US 3209546 A
Description (OCR text may contain errors)
L. LAWTON 3,209,546 METHOD AND APPARATUS FOR FORMING CONCRETE FILES JNVENTOR. LAWRENCE LAWTON 3 Sheets-Sheet l Filed Sept. 21, 1960 ATTORNEY L. LAWTON 32%,546 METHOD AND APPARATUS FOR FORMING CONCRETE PILES Get. 5 E9 65 3 Shae-0561166 2 Filed Sept. 21, 1960 INVENTOR. LAJRENCE LAWTON ATTORNEY @cfi. 5, 3%5 L. LAWTON 34$ METHOD AND APPARATUS FOR FORMING CONCRETE FILES Filed Sept. 21. 196a 3 Sheets-Sheet 3 IN V EN TOR. LAWREEJCE LAWTON 1. 43% hawk,
ATTORNEY diillifillh Patented Get. .5, 1965 3,209,546 METHGD AND APPARATUS Fill? FGG CGNCRETE FILES Lawton, 150-47 Village Road, Jamaica, N.Y. Filed- Sept. 21, 1960, Ser. No. 57,573 '8 Claims. (Cl. 61-536) Lawrence of what action may have taken place underground during the forming of the pedestal.
Among the objects of the present invention is to avoid faults experienced from prior practices and unnecessary expense incident thereto; to remove the element of unpredictability in the forming of a desired footing; and.
to provide a concrete pedestal pile having a' footing of concrete, homogeneous throughout, and a dependable spread or effective horizontal bearing area. The foregoing and other results are attained in accordance with the present invention in an efiicient manner with a great degree of reliabilityas a consequence of the procedure employed to form the pedestal.
The procedure includes the employment of a steel shell having a relatively rigid and inexpansible upper section or shaft casing and anexpansible lower section or pedestal casing. The section of the shell from which the shape and size of the pedestal is derived is so con structed that when it has been expanded to the shape of a pedestal it is, of itself, resistant to distortionfrom the action of external forceswithout the assistance of internal pressure, or a filling of concrete. As a consequence, a number of pile shells can be driven and completely formed before they are filled. A group of shells may be prepared for filling and then filled at the convenience of the operator.
The wall of the lower section is crimped throughout its circumference with bellows-like folds forming ribs running lengthwise of the shell. The upper and lower ends of the expansible section are welded to heavy rings which are welded respectively to the upper section of the shell and to a closure or shoe in a manner to provide pressure-tight connections with the rigid section or shaft casing and with the closure.
The expansible casing is expanded after the shell has been placed in the ground. lnteriorly applied fluid pressure, whose intensity exceeds the passive resistance to horizontal thrust of the soil at the elevation of the pedestal casing, forces the wall of the pedestal casing outwardly into a bulbous shape between its ends. The transverse bends of the original folds provide an expanded wall having ribbed metal arches, because of the uniform distribution and constant intensity of fluid pressure. This arched construction is highly resistant to collapse from pressure directed from the outside. The action of these vertical arches in resisting collapse is enhanced by the lateral support aiiorded by the horizontal continuity of the arched ribs.
The original folds strengthen the expansible casing suhiciently to avoid vertical collapse from the blows of a driving hammer. The vertical collapse of an inexpansible upper casing made of light gauge material can be avoided by employing a core to receive and transmit the driving force to a drive shoe. Advantages of the vention are attainable from the use of a core or of an expandable mandrel carrying devices for determining the dimensions of the chamber which is subsequently formed when the lower section is expanded.
After the shell has been fully driven, the core or mandrel is raised a predetermined distance. Temporary sealing means are made to cooperate between the exterior of the core or internal element of the mandrel and the interior of the shell above the expansible section to efiectively seal off a pressure-tight chamber. The expansible section of the shell is then expanded by introducing a pressurized fluid to the interior of the chamber.
The extent of expansion of the pedestal casing is determinable without discontinuing the pressure. It can be determined by measuring the quantity of the pressurizing fluid used or by devices which are mounted upon the core and are extendable to engage the interior of the expanded casing. By such means it is possible accurately to determine the lateral displacement of the arched walls at any time. When the expansible walls have been displaced a predetermined desired amount, the internal pressure is relieved, the sealing means are collapsed, and the core and all of the attached appurtenances are withdrawn from the prepared shell. Concrete is introduced within the shell to complete the installation of the pile. The concrete of the resulting pile has a footing of known propor-' tions and is wholly enveloped with sheet steel which is an integral part of the pile.
Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, and the manner in which it may he carried out, may be better understood by referring to the following description taken in connection with the accompanying drawing, in which:
FIG. .1 is a vertical sectional view or" a pile shell which has been capped preliminarily to the application of pressure to its interior;
FIG. 2 is a vertical sectional view of a pile shell containing a driving core;
FIG. 3 is a view similar to FIG. 2 with the driving core raised preliminarily to the introduction of pressurized fluid to the lower portion of the shell;
PEG. 4 is a view similar to that of FIG. 3 and illustrating an expanded position of the expansible section;
FIG. 5 is a vertical section taken on the axis of a completed pile;
FIGS. 6, 7 and 8 are enlarged sectional views taken approximately on lines 6-45, 7-7 and 3-3, respectively, of FIG. 4; and
FIG. 9 is a horizontal section taken through the expandable mandrel on line 9-9 of FIG. 4.
Referring first to FlG. l, the shell shown consists essentially oi a substantially inexpansible upper section Iii), an expansioie lower section ill. and a closure 12 sealing the lower end of the lower section. The upper section is in the form of an impermeable hollow cylinder or casing 33 and may conform with usual specifications for pile shells for withstanding blows from a hammer, or for placement in the ground by a core or mandrel. The expansible section includes a casing i l crirnped with deep folds running vertically and defining ridges 15 separated by valleys (E6. 7). The folds in the casing 14 may be produced by impressing a sheet of steel of a predetermined width, curving the sheet into a cylinder and welding the longitudinal edges of the sheet to form an imp meable sleeve. The folds extend to opposite edges o e sheet, but they may be made to terminate short thereof, if desired, depending on the method employed for forming them. T he width of a sheer before crimp ng, or no quantity of material around the sleeve, must be ast equal to, and is preferably greater than, the maxnnum girth desired for the pedestal.
. The vertical folds adjacent theuppcr edges of the expansible casing 14 are swaged or laid over to fit against and engage with the interior of a heavy spacing ring 18, as best seen in FIG. 6. The ring 18 is welded to the casing 14 and the'weld material 19 is used to fill the interstices between the closed folds and the ring so as to provide a pressure-tight connection entirely around the ring. The upper casing 13 is also welded at 20 to the ring 18 entirely around the ring.
Pressure-tight joints with-a heavy ring 21 at the lower end of the casing 14 are made in like manner. The lower end of the expansible casing 14 is also swaged to flatten and lay the folds against the ring 21to which the casing is welded. Welding metal 22 completes a leak-proof seal between the ring and the casing.
The shoe or point 12 may be shaped in any suitable form. It fully closes and seals the lower end of the section to which it is permanently attached by welding. It is desirable that the outer diameter of the shoe or of the ring 21 be sufiiciently greater than the maximum unexpanded diameter of the casing 14 to provide enough clearance around the casing to avoid excessive drag of the soil on the casing, or damage to the casing.
The folds of the casing 14 are formed into deep ribs to provide a high section modulus and beam strength for resisting bending stresses.- The casing is made of metal, preferably of sheet steel having sufiicient ductility to avoid rupture in the process of expanding under difiicult soil conditions. The swaging of the ends of a crimped sectionreduces the depth of the ribs and consequently the section modulus in the vicinity of the rings and facilitates outward bending of the wall of the section adjacent the heavy rings when the section is subjected to fluid pressure during the expanding operation. The showing in FIG. 1 is illustrative of one manner of creating a pressure-tight chamber within a shell. The shell has been capped with ahead 23 which functions as a plug closure through which fluid pressure may be applied to the interior of the shell. The shell may have been placed in an open hole, or it may have been driven either by hammer blows directed against the upper end of the shell, or against a driving core which has been removed. The head 23 consists of a block of metal which rests upon the top of the shell and has'a hub extending within the shell. An annular recess 25 about the hub contains a circular bladder 26 in the form of a hollow torus. This bladder is inflatable to seal the space between the hub and the interior of the shell. Pneumatic pressure is applied to the bladder through pipes 27 and 28.
