US2741910A - Building foundation - Google Patents

Description

April 17, 1956 J. H. THORNLEY 2,741,910

` BUILDING FOUNDATION Filed July 26, 1954 VV v i The present invention relates to methods and apparatus accommodating vertical adjustment of massive structures,

such as large buildings and the like, and particularly, to.

methods and apparatus accommodating loweringiof massive structures in accordance with soil settlements that are not due to settlement of the structure itself. i i

Many areas or localities in the world suffer from the problem of severe soil settlemenn For example, at Mexico City, Mexico, the soil consists of relatively soft `fill in an old volcanic lake, which fill,and parts of the city with it, are settling further and further into the volcanic lake. Some parts of Mexico City have settled three feet or more and are still settling rapidly, as settlements are considered, The bulk of this movement is taking place in a soft clay stratum above a stratum of firm sand, which latter stratum is located about 110 feet below the present ground level. Sidewalks, sewer systems, water systems', and the like, of course, settle'with the stratum of soft clay, as do the smaller buildings which are more or less rested on the soft ll. The larger buildings and more massive structures, however, are supported on piles which extend to andare firmly supported upon the compact sand stratum. This gives rise to a peculiar phenomenon in that, as the clay stratum settles, the larger, pile supported structures appear to be growing, that is, pushing up out of the ground, because surrounding sidewalks, streets and lighter buildings have sunken some three feet or more. Obviously, this creates a very vexatious prob lem in that ingress to and egress from office buildings, apartments, hotels and the like is substantially impaired, public utilities are severed from the buildings, andA so on. And still, the settlement continues without diminution.

In the construction of new buildings, accommodation must be made for such settlement. I am aware of" one endeavor in this respect which consists of freely passing the building piles through holes provided in the mat'or base iloor of the building and employing screw jacks at each pile to connect the mat to the piles, `the jacks being operable to accommodate lowering of the building as a whole downwardly along the piles as settlement ofthe surrounding territory occurs. Two screw jacks are provided at each pile, with the screws rigidly locked to or embedded in the mat on opposite sides of the pile, and a beam or cross bar extends between the two screws and rests on top of the pile to support the building on the pile. Due to the necessity for forming holes in the concrete and reenforcing means of the mat lat each and every pile, and for utilizing two jacks at each pile, the cost of forming the mat and installing the jacks is exceedingly great, notV to mention the cost of the jacks themselves. Secondly, the holes in the mat cannot feasibly be sealed completely and if the ground water level should lise, a drowned basement is practically inevitable. Precautions in this respect are essential since proposals have been made in Mexico City artificially to replace water in the soft fill to check or stop the general surface settlement of the city. Third, the installation of the-number of jacks required raccording to such system in the basement of a building ice eliminatesthe basement as useful storage space, the basement already being full of jacks and piles. In addition, and of primary concern, is the substantial disadvantage that the proposed system is not sound practically `or theoretically. In an assumed cycle of events, the general soil settlement in a few years may amount to, say, twelve inches. Each pair of screw jacks at each pilev is then adjusted in small simultaneous increments until the sumy of the increments equals the soil settlement of twelve inches. Allegedly,v the building should then have been lowered twelve inches. However, this allegation presup- V poses that a uniform free space twelve inches deep existed under the entire mat.

This is not a likely presumption because it would be true only if the soil beneath the entire mat .were uniform from the surface to the sand or bearing stratum and if there were no suction or surface tension between the mat and the soil. Lacking a uniform clear space and uniform soil conditions, settlement of the building would be eccentric, the mat would be subjected to eccentric stresses and serious cracking of the superstructure would undoubtedly result. The mat, being riddled with holes and subjected to eccentric stresses, mostV likely would break up under the strain. Any soil under the mat, in excess of that which would have been there had the soil settlement under the mat been uniform with that of the surrounding territory, would be ejected by the descending weight of the building with consequent damage toadjoining buildings and the surrounding territory. Acv cordingly, it is to be appreciated that the previously proposed system does not satisfactorily solve the existing problems.

