US3248888A - Pre-cast concrete piles - Google Patents

Description

May 3, 1966 c. 1.. WILLIAMS PRE-CAST CONCRETE PILES 3 Sheets-Sheet 1 Filed June 21, 1963 y 1966 c. 1.. WILLIAMS 3,248,888

PRE-CAST CONCRETE PILES Filed June 21, 1963 3 Sheets-Sheet 2 y 1966 c. L. WILLIAMS 3,248,888

PRE-CAST CONCRETE FILES Filed June 21, 1963 3 Sheets-Sheet 3 FIG. 11. 9

FIG. 12.

Patented May 3, 1966 3,248,888 PIKE-(EAST CONCRETE PlLES Cyril Lewis Williams, Kirkella, England, assignor t Composite Piling and Foundations Company, Limited, Hull, England, a corporation of Great Britain Filed June 21, 1963, Ser. No. 289,648 Claims priority, application Great Britain, June 22, 1962,

24,134/ 62 6 Claims. (Cl. 61-56) This invention relates to pre-cast concrete piles.

Pre-cast concrete piles at present in use are, due to their length, cast horizontally and are therefore of square, rectangular or polygonal cross-section, and apart from the limitation as to shape are also limited as to cross-sectional size and length due to the difliculties of raising and handling massive cross-sections and great lengths. Indeed at the present time the greater part of the metallic reinforcement incorporated in pre-cast piles is to cater for bending loads during lifting and moving the piles prior to driving. Also the present horizontally pre-c'ast piles may suffer some disadvantage due to uneven composition as the denser. material will tend to settle at the bottom of the mould. It may also be mentioned that enormous casting yards are necessary due to the space occupied by the moulds and the space required for the equipment for handling such piles. Transporting long, pre-cast piles from the centre of manufacture to the location of their driving is often a costly and laborious operation.

In-situ piles, of which there are several types, offer some solution to the aforementioned problems but are limited in capacity and application.

Now therefore the object of the present invention is to provide a pre-cast concrete pile which is not limited as to shape, cross-sectional size and length, requires less reinforcement and casting space, and which even if not cheaper than known pre-cast piles should be comparable in cost and be more economical in overall cost as a made and driven pile.

To this end the pile according to the present invention is composed of pre-cast concrete sections each of which incorporates a plurality of lengthwise extending throughgoing means to receive or constitute elements whereby a section can be secured by post-tensioning to a previously driven-in section as a step in the driving operation.

The pile is found by first driving in a pre-cast concrete section with an integral or attached tapered nose cone and having a plurality of tensiona-ble cables or rods extending therethrough, connecting the ends of such cables or rods to corresponding cables or rods of a'precast pile section held thereabove, lowering the upper section to abut co-axially the driven in section, tensioning the cables or rods from the top of the upper section and then looking them to hold the tension and secure the one section to the other, and driving in the second precast section wherafter a further pre-cast section may be joined on in like manner and also driven in.

The pile sections may be of any cross-sectional shape but are preferably circular and are also preferably cast vertical in convenient lengths having regard to the crosssectional dimensions.

By making the pile in sections mass limitations applicable to known piles are eliminated and by vertical casting shape limitations do not apply and can give circular cross-section pile-sections. The sections are made in convenient lengths, say of five up to some fifteen feet so that five such fifteen foot long sections would make a seventy-five foot pile, and require less reinforcement than a pile of such total length as the same would not be required to cater for bending loads. Each pile section could be solid, hollow, or have a light-Weight or tubular core and its cross-sectional dimensions or diameter could be anything up to say six feet which is quite impossible with known pre-cast piles and present driving practice. I

Each pile section contains mild steel reinforcement, such as a helix or a plurality of hoops, to give resistance to bursting and assist in distributing the stresses involved in lifting and driving a section. Apart from a pair of straight bars to help maintain the uniform pitch of the helix or hoops spacing of the hoops, these are the only items of reinforcement necessary.

