US2550987A - Foundation system for structures - Google Patents

Description

May 1, 1951 M. G. FLORES FOUNDATION SYSTEM FOR STRUCTURES 5 Sheets-Sheet 1 Filed March 5, 1948 1N VENTOR ATTORNEYS May 1, 1951 M. G. FLORES FOUNDATION SYSTEM FOR STRUCTURES 5 Sheets-Sheet 2 Filed March 5, 1948 m,| IZZ 1N VENTOR ATTORNEYS y 51 M. G. FLORES 2,550,987

FOUNDATION SYSTEM FOR STRUCTURES Filed March 5, 1948 5 Sheets-Sheet 3 INVENTOR MaFloras BY v ATTORNEYs y 1951 M. G. FLORES 2,550,987

FOUNDATION SYSTEM FOR STRUCTURES Filed March 5, 1948 5 Sheets-Sheet 4 5 I I I Z/ Inn I X8 zz w a 7 7 I l 9 Q w a? I [I '/fl 1 N VENTOR ATTORNEYS I. May 1, 1951 M. G. FLORES 2,550,987

FOUNDATION SYSTEM FOR STRUCTURES Filed March 5, 1948 5 Sheets-Sheet 5 INVENTOR v ATTORNEYfi Pa tented May 1, 1951 own-Eo- STATES NT ()FFICE ApplicationMa-rch 5, 194e,, ScriaiN'o. 13,187. In- Mexico March 5, 1947 3 Claims. (01. 6 1-56) 1 The present invention deals witha new method and. apparatus ionlaying. a. foundation on piles for buildingsit. diiiers irony the known methods in the following; theuloadof thestructurexis transmitted to the piles by means of a. special me hod: Q support. The latter makesitpossible to hang fi m-support; level of: thebeamsof .the iqundatiencn the above mentioned piles andwith it, the level of, the building. itself. This; change may be ade. either totalor partial, depending onwhat desire-cl. Also, this. .imrentirm .deals with special devices or jacks for thepurpose of pulling Qutthe wedges. withoutdiminishirig in ny d ree the. pressure. upon thev ile, also. for ascertaining the; relative. mmiement'between the dt e building and. finally, for the purpose of ascertaining the pressure exercisedbythe ui ding; p n the land and part. of rhep les.

lhs hde to realize.theadvantages; ofa-this new methqdof my invention, may; I;,1start. with: a: description of the condition of the groundingem tr i and. i particular Qfithegsuhsoilgof the city of, ,M xico.. The layers the; subsoil of this. city have water, content which. varies around 80% and due to the evaporation of the water, the ground; compacts. As a result of. this. evaporation f hewateri he; grounrlthecity sinks with rese et e hesurrc. .riinahills at a. rate of betweenglfwand 2.0 cenlrneters. per annum: Experience hasshown that thelayersof soil from the le 6.1.0. 191 0.35. metersbelow, sulier. a d ying-up varying betweeiji. -10 centimeters. per annum.

placinga leadonthe. Soilmentioned, the latter, partly supported, bythe. water contained: in thesoil and as. a result; this. water is. expelled through the pores while, at, the same. timethe structure of the soilflwhich becomes. deformed or compacted by bein reduced: in volume; takes up this load. At the moment. when the structure of'the soil supports the entire load, nomore water evaporates" and the soil has sufiered. its maximum deformation. Atthat m'orhentlimight say the ground hasconsolidatedflunden the load or vthe; building load; and as a resultrof suchtconsolidation, the ground is reduced in volume. For thabreaso-ntheload which isontop. of the soil descends or as we, generally say in the case of buildingsit.sinks. I

..The;consolidationv of a givengroundmay be du'e tov two. reasons: (1). to a. load being placed upon it which expels the water by pressureor (2). the removal of the Water through 's'om'eaother means such.;as';.drainage, pumping; evapona'tion; etc;

,Any rigid object which pierces the layers of the soil, such as for example the tube of an artesian well or a pile, due to the drying up of theisoil, will always stick out of the surface more and more as the water is removed from the soil. This seeming protrusionis greater the longer the rigid object is, and particularlyif its deepest 'end is based on a hard sub-stratum.

