US2082773A - Method and apparatus for building subaqueous foundations - Google Patents

Description

June 8, 1937. I w. G. ADAMS 2,082,773

' METHOD AND APPARATUS FOR BUILDING SUBAQUEOUS FOUNDATIONS Original Filed May 2, 19:54 2 Sheets-Sheet 1 RG3 k j l1 I11 I n b7 6 6 4 I A 4 v 45 3 49(3 3 F a A 1 49 2 2 4 2/ 2/ 4 x 71'" 1 m p 22 2 5 22 6 l 2 v i 6 46 INVENTOR June 8, 1937. w. G. ADAMS 7 2,082,773

METHOD AND APPARATUS FOR BUILDING SUBAQUEOUS FOUNDATIONS Original Filed May 2, 1954 2 Sheets-Shee t 2 INVENTOR Patented June 8, 1937 METHOD AND APPARATUS FOR BUILDING SUBAQUEOUS FOUNDATIONS William G. Adams, Richmond,Va.

Application May 2, 1934, Serial No. 723,440 Renewed November 11, 1936 25 Claims.

My invention, pertains to the art of building foundations; and it has particular reference to the building of that class of underwater foundations in which a stem or column, generally of 5' concrete, extends downward to the bed of a river or other O y of water, and, is there connected to and supported by one or more piles, which carry and distribute the weight of the stem and its superimposed 'load to firm material below.

10 Such foundations are frequently used to support bents or piers, under bridges and other structures. My invention particularly pertains to that portion of such structures which lies below the surface of the water. In constructing 15 foundations of this class, the procedure general- 1y followed heretofore has been, after excavating or dredging the foundation site to the desired depth, to drive piles in an area enclosed in a well braced wall which rises from the saidsite to 2 above the surface of the water; and to then deposit a mass of concrete among and around the piles so as to seal the bottom. This is done by the commonly known bottom-dump-bucket method, or the Tremie method. As soon as the as concrete has hardened sufficiently the enclosure is unwatered, and the piles are cut oil close above the concrete seal. The heads of the piles are then encased and capped by more concrete poured on the sealing concrete. In some cases it 30 is preferred to cut the piles off, under water, and a little above the bottom of the excavation, and then to pour the ,,seal course of concrete, which will also encase and cap the pile heads. Forms of the necessary dimensions :are built within the enclosure; reenforcement is placed; and concrete is poured. After the completion of the structure to the waterline, the wall material is removed.

Work on the building of that part of the structure which is to be above the water line is then 4: proceeded with. When pier or bent foundations are built by thislmethod the cost is high, and the time required isi long. The enclosing wall is costly to build, as it must be water-tight :as well as strong enough and well braced enough to withstand the pressure of the water. Whenever work is to be done in "the enclosure formed by this wall, the enclosure must be pumped out, and it must ?be kept "free of water.

The object aof. my improved method of build-' ing underwater :foundations and footings is to eliminate costlywalls, bracing, caulking, all dewatering of enclosures and compartments, and the use of divers and diving equipment; and so togreatly reduce the cost=and difficulty of building foundations-and piersloi this class. Another object is to make the building of such foundations simple to carry out; and to obtain more uniform and certain results. I attain these objects, broadly speaking, by setting on or in the bed of the stream or other water a preformed 5 perforated base element, through the perforations in which piles are driven, down to a firm bearing; by cutting off, under water, the heads of the piles immediately above the perforated base; by placing a form for concrete on the base and around the pile heads; and by depositing concrete in the form to construct a cap upon the base and to encase the pile heads. Upon this cap I set a pre-cast stem or column of sumcient height to rise above the surface of the water. I prefer to set this stem while the concrete cap is still so fresh that a good union may be made. By following the described procedure I obtain a coherent and a unified structure, under water,

very economically. Mechanical aids in the shape of reenforcing rods, dowels, etc., may be used if desired to strengthen the joints. The concrete of the base, cap, and stem are suitably reenforced. Where bracing is necessary I set in place struts or other members designed for resisting lateral pressure, as I will explain more fully hereinaiter. After the underwater concrete has hardened suificiently, that part of the structure which will lie above the water level may be built.