Each section either has a plurality of passages, conveniently formed by tubes of plastic material, cardboard or the like, through each of which extends a post-tensioning cable or rod either prior to casting or thereafter and conveniently immediately prior to driving a section, or has positioned in its mould prior to casting a plurality of cables or rods with a coating of plastic material. Each end of each passage in a pile section may terminate in a portion of larger diameter, of which those at the upper end of a pile section may have tapered walls, and the cables or rods placed in such passages preferably project beyond the ends thereof. When the cables or rods have a plastic material coating and are positioned prior to casting a pile section they may be co-extensive in length to the pile section and have un-coated ends located in recesses in the section ends to enable such cables or rods of one pile-section to be connected to those of an adjacent pile section abutted thereto.

To locate adjacent pile-sections for driving and positively to prevent their relative rotation, with possible shearing of tensioning members, two, three or more pins, or equivalent members, may be located into sockets, formed in each end of each pile section. One of these sockets if provided or otherwise a specially provided socket may accommodate a removable device for use in lifting the pile-section; or a steel lifting eye may be cast into the section, and cut olf, or otherwise removed before the section is driven-in. 4

The pile-section firstto be entered into the ground is either made integral with a tapered nose-cone or toe or is made'fast a nose-cone end portion and the ends of the post-tensioning rods or cables of the first pile section are anchored in such nose cone. The tip at least of such nose cone has a metallic outer surface or sheath.

This first pile section is driven into the ground until the upper end thereof projects only some two feet above ground level. The post-tensioning means of such first section, after tensioning if so desired, are connected by the projecting ends of such post-tensioning being made fast to the projecting ends of the equivalent means of the next pile-section which is place-d co-axi'a-lly thereabove, and if required located by the pin or equivalent members engaging in the recesses in the ends of sections if provided. The sec-0nd pile section is stressed to the driven section from the top of the latter, each of the post-tensioning means being stressed, individually, in pairs, or all simultaneously. The second section may now be driven into the ground so forcing the first section before it until its upper end likewise projects by some two feet above ground level when a third section, and thereafter as may be desired further sections, are joined on and then drivenin in the same manner as the second section.

The pile-sections may all be of uniform cross-sectional dimensions and shape, but if desired the cross-section dimensions of the pile may be increased at any one or more points in the intended length of the pile, by the introduction of sections of the desired longer cross-sectional dimensions, the first of which has a tapered lower end reducing to the size of the section to which it is to be connected, with advantage not obtainable with known piles, as it is above necessary that the post-tensioning means of the larger cross-section sections are in matching position with those of the smaller section(s).

The upper or driving end of a pile section may be provided with a metallic crown or border.

Now in order that the invention may be. clearly understood and readily carried into eifect an embodiment of pile-section is by way of example hereinafter more fully described with reference to the accompanying drawings which are given for purposes of illustration only and not of limitation.

In these drawings: 1

FIG. 1 is longitudinal section through a pile-section,

FIG. 2 shows a cone end of a first pile-section,

FIG. 3 is a cross-section on a larger scale of the driving end of the pile-section,

FIG. 4 is a sectional plan view of FIG. 3,

FIG. 5 is a cross-section on the scale of FIG. 3 of an intermediate portion of the pile-section,

FIG. 6 is a plan view of FIG. 5,

FIG. 7 is a section also on the enlarged scale of the cone end or shoe,

FIG. 8 is a sectional plan of FIG. 7,

FIG. 9 is a cross-section normal to FIG. 3 on a still larger scale of the end of the pile-section,

(FIG. 10 is a plan view of FIG. 9,

FIG. 11 is a section on a greatly larger scale of a socket in the pile end, and

FIG. 12 is a plan view of FIG. 11.

The pile section 1, as illustrated, is preferably of circular cross-section and is cast vertically-in a suitable mould, and it may have a hollow or lightweight core 2. The pile section normally has flat ends but a first section may be made integral with or has connected to it a metallic sheathed cone 3 as illustrated in FIG. 2. This first pile-section or its cone incorporates a metal ring 4 (see also FIG. 7).