The head is bored to receive a union 29 connected to a pipe 30 through which compressed air is supplied to the interior of the shell. In this example, the entire length of the shell is subjected to pneumatic pressure which is employed to expand the expansible casing at the lower end of the shell. eyes fastened to the clamp and to the head, respectively, secure the head to the shell to prevent displacement of the head. The head and shell can be additionally weighted by a hammer 33.
The invention is particularly suited for placing long concrete pedestal piles. The shell of along pile is formed and has the'characteristics of the shell hereinabove' described, with the exception that the portion of the shell above the expansible section may be composed of a series of inexpansible casings which need not necessarily be pressure-tight with respect to one another. The lower expansible casing 14 and the incxpansihle casing if) im- A pipe clamp 31 and ties 32 between mcdiately thereabove, as shown in FIG. 2, are constructed similarly to the corresponding casings illustrated in FIG. 1. They are driven into the'soii by the impact of a hammer on a core 34 having a drive foot 35 which engages the shoe of the shell.
Annular rings 36. 37, 38 are welded to the exterior of? the core. The rings 37 and 3d are separated by an annular space containing a hollow distendablc ring 39, which 2- is inflatable to establish a seal for isolating the leakproof chamber at the lower end of the shell.
The annular space between the rings 36 and 37 contains a plurality of bladders 40 which are distributed around the core, as illustrated in FIG. 9. Each bladder is disposed between the core and a metal strip 41 which is fastened at one end to an angle piece 42, anchored to the ring 36. The other end of each strip 41 is fastened to another angle piece 43 which is anchored to the ring 37. The strips may be installed with an initial tension if desired, to restrain and protect the bladders 40 when the pile forming apparatus is lowered into the shell. The outer surfaces of the strips may be roughened or'provided with gritty material for atfording a high coefficient of friction when the strips are forced into contact with the interior of the casing by pressure within the bladders.
Each bladder 40 is supplied with compressed air through a line extending into the shell, one of which is indicated at 44 in FIG. 2. The hollow ring 39 is inflatable through a line 45 which connects with the ring from within the core 34.
Means for measuring the extent of expansion of the expansible casing 14 are mounted on the lower end of the core 34. They comprise a plurality of operative units 46, in such number as may be deemed desirable, angularly displaced from one another around the core. Collapsed units at diametrically opposite sides of the core are shown in FIG. 2.
Each measuring unit 46 includes a scissors linkage con-' sisting of a series of pairs of crossing pieces, each pair pivoted together in the middle and connected with the next pair at the extremities. As shown in the drawing, the extremity of one piece of the first pair of pieces is pivotaliy mounted at 47 on a cylinder 48, and an extremity 49 of the other piece of the same pair is pivotally attached to a piston 50. The arrangement is such that the linkage is extended by inward movement of the piston. Extended positions of diametrically oppositely located linkages are illustrated in FIG. 4.
Contact of the outermost end 51 of the linkage with the wall of the expansible casing measures the radial position of the wall. This measure is indicated by the position of a piston in a master cylinder (not shown) located above ground and having lines 52 and 53 communicating with opposite ends of the cylinder 48. The master cylinder and piston are operated to control the fiow of liquid through the lines to extend or contract the scissors linkage.
A similar measuring cylinder 55 containing a piston St is mounted on the foot 35 at the bottom of the core. The ends of the cylinder 55 are connected to the opposite ends of a master cylinder (not shown) located above ground through lines 57 and 58, whereby the displacement of the piston in the measuring cylinder 55 may be accurately ascertained. The stem of the piston 56 is slidable through a hole in the drive foot 35. Upon moving the stem into contact with the bottom closure 12 the dis lance between the foot and the closure can be ascertained. Because the change in diameter of the pedestal casing is a function of the change in height of. the pedestal casing, the measuring cylinder 55 can serve to gauge the extent of expansion of the pedestal casing.
The pile-forming operation includes. mounting a prepared expansible casing to an upper casing and a closure, as explained in the foregoing description. This may be done in the field or at the factory. Then the assembled shell is driven into the ground until a load-bearing strata is reached. The driving core is then raised to a position where the radius measuring devices 46 are located at upproximatcly the predetermined level of the maximum girth of the extensible wall of the casing, as shown in MG. 3. This position is determined above ground by the position of the piston in the master cylinder which is connected with the measuring cylinder 55.
