US1229364A - Method of providing substructures for structures. - Google Patents

Description

L. WHITE.

METHOD OF PROVIDING sussmucwaes FOR STRUCTURES.

APPLlCATlON FILED FEB-19,19l'7- PatentedJune 12, 1917.

2 SHEETS-SHEET I.

L- WHITE.

METHOD OF PROVIDING SUBSTRUCTURES FOR-STRUCTURES.

APPLICATION FILED FEB- I9, I9I7. LQQQEQQD Patented June 12, 191.7.

2 SHEETSSHEET 2.

- siren s raps jaranr LAZARUS WHITE, OF NEW YORK, N. Y.

IMETHOD OF PROVIDING SUBSTRUCTURES FOR STRUCTURES.

naaasea,

Specification of Letters Patent. Patented June 12 1917,

Application filed February 19, 1917. Serial No. 149,439.

fully described and represented in the fol-.

lowing specification and the accompanying drawings, forming a part of the same."

This invention relates to a method of providing a substructure for structures, such method being particularly intended for providing foundations for buildings.

In the prior methods of erecting buildings or other structures, it has been customary first to construct the necessary foundations, and after the completion of such foundations, then to commence and carry forward the erection of the superstructure or building proper upon such foundations Therefore, the total time required for the erection of the completed building was that required for the completion of the foundation plus that for the completion of the building proper.

I Where, by such prior methods, the foundation construction involves serious engineering problems, either because of the nature of thebearing soil or because of the great weight of the building load to be carried, or both, there is a material lapse of piers or piles or on supports carried by them. The general methods of construction have been such that such piers or piles gradually received their loads as the weight of the building increased. Consequently, thefinal loads on each of the respective piles were practically unknown, although in the design of such pile foundations the total load on all was known, and it was assumed that each pile carried its average share of the conditions. Such non-uniform settlements of the different piles were serious as they led to cracking of the walls of the building, undue strains on some members of the framework, and other non-calculable eflects. Hence, when the loads on. the foundations Were considerable, it has ipften been considered advisable to carry the foundations even to great depths to reach bed-rock.-

The object of the present invention isto furnish a method of providing foundations for buildings by which it becomes possible to carry on the construction of the building, proper, and its foundations simultaneously, thus materially shortening the time necessary for the completion of the whole structure, A further object is to render it pos- Slbl8 todeslgn and construct the foundations 1n a sclentific manner, so that piles or piers may be used without dangers due to uneven" settlement of such piles or piers, while at the same time the settlement as a whole is materially reduced or avoided and the actual load on each pile or pier may be known within satisfactory limits, so that each pile or pier may be made to carry its proper share of the total load.

With these general objects in view and others which will be obvious-to those skilled in the art from the description hereinafter, the invention consists in the steps and features Which Will first be described in connection with the accompanying drawings and then more particularly pointed out. I

- In the drawings:

Figure 1 is a vertical sectional view partly and a support ready for the erection of a superstructure Fig. 2, a similar view illustrating a later stage in the erection of the superstructure;

Fig. 3, aplan view of the structure illustrated in Fig. 1;

Fig. 4:, a horizontal section on the line F Fig. 5, a view similar to Fig. 1 showing the short columns in place, and

Fig. 6, a detail sectional view illustrating the completed foundation for a column.

in elevation, showing a clump of footings As the soil conditions vary for different heavy one and that the soil is of such a depth that piles or piers of suitable length can be sunk. Also, for the present explanation, it will be assumed that such piles or piers will not reach the bed-rock. Such assumed conditions Will particularly emphasize the advantages of the present invention because under such circumstances pile foundations put in by the old methods might be particularly uncertain, and, hence, would perhaps not be used if bed rock could be reached at any cost which could be endured by the builders. If, however, the use of piles were compulsory, then in order to reduce the dangers due to the uncertainties of loading on the respective piles, it would generally be the practice under the old methods to' drive a large number of piles, with theidea that even if an uneven settlement should occur, there would be enough piles which did not settle too much to carry the load without undue strain of those carrying the heavier loads. Y

In carrying out the present invention un-' der the assumed conditions, any one of several procedures can be employed. Generally, under the best procedure, the first step would be to sink a plurality of footings,

