US1872635A - Method of sinking molding tubes for concrete piles molded in the ground - Google Patents

Description

1932- E. FRANKIGNOUL 1,872,635

METHOD OF SINKING MOLDING TUBES FOR CONCRETE FILES MOLDED IN THE GROUND Filed Aug. 24, 1931 4 Sheets-Sheet l Aug. 16, 1932. E. FRANKIGNOUL METHOD OF SINKING MOLDING TUBES FOR CONCRETE FILES MOLDED IN THE GROUND Filed Aug. 24, 1951 4 Sheets-Sheet 2' L". Finn? zigzwel g- 1932- E. FRANKIGNOUL 1,872,635

METHOD OF SINKING MOLDING TUBES FOR CONCRETEPILES MOLDED IN THE GROUND Filed Aug. 24, 1951, 4 Sheets-Sheet 5 Fair/{2214 3 Aug. 16, 1932. E. FRANYKIGNIOUL METHOD OF SINKING MOLDING TUBES FOR CONCRETE FILES MOLDED IN THE GROUND Filed Aug. 24, 1931 4 Sheets-Sheet 4 j}? I /I I I wa I I I I I I I I I I I I l l I Patented Aug. 16, 1932 u 4 a stars) EDGAEJD FEANKIGNQUL, 0F BRUSSELS, BELGIUIYE METHQD 0F SINKING DECELDIIJG EC EL COl'l't'lEuElTEi FEL'ESEHOLDED IN THE GROUND Application filed'hugust 24,1931, Serial No. 559,114, and in Belgium'Aug ust 29, 1930.

According to the-invention described in iatent :Hslfid-ifil, issued June 17, 1930, a-

limited quantity of a dry mixture of the constituent parts of the concrete is lirstintro- 3 duced into the lower part oi the sinking tube; this quantity istransformed by the impact of a freely tailing element, formed like a ram, into the highly compressed plugin the tube and forms a sinking mass. it is therefore essential tor the mass which forms this plug to be compressible.

According to the improved invention this mass may not for example, be slightly moist, like earth, and may when necessary be mixed with stones. In certain cases it may even be formed solely by stony materials.

As a result of the blows of the ram, which it necessary are struck with great force, this 0 mass is so greatly compressed laterally that it forms a plug which adheres by friction to the wall of the tube. The subsequent blows struck on this plug which now serves asa sinking mass and point causes the tube to be driven into the ground to the desired depth. The plug which is by degrees more and more highly compressed is perfectly fluid-tight as soon as the first blows of the ram have been struck and consequently prevents water so from penetrating into the sinking tube, without it being necessary to employ other means for this purpose. Y

As soon as the tube has reached the desired depth, according to the improved invention :10 a sufficient quantity of water is poured in the tube above the plug in successive; charges so that the mass forming the plug will be softened and will no longer adhere so strongto the wall of the tube. If this mass contains cement it will become concrete and can be worked.

The operation of constructing the pile is now commenced. The sinking tube first of all raised to such a height that the plug can come partly out of the tube, The ram again enters into action. It is no longer employed tor sinkin the tube because the latter is held in its raised position.

It serves for ramming the mass of con crete which is now engaged, but which isbe completely dried, but will,

still soft, so that the greater part otthis mass is driven out of the tube vand compressed against the walls o1 the ground below the tube.

The plug, which inyth'e vfirst place served as a sinking'body, will thus become finally, part of the base of the concrete pile to. be constructed. During this period, a partof the lug will. remain in rthe'tubeinorder to make it fluid-tight, that is to say iii-order to prevent water and mudlentering the lower-end of the tube.

After this, concrete let downwith the necessary quantity ot-"water is then poured. in successive stakes intothe sinking tube r-eachcharge being driven, rammed or forced down bythe action oftheram, sothat the pile' is completed with the same concrete in the known manner by ramming it layer by, l'ayer and, suitably withdrawing thetu'be-each time.

The complete. method for sinking the tube and subsequently constructing the concrete piie molded in "the ground hereinafter described with reference to the diagrammatic figures shown in the accompanyingdr'awings, in which: i i r Figure 1' is a diagrammatic view showing the initial arrangement of the tube, plug-and ram.

Figure 2 is a similar view showing the initial driving action of the ram and the utilization of the plug under. the influence of: the ram as a means r'or forcing the tube into theground. I

Figure 3 is a similar view showing the tube completelyv forced to. its lowermost position by the action of the ram on the plug.v

Figure d is a similar view showingrthe tube and plug in the position similar to Figure- 3, water having been introduced into the tube to soften the plug.

