US2057310A

US2057310A - Metal pile

Info

Publication number: US2057310A
Application number: US728789A
Authority: US
Inventors: Prielipp Walther
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-12-28
Filing date: 1934-06-02
Publication date: 1936-10-13
Anticipated expiration: 1953-10-13

Description

, W. PRIELIPP METAL PILE l l oct. "13, 1936.

Filed June 2, 1934 fig J Hy. fr

m I. 1u la Patented ocr. 13, 1936 UNITED STATES PATENT OFFICE Application'June Z, 1934, Serial No. 728,789 In Germany December 28, 1932 3 Claims.

This invention relates to improvements in or modifications of the invention according to prior Patent No. 2,010,254, August` 6, 1935 which consists in the provision of metal piles or sheet pil- 5 ing members having a thickening or thickenings between the point and the head of the piles the position of said thickening or thickenings being such that it or they are located at the upper limit of the iirrn stratum of the ground. The object of this prior invention was to facilitate ramming and to increase the load carrying capacity of the pile. Although this capacity was increased to a certain extent by the use of such piles of I or channel section, it was impossible to secure the greatest possible carrying capacity of the pile owing to the fact that the position of the thickening in the ground could not be easily ascertained.

According to the present invention in I-sec- 20 tion or channel section piles the highest possible load carrying capacity is secured by so positioning the enlarged portion or thickening within the rm stratum of the ground so that the cores of soil in the channels are consolidated or compressed.

'When an I or channel section pile is driven into sand, gravel, marl, dry clay or similar ground, and the point of the pile has penetrated toa certain depth, the core of soil embraced by the channels is in most cases moved on together with the pile. The displaced soil causes the embraced core of soil at they point of the pile to become so compressed that it is held in the channel to' a certain extent and is carried on, though perhaps not at the full driving speed. At any rate Icompression occurs first of all at the point of the pile only. In the course of continued driving, however, a longer mass of compressed soil isA formed which moves with the pile as an integral part thereof. During further driving the pile does not, therefore, penetrate the soil in the manner of a cutting edge but as if it were `provided with a blunt point. Following this, further consolidation or compression of the soil core adhering to the pile can hardly occur, so `that the soil above the consolidated or compressed mass remains loose. A cavity might even be formed above this loose soil if other parts were not caused to crumble down `due to the Vshocks caused by driving. The loose soil and also that which falls in afterwards cannot produce friction on the surrounding earth. This part of the pile would, therefore, not participate in bearing the load. Y 55 f According to the present invention provision (Cl. (i1-53) is made for the loose soil to be consolidated or compressed and therebypressed against the surrounding soil to produce friction'thereon. This, however, produces the highest degree of carrying capacity, which is obtained by the fact that 5 below the point or lower end portion of the thickening a long and consolidated core of soil is formed. The thickening must, therefore, be 1ocated at a greater distance from the point of the pile, but it must still be located in rm ground when the pile has reached its final position. The thickening must, however, be at such a distance from the point of the pile that it effects consolidation of the core of soil enclosed in the channels of the pile and presses the core of soil against the surrounding ground and maintain such pressure. Although the most favourable position of the point of the thickening depends upon the type of ground, the length of the core of soil enclosed by the channels of the pile and the depth of the point of the thickening below the surface, that is the surface of the stratum which contributes to the carrying capacity of the pile, it is easy to determine the most favourable position of the point of the thickening and therewith the greatest carrying capacity which it is possible to obtain in each case, on the basis of the experiments which have led to the present invention and in accordance with the aforesaid rules. The thickening extends from its point, preferably without reduction of thickness, to the upper edge of that stratum which is to contribute to the carrying capacity by friction. The point of the thickening may be at an acute or lobtuse angle to the axis of the pile, or it may be convex or concave. The thickening itself may be of the same thickness throughout its length, or it may increase in thickness towards the point of the pile and formed according to the ability of the ground to consolidate.

Owing to the application of the point of the thickening to the consolidated and compressed ground the result is obtained that in all cross sections of the pile the conditions which determine its load carrying capacityV become the most, favourable. The inventor explains this action in 'the following manner: f

Owing to the consolidation or compression of `the soil enclosed by the channels of the pile the same effect is obtained below the point of the pile as if its cross section were full. In the portion of the pile directly thereabove the friction actsbetween the core of soil and the surrounding ground. It produces therefore a higher load carrying capacity in this part than is possible in I,5 5

the case of friction between metal and soil or concrete and soil or wood and soil. At the same time the core of soil surrounded by the pile, as well as the soil surrounding the pile is consolidated and compressed to a great extent, so that the outer pressure on the pile is also increased. In the attaching part of the pile extending up to the point of the thickening, the outer pressure is somewhat reduced, on the other hand not only is the higher coefficient of friction maintained due to the consolidation and pressure caused by the upper point of the thickening, but a greater pressure develops between the core of soil and the surrounding soil than is the case in normal piles. At the point of the thickening then again a direct pressure transmission occurs upon consolidated ground, Which in turn again has an increased carrying capacity. The friction between the wall of the pile and the ground acts at the body of the thickening as in a normal pile. Furthermore, the point of the thickening which seals the consolidated ground to a certain extent prevents the subsequent loosening thereof.

The extent of the consolidation obtaining below the point of the thickening can at any time easily be ascertained with the aid of a sounding rod which may be inserted through an opening in the surface of the point of said thickening.