The system of laying foundations on pilesv has come to be general in Mexico City, especially for massive structures. This method provides for a leveling of the heads of the piles. The groundis leveled and rammed in the spot where the foundation beam is suppose-cite rest and the latter is properly reinforced. In this manner the heads of the piles are actually submerged within the concrete of the beam or the latter remain supported in this'manne r first, on the ground and at the same time the piles. Shortly after, however, the piles appear to emerge from the. ground which carries the structure on top of them, creating the efiect of causing the building to rise and the surrounding soil to drop away within a short time. Thus, in case theredoes not existpany hydraulic pressure which might shoulder theburdenof supporting the edifice, we cannot assume that the building would be supported in partby the ground and partly by the piles when actually it rests; entirely on these piles, provided that the number of the piles laid down are suiiicient to carry the entire weight of the building;

This phenomenon constantly causes expenditures in the. way of repairs with regard to the building and considerable, obligations to change and frequently level thesidewalks which surround a given building, as well as .to repair Water ma n s w rs an as Al i cau di putes with the owners of surrounding buildings as well as inmany cases the payment of. indemnities for dama es. c us d by the. av -ins; addition, by leaving theghuildingsolely andexclusively supported'by the piles and completely separated from the ground, the .stabilityof such building becomes endangeredand' there is on way. of regulating sam-esince the headset the piles areembedded in the beam. Concrete examples from the history of Mexico City include the case of the Condesa pumping plant. which up to date has emerged from'the surrounding territory by about 1.50 meters. Or there is the Statue ofIridependence where it wasnecessary to re-arrange its entire circular platform and to construct isolated pieces in order to avoid a new fracture. there is the branch of the- Bank of Mexico wvhi'ch actually rises some 10 centimeters per annum. These conditions are still more aggravated by the fact that since the layer of soil on which the piles are supported, often suffers a consolidation itself, it is possible for some piles to sink at an uneven degree as compared to others, with the result that the building itself becomes inclined.

This same phenomenon may be observed in any well shaft of a depth exceeding 30 meters. If the pipe is of cast iron or of thick sheet metal,

it will emerge from the surface by about to centimeters per annum.

For the reasons above stated, up to date the laying of foundations on pile has proved very unsuccessful in regions of clayey soil such as the city of Mexico.

My invention treats the foundation laying in such manner that the tops of the piles remain perfectly accessible, passing through the beams or between two brackets. Their support of the foundation rests on removable wedges and anchored pins. By means of the latter it is possible, simultaneously with the emergence of the piles, to lower the foundation and building at the same or lesser speed with respect to the surrounding ground. In this manner the building in question will not be detached from the surrounding ground and the building will be supported simultaneously by the ground and by the piles.

This method of control is so devised that this operation may be carried out either totally or partially, on one or on all the piles, depending on whether the emergence of the piles is uniform or that one or several behave different from the rest.

This method of my invention makes it possible to ascertain in a simple manner the load supported by any given pile or whether any of them or several are failing, as well as determine the relative movement between the piles and the ground.

Description The details characteristic of my new system of laying a foundation for buildings on piles is shown clearly in the following descriptions as well as in the diagrams which are attached herewith for the purpose of illustrating the invention. In these diagrams the same symbols are used to indicate identical parts in all ten illustrations.

Figure 1 shows the plan of several foundation beams supported by a series of piles which run through the girders or brackets,

Figure 2 shows a section of a girder or bracket through which a pile runs. The head of the pile slightly penetrates the girder or bracket. From here up to the surface of the foundation the pile continues in a series of wedges or pile extensions and finally, at its uppermost point, in a saddle piece which transmits the weight supported by the pile to pins anchored in the foundation,

Figure 3 shows a section of a girder or bracket penetrated by a pile. This figure illustrates the case of the piles emerging with respect to the surrounding ground. In that case the building can continue to be fastened to the same ground, simply by unscrewing the nuts of the pins which support either part or the entire weight of the building,

Figure 4 shows a plan of the method by which the load (weight) of the building is transmitted to the piles,