Figure 5 is a similar view showingthe soft-i ened plug partly driven from the end of the tube and into the ground, the tube having been slightly raised Figure 6 is a similar view showing the continuation of the process by the addition of material within the tube and the displacement of thismaterial through the tube to form a.

part of the initial plug material, the tube having been further raised.

Figure 7 is a view of the completed pile following successive introductions of material, ramming actions by the ram, and subsequent raising movements of the tube until the material reaches the surface of the ground and the tube has been completely withdrawn.

Figure 8 is a diagrammatic view illustrat ing the application of the process for the driving of an inclined pile.

Figure 9 is a view of an inclined pile completed in accordance with the process.

Figure 10 is a side elevation of a pile driver for driving inclined pile in accordance with the process.

Figure 11 is a perspective view of a pile reinforce used in connection with the process.

Figure 12 is a plan view of the same.

Figure 13 is an enlarged broken sectional view showing the means for connecting the uprights and helical member making up the reinforce shown in Figure 11.

Figure 14 is a view in elevation of a modified form of reinforce.

Figure 15 is a plan of the same.

Figures 16, 17, 18, 19 and 20 indicate successive stages of a pile constructed in accordance with the present process and employing a recess, Figure 20 indicating the completed pile.

Figure 21 shows a reinforced concrete sinking head used in connection with the process.

Figures :22 to 27 inclusive show successive steps of the process wherein the sinking head is employed in connection with the formation of the pile, Figure 27 showing the completed pile.

As the initial step in the process, a limited quantity of a mixture'of concrete (cement, sand or quarry dust, gravel or stones, etc.) or a mixture of stones with or without a binding agent is introduced into the lower part of a hollow form or tube (a) (Figure 1).

The mixed mass, which may be dry or slightly moist, is subjected to the blows of a ram b) (Figure 2) until the fluid-tight plug (a) is formed in the lower part of the tube, serving as a sinking body and point on account of its strong frictional adherence to the wall of the tube.

Under continued successive action of the ram on the plug, the tube (a) by reason of the adherence between the plug and tube is finally driven into the ground to the desired depth, as indicated in Figure 3.

Water for softening the plug is then intro duced and, after the tube has been suitably raised and held against further downward movement, the plug (a) is detached from the wall of the tube by repeated actions of the ram (1)) and is partly driven out of the tube and strongly compressed against the wall of the space formed in the ground below the raised tube (a) (Figure 5). Successive char es-of concrete are poured in the tube and rammed by means of the said ram, in order to form the body of the pile, by compressing the concrete layer by layer in order to press the concrete down in the ground until the body of the pile has been completed, it being understood that the tube is progressively raised to permit the formation of the pile beneath it.

The ram Z), falling freely, thus serves successively for the formation and for the compression of the plug 0; for sinking the tube by means of this plug; for expelling the plug from the tube into the ground after the addition of water; for ramming and compressing layer by layer the mass of concrete poured in successive quantities into the tube until the pile is completed.

According to the improved invention, it is important for the diameter of the ram 5 to be substantially less than the internal diameter of the tube and also for this ram to be given a frusto conical or similar shape at the lower part so as to accelerate the formation of the plug and increase the frictional adherence of the latter in the tube.

The above features, which characterize the improved method for the accelerated sinking of a tube in the ground by means of a ram having a tapered head and the diameter of which is substantially less than that of the tube, are of quite special importance and ad-- vantage for permitting the rational, ra )id and economical construction of inclined con crete piles molded in the ground.

Up to the present time it has never been possible to construct such inclined piles rationally, rapidly and economically, on account of the serious difliculties arising from this very inclination.

With the usual methods, the ram, which is always of considerable weight, encounters a considerable frictional resistance in sliding within the inclined sinking tube. Its kinetic beating and ramming energy is as a consequence considerably reduced and is further reduced by an increasing inclination of the tube. Moreover, the sliding friction of this ram against the wall of the tube causes the latter to be rapidly worn.

Moreover, this ram slides eccentrically in the tube unless complicated and costly means are provided for ensuring a concentric guidance. Further, such means-can no longer be employed when constructing inclined reinforced concrete piles.

The particular method for the forming of inclined piles will be described with more particular reference to Figures 8, 9 and 10.

In Figure 8, a is the sinking tube which bears against the inclined guide track (Z and T is led into a guide ring under the control of a cable 7; b is the ram which, when outside the tube a, also bears upon the inclined guide track (Z and is operated by means of the cable pal emons Thisyram has .a conical head a which is 'not customary for rams usually employedinsinking tubes.