It is an object of the present invention to provide irnproved methods and improved apparatus accommodating the vertical adjustment of buildings in a convenient andV economical manner withoutthe creation of problemsand difficulties over and above those sought to be eliminated. A` further object of the invention is the provision of an improved method and improved apparatus accommodating lowering of buildings which, in distinction tothe previously proposed system in the art, do not necessitate the formation of holes in themat or base of the building, do not require a great number of jacks, do not're'sult in elimination of the basement of the building as storage space, do notpresent problems in eccentric settlement of the building, and which eliminate these disadvantages in a highly practical and economical manner,

According to the present invention, construction of the substructure or foundation of the building is conventional in that piles are installedyin a conventional manner and the base floor or mat of the building is connected directly i and rigidly to the upper ends of the piles. In a reenforced concrete structure, the upper ends of the piles are suitalby embedded in the mat. The walls of the basement are constructed in a conventional manner, suitably integral with the mat, to define a monolithic foundation structure comprising the piles and the mat and sidewalls of the basement. The superstructure of the building, which in allother respects is conventional, is constructed for vertical sliding movement with respect to the aforesaid foundation vstructure by employment of outer walls telescopically associated with the walls of the basement, and the utilization of otherwise conventional superstructure columns which are vertically adjustable with respect to the mat by means of jacks disposed between the columns andthe mat. In the preferred embodiment, the jacks employed are sand jacks comprising a cylinder rigidly locked to or embedded in the mat in axial alignment with each column of the superstructure, a piston on which the respective column rests slidable in each cylinder, and a fill of dry sand in each cylinder between the piston and the mat. Sand jacks are preferably employed because of the incompressi bility, lack of viscosity and density variation, stability,

ease oficontrol and lack of leakage of dry sand. In a building as thus constructed, the superstructure is telescopically mounted for downward vertical movement with respect to a rigid foundation consisting of the basement and pilings of the building, downward vertical movement" being eected by releasing small amounts of sand'simul.- taneously from the jacks. The foundation is rigidly constructed for full superstructure support, both for normal conditions and for seismic disturbances. The superstructure is supported by its columns on the mat in accordance withrecommended and accepted design and the columns are slidably received within the cylinders of the jacks to afford complete design rigidity axially and laterally, not only for normal conditions but for earthquakes and like disturbances as well.

In contrast to the above described. prior proposal in the art, the method and apparatus'of the present invention utilize a rigidly supported and uniform mat or basement of: economical formation. No holes are formed in the basement so that the cost of construction is maintained ata minimum and there is no danger of a drowned basement. The piles are rigidly secured together at their upper ends by the mat to afford optimum foundation rigidity, and to accommodate the utilization and aiford the special benefits of batter piles if desired. Obviously, batter piles cannot be employed in the prior proposal.

Embedding of the jack cylinders in the mat is accomplished at a minimum of expense. The number of jacks employed is vastly reduced compared to the prior proposal, rst, in that only a single jack is employed at each location, and, second, in that the jacks are associated with thel superstructure columns, not with the piles. In a conventional construction, for example, in Mexico City, the number of piles is usually about six times the number of superstructure columns, Yso that the number of jacks emplayed according to my improved method is only about one-twelfth the number employed according to the prior proposal. Further, since only a single jack is employed, and then only at each column, and since the jacks each comprise a cylinder aligned with and only slightly larger in diameter than the column, the space taken up by the jacks over and abovethat of the columns in a conventional structure is infinitesimal. Thus, the full basement space is saved for storage purposes. Also, there is no need for special design, as there would be in the use of the prior proposal, to avoid interference between the piles, jacks and columns.