Important features of my invention are, means for placing and means for holding each pile in its predetermined position; means for cutting of! the pile heads under water; the casting of the pile cap; the means for placing and lining up the stem or column on the pile cap; the setting in place of bracing; the use of precast reenforced members; the connecting and the combining of the several members of the foundation to form a unified whole; all while under water. Embodied in my improvements are special guide 40 posts detachably fixed to the perforated base, whereby the position of the base may be determined and controlled, and by which parts forming 'units of the structure may be guided to their seats on or above the base; also the pile cutting rig; ;the form for the cap; and the means for accurately placing and controlling the saw rig, the form, and the pre-cas't stem or-column.

In foundations as generally constructed heretofore in the class to which my invention belongs, the supporting piles cannot always be loaded as efliciently as desired by reason of the well known fact that during the process of driving the piles will shift laterally; especially when the material being penetrated is soft. When their heads are exposed on unwatering the foundation, they are often found to be unsymmetrically located with respect to the contemplated center of loading of the foundation; and some are found to have shifted so much as to interfere with the building of a form or dam around the pile heads, or so as to lie so tightly against the wall of the dam as to make it impossible to eifectively encase and cap the pile with concrete to protect the timber of the pile from the ravages of wood-boring enemies, such as infest coastal waters. An object of my invention is to provide the means for assuring the accurate locating of all of the piles in their predetermined positions in the foundation; thereby ensuring their emcient use with respect to the support of the load; and thereby also ensuring a positive protection and encasement in concrete of all the piles near the outer boundary of the foundation. I also avoid the pouring of concrete directly upon a soft bottom. When this is done, particularly under water, the mud is very apt to mix with the concrete, and so weaken and ruin the concrete.

Another object of my invention is to provide a bent or pier, the supporting elements of which embody in combination a pre-cast stem resting upon an improved foundation with pile support; the stem being pre-cast as a separate unit before placement in its underwater position, so that its water contacting surfaces may be prepared by a treatment such as has been devised for forestalling the peculiar disintegrating action often found to be destructive to concrete that has been allowed to cure or harden in place when exposed tosea water, especially between the high and low water marks. The surfaces of the well known concrete piles are often prepared by such treatment, and for the same purpose. Even though so treated long concrete piles of comparatively small cross section develop in their surfaces cracks which are due to the transverse stresses which arise during the handling; and the' sea water, penetrating these cracks, causes rusting of the reenforoing steel, with the consequent destruction of the encasing concrete. It is obvious that such conditions will not arise in the handling of my comparatively short pre-cast stem. Moreover: the comparative shortness of my pre-cast stem enables me to use galvanized steel for reenforcement, for the stresses arising from handling are so small that high efflciency of surface bonding on reenforcing bars is not essential. .The cost of providing equipment of sumcient capacity for handling and driving long concrete piles is great in comparison with the cost of the equipment required in the building of my improved foundation, for equal superimposed loads. For example: in a given case, the weight of my heaviest piece, the stem, will be about six tons, and the longest piece, the said stem, will be about twenty feet. Whereas, for a like superimposed load, if the older form of foundation is used, the equipment must handle concrete piles more than three times as long, and weighing about fifteen tons each. The great advantage of having to handle so much lighter and short concrete members is obvious.

The improved details of my construction. and the arrangement and combination of the parts of the same, are hereinafter described and claimed; and are illustrated in the accompanying drawings, in which-,

Figure 1 is an elevation of a bridge pier or bent. Figure 2 is a partial view, partly in vertical sec- 75 tion, showing a base and a column 9! $3. m of the bent, with details of construction. Figure 3 is a detail view of a stem or column in elevation. Figure 4 is a cross section taken on line 6-4 in Figure 2, showing a stem of square section centered on the base. Figure 5 is a plan of a preformed perforated base. Figure 6 is an elevation of a base with a form for concrete mounted thereon. Figure 7 is a detail view of a brace or strut. Figure 8 is a side elevation of a base, with guides, and with means for sawing the piles to length. Figure 9 is a detail view in plan of a base with the sawing rig in place. Figure 10 is a. detail in elevation showing a method of guiding a form for concrete into position on a base. Figure 11 is a broken view of the same in plan. Figure 12 is a partial view in elevation and part section showing a method of supporting a base in soft foundation soil. Figure 13 is a plan of the detail shown in Figure 12. Figure 14 is a partial view in plan showing a modification of a part of the mounting for the saw rig.

