US2378995A - Foundation structure - Google Patents

Description

June 26, 1945.

l R FREEMAN FoUNpA'TIoN STRUCTURE Filed Jan. 2e,l 1945 Patented June 26, 1945 UNITED sTATEs PATENT OFFICE FUNDATION STRUCTURE Thomas Richard Freeman, si. Louis, M0.l

Application January 26, 1945, Serial No. 574,647

(Cl. 61-51) v 15 Claims.

This invention relates generally to foundation structures foi buildings andthe like, and has particular reference to improvements in means and methods for raising foundations which have dropped or settled because of erosion or faulty sub-soil condition, for stabilizing foundations and the soil adjacent thereto to prevent slippage and settling, and for effecting lateral displacement or replacement of foundation walls and columns.

The present invention entails the hydraulic injection into the ground of a plastic, settable composition which functions to exert an elevating force on a wall, floor or column to be raised or stabilized, and to ll cracks and voids in' and to harden the sub-soil for purposes of preventing erosion and soil-slippage in the regions about and under floors and footings.

The hydraulic injection of a filling material for soil stabilization purposes has heretofore been known and practiced, chiefly in connection with highway maintenance where the method is used for raising concrete paving slabs which have sunk below the normal grade. In the past several years the so-called mud-injection process has been em.

ployed, with indilferent results, for stabilizing the foundations of buildings and to prevent the further settling of buildings where such condition has been found to exist. In using the process for foundation stabilization the practice has been to bore a series of holes into the ground to a depth a substantial distance below the foundation footing, the series extending along the foundation wall, spaced to the outside of and away from the wall a distance of three or four feet. A mixture of mud and cementl is then injected into the holes to ll voids and crevices caused by water erosion or the drying and shrinking of the soil, and, when possible, to compress the soil against the footing. The method has met with some success for the stated purpose where the faulty soil condition is not due to subterranean water erosion, but where such condition exists the described method cannot be relied upon. Although the raising of sunken paving slabs has for years been successfully practiced by injecting a mud composition below the slab, the described methods heretofore prevailing are not adapted to the raising of thev foundations and walls of buildings. One reason for this is that the lifting forces cannot be localized or confined tothe precise areas of the foundation where lift is desired, since the flowing mud may find a low resistance path and spread to other areas of the foundation, to exert a lifting force thereon at a point where such would be damaging. Since by former methods it is impossible to maintain uniform the lifting forces at definite points along a foundation wall, there is produced internal stresses that tend to fracture the foundation and produce cracks in the masonary wall which it supports.

The chief object and purpose of the present invention is to provide a simple, inexpensive'and highly satisfactory method for raising or restoring to an original location, foundation structures which have become displaced due to faulty subsoil conditions, to stabilize such foundation structures and to effect a permanent support therefor so that they will remain in their normal or restored positions irrespective of shifts, slippage or erosion of the adjacent soil.

Several example of means and methods for putting into practical eifect the teachings of my invention are set forth in the following description, wherein reference is made to the accompanying drawing. In such drawing,

Fig. 1 is a sectional elevational view of a foundation wall, showing a vertical bore in the earth adjacent the wall, the provision of which bore constitutes an early step in the method;

Fig. 2 is a plan View showing the location and spaced arrangement of a plurality of bores along the foundation Wall;

Fig. 3 is a sectional elevational View illustrating the lifting and supporting installation at a later stage in the method;

Fig. 4 is a sectional elevational view illustrating the manner in which the method of my invention is employed to produce lateral displacement or replacement of a. foundation wall, and

Fig. 5is a sectional view of the lower end of the bore, illustrating a fitting which is preferably employed to facilitate the method.

Describing now the means and method of my invention in detail, reference numeral l0 designates a concrete foundation wall having the customary footing Il. Closely adjacent to the foundation and preferably located at the outer side thereof so as to clear the footing, there is formed a vertical bore l2 which may be produced by a hand or power-driven earth auger known and available to the trade. The bore l2 extends downwardly below the footing Il to a -depth which will be determined by the character been found suitable. Where a wall or other extended structure is to be raised or stabilized a series of such bores suitably spaced along the wall are provided as shown in Fig. 2.

After the bore or bores I2 have been drilled the auger is removed and a cut is made in the side of each bore to produce a cavity I3 immediately below the foundation footing II, a suitable tool having an off-set digging head being employed for this purpose.