According to the improved method this ram is employed for the. formation of the concrete plug 0 in the lower part of the tube a, for s1nkin the tubelby strikingthis plug, for

expelling the plug from the tube when the latter has been driven into the desired depth, forconstructing the enlarged base 0 of the pilev in part by means of this plug and for ramming successive charges of concrete poured into the tube a for forming the body j ofithe'pile.

When the ram a-descends along the guide d, its position is naturally eccentric with respect to the tubea the internal'diameterof which is substantially larger than that of the ram.

The lower end of this ram then encounters, by means of its conical surface 6, the upper edge a of the tube a, the efiect of which is to alter the direction of descent of this ram and make it follow a path which very closely approaches the axis of the tube a, so that the said ram, during its travel inside the tube, remains approximately on the axis of the tube without being in frictional contact with the wall of the latter.

As a consequence the considerable loss of speed and kinetic energy of the ram on ac count of the usual friction with the inner wall is avoided.

The pathof the ram inside the tube is obviously not absolutely rectilinear and does not follow exactly the axis of this tube, but it is an extremely flat curve so that the ram does not touch-the wall of the tube.

It is quite easy to distinguish the ringing sound produced by the ram whenit enters the tube and the dead sound when the ram strikes the concrete .at the bottom of the tube,.bnt no noise produced by friction against the wall of the tube can be noticed.

According to the diameter, the length and the inclination of the tube, the height'of fall of .theram and if'necessary its angle of conicity can be varied, the latter by providing removable heads of different tapers,

i so that in all cases the sliding friction in the tube and the resulting loss of energy will be avoided.

It is observed in practice that the loss of energy due to the impacts of the conical head of the'ram against the upper edge or the tube is practically negligible.

Approximately the same rapidity of sinking of the tube, the same compression of the soil, and the same compression of the concrete are obtained for constructing the pile with identical heights of fall and weights of the ram, whether the tubes are vertical orinclined.

The invention also provides for the ram to be guided if desired outside thetube in sition of the tube will not present any serlous objection.

.The presence of the well known basket frame inside the tube will not prevent the ram from penetrating into this basket in order to force the successive charges of concrete into it and centre the basket perfectly inside the tube. It is sufficient to employ a ram of suitable diameter, that is to say substantiallyless than that of the basket, exactly as in the case of a vertical reinforced pile. V

The centering of the basket is improved in the case of baskets employed for reinforcing the upper part of the pile, which is generally the case in practice.

It is also to be noted that the impact of the ram on a plug formed in the lower part of the inclined tube facilitates the sinking of this tube and preserves much better the direction and inclinationof the sinking than if the tube were sunk by the usual method by striking on its upper edge.

Moreover, the breaking up of the ground is much less noticeable.

Finally, the fact that the ram acts concentrically in the inclined tube forramming and for driving the concrete out of the tube during the whole period of construction of the pile ensures a uniform compression of ground and a maximum strength of the pile.

It has been found that all the ei'lects and. advantages described above are obtainable at all the inclinations necessitated by the requirements of practice.

The pile driver shown in Figure 10 is arranged for sinking tubes and constructing piles at all inclinations.

It is also suitable for'constructing vertical piles.

This pile driver comprises the] post it u on which are provided the tracks and iding means for the tube a and the ram 6. This post'can be inclined by pivoting about a pin 79 mounted onthe usual carriage 0 carrying the machinery. Two supports 2' adjustable in length or in position at their base 25 by known means permit the inclination of the post it to be varied and consequently that of the tube and of the pile. The carriage is levelled up and locked in position by any usual'means. I

The invention also provides for the fact that in the construction of vertical or inclined piles, it is necessary to obtain as far as possible a considerably greater compression of the ground by considerably increasing the force of the blows struck by the ram when ramming the concrete which is much greater than that considered necessary up to the present time, and this as far as the extreme limit.

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This increase in the strength of the blows is also very advantageous in the formation of the concrete plug and when sinkingthe tube, so that it accelerates the work and improves the general result obtained from the method.

The compression of the ground which is caused by the sinking of the tube depends essentially on the diameter only of this tube; the increase in the force of the blows struck by the ram only serves in this case to accelcrate the formation of-the concrete plu and the sinking of the tube. But it is otherwise with the influence which tne force of the blows of the ram exerts on the compression of the ground by the ramming of the concrete during the construction of the pile.