Figure 5 shows a diagram of the method by which it is possible to remove the wedges without diminishing in the slightest, the pressure exer cised upon the piles,

Figure 6 shows the layout of the above attachment or special jack with all its components, with a part of the piece resting on the wedges removed,

Figure '7 shows a section of the beam or bracket passed through by a pile and its wedges, as well as the position which results when a wedge is removed, and the special jack has been withdrawn so that the frame rests on the next wedge,

Figure 8 shows in perspective, a wedge shaped like a step and this figure also shows the half rings (rims) which serve as packing for the step-like wedge,

Figure 9 shows the arrangement which serves in order to ascertain the relative movement between the ground and the building,

Figure 10 illustrates the method used to ascertain the pressure exercised by the building on the ground. 7

Figure 11 is a perspective of a jackarm.

In accordance with the method herein, we proceed with the laying of a foundation for a structure or building on a given ground, as follows:

We proceed to investigate the ground in the same manner and utilizing the same means as those now customarily used, establishing the head of every pile l on the corresponding level, in accordance with the number of wedges to be laid on top. In general this will be at the level of the ground.

Where the extreme top of every pile remains in an accessible place, there arises under certain conditions the necessity of using hollow piles, practically in their entire lengths. In this manner I make it possible for the pile to be filled with provisional metallic core which enables it to enter more easily and avoids any flexing. Also it makes possible its sinking by a method different from ramming.

Since the hollow part is free, it is possible by means of a rod or some other device, to know whether the pile remains straight, vertical and complete.

On top of each pile I is arranged a series of wedges or removable extensions 2 which altogether result in an elevation slightly higher than the beam through which they pass. This series of wedges is arranged in the interior of a tube or opening 3 in the beam which protects the same in passing through the beam and leaves them free to move vertically.

These wedges 2, according to Figure 8, have been given a special form, consisting of two bodies or cylinders m and n of which the upper one m has a smaller diameter than the lower one Generally, they are constructed in cylindrical form and are made of concrete or some other suitable material.

The pieces 5 are a number of half circles or crowns which look up the wedges, fitting in with the steps of the upper part m of the wedges.

Parallel to the tubes or opening 3, there have been anchored to the beam, two or more pins with screws 6. These pins are capable of supporting a traction equal to the largest load which the pile is capable of supporting.

To these pins 6 is fastened by means of screws 1 the saddle 8 which, resting on the uppermost wedge 2 of the beam, transmits the entire load of the beam to the pile.

The general support or saddle 8 is equipped with openings for the pins 6 which are sufficiently 5 large orderto avoid damage to the thread or these screws whenever one is tightened more than the other. Between the screw" 1 and the a der is arranged a piece 9 'whichhas aglobu= airness and permits the saddle 8 to rock without bendingthe screw and with it, pin 6.

As soon as each pile has been equipped with its wedges, tubes or special center pieces, an saddle frames, I, proceed to install the beanisaiid brackets of the foundation. In this manner the entire load is transmitted to the piles by means of the saddle 8, thus leaving. the foundation eds pended on these general supports.

In case the foundation happens to be located beneath the subsoil level, the water will have the tendency of coming between the wedges 2 and the beam. In order to avoid this, a stopper has been provided whichwill block this process. This stopper eonsists of a packing [0, a sonar n in: sulated and fixed in the cement and between these two, a burr l2.

In case the foundation does not happen to be beneath the subsoil level, the necessity or avoid ing' the entry of water no longer exists.

Method for ascertaining the relative displacement or movement between ground and building.

Whenever the piles begin to protrude as result of the phenomena mentioned above and if as a result of this, the building begins tobecome separated from the surrounding soil, such move''- ment may be easily ascertained by means of the difference in level between a fixed mark located in the ground and the structure of the building. However, the most practical means for this pun pose has been provided by me in form of the ue: vice indicated in Figure 9. Here a tube Sis chored in the cement of the building. Thistube protrudes from the building by a length exceeding the level of the subsoil water. v I is provided a rod l4 marked equally with divisions and subdivisions. The lower end of this rod jis' anchored in a section l5 of concrete resting di rectly on the ground. I

Whenever the structure supported by the pil es begins to become separated from the ground, the rod M permits us to read ofi the length of this separation and, in accordance with these readings, the corresponding corrections of the'piles can be made.