In the drawings all views showing piles indicate a group of five; but my improvements apply also to foundations where a greater or a smaller number of piles may be required. In Figures 1, 2, 5, 6, l2, and 13 a. preformed base is indicated by the numeral I. It may be made of reenforced concrete, or of wood, or of cast-iron, or of other suitable material; and it may be formed in any convenient shape. It is here shown as being made circular in plan and of considerable depth, in which form it is conveniently made of reenforced concrete. In practice it may be formed and poured at some convenient point on land,

where it is cured or hardened before it is put in the water. The base I is perforated with vertically disposed holes i5, of a diameter suiiicient to permit the passage of piles 8 of the contemplated dimensions to be used in the foundation. On opposite sides of the base are attached anglelugs ill, for attaching the vertical guide posts 9, 9. Near the upper surface of the base, and vertically above the lugs Hi, I attach guide jaws i2, 12, arranged to slidably engage the guide posts 9, 9. These lugs l0 and jaws l2 may be bolted to the base I or "they may be provided with projecting parts whichare cast into the concrete of the base.

The guide posts 9, 9 are of sufiicient length to' extend well above the surface of the water.

They are preferably made of steel Il -beams, or

ofany other convenient and suitable structural shape. At the foot of each guide post 9 is an angle-lug 54, arranged for bolting to the anglelug ill by a tap-bolt l3 which engages with a threaded hole E6 in the lug Ill. The posts 9 are disconnected from the base i by removing the tap-bolts i3, and then by sliding the posts vertically through the jaws l2. The unscrewing of the tap-bolts i3 may be done by means of long rods ll, held in guides on each side of the posts 9; the rods H having at their lower ends sockets to take the heads of the tap-bolts l3. Or the rods may be made integral with the'bolts. There is a rod on each post for each tap-bolt. I have found this to be a convenient way of attaching the posts to, and of detaching them from the base i; but I reserve the right to use any other convenient and eiiicient way. I connect the two guide posts 9, 9 together, near their upper ends, by means of the ring H, which is preferably made of steel. It is attached at such a height that it will be above the surface of the water after the base has been set-in the final position. It will be noted that the base I, the posts 9, and the ring I7, form a frame; by which term I shall refer to this particular assembly. The ring I! is attached to the outside faces of the guides 3, 3, so that the inner and opposingfaces may not be obstructed.

In order that the base I may beplaced in its desired position on the river bed or other submerged foundation site, I'first dredge the bed to a uniform depth at the proposed location. "I assemble the frame consisting of the base I. the guide posts 9, and the ring I1; and when the concrete form 2 is to be secured to the base, I now secure it, and by means of bolts 23, (Figure 6). ,I then lift the assembled frame, in a vertical position, by means of a derrick. Theframe is plumbed, then swung into position, which can be determined by lining it up by predetermined marks. If desired, the rods which have female threaded ends l9 are now screwed onto the stub bolts l8 which are cast into or otherwise attached to the base i. .The frame is now lowered so that the base is set down in its desired position on the foundation site. If the base does not take a firm seat and a level one, and if the bottom is soft, leveling-may be done by raising and lowering the frame; or while the weight of the frame is taken by the derrick, bed material may be rammed under the base by any convenient form of rammer. The leveled conditionof the base will be indicated above water by the condition of the ring I1, and of theguide posts 9, 3. If it is. practicable and convenient I sometimes drive a center pile at the spot on which it is intended that the center of the base I shall rest. I stop driving while the head of the pile is still within reach, either above or below the surface of the taut vertically the point of the pile readily finds the hole. The pile is then plumbed and driven.

After the piles are driven, through the perforations in the base I, and to the desired depth, I cut the heads off to a suitable height by means of the sawing rig shown in Figures 8 and 9; 23 being the saw mounted on the lower end of the vertical shaft 25 which rotates in bearings 26. Two or more of these bearings are attached to a telescopic member 21. 21a, by arms 3|. The telescoping member 21a carries at its lower end the curved arm 35 (Figs. 8 and 9). One end of this arm carries one of the bearings 25 of the saw shaft 25; whilethe other end of it carries a downwardly projecting pin 33, threaded at its end,

. and provided with a holding nut 33a. The pin 33 engages in holes 35 in a plate or jig 32; the holes 35 being so locatedthat when the pin 33 engages in one of them the saw 24 is in position to cut an adjacent pile. The jig 32 is also provided with holes 39 spaced to slidably engage the vertical rods 20 (Figures 8 and 12), which, as hereinbefore noted, have female threaded ends I 9, threaded to engage the threaded stub bolts i 8 which are cast into the base I. The rods 20 form vertical guides for the vertically moving jig 32. When they have fulfilled their purpose they are removed by unscrewing them from the bolts l8. The upper ends of the rods 20 are held in place'and in spaced relationshipby securing them to the ring l'l, temporarily; or to a scantling through one of the piles which are to be cut ofi.