With respect to the storage volume of the basement, I prefer to design the building structure for a given minimum basement headroom andY to associate the superstructure with the foundation structure in such manner originally as to provide the minimum basement headroom plus substantially the headroom required to accommodate lowering` of the superstructure by the amount of calculatedV soil settlement during the life of the building, or at least for aconsiderable period of time, thus to maintain at least a minimum basement storage volume irrespective of superstructure adjustment.

In contrast to the eccentric settlement of the building upon actuation of the jacks of the prior proposal in the art, the present invention insures uniform settlement of the building, superstructure. If the superstructure is designed to telescope into the interior of the basement, no resistance to settlement is presented and the superstructure will decend uniformly as sand is removed in small increments simultaneously from the jacks. lf the superstructure is designed to telescope over the basement, the only area of resistance presented is that of the bottom edge of the side walls of the superstructure, which would not be adequate to afford any degree of support, and thus the superstructure would descend uniformly. Also, the amount of soil to be displaced upon descent of the super structure in the latter instance would be exceedingly small, equal only to the volume of the side walls of the superstructure to be lowered into the soil, and accordingly, would create no substantial problem.

Considering earthquakes, tremors and like seismic disturbances, it is well accepted that buildings in Mexico City must be designed with reasonable precaution against such disturbances. According to the present invention, rigidity of the substructure and strength of attachment of the substructure and superstructure isassured. The piles are rigidly restrained laterally both at the top and bottom thereof and batter piles can readily be employed to sustain lateral load. Attachment of the superstructure to the substructure is strong and completely adequate as will be appreciated from the foregoing. In contrast, the superstructure inthe prior proposal must have a relatively loose lateral association with the piles if relative movement of the piles through the holes in the mat is to be accommodated. Secondly, the piles are not restrained at the upper ends thereof and reliance must be placed upon lateral restraint at some distance substantially below the mat. And third, the usey of batter piles is completely prohibited.

Thus, the problems and expense of sustaining the building against seismic disturbances are vastly reduced according to the present invention.

From the foregoing, it will be appreciated that the present invention atfords substantial advantages over the principal previously proposed system in the art, and affords highly economical and practical methods and apparatus accommodating vertical adjustment of buildings.

Other objects and advantages of the present invention will become apparent in the following detailed description of one embodiment of the apparatus of the invention.

Now,- in order to acquaint those skilled in the art with the manner of practicing the method of the invention and constructing and using the apparatus of the invention, I shall describe, in connection with the accompanying drawing, a preferred embodiment of the apparatus of the invention, and the preferred method of using such apparatus.

In the drawing:

They ligure is a fragmentary vertical sectional view of a massive structure, such as a large building, constructed in accordance withv the present invention.

Referring to the drawing, I have shown a massive structure or building constructed according to the invention and comprising, generally, a superstructure 10 and a substructure or foundation 12. The superstructure 10 is conventional, `as considered generally, and comprises vertical side walls 14, one or more horizontal floors 16 and a plurality ofvertical supporting columns i8 extending between floors. and depending downwardly from the lowermost oor. The columns 18 may be of circular or any other desired cross section. As shown in the drawing, the superstructure is constructed of reenforced concrete, but other known types of construction may be employed with` equal facility. The substructure or foundation 12, as considered independently of the superstructure, is also generally conventional and comprises a plurality of piles 20, a mat 22 rigidly connected to and interconnecting the upper ends of the piles 20, and side walls 24 extending vertically upward from the mat. As will be appreciated, the mat 22 and walls 24 together define a basement which is supported by the piles 24].

