US2529220A - Foundation pile - Google Patents

Description

NOV. 7, v1950 J- w. LEVASSEUR ,220

FOUNDATION FILE Filed March 26, 1947 2 Sheets-Sheet 1 n -i Inventor N I v A 7 2 C 39 ljems v y I j Attor y Nov. 7, 1950 J. w. LEVASSEUR 2,529,220

FOUNDATION PILE Filed March 26, 1947 2 Sheets-Sheet 2 Ihventor iirga/afllemwear By Attorneys Patented Nov. 7, 1950 UNITED STATES PATENT OFFICE FOUNDATION PILE Joseph W. Levasseur, Nicolet, Quebec, Canada Application March 26, 1947, Serial No. 737,320

2 Claims. 1

The present invention relates to piles and, more particularly, foundation piles of large diameter adapted to be assembled in place into a solid column.

The primary object of the invention, therefore, resides in the provision of sectional foundation piles of improved performance for specific purposes.

Another object is the provision of a concrete sectional foundation pile adapted to be assembled easily and quickly into a monolithic unit of great strength and rigidity.

A further object of the invention contemplates a concrete pile of the character described, the sections of which can be pre-cast accurately within close limits for obtaining standardized foundations.

Still another object of the invention concerns a foundation pile having great frictional contact with the soil into which it is sunk.

A still further object envisages a concrete sectional foundation pile armored in a manner such as to resist without breakage tremendous sinking stresses.

Other objects and advantages will become apparent, or be pointed out further, during the description to follow.

The foundation pile of the invention is a pre-cast reenforced concrete unit especially intended for driving into soft clay or like soils where a hard sub-stratum cannot be reached conveniently: more specifically, this pile is calculated to bear, by friction alone, loads in excess of those normally applied to piles of conventional cylindrical solid form. Furthermore, it is an intended feature of the pile, object of the invention, that it be adaptable to reenforcement of structures already existing, which structure lack adequate foundations or tend to sink in soft or shifting soil.

For the purpose above noted, the piles of the invention are so contoured that a great area of frictional engagement is available on the sides of the pile, while retaining the volume thereof within limits of compactness, lightness and adaptability to a wide range of conditions.

Furthermore, for internally reinforcing the piles, an inside metallic armature is accurately disposed inside the cast concrete sections, said armature, including longitudinal tie rods adapted to be secured together from one pile unit to the next, as said units are sunk, for tying the units into a rigid non-bending column,

Finally, the pile units are adapted to be made in axially-divided sections relatively easy to cast and manipulate, but connectable together on location for forming large piles, or caissons, capable of wide applications and of great weight-carrying capacity.

As an example, and for purposes of illustration only, embodiments of the invention are shown in the annexed drawings wherein:

Figure 1 is an elevation showing a possible application of the invention to the reenforcement of a railroad trestle;

Figure 2 is a plan View of a large pile according to the invention and of generally square cross-section;

Figure 3 is a similar view of another pile of circular cross-section;

Figure 4 is a transverse vertical section taken through the pile of Figure 3;

Figure 5 is a partial vertical section through the pile joint showing the connecting means;

Figure 6 is a plan view of said connecting means; v

Figure 7 is a partial vertical section through adjoining piles showing the tie rods welded together and the welding aperture grouted;

Figure 8 is a view similar to Figure 7 before the grouting operation;

Figure 9 is a partial enlarged horizontal section through the end of a pile arm showing the reenforcing armature and its relation with the vertical rods thereof; and

Figure 10 is a similar view through the horn of the pile of Figure 2.

Referring to the drawings, wherein similar reference characters represent corresponding parts throughout, the reference letter P indicates generally a foundation pile according to the invention which pile, as clearly shown in the several figures may effect a general configuration resembling either a circle or a square. This geometric definition is, of course, based on the shape of the theoretical line that subtends the end of the adjoining arms of the pile and, consequently, represent thereby a quadrangle or a many-sided polygonresembling a, circle.

Whatever the ultimate shape of the pile, however, the arms A all have the same general proportion throughout the modification, irrespective of the sizes thereof. More particularly said arms are of generally elliptic form comprising a medial swelled portion 20 extending from a reduced neck portion 2| and terminated into a point 22 slightly convex at its extreme end. Said arms project radially from an annulus 25 having a central bore 26 the diameter of which varies in proportion to the size of the finished pile section. The relative proportions existing approximately between the thickness of the arms and the neck are somewhat in the ratio of 7 to 4 while the ratio of the length of the arms, from the neck thereof, to the tip is roughly three times the width of said arms.

