US1475696A - Constructing foundation columns and the like - Google Patents

Description

Nov. 27 ,'1'923 c. R. GOW

CONSTRUCTING FOUNDATION COLUMNS AND THE LIKE Filed June 6, 1922 INVENTOR ATTORNEYS Patented Nov. 27, 1923,,

men STATES RLEQ R. GOW, 0F BOSTON, MASSACHUSETTS, ASSIGNOR T0 CHARLES R. GOW CUM- EEANY, 0E BOSTON, MASSACHUSETTS, A CORPQBATION OF MASSACHUSETTS.

CONSTBUGTIHG FOUNDATION COLUMNS AND THE LIKE.

Application filed June 6,

To all whom it may concern:

Be it known that I CHARLES R. Gow, a citizen of the United States of America, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Constructing Foundation Columns and the like, of which the following is a full, clear, and exact description.

This inventionrelates to the making of foundations and the like for buildin s and other structures, particularly foundations of the concrete pier or column type in which the column is supported on and rises from an enlarged base or footing by which the load on the column is distributed on the underlying bearing material. As will be seen from the subjoined description, the invention isuseful under widely different conditions, but its chief object is to provide a system or method of construction which can be employed in sand or gravel and ,other loose or soft soils, and also in water-bearing materials generally, in which previous methods are unavailable or disadvantageous. Another object is to provide a simple and efficient method by which a'concrete caisson can be sunk without the use of compressed air and without requiring heavyweights or other apparatus to push the caisson down. To these and other ends the invention consists in the novel features hereinafter described.

In carrying out the invention in the pre ferred manner a suitable caisson is established in the ground, at or just below the surface thereof. If the caisson is to be of concrete it may be convenientllymade by digging a pit of sultable size and depositing concrete in the same, around a form extending upwardly from the door. An opening is left in the top of the caisson at the center thereof, and above this opening is a working shaft, which may be of reinforced concrete 'or composed of concrete pipe sections placed one on top of the other as the work proas will be readilyun 1922. Serial No. 566,232.

around the working shaft, to keep the pit substantially fulL. The load thus imposed, combined with the weight of the caisson itself, forces the latter downward as fast as the excavation proceeds and eventually brings it down to the desired position. As the caisson descends, additions are made to the working shaft at the top thereof from time to time, as by means of precast pipe sections secured together in any convenient manner. When thecaisson has been sunk to the proper position the caisson and the working shaft are filled with concrete, with or without metal reinforcement.

The scheme outlined above is illustrated in the accompanying drawing, in which- Fig. 1 is a vertical central section of the caisson cast in the ground, before excavation inside of the caisson is begun.

Fig. 2 is a vertical section showingthe caisson sunk a short distance in the ground.

Fig. 3 is a vertical section showing the completed column and footing.

The caisson which later formspart of the footing or enlarged base of the column may be constructed in any convenient manner. Preferably, however, I proceed as follows. A pit 10, of suitable size, is dug in the ground, and its sides are lined. orsheeted with thin planking or'boards' '11 so that the sides of the cast caisson will be relative- (as is in most cases the most convenientmethod) the caisson must be large enou h to admit a man and permit him tower and hence for the present purpose it may be assumed that the pit is about twelve feet wide and six or seven feet deep. In plan it may be of any suitable'shape, say circular or square. On the bottom, concentric therewith. is placed a shell in the form of a metal ring 12, preferably slightly conical, as indicated, to give thecaiss'on a sharper cutting edge and thus facilitate its descent. The ring is filled with earth, which'is leveled off at the top, and on this is placed a concentric ring 13 which is also filled with earth. Other rings, as 14, 15,-may he -,arranged in a similar manner as many as needed or described, to brin the upper edge of the topmost ring up to t e proper height, erstood. These rings may be of any suitable sectional or collapsible type, not shown, so that they can later be removed for re-use, or they can be continuous and hence left in place, whichever is most convenient or suitable under the circumstances. In speaking of the shells 12, 13, 14, 15 as rings it is of course understc ad that they need not be circular. At least the lowermost shell should (preferably) conform to the plan of the pit, in order to provide a uniform cutting edge all around.

The mold constructed as described above is now filled with concrete, thus forming in the ground the caisson 16, the interior of which has an upward taper, as indicated. I may also cast in place the lower section 17 of the working shaft, or this section may be a section of pipe, preferably precast concrete, secured tothe top of the caisson in any convenient and suitable manner, not shown. In general, metal reinforcement is not needed in the caisson, especially if its walls have a cross-sectional contour of the type shown, which is practically a dome and hence is well adapted to withstand heavy loads. Also, reinforcement is seldom if ever needed in the walls of the working shaft, since practically all the stresss to which these walls are subjected are directed laterally and are taken in compression.