The piles 20, as is conventional, are extended to and supported on a firm bearing stratum 26 located some distance below the surface 2S of the ground, the stratum Zbeing adequate to support the piles, the basement and the superstructure, and developino adequate bearing strength to support loads to which the building is subjected in addition to the vertical load component. lf the bearing stratum 26 comprises bed rock, l prefer to employ drilled-in caissons as the pile means. Two such caissons are shown at the left in Figure 1, one caisson being disposed on a batter. Drilled-in caissons are well known in the art and comprise a tubular shell 3i) formed of one or more tubular sections and driven to bed rock, the shell sfrenato 30 carrying a cutting shoe 32 at the lower end thereof to bite into the rock. After driving, the material within the interior of the shell is removed in a known manner and a socket 34 is drilled into the rock in axial alignment with the shell 30. A reenforcing member 36, suitably in the form of a steel H beam, is inserted in the shell to extend beyond both ends of the shell, namely, into the socket 34 and beyond the upper end of the sheil. Thereafter, the socket 34 and shell 30 are lled with concrete to comprise a rock-socketed or locked-in-rock pile capable of sustaining loads axially of the pile in both tension and cornpression. If the bearing stratum 26 is other than bed rock, such as rm sand or the like, or if drilled-in caissons are not to be employed, any conventional form of `pile may be employed, such, for example, as cast-in-place concrete piles. Two piles of a conventional nature are shown at the right in the figure.

As referred to hereinbefore, Mexico City, Mexico, is experiencing a very substantial problem with respect to soil settlement. In Mexico City, a firm bearing stratum of sand, such as the stratum 26 in the figure, is located approximately 110 feet below the present surface level, and such stratum is stable. n The overburden, indicated at 38 in the figure, comprises soft clay, which, due to compacting, loss of water content and possibly other causes, is settling rapidly. Since the bearing stratum is firm sand, conventional piles would normally be employed, the same extending to and being supported on the stratum 26. According to the present invention, some of these piles may be disposed vertically and others may be disposed at a batter or inclination to the vertical. In the construction of buildings in Mexico City, forces, suchasV those resulting from seismic disturbances, which exert a lateral force on the building must be considered. To sustain such loading, batter piles are of particular benefit and, accordingly, I prefer to employ batter piles as well as vertical piles irrespective of the form of pile employed. At the lower ends thereof, the piles are fully restrained against lateral movement at least by the overburden, and to restrain fully the upper ends of the piles, I rigidly interconnect the upper ends of the piles by means of the mat 22. ln the embodimentshowmthe mat 22 and walls `Z4 of the basement are constructedlof reenforced concrete and the upper ends of the piles, and any reenforcement therein, are embedded directly in the mat. As will be appreciated, such construction affords a rigid, monolithic foundation or substructure fully supported and restrained against all loadings to which the building may be subjected.

As thus far described, the superstructure and the substructure 12 are of conventional construction and any other `forms of superstructure and rigid foundation may as well be employed in the practicer of the invention. Accordmg to the present invention, it is principally the association of a superstructure and a rigid substructure that departsl entirely from known practices. Specifically, the predominant feature of the present invention resides in the adjustable support on the rigid foundation, or on the mat 22, of the columns 18 of the superstructure, incon- 1 junction with associationjof the walls of the superstructure and the basement for free telescopic movement, whereby the superstructure may be adjusted vertically with respect to the substructure according to requirements imposed by variations in the elevation of the soil surface 2 8. Since the conditions in Mexico City, the specific example referredto, are primarily that ofv soil settlement, reference is made herein principally to accommodation for lowering of buildings. However, it will be appreciated as the description proceeds that vertical adjustment upwardly and downwardly may be effected according to the invention.