Achain-sling 31 is provided, for picking up the saw rig with a derrick. When I am about to use the saw 24, I lift the rig over the foundations so .that the rods 20 may be inserted through'the holes 33 in the jig 32. The jig is then lowered until the bolsters 34, which project from the under side of the jig, come to rest upon the base I. The saw is then properly positioned for swinging about the pin 33 to cut off a pile. The bolsters 36 are provided ofdifferent lengths so that the several piles may be cut off at such suitable elevations above-the base i as will prevent fouling of the saw by a cut off pile during the cutting of an adjacent pile. Suitable timbers and stays are placed on the ring II for. holding the upper part of the sawing rig during thesawing of a pile. After all of the piles have been driven, and then cut off to the desired lengths, the rods 20 are removed by unscrewing them from the stub bolts l3,

after thesaw rig has been raised and removed.

If I set reenforcement in the form 2 at this time I can do so before the rods 20 are removed, using them as a guide for a preformed reenforcement.

I now fill the form 2 with concrete, depositing it through the water by any approved, method. While this concrete 5 is still soft, the pre-cast stem 3 is lifted by the derrick to a position over the foundation; and it is lowered to its seat on the concrete 5 in the form 2, being guided in its descent by a. guide frame 2i, which is composed of side pieces 2| and notched end pieces 22. These end pieces slidably engage the guide posts 9, 9. Referring to, Figure 3: the stem 3 is built of concrete, reenforced in the usual manner by rods 6, which rods for some distance project from each end .of the stem for the purpose of tieing into adjacent masses-of concrete. The rods 6 which project from the-lower end of the stem 3 penetrate the soft mass of concrete 5, so that when bonded to the hardened concrete they will tie the stem 3 to the concrete 5. This plastic mass of concrete 5, which. under the weight of the stem 3 will be pressed into close contact with the top of the base I, and which bonds with'the base of the stem 3 and so holds it from lateral movement with respect to the piles, and which also bonds together the heads of the piles, serves to distribute uniformly to the accurately positioned pile heads the load for which the foundation is designed.

Where a structure is to be built on a site at which the substructure units w ll have to resist pressure from accumulated floating ice or drift, it maybe desirable to introduce into the design an inclined strut or brace member, as shown at' in Figure 1; wherein 45 is a pre-cast strut or brace (see also Figure 7) so built into the bent as to provide resistance against lateral pressure. Reenforcing rods 48 extend through the length of the brace 45, and project some eighteen or twenty-four inches from each end. After completing the left hand leg of the bent to a height just above the water line, and immediately after setting the right hand leg or stem 3 on its supporting concrete 5, the brace 45 is picked up by the derrick and swung into position. The surface 41 at the lower end of the brace .45 is brought into contact with the face 49 of the right hand stein 3; the said stem being provided at its base with a slot 46 (see Figure 3) into which the lower end of the brace 45 fits easily. If necessary, guide boards, or other guiding means are fitted to the stem 3 to guide the foot of the brace 45 into place. As the brace is lowered into place the bottom projecting rods 48 will penetrate the soft concrete 5; and the brace will come to rest with its foot firmly resting on that same concrete 5, to which it will become tied as well as cemented. The upper end of the brace is positioned as shown in Figure 1; and it is temporarily held in place by attaching it to the top of the left hand stem 3;

the bent ends of the rods 48 projecting over the top surface I of the said stem 3. When the upper part 4 of the bent is built, these projecting rods 48 will be encased in the concrete; and the brace 45 will then become an integral part of the substructure unit, and will provide substantial bracing means for resisting lateral pressure.

This adaptability to economical lateral bracing is a great advantage of my system. To incorporate under-water bracing between up and down stream legs of a bent where any form of unwatered cofierdam is employed would be impracticable where unwatering for one leg at a time is accomplished by providing for each leg an individual, surrounding, cylindrical shell or dam. This method of unwatering has been generally considered aneconomical one for building unare enclosed in one dam. And where 'each leg is enclosed in an individual dam, and each dam is to be unwatered, it is obviously impracticable to install any connecting brace or strut member between the legs of the bent.