The description of the arms just given apply,

more particularly, to the pile of Figure 3 which consists of a number of said arms equally distributed radially around the annulus'25. In the case of the square (pile of Figure 2), however, the arms A are disposed in diametrically-aligned pairs arranged in right angular formation, each of the arms pointing to the corner of, the theo-, retical square. In the spaces between adjacent arms, there are formed shorter tapered horns H projecting outwardly in pairs and the ends, or-

tips of which terminate on the theoretical 'sides of the square. The axis of each horn is not quite radial, however, but more or less "parallel to a radial diametral line'extending midway between adjacent arms A. s

As previously stated, the piles of the invention are'reenforced internally by means of a special armature of a suitable metallic wire which is trained in a special manner over and around vertical tie rods and armature rods disposed in the arms and horns respectively. The said wire armature is shown in plan view in Figures 2 and 3, said showing being in solid line for purposes of better comprehension although, actually, the armature is inside the pile and not visible externally.

In the specific example of Figure 2, the tie' rods are disposed 'in'the ends of the arms, vertically, an armature rod 3i also disposed vertically in the neck thereof. Conversely, the horns comprise only one armature, rod 32 placed substantially a little inside-the medial portion thereof, the said rods being tied together, and with annulus rods 33 and connector rods 3 1 by means of the armature proper to be described presently. The said "armature may semester a metallic wire of suitable size and trainedaround the rods in a manner clearly shown inthe figuresr' more specifically, the tie rods 30; are connected together, in each portion of a'pile section, by means of an arcuate length ofwire 35' which is doubled or folded back around the tie rods '38 and reversed into the'arc 36 directed toward the connector rods 3 of its pile portion, crossing on its way to said connectorrods'the a'rcuate wire ts on both sides of the armature o'r neck rods 3| to which the wires are welded or otherwise secured. From the connector rods' 34 the armature con tinues to the nearest horn H, extending to the.

tip thereof and coming back around the rods 32' from which it extends to the first horn H past the intervening arm A and back again tothe medial armature rod 33, to the next horn Hand from there to the last horn and from there to the tie. rods 33 passing'on the way around the rods reenforced pile having a metallic armature embedded therein.

Due to the large physical size of the pile section which may have a diameter up to about eight feet and a thickness of 30 inches or so, it is not expedient to cast the same in one monolithic unit due to transportation and installation difficulties. Consequently, it is an object of the invention to cast the piles in portions, that is: the pile section is normally manufactured in halves cutting the section'longitudinally along the line C of Figure 2, the individual portions of each pile section being thus more easily transported and manipulated, the connecting together ofthe portions being effectuated on the spot by means to be described.

" The saidpile-portion connecting means con- ..sist in an elliptic link 40 engaging both connector rods 34 facing each other across the dividing line CC. Thesaid links are disposed in a semi-elliptic cavity 4 I formed in each pile-portion, at the time of casting, the said cavities being filled at the time of assembly with a cement grout forming a cover 42. (See Figures 5 and 6.)

The pile-portions are further cemented together by means of thin concrete poured in a space left between the facing edges of each pileportion, said cement constituting a bonding trip 43 between the portions. Again, forpurposes of solidity, a semi-circular axial groove is formed in each face of the pile-portion edges to form when in register a longitudinal circular channel 44 also adapted to receive the bondi'ng cement and thus increase the solidity "or the joints between the pile portions.

A circular collar 35;;is provided at the top end of the pile bore 26, said collar extending above the pile section and adapted to enter an annular cavity 18 formed at the bottom of the bore of the superposed'section. Inasmuch as'the cavity Q6 is somewhat larger than the outer diameter of collar d5, it is feasible at thispoint also to introduce a bondinggrout at" the time of assembly for bindingpurposes. I

So as to render the lower end of the rods 30 accessible for welding, as will beex'plained later on, the extreme tips of thearmaimmediately adjacent the rods, are raised somewhat as shown in Figure 4 to expose the lower end of said rods.

