US2942426A - Split-end bearing pile - Google Patents

Description

June 28, 1960 u. w. STOLL- 2,942,426

SPLIT-END BEARING PILE Filed June 4, 1954 I: INVENTOR. w w j BY 36 Gig '9 44- /4 4TTORNEYS.

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' to facilitate penetration of the soil, an

The invention described herein may fb'e manufactured .and'used'by orfor the Government oftheiUnited States of America for governmental purposes without the paymehtof any royalties thereon or therefor. I p

This invention relates to a pile having its lower end or base formed to be expandedafter' the pile is driven into "the ground.

In a preferredembodiment, the pile, in the form of a metal tube having pre-weakenedsections provided with radial fins, is .provided with an inner drive rod which takes most of the driving stress. The drive" rod is provided with a separable plug to facilitate penetration into the soil, and has a tapered shoulder .portion ofgreater diameter than the tube. when the pile has bee'nidriven to the desired depth, the drive rod is withdrawnfandthe ,"pile *drivinghamm'er is applied-directlyto the tub'ejcausing the lowerendof thetube, with its attached fins, to a be: spread outwardly to form an expanded base capable of sus'tainiiig great bearing loads.

It is an object of the invention to provide a pile having high pulling resistance and load supporting capacity.

i A furthe'r object ofthe inventionis to provide an im-' proved pile of simple design and economical to manufacture and install.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description.

Fig. 1 is a view in longitudinal section of a pile embodying the invention;

Fig. 2 is an enlarged view in elevation of the lower end of the pile in unexpanded condition;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is a sectional view taken on the line 4-4 of Fig.2;

Fig. 5 is a view in elevation of the pile with its lower end in partially expanded condition; and

Fig. 6 is a similar view showing the base fully expanded.

The pile shown in the drawing consists of a pipe or tube 10 having its lower end formed with a plurality of longitudinal slots 12 which divide the tube into a number of segments 14. To each segment is secured as by welding a fin 16 having a tapered forward end 18 and an inclined rear edge 20 designed to rest against the periphery 'of'the tube when the lower end or base of the tubular pile is expanded. In order to facilitate bending of the segments in the expanding operation, it is advisable to form a portion 22 of the tube to a square section, as shown in Figs. 2 and 3, the lower end of the tube remaining cylindrical as shown in Fig. 4.

For the driving operation, a driving rod 30 is provided for insertion in the tube 10 and is formed at its upper end with an enlarged cap 32 which extends over the top of the tube to transmit driving force thereto. In the lower end of the tube 10 is placed a penetrating member or plug 34 having a lower surface 36 in conical form face or shoulder $8 designed to exert sgemien s 14 and 'fins shan receive driving-forcefrom; drivingl od' ispreferablymadeofconcrete.

'In "order to empl-ac'e the ile, the magnum; 30 are inserted in place in heavywalld-tube-br as shown in Fig. l and' driving blows are 5 3 51 cap' 32. Because the shell or't ibe l fl nieets h I ance, the major force ofthepile' drivingliammer is taken 7 by the rod'30, v vhich transmitslthe ,forceftof-the' 34. Whenthe, pile is driven nearly to i the desired depth; the

driving rod '30' isfwithdrawn, andhaminer blows I "re" a'pplied directly to the upper-'eiid-of thetube Tlfe' lower ends of segments 14 tliein impingejforcefilllyfupon ithe surface 38 of therelativelystationaryplugi34,"wliich' acts ias a'cam 'inforcing themoutwardly as indicated in'Fig.

5," bending of I the tube material occurring inthefsquare section 22 at the base "ofthe fins 16 iAfte'rfthetpile-lias been. thus'driven through a; predetermined distance, the