Up to the present time this force of impact has been chosen solely with a view to obtaining the pressure which is thought necessary for ramming, without wishin to exert any particular influence on the compression of the ground.

One of the features of the invention con sists in considerably increasing the force of the blows when ramming so as to obtain not only a much greater compression. of the ground but also a considerable improvement in the quality of the concrete pile.

The increased compression of the ground is due to the fact that when ramming with considerable kinetic energy a succession of annular projections are formed on the surface of the pile which transmit the pressure of the ramming action to the ground in a ra dial direction; these projections, after hardening, exert compression in the axial direction of the pile.

Vhen the force of these blows is considerably increased. each projecting ring spreads rapidlyin a radialdirection and can thus harden more quickly, so that it acts on the ground, in the neighbourhood of the pile, almost like a rammer working on this ground and the increase in the force of the blows struck thus produces a considerably greater compression of the ground around the pile.

This increase in the force of the blows eX- erts no unfavourable influence on the quality of the pile. In fact, the increased radial spreading of the concrete, in the form of projecting rings or flanges, prevents this concrete from being exposed to an excessive pressure which would cause it to harden immediately. It is exposed solely to a pressure which exerts the best influence for producing a rapid hardening by normal means.

The disadvantages whicn may result from blows struck with great force on the upper edge of the tube, for sinking the latter, are here, as already stated, considerably reduced on account of the fact that these blows are struck on the plug at the base of the tube as above described.

In order to give a concrete example, the following figures will be given:

Internal diameter of the tube500 mm.

Weight of freely falling ram3000 kgs.

Height of fall4 to 6 metres.

Pressure of blowsl2,000 to 18,000 kgs.

Under a test load of 250 tons, the pile con structed in accordance with the data given above sank only 2 mm., while for a similar pile constructed with a force falling within the usual limits, the sinking resulting from the same load is several cms. at least.

It can be estimated that according to the invention the blows are struck with a minimum force comprised beween and 90 kgs. per cm Another feature of the improved invention is that it makes it possible to construct rationally reinforced concrete piles molded in the ground by ramming the concrete.

The fact that the high compression of the concrete in the ground and consequently the high compression of the ground require the use of a ram of substantially smaller diameter than that of the tube, permits this ram to be made to descend easily in the interior of a basket frame forming a hollow perforated cylinder constituted of axial bars connected to each other by a round iron bar wound helically over the whole height.

The straight bars, forming the generating lines of the cylindrical basket lowered into the tube, may be arranged at a small distance from the wall of this tube and consequently from the wall of the hole hollowed in the ground by this tube, that is to say in the ef fective reinforcing zone of the pile.

On account of the high compression of the ground which may be produced in this zone by the very firmly rammed concrete, the said bars and their helically wound connecting framework, are completely enclosed by highly compressed concrete and consequently work under the best conditions for giving the pile a maximum strength.

This detail of the process will be described with more particular reference to Figures 12 to 20. V i

In Figures 11 to 13 the longitudinal bars are formed by flat iron members we connected together by a round iron member n (wound helically) passing through notches in the bars m.

In Figures 14 and 15 the longitudinal bars are formed by round iron members m which are connected to the helically wound iron members at by iron wire connections 1".

In order to construct the piles shown in Figures 16 to 20 the tube is first of all driven in and its base is formed in the ground by a mass of rammed concrete comprising the expelled plug. The cylindrical basket nm is then lowered into the tube, leaving a small free space between itself and the wall of the tube (Figure 17).

nemesis A mass of fresh concrete is then introduced. into the basket up to a predetermined height so that the lower part of the basket is embedded in the mass of fresh concrete (Figure 18).

The ram 6 then acts in the interior of the basket (Figure 19) in which it can descend easily by virtue of its tapered point e; and it rams the concrete while forcing it laterally when the tube a has been raised sufliciently for the mass of concrete situated below it to be spread out and compress the ground while enclosing under high pressure the framework of the basket the longitudinal bars of which bear on the enlarged highly compressed face of the pile which is shown in the completed state in Figure 20.

The same basket framework can be employed for inclined piles as stated above, with the same advantages as for vertical piles.

The improved invention finally provides for the case when the concrete plug formed at the lower part of the tube and constituting a sinking head for the latter encounters at a certain depth a layer of ground offering an unexpected and extraordinarily high resistance.

When such a case occurs, the sinking tube with the concrete plug must be completely removed and replaced by another tube provided at its end with a sinking point permitting the resistance of the layer to be traversed to be overcome.