Thereafter, a length of pipe I4 is` inserted vertically in and centrally of the bore as shown in Fig. 3, such pipe being of sufficient length to extend from the bottom of the bore to a point above the ground level, the pipe having a joint located a short distance below the groundlevel and the sections being connected together by a threaded sleeve coupling or'pipe nipple I5. The

upper pipe section, designated I4 isprovided at its upper end with an elbow joint tting I6 to' facilitate connection with a pumping device, and with a cut-off valve I'I the purposes for which will also be subsequently explained. At its lower end pipe I4 is preferably provided witha dished or bell-shaped flange-like fitting I8, screw-threaded thereto. This `member is of diameter slightly less than that of the bore to facilitate placing it at the bottom thereof, and serves to centralize the lower end of the pipe in the bore.A Flange I8 serves the further important function of holding the pipe end out of contact with bottom of the hole, which otherwise would tend to obstruct the egress of mud or other composition-employed in the process in the manner to be hereinafter explained. Although the size of the pipe I4 is not critical, a two inch diameter pipe has Abeen found to be well suited for use where the bore is eight inches in diameter as heretofore recommended, such size permitting the plastic composition to flow-.therethrough withoutunduerestriction; and in other respects adequately fulfills -thepurpose of reinforcing the column to be cast aroundit. Suitable reinforcing-means in the Ioffset cavity I3 are provided, desirably consisting-of appropriately bent pieces I9 of steel-reinforcing rod-which may be initially held iniplace by securementv to the pipe I4 as by wireties or the like.-l

The space around the pipeI4 within the bore I2, and the cavity I3 is filled with cement, as appears in Fig. 3,'the-cement filling extending upwardly to `a-point above the foundation footing and preferably below the ground level.V Before proceeding fur-ther the-cement is allowed to set. Thereis thus produced a `concrete column Y2l), having an integral,-reinforcedl-corbelor bracket 2I subjacent the foundation footing, the vcolumn being reinforced by the pipe I4 -which a'l'so serves to provide a central fluid passage that extends longitudinally completely therethrough.

The described installationis now ready for the lifting and stabilizing phasesl ofthe process. These are carried. out byinjecting, .by suitable pumping apparatus, a plastic, hard-setting composition into the upper end of'pipe I4. SuchV an apparatusy indicated generally at 2| infFig; 3, is known in the trade as a mud-jack. Y Its particular construction does not 'comprise la part ofy the present invention andanyrsuitable hydraulic apparatus adapted to. exertssuiicientpressure on theplastic composition to Vcause it to flow through the column 20 will serve thepurpose. The device illustrated may briefly be describedfor .pur-poses of completeness as including 1a `hopper..22, the bottom Yof which slopes toward one end and. there communicates with a pumping. chamberv or cylinder 23 containing a reciprocating power-driven piston or plunger 24. The pumping chamber discharges into a horizontal pipe section 25 which is connectedto the cut-off valve I'I and through that member to the pipe section I4-.

A composition found suitable for injection into and through the column is made by mixing loose top soil or silty loam, comparatively free from sand, with water to form a thin mud. A small percentage of cement (about 5%) is added for setting purposes and to reduce shrinkage of the mud.

This composition is injected into the pipe I4 with suflicient pressure to cause it to flow through and out of the lower end of the column. The mixture is thus caused to ll all voids and fissures which may exist in the vicinity of the base of the column. After such openings have been lled, by continued pumping the hydraulic pressure on the lower end of the column exerts a lifting force which gradually raises the column, and with it the foundation resting on the bracket portion 2|. When the structure has been raised to the desired level the valve I'I is closed so as to trap and coniine the mud composition under pressure within and below the column. Following the elapse of sufficient time to allow the mud composition to harden the pipe section I4 is disconnected atthe joint I5 and removed from the column; thereafter, the cavity remaining above the column is filled with soil up to the ground level. l

Where a foundation wall is to be raised .by the described process by means of a series of columns in the manner suggested by Fig. 2, suitable transverse piping 28 is provided to connect the upper ends of all of the column passages, and the mud composition is pumped through the columns simultaneously, so that equal lifting forces and uniform upward displacement of the columns will result. A valve 29 serves to maintain thev mud composition under pressure during the setting period.