Method for ascertaining the load carried by each pile Between the nuts I and the brackets or saddles 8 or, better still, between the uppermost wedge"! and the overall frame, there may be installed pieces of metal with a low elasticity, i. 'e., which have very important deformations with respect to a low stress and nevertheless have a very high elastic limit. By means of an extensom'eter these deformations are measured and we then know the charge which they support and with it, the charge Which is transmitted onto a given pile. Knowing this, we can of course, easily adjust the pile in question, augmenting or diminishing its pressure. By deducting from the totalweight of the building the sum of the loads supported by the piles, we indirectly obtain the pressure which the building as such exercises or brings to bear upon the ground.

Method of ascertaining directlyand checking-the pressure exercised by the building on the soil For the purpose of accomplishing the latter, I have designed a device illustrated in Figure 0.

Within this tube estates "onsist's of two'plates' whose periim 4 ned it and theinteriof'of which'is c'dnnect'edby a tube J1v which in turn projects "the building. This tube filled with'wa'ter, mercury'orscme other liquid which easily indi dates" the pi'fessure in question. The plates l6 are contained in between a concrete beam of the striicture and another plate which may be of concrete too, and which rests on the ground. The presents-to which the enclosed receptacle is 'subjedted may be easily read off by the height of theliduid ithe tube I1 which in its upper portion I is transparent.

Method of causing the structure to sink so as to .make *itrrest permanently on the ground and thepiles" Whenever the observation is made that the buildihgis rising off the ground, say by 2 or 3 tion upon the ground and the piles, then'the structure shouldbe caused to descend before it; rises or becomes separated off the ground, i. e.,. whenever it is noticed that the pressure uponia;

given piece of ground has lessened.

When the operation of the nuts 1 being loosened continues, then the rods 6 must be ratherlong and there of ten arrives the moment when the operation cannot be any longer continued, dueto the fa't that the length of therod has been used up. In order that the system herein may be used to its full capacity, it is necessary to allowfor a descent up to one or two 'r'neters, since the drying up process of the ground in the city of Mexico assumes such proportions.

In order to succeed in such a descent of 1 or 2' meters I have provided the wedges 2 on top or each pile for the entire height of the foundation and even for a "much lower descent of the general level, if so desired. I There are three chief methods of eliminating the wedges 2 in proportion to the rising piles:

(a) Considering the fact that it is possible to have the building always supported by the ground, the nuts 7 can be easily loosened from an individual pile in a degree sufiici'ent for removing one of the wedges and then causing the saddle frame 8 to drop until it rests again on the next wedge. Whenever this is done the ground undergoes at that moment an overstress which, however, may be shortened to so brief a period thatit is-of no importance.

(b) When the total weight of the building is resting on the piles, additional piles may be put the ground in such manner that, even if a wedge is left out from one pile without any special preoaution the remaining piles will easily suppor tthe additional weight.

Infb'oth' cases mentioned steps should be taken to the efiect that the structure should be able to support the secondary forces caused by this operation. v

(c) Finally, if it is thought undesirable to create additional stress on the ground, it is sufficient tomake use of the device or jack for removal ofthe wedges 'asillustrated in Figures 5, Band '7.

This special j ackfacc'ording "to theillus'trations, is composed of two or more pieces l8 which at their lower end are formed of two curved arms extending right angularly from an upright piece. The upper end of each piece l8 has an opening through which a pin 19 extends. In turn, these pins extend through two arms of a second saddle 20 and at each end this saddle is provid- 'ed with openings for insertion of the rods 6 and for securing same by means of the nuts 2|.