In order that the invention may be more clearly understood various embodiments thereof will now be described with reference to the accompanying drawing wherein Fig. 1 is a longitudinal section through one form of pile, Fig. 2 a section on the line d-e of Fig. 1, Fig. 3 a section on the line i7c of Fig. 1, Fig. 4 is a side elevation of a pile similar to that shown in Fig. 1, Fig. 5 a section on the line r-s of Fig. 4, Fig. 6 is a longitudinal section of a further form of pile, Figs. 7a and '7b are sections on the lines t--u and v-w of Fig. 6 respectively, Fig. 8 is a longitudinal section through a further form of pile, Fig. 9 a cross-section of a still further form of pile, and Fig. 10 is a longitudinal section through a pile provided with means for testing or sounding the soil below the point of the thickening.

Referring to the drawing, Fig. 1 shows an I- section iron pile which is driven through a stratum a which possesses no friction for instance, water or air, then through a stratum b which possesses only slight friction, for example mud, and is, therefore, unable to contribute to the carrying capacity, then into the stratum c upon the carrying capacity of which the carrying power of the pile depends. At its lower end the pile is of I-section, see Fig. 2 (section (1 -8) During the driving the soil enclosed by the chanels is so consolidated that it i'llls the channels in the form of a solid compressed mass f-g and is pressed against the surrounding soil. The superposed section g--h which originally consisted of loose earth is consolidated under the action of the point C of the thickening to such an extent that it has at least the same density as the surrounding soil. 'I'he thickening is formed at this point according to Fig. 3 (section f lc) by means of strips of sheet metal secured to the edges of the flanges of the I-section pile, for example by welding, the ends of the strips being bent down towards the web and secured thereto, so that here the point C of the thickening is formed. The stripsl determining the external shape of the thickening extend approximately to the upper edge of the stratum c. The space between the strips and the web of the pile is preferably filled with con crete, sand or the like.

In the pile according to Fig. l the cross sectional area of the thickening is the same from its point up to the upper surface, of the stratum c, but in the pile shown in Fig. 4, the cross-sectional area of the thickening is greater in the upper part of the stratum c. In this gure various possibilities of increasing the cross-section area of the thickening are shown. According to the lines 0 1- m--p the enlargement of the thickening has parallel bounding surfaces, while according to the vilines o-l-mfp the bounding surfaces are divergent, so that the thickening is formed with a wedge shaped enlargement. In some cases asymmetrical formation of the thickening or its enlargement may be advantageous.

Fig. 6 shows a pile with four channels and the corresponding four thickenings. All points of the thickenings are in the same level. There is, however, no objection to the level being relatively displaced to some extent. 'Ihe thickenings are here made wider than in the foregoing figures and wider than would be the case if the edges of the pile were used as bounding surfaces. By this means in sandy soils or other soils of a. loose character the compression of the ground and thereby the friction is increased.

Fig. 8 shows an I-section pile in longitudinal section having tapering flanges, the thickening being also tapered. Such form of piles may be economically produced with modern methods of welding. With this basic form of pile obviously any of the embodiments described with reference to Figs. 4 to 8 may be utilized.

Fig. 9 is a cross-section of a pile with four trough shaped channels :c and four angular channels y, wherein thin edges only protrude outwardly. The zones of the soil cores are conned by thickenings.

Fig. l0 is a longitudinal section through a test pile and shows an arrangement for facilitating examination of the soil below the thickening by means of a sounding rod. The wall l of the thickening is provided at the point 2 of the pile, with a hole 3 which opens into a tube 4 mounted within the thickening. A rod 5 is inserted into the tube in order to prevent the soil from entering the tube 4 and is suitably secured to the pile during driving so as to enable it to close the hole 3 from passing through it during driving. When it is desired to ascertain whether the core of soil enclosed by the channels of the pile is sufficiently consolidated, the driving is interrupted, the means connecting the rod with the pile released, and the test-as to whether the core of soil has been sufliciently consolidatedis effected by driving the rod into said soil. If this test shows that the consolidation of the core of soil is sufficient, the assurance is given that the highest possible carrying capacity has been achieved. There is no need then to drive the pile any deeper. After this test has been carried out with one or two piles it is unnecessary to make any further tests for the remaining piles. In this manner all the necessary data for the calculation of the remaining piles may be obtained. If the soil conditions are suitable the usual trial loading may be dispensed with, and the expense thereof may be saved.

It is also possible to increase the carrying capacity of existing piles of different construction in accordance with the invention, the necessary conversion being effected prior to ramming in. If I-section bars or girders are utilized as piles it is preferable to employ girders with wide flanges, wherein the width of the flange is not ,75

smaller than the height of the web.

what I claim and desire to secure by Lei-,tersl said channel member extending from said point 1 i to that portion of the pile which lies in the plane of the upper surface of the layer of the ground which has carrying capacity, the forward vend of said strengthening means forming a partition across the channels of said channel member at a substantial distance from the forward end of the pile and closing said free channel or channels whereby the cores of soil in the channel of the pile are consolidated during ramming, the partition formed by the strengthening means being apertured and a rod passing through the aperture and supported in said strengthening means.

2. A metal sheet pile having in combination a longitudinal channel one end of which is adapted to penetrate the ground, a ground engaging member secured in the channel a substantial distance above said penetrating end adapted to consolidate the ground in said channel below said member, said member having a surface extending upwardly the greater portion of the remaining length of said channel and adapted to furnish sufficient ground skin-friction to substantially aid in supporting the pile.

3. A metal sheet pile having in combination a longitudinal channel one end of which is adapted to penetrate the ground, a ground engaging member secured in the channel a substantial distance above said penetrating end adapted to consolidate the ground in said channel below said member, said member having an upwardly flaring surface extending throughout the greater portion of the entire remaining length of said channel to furnish auxiliary support to the pile.

WALTHER PRIELIPP.