It will be understood that the mud composition spreads outwardly from or at the lower ends oi thecolumns and produces an effective base or footing for these supports. It will further appear that the lifting forces on the foundation structure are definitely confined to the bearing areas afforded by the bracket portions 2l and the operator is in full and complete control of the acting forces, in degree and points of application.

The method for effecting lateral displacement of a wall or other support 29 is illustrated in Fig. 4 and in general accords with the method previously described. In this case an opening 30 of size sufcient to receive a workman is made in the ground adjacent thesupporting structure to the depthl of the base thereof. Next, a horizontal bore 3l leading from the opening 30 is .made by'suitable boring tools. Piping 32 and 33 leading from the base end of the bore to a valve 34 and a mud-jack is installed, and the bore v3I is filled about the pipe 32 with concrete to provide a strut member 35, as shown. Thereafter, `mud composition is pumped through the piping to effect displacement of the concrete strut 35 and foundation structure 29 in the manner explained inl connection `with Figure 3. Where a foundation member ,of substantial depth is encountered, requiring lateral displacement, the provision of additional horizontal concrete struts located at varying levels below the grade, is recommended in order to .reduce bending stresses, in the foundation. In such case the fluid passages through the strutsv are interconnected by suitable piping as suggested by Fig. 2, and the struts are pumped simultaneously in the manner and for the purpose heretofore mentioned.

I have described my invention with reference to several examples setting forth preferred methods of putting it into practical use. It will be understood that the invention is not confined to the particular methods and uses described herein, and is not intended to be so limited.

What I claim and desire to secure by Letters Patent is:

1. The method of raising and stabilizing a building foundation which comprises installing a hollow column vertically in the earth in supporting relation to the building foundation, forcing hrm-setting fluid material through and out of the lower end of said column to elevate said column and foundation bythe hydraulic pressure at the lower end of said column, and allowing said material to set while maintained under pressure.

2. The method of shoring a building foundation which comprises installing a hollow, openended column reaching downwardly to a substantially unyielding sub-strata of the earth, in supporting relation to said foundation, forcing firm-setting fluid material into and through said column untilhydraulic pressure at the lower end is suihcient to raise the column, and maintaining said pressure while said fluid sets.

3. The method of shoring a building foundation which comprises installing a hollow, openended column in the earth adjacent said foundation and in supporting relation thereto, with the open lower end of said column reaching downwardly to a substantially unyielding substrata of the earth, forcing a firm-setting fluid material through and out of the lower end of said column until hydraulic pressure at said lower end is sufficient to raise the column, and maintaining said hydraulic pressure during the setting of said material.

4. The method of shoring a foundation structure which comprises forming in the earth in supporting relation to said foundation a concrete column having a fluid passage extending longitudinally therethrough, forcing a firm-setting fluid material through said passage to produce hydraulic pressure at the lower end sufficient to raise said column, and thereafter closing said passage to maintain said pressure during the setting of said material.

5. The method of shoring a foundation which comprises forming in the earth adjacent the structure a hollow, open-ended concrete column having a portion. thereof extending underneath said structure, forcing firm-setting fluid material into the upper end, through, and out of the lower end of said column, and continuing the introduction of said material until hydraulic pressure at the lower end is sulcient to raise said column, and thereafter maintaining said pressure on the material during the setting thereof.

6. The method of raising a foundation structure which comprises forming in the earth adjacent said foundation a concrete column having a longitudinal fluid passage, and an integral bracket portion extending subjacent to said foundation structure, lling said passage with firm-setting iiuid material, forcing additional of said material into said passage at its upper end so as to create hydraulic pressure on the lower end of said column sufficient to raise the column and foundation structure therewith, and thereafter closing off said passage at its upper end whereby to maintain said pressure during the setting of said material. Y

7. The method of raising afoundation structure which comprises forming a bore in the earth adjacent said structure, excavating the earth below said structure ito forma cavity communieating laterally with said bore, inserting a tubular reinforcing member-longitudinally within `the bore, filling said bore about said member and said cavity with concrete, and allowing said concrete to harden toproduce a supporting column,

forcing rm-setting-fluid material through and out of the lower end of said tubular member whereby to effect a raising of saidcolumn and foundation structure by hydraulic pressure at the lower end of the column, and allowing said material to set while subjected to said pressure.