Each pile-section 1 has a plurality of preferably annularly arranged, tubes 5 made of plastic material, cardboard or such like through each of which may slide a post-tensioning cable (or rod) .12. In a first pile section, these cable are anchored at the bottom in the cone by means of an'anchor-ring 4, or simply by forming the cable ends into loops cast directly into the concrete to be retained therein with or without other means of anchorage. For the upper end of a first pile section and each end of the second and subsequent pile sections, the lead to the tubes 5 takes the form of larger diameter recesses 6.

The pile section is reinforced by a mild steel helix. 7, which is located prior to casting by being secured to the tubes 5 and/or to straight bars (not shown) which maintain the pitch spacing of the helix and by connection to the anchor members of an annular metal crown 8 provided at the driving or upper end of the section.

In each flat end of a pile section there is preferably provided at least two, recesses 9 which may contain metal bushes and be held by anchors 10. The recesses 9 are intended to receive members such as metal rods for holding adjacent pile-sections in alignment and for preventing their relative rotation during driving. At last one of such recesses at the upper end of the pile-section when provide-d has its bush internally threaded (see FIG. 11) to receive an eye bolt or the equivalent for facilitating the handling of the pile-section as by means of a crane, or a specially provided recess may have such threaded bush for such purpose while in an alternative a metallic lifting eye may be cast into the section end and subsequently removed as by cutting off prior to driving.

The pile-section 1 first to be entered into the ground namely that having or connected to the cone 3 is driven into the ground until the upper end thereof with the crown 8 projects only some two feet above ground level.

A resilient disc 15 of plastic material or rubber, suitably apertured for the cables, may advantageously be placed over the top flat end of the driven pile section. The projecting ends of its post-tensioning cables 12 of such cables are connected as by means of a commercially available coupling device or by mechanical splicing to the ends of the post-tensioning cables of the next pile-section which is held thereabove. Locating rods are. positioned in the recesses 9 and the second pile-section is lowered to abut the first with the coupling device or cable joints received in the recesses 6. The cables 12 of the upper section are now tensioned as are those of the first section to which they are connected by means of jacks or equivalent tensioning means and such tensioned cables are then locked to hold their tensioning as by means of the cone locking devices. Excess lengths of the projecting cables 12 may be cut off. The second pile-section is now driven into the ground so forcing the first section before until its upper end likewise projects above the ground by some two feet when a third section, and thereafter as may be desired further sections, are joined on after post-tensioning its cables or rods.

A disc 15 of plastic material or rubber may be placed between all pile sections.

I claim:

1. The method of providing a concrete pile foundation which comprises the steps of (a) casting in vertical aspect a bottom column section having a nose cone at its bottom end, a flat top end and a plurality of cables anchored in said bottom section and extending through said flat top end, (b) casting in vertical aspect a plurality of relatively short intermediate column sections having top and bottom flat ends, a plurality of vertical passages extending .therethrou-gh and enlarged openings at the passage tops and bottoms, (c) driving said bottom section into ground until its upper flat end is near ground level, ((1) passing a plurality of cables through the plurality of passages in an intermediate column section, (e) positioning in vertical aspect the intermediate column section above the driven portion of said pile, (f) attaching thelower portions of the individual cables in the intermediate column section to the top portions of individual cables extending from the driven column section, (g) lowering the intermediate column section to abut the driven column portion of said pile and tensioning the plurality of cables extending from the top of the intermediate column section, (b) attaching the tensioned plurality of cables to an upper portion of the intermediate section in a manner so as to arrest loss of tension in the plurality of cables but to permit adding additional tension thereto, (i) driving the intermediate section in the ground until its upper end is near ground level, and (j) repeating steps (d) to (i) with a selected number of the intermediate sections of said plurality of intermediate sections.

2. Method according to claim 1 including the steps of casting said bottom and intermediate column sections with a circular periphery, casting a plurality of alignable sockets in each of the abutting ends of said column sections and inserting rod members in said aligned sockets prior to tensioning the cables between abutting column sections, whereby relative rotation of the column sections which would shear the cables is prevented.