edges .20 of the fins will have been movedinto c'omact wim the t wall'iof the t be 10; and "the base will' b'e" fully expanded as 'shown in'Fig. 6 Q'Iheplu'g' 34 remains as=a 'perman'ent'part' of the expandedba's'epositions shown 'in Fig. 1 to" the positions-shown in Fi 6 .involvesbut little lateral displacement of tliefs'oil. [More- 6.' The xpa e assent whichplug 34ft ms a part, has an areawhichenables the pile to sustain 'lo'a' base, tliisf'eifect beingiheig'htened i by the. arrange 35' i It wi-ll be seen that the. movemenfof iinsllS fromthe over, as the segmentsi'l iaie mov'ed downwardly and outwardly, their undefs idesact to consolidate andfcdr'npact the underlying soilgeneiially indic times in excess of the capacity of a pile without the segments, 'which t'o "some degree"en'clo'se1 a mass of soil. It is notnecessary to fill the ti1b'e =concft'e in order tonne-teaseas beaitng area, that function being performed by plug 34. As may be noted, obviously fins 16 prevent the tube 10 from turning or rotating as it is being driven into the bearing strata and prevent its rotation after being driven into place.

Obviously many modifications and variations of the I present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise'than as specifically described.

What is claimed is:

1. The method of driving a high compression load bearing pile, which method comprises:

disposing a plug in the ground at the location where the pile is to be driven, said plug having a drivingpoint adapted to enter the ground, a cylindrical shank portion with a driving top substantially normal to the axis of said plug, a central cylindrical section of greater diameter than said shank portion, and an inwardly tapered I conical shoulder connecting said central cylindrical portion and said cylindrical shank;

disposing the bottom end of a vertical heavy walled tube over the cylindrical shank portion of said plug and permitting the said bot-tom end of said tube to rest on said inwardly tapered conical shoulder of said plug, said tube having a plurality of longitudinal slots formed in the bottom end of said tube, an equal plurality of segments formed in said bottom end of said tube by said slots, means in said tube at the upper end of said seg- V .P en e {use 8 1269 the driving top of said plug, said driving rod having an enlarged drivingcapat its upperend which restson the top'of said tube; :AJ-Q' applying a driving force to said driving cap whereby said plug and said heavy walled tube are driven into the said rod being of a diameter substantially equal to the inner diameter of said tube and resting on ground strata the desired distance, the major portion of M the bottom portion of said tube is driven downwardly past said plug, forcing said segments and radial fins downwardly and outwardly substantially beyond the diameter of said central cylindrical portion of said plug until the upper edges of'said radial fins abut against the cylindrical wall of said vertical tube adjacent the upper ends of said segments thereby limiting the further outward bending of said segments and transmitting the compressive load reaction forces acting vertically upward under said segments to said heavy-walled vertical tube whereby said plug, said outwardly bent segments, and said radial fins comprise a non-rotativemaximum compression load supporting base for said pile.

2. A high compression load bearing pile comprising in combination:

a heavy walled cylindrical metal tube of sufiicient length to form a load bearing pile after being driven into a load bearing ground strata;

a plurality of longitudinal slots formed in the lower end of said tube to provide an equal plurality of segments; 1 f t means located at the upper ends of said segments for facilitating their bending outwardly as said pile is driven ing the outward bending of said segments, said means being adapted to support a compressive load between each of said segments and the wall of said tube adjacent to the upper end of said segments and comprising a longitudinally extending radial fin secured to each segment, each fin increasing in radial extent in an upward direction and having an upper edge disposed at an acute angle to said tube; and n separable ground penetrating plug means inserted in the lowerend of said heavy walled metal tube and forcing said segments tobend outwardly into said ground strata until mid compressive load means associated with said segments abut against the outer surface of the said tube as the lower end of said tube is driven downwardly over and past said ground penetrating means, said plug means comprising a cylindrical shank adapted to be inserted into the lower end of said tube, a conically pointed lower end adapted to penetrate said ground strata, a central cylindrical section having a diameter greater than the external diameter of said tube and an inwardly tapered conical section joining said central section and said shank further characterized by making the acute angle formed between the upper edge of said radial fin and the wall of said tube substantially equal to the angle of the inwardly tapered conical section joining said central section and said shank of said plug with the longitudinal axis of said shank.

References Cited in the file of this patent UNITED STATES PATENTS 1,035,893 Miller Aug. 20, 1912 1,224,925 Hindmarsh May 8, 1917 1,413,503 Stevens Apr. 18, 1922 1,600,020 Tomkinson Sept. 14, 1926 2,465,557 Thornley Mar. 29, 1949 2,588,712 Ferris Mar. 11, 1952 FOREIGN PATENTS 896,328 Germany Nov. 12, 1953

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