- such, for example, as piles. The total number of footings which are to be sunk need not all be put in place before the erection of the building proper or superstructure, but only such as are required to carry .the initial load. Directly over these footings and at such a height above their upper ends that space will be provided for subsequent work as hereinafter explained, a suitable support for the column of the building is then constructed, suflicient provision being made to hold this support at the required height without interfering with the plurality of footings which is intended eventually to carry the load on such column. In

the present illustrated example, the footings are piles, indicatedat A to A inclusive. The support is indicated at B, as a reinforced concrete slab which overhangs the corresponding footings for the column which is to be erected on the support.

In practice, the support B may comprise a series of'structural steel beams, such, for example, as the I-bea-ms indicated at b entirety,as, for example, by inclosing' the beams. in concrete, as will be understood from the drawings.

The support B is arranged. to be sustained with its bottom at such a height above the upper ends of the footings A to A" that room is provided for the subsequent work between the pile ends and the lower face of the support B. Generally a height of about four feet is satisfactory.

' In order to sustain the'support B at the desired height without blocking access to the piles, any suitable sustaining means may be used. In the particular example 1llustrated, this sustaining means may be a block taining means generally will be only a temporary device to sustain the support until the load on the support is carried by the footings, as more fully explained hereinafter.

\Vhen the footings and the corresponding support have been completed, the erection of the column, indicated at D, may commence. Sinking the footings and constructing the support and its sustaining means proceed relatively quickly, and it is only necessary initially to fllIItlSlhGIlOllgh supports and footings for the 1n1t1al load for those columns which are first to be erected. As the supports are completed, the erection .of the superstructure may be commenced and carried on in the same way as heretofore, and hence needs no further description. .Of course, such constructlon is progressive and results in a progressive increase of the load on the respective supports C. IVhenthe load on any given sup-' port becomes 'suflicient to provide a re-- ber C, it is then possible to insert jacks J between two piles and the bottom of the support B, and by operating these jacks to exert a pressure downward on each of said piles and a corresponding reaction upward against the support B, sufiicient to relleve the sustaining means G from the load. See Fig. 2. As rapidly as the load on the column increases, the load on the jacks may be increased, until finally the piles beneath said jacks have received a load sufiiciently in excess oftheir intended eventual load to constitute a good test load. During such application of the load by the jacks, the

loaded piles will settle, and the jacks are operated to maintain the desired load on them. When the loaded piles havereceived their maximum load, which is in the nature of a -test load in excess of that'which they are intended togcarry eventually, and when the settlement of .such loaded-piles ceases, short columns of suitable material lowing their respective piles to become free from load. The jacks may then be removed. The operation of inserting the columns and wedging them may be carried out in the manner described in my Patent No. 1,217,128, dated Feb. 20, 1917, which fully explains the reasons Why the footings should never be freed from loadafter settlement under the test load has ceased.

The caps for the piles are indicated at a,

Q the short columns at E. At this time the two piles will be carrying loads through the short columns E equal to their'maximum" test loads. Jacks are now placed between the support and another or second pair of footings and operated to put a pressure on this second pair and a corresponding reac-,

place over such piles, such compression be-- ing a. function of the pressure on such columns.

As the building load increases on the supports, the jacks are operated, if necessary, to transmit the increase to the se'condset of piles, and to maintain such load on the said piles even though they settle. When the load is s-uiiiciently in excess of the eventual load to constitute a good test load and it has remained on the piles Without any settlement of the latter for a suitable time, the short columns are put in place and wedged up to the proper extent without allowing the corresponding piles to become free from load. Then the jacks are removed. The next pair of piles are then brought into operation by inserting jacks between them and the bottom of the support and the operation continued as before.

It will be observed that when a new pair of piles is loaded up to the maximum test load, which is usually about one and one half times the eventual load for such piles, the previously set piles are relieved from some of their load. When the last pair of piles is finally loaded to its maximum test load, if this be as much as one and one half moved, thereby unloading the last pair of piles so that they finally carry only their proper eventual load.