8. The method of shoring and stabilizing a foundation structure which comprises installing a plurality of columnsv having. longitudinal passages therethrough inthe earth, in supporting relation to the foundation structure and spaced therealong, pumping firm-setting iiuid material through said columns, simultaneously and at uniform pressure, whereby to provide uniform hydraulic pressure at the lower ends, sufficient to raise said columns, and maintaining said pressures during the setting of said iiuid material.

9. The hereindescribed method of raising and stabilizing a vfoundation structure which comprises installing a plurality of columns having longitudinal, interconnected uid passages therethrough, in supporting relation to and spaced along the foundation structure, pumping firmsetting fluid material into said passages whereby to produce uniform hydraulic pressure at the f lower ends sufficient to raise said columns simultaneously, and allowing said material to set while subjected to said pressure.

10. The herein described method of raising a foundation structure which comprises forming a series of vertical bores in the earth, adjacent to and spaced along said foundation, excavating the earth at the sides of said bores to form cavities immediately below the foundation, inserting lengths of pipe to extend longitudinally in said bores, substantially the full length thereof, filling the bores around said pipes and said cavities with cement and allowing said cement to set, pumping firm-setting fluid material through said pipes simultaneously, to produce uniform hydraulic pressure at the lower ends sufficient to raise said columns, and thereafter closing said passages to maintain said pressure while said material hardens.

11. The herein described method of raising a foundation which comprises forming a series of bores in the earth adjacent to and spaced along said foundation, excavating the earth at the sides of said bores to form cavities subjacent the foundation, inserting pipes longitudinally Within the bores, to extend substantially the full length thereof, inserting reinforcing means in said cavities, interconnecting said pipes, filling said bores around said pipes and said cavities with cement and allowing said cement to harden, pumping a firm setting fluid composition through said interconnected pipes, and out of the lower ends thereof, whereby to provide uniform hydraulicv pressure at the lower ends of said columns sumcient to raise the same, and thereafter closing off said passages to maintain said vpressure While said composition hardens.

12. The herein described method of moving a previously formed foundation structure which comprises forming a bore intheearth thatextends away from said foundation,;paralle1ito the direction .in which said; foundation is to. be moved, dsposingta pipe l.lengthwise insaid bore, filling said bore around saidpipe with concrete and lallori/'ing the concrete to harden wherebyto form a hollow concrete'strut, pumping afirmsetting fluid .material through .saidxstrut ,to .provide hydraulic pressure atth base ofzsaid strut sufficient to vmove thersame longitudinally in the direction toward the foundation, and maintaining said pressure while :said materialhardens.

13. The method for moving-apreviously formed foundation structure which comprises forming aplurality of laterally spaced bores thatextend :from saidv foundation, parallelto the direction ,in which ithe foundation is to be moved, disposing pipeslengthwise iny said bores, interconnecting said pipes, filling 'said bores raroundsaidpipes with cement and allowingvsaid cement to harden, whereby to. produe a plurality of hollow concrete struts, pumping firm-.setting fluid materia-l into and through the .interconnected pipeswhereby to provide uniform hydraulic pressure atthe base ends of said struts, sufficient .to move the same simultaneously` in. the directiony toward the foundation, andthereafter maintaining said hydraulic pressure while :said material `hardens.

14. The herein described methodfor leffecting lateral displacement ofv a previously` formed foundation structure, which comprises forming a bore in the` earth that 4extends substantially at rightangles to the foundation structure, disposing a pipe lengthwise insaid bore, lling'said bore around said pipe witnconcrete andallowing said concrete to harden whereby to form a hollow strut, pumping a fluid, hrm-setting material through said strut to provide hydraulic pressure at the base end. thereof sufficient to move saidy strut and the foundation. therewith, and maintaining said pressure while said Vmaterial hardens. l

15. The herein described method for effecting lateral displacement vof a previously Vformed foundation structure, which comprises excavating the earth to form a hole at 'one side of the .foundation structure, extending to the base thereof,` .form-.-

ing a bore in said earth extending from the bottom of said hole ina direction at .right angles to the foundation structure, disposing a pipe lengthwise Within said bore, substantially the full length thereof, filling said bore ,around said pipe, and the bottom of said hole with concrete and allowing said concrete to harden, whereby to produce a cast in situ hollow concrete strut, pumping a uid, firm-setting material through said strut and out of the base end thereof, whereby to provide hydraulic pressure on the end of the strut sucient to move it lengthwise in the direction toward the foundation structure, andthereafter maintaining said pressure while saidmatef-

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