The concrete of the caisson having been allowed to harden, the interior is dug out and the workman continues the excavation underneath, working as evenly as possible around the edge so as to cause the caisson to descend without tilting. The excavated earth may be hoisted out through the working shaft by means of a bucket, 18, and dumped into the pit around the shaft as indicated at 19, Fig. 2. The load thus added to the weight of the caisson itself will be found sufficient, in practically all cases, to cause the caisson to keep pace with the excavation.

Experience has demonstrated .that the friction of the back filling 19 on the sides of the excavation above the caisson does not materially lessen itsefl'ectiveness in forcing the caisson down. This back filling is composed of loose earth and settles readily into the hole faster than it can consolidate into a solid mass, as the caisson descends.

As the work advances, the working shaft is increased in height by additional pipe sec tions, as 20, laced in position from time to time as nee ed. The sheathing boards 11 may be pulled out as soon as the caisson has descended far enough to free them. It is of course more convenient to remove the boards before any dirt is deposited on the caisson, in which case the dirt removed from the caisson can be piled at the side of the pit and then shoveled in after the sheathing has been removed.

Water seeping into the excavation may be removed in any convenient way, as by means of a hose 21 and pump 22. In some cases it is convenient to keep a sump 23 in the bottom of the excavation, in which the water may collect, as indicated.

When the caisson has been sunk to the desired position the caisson and working shaft are filled with concrete, as in Fig. 3, thus producing a solid concrete column or pier and a broad base or footing which serves to distribute over a safe area the load lat-er imposed on the column] Preferably the working shaft is of concrete. as stated above, but it may be made of other material. In some cases the shaft may be withdrawn for re-use, especially if it is made of metal. If the excavation is not too deep, and the material around the shaft is not so loose as to cave in when the shaft is withdrawn, the latter may be entirely removed before the filling with concrete begins. Otherwise it may be necessary to pull up the shaft or casing gradually, or step by step, as the filling proceeds.

The system described possesses several important advantages. In the first place the amount of material in the column and foot ing can be the minimum needed to carry the load with the proper margin of safety. The excess weight needed to crowd the caisson down into the excavation is provided by the excavated material deposited on top of the caisson, a method which also disposes of the material, or the major part of it, without additional expense. It will be noted, too, that as the caisson descends and is therefore subjected to greater friction by increased lateral ressure on its sides, the weight of materia deposited on it is also increased. Ordinarily, seepage water can be pumped out. as fast as it enters, but should that not be possible or practicable the man can work in a diving suit. In either case the use of compressed air is unnecessary, and I am therefore able to effect a substantial saving in that direction over other methods, at the same time avoiding the buoyant effect of air in a closed caisson and the additional weighting required to'carry it down as the work of excavation proceeds.

It is to be understood that the invention is not limited to the details herein specifically described, but can be practised in other ways without departure from its spirit.

I claim-- 1. In the art of making footed foundation-columns and the like,- the improvement comprising excavating a pit in the ground and casting therein a concrete caisson and providing the latter with an upwardly extending relatively narrow, working shaft, excavating under the caisson to permit the latter to descend and depositing more or less of the excavated material upon the caisson around the working shaft to aid the descent of the caisson as the work proceeds, and when the caisson has been sunk to the desired position, filling the same and th working shaft with concrete.

2. In the art of making footed foundation-columns and the like, the improvement comprising establishing in the ground a concrete caisson having a relatively narrow working shaft extending upwardly therefrom, and removing earth from under the caisson andtdepositing more or less of such earth upon the caisson to aid the descent of the latter as the work roceeds.

3. In the art of making footed foundation-columns and the like, the improvement comprising forming a pit in the ground and on the bottom of the pit an upwardly extending earth-filled form, casting concrete around the form between the same and the sides of the it, to providea hollow concrete caisson aving an opening in its top, removing through the said opening, material from inside of and under the caisson and depositing more or less of such material on the caisson, and as the caisson descends erecting a working shaft of increasing height over said opening to exclude excavated material and provide a mold for casting a concrete column.

4. In the art of making footed foundation-columns and the like, the improvement comprising establishing in the ground a conwhile preventing the maternal from falling back into the caisson and leaving a passage -'extending upwardly from said opening; and when the caisson has been sunk to the desired position, filling the same and said upwardly extending passage with concrete to form a laterally extended footing and a column thereon.

5. In the art of making footed foundationcolumns and the like, the improvement comprising establishing inthe round a concrete caisson having an opening in its top and forming above said opening a working shaft of concrete; excavating beneath the caisson and depositing material, removed through said shaft, around the latter, and as the caisson descends adding concrete sections to the working shaft to keep the upper end thereof at a suitable height above the to the desired position, filling the same and the working shaft with concrete to'form a 'u'mn thereon.

In testimony whereof I hereto afix my signature.

CHARLES R. GOW.

'55 caisson; and when the caisson hasbeen sunk

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