3.- Method according to claim 1 including the step of inserting a resilient disk between abutting ends of said column sections prior to tensioning said cables between abutting column sections.

4. The method of providing a concrete pile foundation which comprises the steps of (a) casting in vertical aspect a bottom column section having a fiat top end and a plurality of vertical jacketed cables positioned therein, each cable being anchored inthe interior of the bottom column section and extending to through the top flat end of said vertical bottom column section, (b) casting in vertical aspect a plurality of short intermediate column sections having flat top and flat bottom ends, a plurality taching the plurality of cables in said intermediate section to an upper portion thereof in a manner so as to arrest loss of tension in the plurality of cables but to permit adding additional tension thereto, h) driving said intermediate section in the ground until its upper end is near ground level and (i) repeating steps ((1) to (h) with a selected number of said intermediate sections of said plurality of intermediate sections.

5. Method according to claim 4 including the steps of casting said bottom and intermediate column sections with a circular periphery, casting a plurality of alignable sockets in each of the abutting ends of said column sections and inserting rod members in aligned sockets prior to tensioning said cables between abutting column sections, whereby relative rotation of the column sections which would shear the cables is prevented.

6. Method according to claim 4 including the step of inserting a resilient disk between abutting ends of said column sections prior to tensioning said cables between abutting column sections.

References Cited by the Examiner UNITED STATES PATENTS 938,140 10/ 1909 Goucher 50-'-408 982,769 1/1911 Berle 131 X 1,567,301 12/1925 Ross 408 X 2,065,507 12/ 1936 Alexander 61-56 2,342,243 2/ 1944 Brizay 6156 X 2,371,882 3/1945 Freyssinet 50--135 2,507,259 5/ 1950 Lavesseur 6156 3,151,464 10/1964 Sato et 'al. 6156 X FOREIGN PATENTS 181,827 4/ 1955 Austria. 1,044,695 6/ 1953 France.

582,249 11/ 1946 Great Britain.

783,624 9/ 1957 Great Britain.

CHARLES E. OCONNELL, Primary Examiner.

25 JACOB SHAPIRO, Examiner.

Claims (1)

1. THE METHOD OF PROVIDING A CONCRETE PILE FOUNDATION WHICH COMPRISES THE STEPS OF (A) CASTING IN VERTICAL ASPECT A BOTTOM COLUMN SECTION HAVING A NOSE CONE AT ITS BOTTOM END, A FLAT TOP END AND A PLURALITY OF CABLES ANCHORED IN SAID BOTTOM SECTION AND EXTENDING THROUGH SAID FLAT TOP END, (B) CASTING IN VERTICAL ASPECT A PLURALITY OF RELATIVELY SHORT INTERMEDIATE COLUMN SECTIONS HAVING TOP AND BOTTOM FLAT ENDS, PLURALITY OF VERTICAL PASSAGES EXTENDING THERETHROUGH AND ENLARGED OPENINGS AT THE PASSAGE TOPS AND BOTTOMS, (C) DRIVING SAID BOTTOM SECTION INTO GROUND UNTIL ITS UPPER FLAT END IS NEAR GROUND LEVEL, (D) PASSING A PLURALITY OF CABLES THROUGH THE PLURALITY OF PASSAGES IN AN INTERMEDIATE COLUMN SECTION, (E) POSITIONING IN VERTICAL ASPECT THE INTERMEDIATE COLUMN SECTION ABOVE THE DRIVEN PORTION OF SAID PILE, (F) ATTACHING THE LOWER PORTIONS OF THE INDIVIDUAL CABLES IN THE INTERMEDIATE COLUMN SECTION TO THE TOP PORTIONS OF INDIVIDUAL CABLES EXTENDING FROM THE DRIVEN COLUMN SECTION, (G) LOWERING THE INTERMEDIATE COLUMN SECTION TO ABUT THE DRIVEN COLUMN PORTION OF SAID PILE AND TENSIONING THE PLURALITY OF CABLES EXTENDING FROM THE TOP OF THE INTERMEDIATE COLUMN

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