Also, where both legs of a bent are enclosed in one large dam, and the dam is unwatered, lateral bracing can be incorporated in the general structure, and can be 'cast with the other items of the underwater structure; but, as it has been noted before, it is necessary to unwater the large dam to do this; and this is a costly operation, as all surfaces of the large dam, and particularly its flat surfaces, have to be heavily braced to withstand the pressure of the water on .the outside; and it has to be made waterproof. By my method of installing the bracing I avoid all of this heavy expense.

After the under-water structure has been thus far completed, and the concrete 5 in the form 2 has suificiently hardened, forms are secured to the upper ends of the stem elements 3 for the casting of the superstructure, which I have indi-.

cated in Figure 1 by the numeral 4. The concrete poured into these forms rests upon the top surfaces I of the stems 3, and is bonded thereto in an approved manner and by the reenforcingrods 6 (Figure 3) which project from the top of the said stems. At the same time the concrete encases and bonds with the reenforcing rods 48 (Figure 7) which project from the top of the brace 45, and extend over the top of the left hand stem 3. If desired a notched or other form of joint can be made at this time between the top of thebrace 45 and the vertical 4 of the-superstructure.

When it is desired to make the base I as small as possible in proportion to the number of piles required to support the load, it is better to set the base and cut off the piles to the desired heights before lowering and setting the concrete form.'2,

in order to allow more freedom and space for the 4 aoaavvs control and setting of the saw rig 24 during the operation of cutting off the piles. In such a case I omit the rods 20; and I guide the saw jig'32 mass 5. The interior of this concrete then may harden before the entire mass can be finished and made ready to receive the lowered stem 3; so much so that on lowering the stem the rods 6 may fail to satisfactorily penetrate the hardening interior. To avoid such possibility when using a small mixing plant, the procedure after lowering the form 2 to position on the base I would be changed from that outlined and would be as follows: Before pouring the mass 5 the premoulded stem 8 is lowered to its final position, the rods Ii projecting into the form 2. The stem is supported in this position by suitable temporary means during depositing ofconcrete, which is the next step. Depositing in the form 2 is continued until the volume of concrete poured is sufficient to press firmly up against the bottom surface of 3. Temporary support of the stem during depositing of the concrete may be by means of suspension from pile supported scaffolding or by will slide through the base jaws I2 and the form other convenient method such as having the reinforcing rods Ii so located and of such projecting length below 8, as will result in their bearing on the heads of some of the piles, 8, the piles and the reinforcing thus providing the necessary support for stem during pouring of the cap 5. The result is the same irrespective of method used, namely a concrete cap serving to join and to tie the bottom of'the stem to the heads of the piles.

If it is found that the bottom on which the foundation is to be built is too soft to support the weight of the base I with that of the concrete 5 and the stem 3-which stem it will be noted is placed before the concrete 5 poured on the base I has had sufficient time to thoroughly bond with the heads of the piles 8the weight of the base can be temporarily carried by swinging it from a beam 42 (Figures 12 and 13) which is arranged to rest upon one or more of the piles 8, and from which the base I is suspended by means of female threaded rods 44 which engage with the stub bolts I8 and which pass through the beam 42 and are held on the upper side of the beam by nuts and washers 43. The upper ends of the rods 44 are bored and threaded to take the male threaded ends of the rods 20a. The rods 44 and the rods 20a were assembled and attached to the base i before it was lowered into the water, preferably. The piles are cut oil, and the saw rig removed. The beam is then lowered into place by sliding it down over the guide-rods 20aand the short rods 44. The nuts and washers 43 are then slid down the rods 20a until they engage the upper bodies of the short rods 44, which upper bodies are externally threaded as well as internally. The nuts are tightened or loosened by means of a long socket wrench which is passed down over the rods 20a the top of the wrench extending above the water level. Such a wrench can be made from a piece of pipe;

. or by welding a shaped socket wrench head to the end of apiece of pipe. The rods 20:: may

. then be unscrewed from the rods 44 while holding the nut 43 with the long wrench.

In the foregoing specification I have described methods and means by which I may carry out the particular way of using the said parts. Nor do I confine myself to the described means by which I place them in position. In some cases one method of handling will be best; in other cases another will be best. Much will depend upon the local conditions to be met and overcome. I reserve the right to use my system of construction with any suitable means.

I claim:

1. A subaqueous foundation comprising a preformed base portion perforated with spaced apart holes, and piles driven through the perforations in the base and into the underlying loose material where the latter contacts the base portion intervening its said perforations.