With respect to the telescopic association of the side Walls of the 'superstructure and the substructure, the side walls 14 of the superstructure 10 preferably include portions 40 depending below the ground or street oor of the building, which portions normally extend into the soil or overburden 38. The wall portions 40 may tele- 6v scope into the interior of the basement or may telescope over the basement walls 24, that is, immediately outwardly of the walls 24, as is shown. Preferably, the wall portions 40 overlie the walls 24 sufficiently to afford a degree of bearing surface adequate to prevent, or assist in preventing, -toppling of the superstructure and 'to insure transmission of lateral loading to the rigid foundation. With vthe wall portions 40 telescoping over Ithe basement, 4the originalrelativeV disposition of the basement and the first floor of the superstructure is such as to define adequate room between the lower surface of the floor 16 and the upper surface of the wall' 24 to accommodate such lowering of the Vbuilding as would'be calculated to be required during the life of the building. Of, course, -if lowering in excess of precal-culations were necessary, the upper portions of the walls 24 could be removed to accommodate such lowering as would be necessary. lf the superstructure were to telescope into the interior of the basement, this precaution would not be absolutely essential. However, with either form of telescopic association, l prefer to design the building with a minimum headroom `required in the basement for adequate storage space for the occupants of the building. For example, if proper design dictated a basement nine feet in height, I would form the basement wall 24 of substantially that height and would spa-ce the first oor 16 of the superstructure 10 sufliciently above thewall 24 to accommodate such` lowering of the superstructure as would be calculated to be necessary during the life of the building. Asa practical matter, however, the end design would not necessarily have to be concerned with the total soil settlement expected to take place during the life of the building if the expected settlement were:

to exceed, say, ten feet, for certainty, some measures would be tak-en to check settlement and/or to restore soil and street levels, and to restore or `rebuild public utility facilities, long' before settlement reached such extreme. A calculated settlement of ten feet and even greater can readily be accommodated according to the present invention by appropriate construction ofthe basement and related components of the structure, but as a design practicality, provision for a settlement of six feet should be'adequate in view of the above considera-l tions. According-ly, in 4the example given, the construction could suitably be such as -to dispose the first floor 16 of the superstructure at ground level `and original-1y to locate the mat f-t'een feet below ground level. Then as soil settlement occurs, adjustments can bel made, in a manner to be described, to lower the superstructure on the foundation to maintain *the original relation between the first floor 16 and the ground level. lf desired, a seal 42 may be provided at the telescopic juncture of the basement wall 24 and the wall portions 40 of the superstructure.

Adjustability of the superstructure 10 with respect to the rigid foundation 12 -is 4accomplished according to the present invention by the installation of jack means 44 between each column 18 of the superstructure and the mat ZZ, the jack means being operable to adjust vthe vertical disposition of the column with respect to the surface of the mat. Each jack means preferably comprises a cylinder 46 locked or rigidly connected vto "the mat 22. When a reenforced concrete mat is employed, as is shown, the lower end of the cylinder 46 may suitably be embedded directly in the mat when the malt is poured.

Each cylinder 46 is disposed vertically, in axial alignand the piston 48 so as to be confined, in effect and for operative purposes, between the lower end of the respective column 18 and the upper surface of the mat 22. In

construction, the lower portions of the column 18 are inserted within or constructed in the jack cylinders 46 and the remainder of the superstructure is built up on the lower portions of columns 18. Thereafter, variations in the amount of the load carrying charge 50 in the jacks. will result in vertical adjustment of the superstructure.

By employing jacks of the cylinder type, the amount of floor and basement space occupied by the jacks is only very slightly greater than the space that would be occupied by nonadjustable columns in a conventional structure. The cylinders 46 are of `a diameter or cross `sectional size only slightly greater than the correspondingl dimension or size of the column, slidably -to receive the column and -to afford lateral restraint ofthe column. The length of the cylinders, the amount of load supporting charge and the length of the columns is dependent upon the amount of adjustment that is to be accommodated. In the above given example of basewalls nine feet in height with an original six foot spacing between the top of ther walls 24 and the rst floor 16 of the superstructure, the columns 18 from the floor 16 tothe lower end of the column could suitably be nine feet in length, the cylinders 46 could extend above the mat 22 eight or nine feet, and the load supporting charge in each cylinder would occupy six feet of the length of the cylinder, thus to accommodate a six foot settlement or descent of the superstructure, while atording full lateral restraint against seismic disturbances and the like. Also, the utilization of the jacks does not decrease` by any practical degree the amount of storage space available in the basement. By making utility connections and the like to the superstructure, settlement of the util-ity facilities in accordance with soil settlement need not result in disruption of service to the building.

