions, providing an economical and durable connection between the piling and the end cap.

Piling end cap 40 is advantageously rectangular in shape, as illustrated in FIG. 3, but it will be understood that it may have any desired shape, as required.

Referring now more particularly to FIG. 4 of the accompanying drawings, there is shown a piling constructed and being installed in place according to preferred teachings of the present invention. Thus, the enlarged pile base 1 and shell 4 positively and liquid-sealingly joined thereto have been driven by drop-hammer 30 through an upper soil stratum 50, unsuitable for bearing support, and the base 1 has just reached a lower stratum of bearing soil 51.

Referring now more particularly to FIG. 5, a plurality of pilings 55 constructed in accordance with the invention are shown with the base members 1 embedded in a bearing soil stratum 51 and their trailing ends capped by a common piling end cap 56 constructed in accordance with the invention, having a plurality of passageways (not shown) similar to passageway 45 of cap 40.

Referring now more particularly to FIG. 6 and 7 of the accompanying drawings, there are shown alternate embodiments of the configuration of the enlarged pile base of the invention. Thus, as shown in FIG. 6, a base 60 is provided in which the leading or bottom end 61 is flat. In FIG. 7 there is shown a base 70 in which the leading or bottom end 71 is flat and the sides are slightly upwardly tapered a short distance at 72 and then taper inwardly toward the trailing end, as shown at 73.

The invention in its broader aspects is not limited to the specific embodiments herein shown and described but departures may be made therefrom within the scope of the accompanying claims, without departing from the principles of the invention and without sacrificing its chief advantages.