2. A subaqueous foundation builtin the wet instead of by pneumatic. caisson means comprising 'a preformed base portion perforated 'with spaced apart holes for the passage of piles, piles driven through the perforations in the base and into the water-bed below thebase; and a cap cast upon the base and encasing the heads of the piles.

3. A subaqueous'foundation comprising a perforated base; piles driven through the perforations in the base and into underlying loose material where the latter is in contact with the perforated area of the said base; a cap comprising cast in place concrete deposited upon the base and encasing the heads of the piles; and a stem resting upon the cap.

4. A subaqueous foundation comprising a preformed base portion perforated with spaced apart holes for the passage of piles; piles driven through the perforations in the base and into the waterbed below the base; a concrete cap cast upon the base and encasing the heads of the piles, the

said cap comprising the lowermost concrete cast in contact with the said piles; and a stem lowered to position upon and tied into the cap while the latter is still plastic.

5. A subaqueous foundation comprising preformed bases-perforated with spaced apart holes for the passage of piles; piles driven through the perforations in the bases and into the waterbed below the bases; caps comprising masses of concrete cast upon each base and encasing the heads of the piles, the said caps comprising the lowermost masses of concrete cast in any space intervening the said piles; and preformed stems set upon and tied into the caps while the latter are still plastic.

6. A subaqueous foundation comprising preformed perforated bases; piles driven through the perforations in the bases and into the waterbed below the bases; a formed concrete cap cast upon each base and encasing the heads of the piles; preformed stems set upon and tied into the caps while the latter are still'plastic; and a preformed brace set upon and tied into one of the said plastic caps and inclined to brace the stem on an adjacent cap. g

7. A subaqueous ibundation consisting of a preformed perforated concrete base; piles driven through the perforations in the base and into the water-bed below the base; and cut oil. above the base; a formed concrete cap cast upon the base entering the-perforations around the piles and encasing the heads of the, .piles, the said cap comprising the lowermost mass of concrete cast in any space intervening the driven piles;

and a preformed concrete stem set upon and tied into the concrete cap.

8. In a bent having subaqueous foundations constructed by means obviating the use of pneumatic caisson means, the combination 'of perforated bases; piles driven through the perforations in the bases and into the water-bed below the bases; formed concrete caps cast upon the bases, the concrete entering the perforations in the bases around the piles and also encasing the heads of the piles; preformed concrete stems set upon and tied into the concrete caps; and a superstructure built upon the stems.

9. The method of building a subaqueous foundation consisting of setting a perforated preformed concrete base upon a leveled water-bed; driving pilesthrough the perforations in the base and into the water-bed; placing a form upon the base and around the heads of the piles;

and casting a concrete cap in the form and on the base and encasing the heads of the piles; whereby the use of pneumatic caisson means is avoided. 10. The method of building a subaqueous foundationconsisting of setting a preformed perforated concrete base upon a leveled water-bed; driving piles through the perforations in the base and into the water-bed; cutting ofl the heads of the piles; casting a formed concrete cap upon the base and encasing the heads of the piles; and setting a preformed concrete stem upon and tieing it into the concrete of the'cap while it is still plastic, whereby a foundation having the advantage of assured accurate spacing of piles may be built in the open rather than by pneumatic caisson means.

11. The method of building a subaqueous foundation consisting of setting preformed concrete perforated bases upon a leveled water-bed; driving piles through the perforations in the bases and into the water-bed; cutting off the piles above the bases; casting formed concrete caps upon the bases and encasing the heads of the piles; setting preformed concrete stems upon and tieing them into the caps while the concrete of the latter is still plastic; and bracing the stems by setting preformed concrete braces upon and tieing them into the concrete caps at one of their ends and tieing their other ends into the structure in the side of an adjacent stem.

12. The method of building a bent in the open rather than by compressed air means, consisting of setting preformed perforated concrete bases upon a leveled water-bed; driving piles through the perforations in the bases and into the water-bed; cutting off the piles above the bases; casting formed concrete caps upon the bases, the concrete entering the perforations in the bases around the piles and also encasing the heads of the piles; setting preformed concrete stems on the concrete caps'while the latter are still plastic; and building a superstructure from stem to stem.