This is accomplished preferably by introducing in the mould, around the bottom of the rod, an easily destructible, collar of pasteboard, pressed straw matting or the like which can be removed after the cement has set to form the cavity 41 around the rods at the end of arm A. (See Figures 7 and 3.) a

The above description of the pile shown in- Figure 2 applies also to the circular pile of Figure 3 with the exception that the tie rods 30 are provided at the end of every second arm only, the the intervening arm having a smallerarmature rod 50. The wire armature is very substantially the same as the pile of Figure 2, the absence ofintervening horns providing a more symmetrical arrangement, however. Thus, the two tie rods of one pile section are connected together by an arcu'ate length of wire andthe smaller armature rods 50 being similarly connected, the arcuate lengths being welded or joined'to the medial rods 3 l and also to the connector rods 34-.

The method of connecting together the individual pile sections, as the sinking work pro gresses, shouldbe fairly obvious from Figures 7 and 8: as one pile is almost sunk by means or hydraulic jacks or whatever apparatus is used;

for the purpose, another section is placed on top, over a thin layer L of mortar or cement laid on the top surface of the lower pile and the position of the upper pile is carefully adjusted until the tie rods 30 are all axially aligned and in good contact with each other. Thereafter, the contacting ends of the rods are Welded together as shown in Figure 8, said welding taking place inside the cavity 4'! by suitable welding means. This cavity is afterwards filled with cement as shown in Figure '7 thereby completing the joining of one pile with the other.

As one pile is being sunk, another is placed immediately on top, said pile being connected as described above, and the process repeated until sufficient depth has been reached so that the frictional surface of the pile is sufficient to hold the structure being stabilized, or until a sand or rock bed has been reached. This can be ascertained by means of the inside bore of the pile section which, as shown in Figures 2 and 3 can be made sufiicient to allow the passage of special pumping or surveying means or even an operator.

The pile sinking operation being completed, and the individual sections all tied together as described above, the space above the pile and the supported structure may be filled by plain concrete blocks B as shown for instance in Figurev 1 wherein a railway trestle T the foundations of which are insufficient have been reenforced by means of the piles described. Due to the novel features of having large pile sections divided diametrally, it is possible in the case of the railway trestle, for instance, to lower each portion of the pile section between the railways tracks without having to remove more than a few ties, a feature which renders unnecessary the discontinuance of traflic on the trestle. As stated previously, each individual portion is joined to its mate and the so-formed sections thereafter manipulated as a whole. And, of course, the divided portions can be transported and handled more easily on railroad flat cars, trucks or whatever transportation means are available.

From the foregoing description it should be evident that the present invention is an advance in the art of pile driving in that pile sections may be assembled together in a manner which permits perfect rigidity in the finished pile column which is quite resistent to bending stresses, due to a special inside armature, and consequently less liable to distortion and capable of being driven downwardly in a perfectly straight line. Furthermore, due to the fact that each section of the pile is strongly connected to the column as a whole, the possibility of losing sections While traversing a sub-terraneous pool of water, for instance, is completely avoided.

Also, due to the equal distribution of tie rods around the periphery of the pile, the sinking stresses may be more uniformly applied to the pile so as to prevent crushing or breaking off of the rather slender arms thereof. This has been demonstrated in practice where many sided piles having the general characteristics described in this text have been driven in soft ground for 107 feet or so without difficulty, the pressure required being of the order of approximately a hundred tons applied by hydraulic jacks.

It must be understood that various changes as to the shape, size and arrangement of parts may be resorted to Without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

1. In a sectional foundation pile, an annular body section cut diametrally to form independent portions, arms projecting radially from said body in uniformly spaced relation, shorter substantially parallel horns projecting between the arms, tie-rods disposed vertically at the ends of the arms, armature rods also vertically disposed medially in the horns and annulus, a wire armature connecting together the tie-rods and the horn armature rods to the annulus rods, wire links joining together the portions of one pile section, a collar inside the annulus projecting above the section top surface to enter the annulus of a superposed section, and means for tying together the tie-rods of successive sections to form a rigid whole.

2. In a pile section as claimed in claim 1, a vertical channel between the portions of the pile section for admitting a cement grouting.

JOSEPH W. LEVASSEUR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS- Number Name Date 1,555,989 Kisse Oct. 6, 1925 2,351,288 Riches Jan. 13, 194.4

FOREIGN PATENTS Number Country Date 391,085 France 1908

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