In order to remove a wedge of a pile by means of this jack, the crown (rims) 5 of the second wedge are removed and in their places the beams are supported by means of the base of the jack pieces I8. These pieces 18 are secured to the upper saddle 20 by the pins [9. By means of the nuts 2| a pressure is brought to bear upon the second wedge. This pressure is equal or even larger than the one which was exerted on the saddle frame 8. Under these conditions the nuts I are loosened with the result that the saddle frame 8 comes loose and can be lifted, for the purpose of eliminating or removing the first wedge 2. After this wedge has been removed, the nuts I are tightened again until the saddle frame 8 rests with the same pressure as before on wedge No. 2 (see Figure 7). At this moment the jack which has served for removing the uppermost wedge may be removed, without the pressure on the pile being diminished.

By means of this method it is possible to modify the level for the building in any desired manner, without changing in any way the existing forces or pressures and even incline the building, if necessary.

The most suitable length of the rods 6, in view of dislodging the wedges, does not need to exceed a height of two or three of these wedges. As shown in Figure 8, these wedges have two levels and the load can be applied to any one of them and they are capable of supporting the entire load on any one of these two levels.

The crown 5 of the wedges 2 are good for two purposes: first, they aid in transmission of the load and second, they facilitate the keeping out of the water.

These wedges may be used either singly or.

joined to each other. However, if it is desired to give them additional strength, they can be joined together with mortar and a rod in such manner that this combination can be easily broken in order to remove the wedges.

Once the last of the wedges has been removed and there still exists the necessity of lowering the building, the operation may be continued by cutting down the pile to a shape paralleling that of the removed wedges, i. e., they can be cut up first into a crown and later into what would correspond to a wedge. In this case the operation of a temporary support would be carried out exactly in the same form as if the wedges were there.

It will be understood that the foregoing descriptive memorandum does not intend to limit my rights to this invention strictly to the letter of same nor much less to the illustrations herein, since it will be possible to effect some changes and modifications which, however, would in no way change the essence of thi invention.

As a result of the foregoing, the wedges 2 may or may not consist of one piece as the samples in the illustrations or they might even be three and have two levels of such kind that, alternatingly, the center one or the two lateral ones could support the load of the pile whereupon the jack for the removal of the wedges may be supported either by the side ones or the center one.

The wedges 2 may be circular, square or of any other geometric form and they may or may not be covered by a cover which would prevent still more the entry of water. When the wedges are removed, the water can drain off until the level of the water is lowered and the work can proceed under dry conditions.

The piles may be either massive or hollow, partly or entirely, and may consist of wood, cement or any other material and may be the same as the wedges.

The packing between the pile and the frame also may employ either a liquid or a granulated material and its evaporation may be controlled by means of a valve.

The frame may consist of one, two or more pieces, rectangular or of any other geometric form according to needs.

What I claim is:

1. The combination with a building structure having a foundation beam formed with vertical passageways therethrough, piles projected into the ground in alignment with said passageways, removable pil extension members disposed in superposed relation on the upper end of each pile and projecting upwardly through each passageway, and vertically adjustable means spanning each passageway secured to said beam and the upper one of said extensions for supporting the beam on the pile.

2. The combination with a building structure having a foundation beam formed with vertical passageways therethrough, piles projected into the ground in alignment with said passageways, removable pile extension members disposed in superposed relation on the upper end of each pile and projecting upwardly through each passageway, vertically adjustabl means spannin each passageway secured to said beam and engaging the upper one of said extensions for supporting the beam on the pile, and means whereby the upper one of said extensions may be removed, said first named means including adjustable means whereby the beams may be lowered after removal of a pile extension.

3. The combination with a building structure having foundation beams formed with vertical pasageways therethrough, piles projected into the ground in alignment with said passageways, removable pile extension members disposed in superposed relation on the upper end or" each pile and projecting upwardly through each passageway, means spanning each passageway secured to a beam engaging the upper one of said extensions for supporting th beam on the pile, said means including upstanding threaded bolts fixed at their lower ends to said beams, a saddle loosely engaging pairs of said bolts and spanning an opening, and nuts threaded onto said bolts; adjustment of said nuts effecting vertical movement of the foundation relative to the piles.

MANUEL GONZALEZ FLORES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 570,370 Breuchand Oct. 27, 1896 1,750,612 Gooder Mar. 19, 1929

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