The employment of jacks between the columns of the superstructure and the mat of the rigid foundation results in a minimum number of jacking points to accommodate vertical adjustment of the superstructure. About the only other suitable jacking points available would be -the piles 20, but since conventional recommended design leads to the utilization of approximately six times as many piles -as columns, particularly in the Mexico City area, use of the piles as jacking points would present considerably more expense and problem, as has been described in the introductory portion of this specification.

Since the problem herein solved is one principally of accommodating lowering ofl building superstructures in conformity with soil settlement, I prefer to employ sand as the load supporting charge 50 in the jack cylinders 46, and I equip each cylinder with a drain plug 52 adjacent the bottom thereof to accommodate release of the sand from the jacks, thus to accommodate descent of the columns 18 and the superstructure. Sand jacks are extremely well suited to support and accommodate lowering of massive loads since dry sand, once packed, is stable, is not subject to viscosity or density variation, is quite easily controlled, does not leak and does not set up any substantial lateral bursting strain on the cylinder. The wall thickness of the cylinder when sand jacks are employed will be dictated by the bending stress in the column which the jack is to carry or support, rather than by any bursting requirement. With sand jacks, there is no danger of creep due to leakage, which is practically inevitable with uid jacks in which pressure must be maintained over a long period of time. However, if adjustability both upwardly and downwardly is required, hydraulic uid may be employed as the load supporting charge. With hydraulic jacks, frequent checking against leakage may be necessary, but with appropriate care and supervision such jacks will be entirely practical. Also, it may in some instances be feasible to utilize combined hydraulic and sand jack means Where it is desired to accommodate adjustment of the superstructure both upwardly and downwardly. Other variations within the scope of the method and apparatus of the invention will undoubtedly suggest themselves to those skilled in the art.

In view of the foregoing, it is to be appreciated that the proposal of the present invention is to achieve adjustment of a massive building superstructure to an outsideY and independent soil movement, that isV not due toy settlement of the structure itself, by telescoping the columns of the structure to telescope the superstructure downwardly on the building foundation. At the same time, full earthquake resistance customary for such structures is maintained; usable space within the building is maintained; and telescopic adjustment is accommodated in the most economical and practical manner.

According to the method of the present invention a vertically adjustable building is constructed by extending` piles to and supporting the same on a irm bearing stratum, connecting the upper ends of the piles together and uniting a mat thereto, preferably by uniting a complete imperforate basement structure to the upper ends of the piles, supporting and preferably uniting and rigidly connecting a plurality of jacks on and to the mat, supporting superstructure columns on the jacks ory on a load supporting charge in the jack cylinders with the columns slidably received in the cylinders, and constructing the remainder of the superstructure on the columns in telescopic relation with respect to the basement. Then, to eect adjustment of the vertical disposition of the superstructure, it is only necessary to operate the jacks substantially simultaneously in relatively small increments. In the specic example, the method of accommodating lowering of the building superstructure comprises the steps of supporting sand jacks on the rigid foundation of the building, supporting the columns of the building superstructure on the sandV in the jacks, and substantially simultaneously withdrawing small amounts of sand from the jacks. Once the building has` been constructed in accordance with the invention, of course, all that is required is to release small amounts of sand from the jacks to accommodate lowering of the superstructure.