The mandrel bladders 4d are then inflated to hold or secure the core firmly in fixed position relatively to the pansible casing. Hydraulic pressure may also be used as an expanding pressure medium. As this is being accomplished, the degree of expansion can be followed by use of the scissors linkages 46 and controlled master cylinders above the ground.
Expansion continues until the expansible casing has reached a girth encompassing the desired bearing area for the pedestal. The lifting force on the core caused by the pressurized fluid is resisted by the weight of the core and the friction eifective between the expanded mandrel and the shell and this downward force can be augmented by the weight of a hammer 33.
After the form for the pedestal has been completed, the pressure contained within the expanded wall is relieved, the scissors linkages are collapsed, and the mandrel bladders and sealing rings are deflated, whereupon the core and the attached appurtenances are withdrawn from the shell. If hydraulic pressure means have been employed, the liquid is removed from the pile shell. The shell is then filled with concrete 6!), as shown in FIG. 5.
Either a gas or a liquid is used as the pressure exerting medium. The employment of hydraulic pressure offers several advantages. An incompressible fluid, such as water, enables determination of the extent of expansion of the pedestal casing by measuring the quantity of the fluid used. Also, the energy consumed in increasing the pressure of an hydraulic fluid is expended almost entirely on enlarging the pedestal casing in contradistinction to the loss of energy entailed in compressing a larger volume of air, as when an entire shell or most of a shell is sealed by an apparatus in the nature of that shown in FIG. 1, for example. The energy consumed in compressing'the gas above the pedestal casing performs no useful work. Particularly in the application of the method for forming a pedestal on along pile shell, as described with reference to FIGS. 2, 3 and 4, for example, this disadvantage of pneumatic pressure is overcome because a core may be used as an element of a'sealing plug or temporary closure whereby the pressure-tight chamber encompassed by the pedestal casing is isolated from the remainder of the pile shell. The choice of the fluid medium is largely dependent on which fluid medium will serve most. efiiciently and economically to bring about the results desired.
While the invention herein shown and described is adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the use of the specific forms of apparatus herein disclosed, for it is susceptible of embodiment in various manners all coming within the scope of the claims which follow.
What is claimed is:
l. The method of making a concrete pedestal pile with a metallic impermeable pile shell comprising a fluid-tight expan'sible tubular pedestal casing with folds extending continuous for substantially the height of the casing, said pedestal casing completely closed at its lower end and having its upper end fixedly and hermetically connected to a tubular fluid-tight rigid casing, said method comprising inserting a mandrel into the pile shell and driving the pile shell into the soil to a desired depth, establishing a seal interiorly of the shell between the mandrel and the rigid casing and thereby creating a fluid-tight chamber encompassed by the pedestal casing, expanding the wall of the pedestal casing with pressurized iluid within the chamber whose intensity of pressure exceeds the passive resistance ofthe soil at the elevation of the pedestal casing, continuing the expansion of the wall of the pedestal casing with pressurized lluid until the pedestal casing is vertically arched outwardly into a sell-sustaining bulbous structure, relieving the pressure in the chamber, removing the seal between the mandrel and the rigid casing, withdrawing the mandrel and removing the pressurizing fluid and filling the pile shell with concrete to complete the forming of the pedestal pile.
2. The method of making a concrete pedestal pile with a metallic impermeable pile shell comprising a fluid-tight expansible tubular pedestal casing having folds extending continuous for substantially the height of the casing, said pedestal casing completely closed at its lower end and having its upper end fixedly and hermetically connected to a tubular fluid-tight rigid casing, said method comprising driving the pile shell into the soil to a desired depth, sealing oil the lower portion of the pile shell above the pedestal casing to render the lower portion of the pile shell fluid-tight, subjecting the interior of the sealedoff lower portion of the shell to fluid under pressure and thereby expanding the wall of the pedestal casing beyond the girth of the rigid casing, measuring the diameter of the maximum girth of the expanded pedestal casing while maintaining pressure in the sealed-0H lower portion of the shell, continuing the expanding pressure and measuring until the pedestal casing has been expanded into a vertically arched self-sustaining bulbous structure, and removing the pressurizing fluid and filling the pile shell with concrete to complete the forming of the pedestal pile.