If the former, method of takingthe excess for a test load from the piles already set, be followed, it is advisable to have all the previously set piles equally relieved or substantially so, for the reason that in this way, the reduction or deficiency of-load on each is a minimum, and when the number of piles is great enough, will not constitute such an unloading as to injure the setting and cause the piles to commence to settle under their subsequent eventual load. For example if the total eventual load on a column support be 240 tons and eight PllGS serve as footings to carry it, then the theoretical eventual load on each'pile would be thirty tons. In this case thetest load on each pile could be forty-five tons. Thls 1s readily obtained for each pair of piles, up to the last pair, from the increasing building load. With the last pair of piles, however,-if a test load for forty-five tons be placed simultaneously on each, there would be only 150 tons to be carried by the SIX piles previously set,viz., 25 tons per pile. This is less than the 50 tons which each pile is to carry eventually, but is not sufliciently less to bring about the disadvantages resulting from allowing the piles. to reach a non-loaded condition.

' Furthermore, the extent to which all the piles except the last pair are relieved of on such pilesmay be decreased by setting the pilesof the lastpair, one at a time. In this way the testload for the next to the last pile is easily obtained from the building before it is completed. As the excess load for testing the last pile is onliy tons, this, if taken from the loa on the remaining seven piles, only causes a deficiene on each of the previously set piles of slightly over two tons, which is practically negligible. Moreover, this is only for the short time necessary to test and-finally set the last pile. The last pile or pair of piles are only wedged up to the Point when it or they receive the eventual load assigned to them. i

When all the piles have been set with their respective short columns in place,'the latter may be inclosed with a body of concrete extending between the pile heads and the base of the support in the manner described in my Patent No. 1,217,128, hereinbefore referred to.

In the description hereinbefore, the method is described as carried out when the piles are brought into bearing a pair at a multaneously with such a pair at a time, no

eccentricity of loading of the support or building column, can occur. However, the piles maybe brought into bearing individually instead of in pairs, when this is desir able, because often the eccentricity of loading will be within safe limits.

.By constructing the footings for the respective building columns in the manner desired, and while the erection of the building proper is progressing, the foundations are completed at about the same time as the superstructure. Hence,.plenty of time is allowed for the careful-construction of the foundations in -a scientific manner, by a small force of workers, without any interruption to the erection of the superstructure.

The description hereinbefore has said nothing about excavations,-as for cellars.

This may be done first and the footings" started at the level of the bottom of the the building. The additional footings reings may be sunk, and as the building proquired may be sunk and brought into bearing as the erection of the building progresses.

Further, the support or supports may be constructed on any suitable sustaining means before any footings are sunk, and then the erection of the building commenced on the support or supports. Thereafter the footgresses, the said footings may be brought into bearing as required in the same way as hereinbefore described. In other words, the time at which the footings are sunk is not always important, provided it be soon enough to provide footings adjacent the respective supports so as to provide the required number of footings in time to be brought into bearing before the sustaining means is unduly loaded.

What is claimed is:

1. The method of erecting buildings, which consists in starting the building on a support, continuing the erection of the building, and progressively subjecting suitably sunk footings toload derived from said support.

2. The method of erecting buildings, which consists in providing a sustaining means and support thereon arranged to proride a free space between the support and the ground, erecting the building progressively on said support, and progressively subjecting suitably sunk footings to load derived from said support.

3. The method of constructing foundations for buildings, which consists in sinking tions for superstructures, which consists in sinking a plurality of footings, constructing a suitable support, commencing the erection of the superstructure on said support, proceeding with the erection until the weight on the support is suflicient to give the desired reaction, inserting a jack between the support and .a footing, applying load by means of said jack to the footing and a corresponding reaction to the support, whereby the footing is loaded, maintaining said footing under load until settlement thereof ceases, inserting columns between the footing and the support, wedging the columns to transmit the desired load to the corresponding footing without freeing the footing from load, continuing the erection of the superstructure until additional weight thereby brought on the support is sufiicient to give the desired reaction for bringing into bearing another footing, jacking down said footing and inserting columns and Wedging as before and continuing in the same man-' ner until the weight of the completed superstructure is distributed as desired to the footings.

In testimony -Whereof,' I have hereunto set a my hand.

LAZARUS WHITE.

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