13. A subaqueous foundation comprising a preformed perforated base; piles driven through the perforations in the base and into the water bed below; means comprising metal ties extending upwardly from the base and having their upper ends attached to a member resting over the head of a pile whereby weight on the perforated base is conveyed to the said pile; a cap cast upon the base and encasing the heads of the piles; a stem set upon and tied into the cap while the latter is still plastic.

14. A subaqueous pier structure embodying a spread lower portion, the said portion comprising an underlying base member formed before placement in the water and having holes through which the heads of piles project; piles driven through the holes into underlying loose material; concrete cast in place on the said member and embodied in the said spread portion to encase v the heads of the piles; and an overlying upright stem extending upwardly from the spread portion.

15. A pier structure of the inverted mushroom type, having a subaqueous foundation comprising a preformed perforated base portion, piles driven through the perforations in the base and into the water bed below, a mass of poured-inplace concrete resting on the said base and encasing the heads of the piles and an upright stem resting thereon and extending upward to the surface of the water.

16. In the construction under water of a foundation comprising, a preformed base having holes through whichthe heads of piles project, piles driven through the said holes, an overlying upright stem portion, and a formed-inplace cap intervening between the said base and stem; means for cutting off the piles at a given elevation, the said means comprising a frame carrying a cut-ofi saw, guide members extending upwardly from the said preformed base, and a templet pivotally connected to the frame and having connecting means slidably engaging the guide members.

1'7. In the building of a subaqueous foundation comprising a supporting pile, an overlying upright stem, and an intervening poured-inplace concrete cap encasing the head of the pile, means for cutting off the pile under water, the said means comprising an underlying base portion having a hole through which the pile projects, an upright guide member projecting upward from the base portion, a saw unit having means slidably engaging the said member, whereby, when lowered to position above the base portion the saw is maintained in predetermined relative position with respect to the pile.

18. In the construction under water of a foundation comprising a preformed stem, 2. poured in place cap beneath the stem, and piles supporting the cap and stem; means for assuring accurate relative predetermined positioning of the stem and the piles, the said means comprising a preformed base having perforations through which the pile heads project, guide members projecting upwardly from the base, and connec-' tions on the stem slidably engaging the said members.

19. In the construction of a subaqueous foundation comprising a preformed stem connected to a preformed base portion by an intervening poured-in-place concrete cap; means for forming the said concrete cap in its correct relative position on the base, the said means comprising a box embodying sides but being without top, or bottom, guiding means extending upwardly from the base, and connecting means on the box slidably engaging the said guiding means whereby the said box may be guided to and retained in its correct position upon the under-water base.

20. In the building under water of a foundation structure comprising a group of piles, a poured in place concrete cap encasing the heads of the piles, and a preformed stem portion resting 'on the cap; means operative through the water for assuring correct relative positioning of the inaccessible component parts of the structure; the said means comprising temporary upright guide members having a predetermined fixed position with respect to the said group of piles and exupright guide members whereby the stem portion when lowered beneath the water to its place over the cap will be assured of accurate setting in a predetermined position with respect to both the cap and the group of piles.

21. In the building of a subaqueous foundation comprising supporting piles, an overlying upright stem, and an intervening poured in place concrete cap encasing the heads of the piles; means for assuring accurate driving of the piles in predetermined position in the foundation, the said means comprising an underlying preformed base portion lying below all of the poured-inplace concrete in the structure, the said base having openings through which the piles are driven.

22. In the building of a subaqueous foundation; a pile driven partly into the water bed; and a preformed base in which are formed a number of holes, spaced apart, by one of which the base is passed over the head of the pile. 23. In the building of a subaqueous foundation; a pile driven partly into the water bed; and a preformed concrete base in which is formed a hole by which the base is passed over the head of the pile.

24. In the building of a subaqueous foundation; a preformed base portion perforated with spaced apart holes for the passage of piles; guide arms attached to the base and connected at their upper ends by cross pieces to form a frame for the purpose of leveling up the said base in position; piles driven into the water-bed and extending upward through the perforations in the base; a formed cap of concrete cast in situ upon the base and embracing the heads of the piles, and adapted to carry upon its upper face a pier supporting a superstructure. 25. In a subaqueous foundation having pile support and comprising a preformed base portion having a hole through which a pile projects a spaced distance, and a concrete cap cast in situ upon the surface of the said base to encase the pile head; a transverse beam resting on the pile head and encased in the said cap, and threaded rod means suspending the base portion from the transverse beam.

WILLIAM G. ADAMS.

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