3. A method for making a concrete pedestal pile within a pile shell by using a shell comprising an impermeable, relatively rigid and inexpansible tubular metallic casing open at its upper end and having its lower end hermetically joined to an impermeable expansible tubular metallic casing completely closed at its lower end, said method comprising the steps of driving the pile shell into the ground, sealing oil the interior of the expansible casing by sealing the pile shell above the expansible casing to make the interior of the shellabove the closed lower end of the expansible casing available as a fluid-tight chamber for containing fluid under pressure, filling the fluid-tight chamber with a fluid under pressure, expanding the expansible casing by increasing the pressure of the fluid contained by the fluid-tight chamber and thereby forming the expansible casing into a bulbous structure self-sustaining against the inwardly directed pressure of V the soil surrounding the bulbous structure, relieving the pressure of the fiuid, removing the previously applied seal of the shell and thereby making the entire interior of the shell accessible from its upper end, removing the fiuid and introducing into the shell a suificient quantity of concrete to fill the shell and form, upon hardening, an integrated pedestal pile having a concrete pedestal within the expanded casing which is conterminous with the expanded interior surface of the expanded metallic casing.
5. The method according to claim 3 wherein a compressed gas is employed for expanding the expansible casing.
5'. The method according to claim 3 wherein a pressurized liquid is used for expanding the expansible mota r lie casing and the liquid is removed from the interior of the fluid-tight chamber before the shell is filled with concrete.
6. In a pile shell, a pedestal casing, arelatively inexpansible rigid ring at each end of said pedestal casing, said pedestal casing comprising an impermeable metallic sleeve crimped with deep folds running longitudinally of the sleeve to adjacent an annulus at each end of sleeve, each annulus formed by contiguous parts of the folds laid over onto one another whereby the outside diameter of the annuli is less than the maximum outer diameter or" the sleeve between the annuli, the outside of one of said annuli engaging the inside of one of said rings, and the outside of the other of said annuli engaging the inside of the other of said rings, means pcrmanently joinning said annuli at the ends of said sleeve to said rings and sealing against leakage at the joints between the sleeve and the rings, a tubular shaft casing having a lower end fixedly attached to one of said ringsin sealing relationship throughout the circumference of the ring, a fluid-tight closure means fixedly attached to the other of said rings and closing the lower end of said pedestal casing, and means sealing against leakage at the jointure between 'said pedestal casing and said closure.
7. In a pile shell in situ, a metallic shell comprising a hollow upper section and a 'hollow lower section with adjoining ends fixedly connected together and hermetically sealed throughout their circumference, said upper section comprising a pile casing which is relatively rigid and inexpansible laterally, said lower section comprising an impermeable ribbed wall of sheet metal vertically arched outwardly intermediate the upper and lower. ends of the lower section, said wall forming a bulbous structure selfsustaining against the inwardly acting pressure of the soil surrounding the bulbous structure, said wall having longitudinally extending folds, alternately reversed transversely around the wall and varying in depth from deep folds adjacent the ends of the lower section to shallow folds as the distance increases from the ends of the lower section to the maximum girth of the lower section, impermeable metallic closure means closing the lower end of said lower section, and means hermetically sealing against leakage between said closure means and said ribbed wall.
8. A pile in situ, said pile comprising the pile shell according to claim 7 containing a filling of concrete.
References Cited by the Examiner UNITED STATES PATENTS 961,492 6/10 Goldsborough 61-5 3.6 1,296,995 3/ 19 Miller 61-53.6 1,827,015 10/31 Jenkins 61-5332. 2,497,377 2/50 Swann 61--53.6 2,741,093 4/56 Riker 6153.72 2,876,413 3/59 Saurenman.
3,005,315 10/61 Cobi 6153.72 3,046,601 7/62 Hubbert et al. 166-4 FOREIGN PATENTS 703,654 2/54 Great Britain. 292,903 7/ 16 Germany.
EARL I. WITMER, Primary Examiner.
WILLIAM I. MUSHAKE, JACOB L. NACKENOFF, Examiners.