Considering the structure shown in the figure, and assuming a soil settlement of such magnitude that the surface of the ground has settled from the original elevation at 23 to the dotted line 28a, so that the ground oor 16 of the building is no longer at ground level, lowering of the superstructure 10 to reestablish the original relation of the ground surface and the ground floor 16 is readily accomplished. Should simultaneous actuation of the jacks be deemed essential, a jack crew of no more than two men, one to open and close the drain aperture and one to measure column descent, is located.

at each jack. Upon appropriate orders from a foreman or superintendent, each drain plug is opened to accommodate. egress of sand due to the weight of the superstructure. When the respective column has descended a given increment of the total adjustment to be made, the crew member measuring descent orders his co-crew member to close the drain. When all columns have descended by the given increment and all jack plugs have been closed, a check on the uniformity of settlement and any minor adjustments deemed necessary may bev made. Incremental adjustment is then continued until the sum of the incremental adjustments` at each column equals the soil settlement, or until the main floor 16 of the buildingy is disposed in a predetermined desired relation to the new surface level. During such descent, in the embodiment shown, the superstructure does not engage a sufticient area of soil in relation to its weight to. give rise to any practical. degree of resistance to uniformv settlement of the superstructure. The wall portionsy 40, in` embedding themselves deeper in the soil, do not displace such amount of soil asl to present any particular problem. Accordingly, adjustment of the building is accomplished with a minimum of expense and disturbance. If

the superstructure were designed to telescope into the interior of the basement, that is, if the walls 14 and wall portions 404 of the superstructure were designed to iit within or inside of the walls 24 of the basement, no problem whatever of soil displacement or soil'resistance to settlement would be presented and adjustment of the building would be readily carried out.

From the foregoing, it is to be appreciated that the present invention affords very substantial improvements in means and methods accommodating vertical adjustment of massive-buildings. The foundation as comprised of piles and a mat or basement rigidly united to the upper ends of the piles ailords a rigid foundation structure that is fully restrained and that accommodates the utilization of any desired form or type of pile, inc1uding batter piles. `The basement is imperforate and there is no danger of' leakage, drowning of the basement, or the like. The basement of the building is fully usable for storage purposes, while at the same time accommodation is made for lowering the building superstructure to the point of maximum soil settlement. With the present invention, even if soil settlement is brought under control and no adjustment of the superstructure is needed, the basement will remain permanently as fully usable storage space. A's jacks are provided only at the superstructure columns, installation expense is minimized, as are adjustment costs. The superstructure is telescopically mounted with respect to the basement, both as to the telescopic association of the walls and as to the telescopic reception of the columnsin the jack cylinders, so that uniform descent of the building is assured, and no substantial amount of soil is displaced by reason ofv such descent. Further, and of particular importance, the construction afforded by the present invention not only assures full support of vertical loading, but also assures and maintainsfull earthquake resistance.

While I have described what I regard` ,to` be a preferred embodiment of my invention, it will be appreciated that various changes, rearrangements and modiiications may be made therein without departing from the scope ofthe invention, as defined by the appended claims.

1, In a building, in combination, a' rigid foundation comprising a plurality of piles extended to and supported `onda rm bearing stratum, a mat rigidly connected to cylinders between the respective column and said mat, Y

and means` for varying the amount of said charge to accommodate vertical movement of said superstructure with respect to said foundation. Y

2. In a building, in combination, a rigid foundation comprising a plurality of piles extended to and supported on a rm bearing stratum, a generally horizontal mat rigidly connected to and connecting the upper ends .of said piles, and walls connected to and exten-ding vertically upward from said mat, a superstructure disposed above said foundation, said superstructure including a plurality of vertical columns extending downwardly toward said mat and vertical Walls'telescopically associated with the walls of said foundation, a cylinder embedded in said matin` axial alignment with each of said columns, said columns being slidably received within said cylinders, a charge of sand in each of said cylinders between the respective column and said mat to support the vertical load of said superstructure on said mat, and drain `plug `means in each of said cylinders accommodating the withdrawal f y of sand to ,accommodate vertical lowering of said superstructure `with respect to said foundation, said walls and said cylinders and columns restraining lateral movement of vsaid superstructure with respect to said foundation.

References Cited in the le of this patent `UNITED STATES PATENTS j 1,049,221 Frankignoul Dec. 3l, 1912v FOREIGN PATENTS 82,381` y Switzerland of 1919 587,218 France .V.. of 19241 680,177

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