The improved invention allows the work to be continued with the same initial tube by placing then above the concrete plug an extremely strong point upon which the blows of the ram are struck at the same time as a certain quantity of water is poured in in order to soften the plug and expel it from the tube.

A new plug of concrete is then formed by ramming over this point and this new plug, under the efiect of the ram, continues to carry the tube into the ground to the desired depth.

Figures 21 to 27 illustrate by way of example this improved mode of sinking by means of a free pointed head in the tube and a concrete plug formed below it in this tube.

The pointed sinking head shown in Figure 21 consists of a conical-cylindrical body 4) formed of reinforced concrete and terminating at the lower part in an iron or steel point 8.

When it is observed that the sinking of the tube by means of the concrete plug can no longer be continued on account of the presence of extraordinary obstacles (Figure 22) the ram 2) is removed and the concrete body o provided with the iron point 8 is inserted in the tube and rests upon the concrete plug 0 formed in the lower end of the latter.

Then, by means of light blows on the body '0 with the ram, the point 8 is made to penetrate into this plug which is softened with water (Figure 23) (Figure 23) concrete a which is intended to form anew concrete plug is rammed. I

.TlllS mass it protects on th-eonc handthe reinforced concrete body 4) from the blows of the ramwhile providing afluid-tight joint preventing the entry of water from the ground, 1

7 By continuing to strike on the plug a the tube a continues to be driven in (Figure25) the pointed body a expels the initial con.- crete plug 0 below thetube and spreads it out in the ground laterally below the tube so that, the iron point 5 upon which-the ram crintinues to act through the new concrete pug which are displaced by the sinking body 4; inorder to permit the driving of the tube to be continued down to the desired depth (Figure 26;). i

Finally the tube is gradually withdrawn from the ground in the known manner and the concrete pile is constructed in the manner indicated above, by ramming successive chargesof concrete poured into, the tube during the gradual withdrawal of the latter until the pile is finally completed, the sinking points c 8 remaining in the ground.

Claims. H 1. Method of constructing concrete piles molded in the ground by means of a pipe temporarily sunk to the desired depth, in accordance with the principal patent, comprising in combination: the formation of a slightly moist concrete plug at the lower part of. the pipe, the use of a ram, the diameter of which is substantiallylessthan that of the terminating below 1n a trunconic portion, the use of this ram to compress said plug, to drive in the pipe by direct impact on this plug, for expelling said plug and for ramming the concrete of the pile, the addition of water after driving in the pipe tofacilitate the expulsion of the plug, the use of means to guide the ram at an inclination, and means to overcome abnormal resistance of the ground.

2. Method according to claim 1 for constructing inclined concrete piles molded in the ground, comprising in combination the guiding of the sinking pipe on an inclined path with slight frictional resistance, the guiding of the ram on this same path during its movement outside the pipe, the use of a ram with a trunconic head, intended to divert the direction of descent of the ram when this latter meets the upper edge of the pipe, and the use of means to modify the deviation of the ram, and means to overcome abnormal resistance of the ground.

pipe. and

After this a sufficient. quantity of dry or slightly moist concrete oris introduced into the tube 0b. above the holy 2) after which thisquantityv of,

a traverses the extraordinary obstacles 3. Method according to claim 1, for constructing inclined concrete piles, comprlsmg 1n combination the guldmg of the sinking pipe and of the ram with trunconic head on an inclined path having slight frictional resistance, the arrangement of an armature, forming a cylindrical, large mesh basket, in the pipe, the use of means to modify the deviation of the ram when it meets the upper edge of the pipe, and means to overcome abnormal resistance of the ground.

4. Method according to claim 1, for making inclined concrete piles molded in the ground, comprising in combination the guiding of the sinking pipe and of the ram on an inclined path having slight frictional resistance, the use of a ram having a trunconic head which is removable and adapted to be replaced by another of different conicity, and means to overcome abnormal resistance of the ground.

5. Method according to claim 1 for making concrete piles molded in the ground, com prising in combination, the introduction of the plug from above into the pipe, an auxiliary sinking member having a pointed end, the formation of a second plug above the auxiliary driving member, by ramming a mass of slightly moist concrete, and sinking the pipe by direction impact of the ram on said second plug.

6. Method according to claim 1 for constructing concrete piles molded in the ground, comprising in combination, introducing into the pipe, above the sinking plug, a cylindrical concrete driving member terminating in a metallic point, the formation of a second plug by ramming slightly moist concrete above the auxiliary driving member, and driving in the pipe by direct impact of the driver on said plug.

In testimony whereof I aflix my signature.

EDGARD FRANKIGNOUL.

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