US2021014A - Sinking cellular piers and the like - Google Patents

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Nov. 12, 1935. D. E, MORAN 2,021,014

SINKING CELLULAR PIERS AND THE LIKE v Filed June 9, 1934 5 Sheets-Sheet l INVENTOR. DAN/EL ATTORNEYS Nov; 12, 1935.

D. E. MQRAN SINKING CELLULAR PIERS AND THE LIKE 5 Sheets-Sheet 2 Filed June 9, 1934 vl\lll|ll .1 Ililil?! IIIII. Iiiltiiillllillillli SINKING CELLULAR PIE RS AND THE LIKE Filed June 9, 1954 5 Sheets-Sheet 3 INVENTOR. DA N/EL EfifOEA/V.

' ATTORNEYfi Nov. 12,1935. L O AN 2,021,014

SINKING CELLULAR PIERS AND THE LIKE Filed June 9', 1934 5 Sheets-Sheet 4 INVENTOR.

DAN/ELEMO-EA/V.

ATTORNEYS Nov. 12, 1935. D. E. MORAN 2,021,014

SINKING CELLULAR PIERS AND THE LIKE Fi led June 9, 1934 5 Sheets-Sheet 5 wavy/7% ATTORNEYS Patented Nov. 12, 1935 UNITED STATES PATENT OFFICE smxme CELLULAR PIERS AND THE LIKE Daniel E. Moran, Mendham, N. J. Application June 9, 1934, Serial No. 729,784 15 Claims. (01.61-81) The invention relates to improvements in methods of constructing and handling bridge piers, caissons, foundations and similar structures which are to be sunk in water and by excavation through mud and other materials.

The invention is applicable to a variety of situations, but probably finds its greatest economy in the largest type of pier foundations under Water.

In a previous co-pending application, Ser. No. 617,339 (Patent No. 1,971,046 of August 21, 1934) there is described a method of building, floating and sinking such submarine structures until they cometo rest upon the bottom of the river or other body of water; and the subsequent dredging of the river bottom to sink the structure to its final position. The structure in said application is of concrete, or other masonry, through which exten shafts open at the bottom, extensible upward and with caps which close them airtight during transportation and the first sinking operations and which are removable to permit dredging when the caisson rests on the river bottom.

The present invention relates to the construction and sinking of such structures, particularly to the operation of sinking the cutting edge through soft alluvial clay, silt or mud which is adapted to enter the lower ends of the shafts. Such mud is apt to form a watertight and airtight seal even when it is quite plastic, and thus impede or stop the free fiow of the water out of and into the shaft as described in my above application.

The present invention provides methods and means for controlling the rate of sinking under such circumstances and for controlling the level while sinking. This may be done by replacing water in the shafts (above the mud) by air under a controllable pressure. Either before or after such replacement of water, the compressed air in the shafts may be let out gradually, to a greater or less extent in the different shafts so as to control the level, permitting the mud to rise in the shafts and then removing the caps and dredging out the shafts so as to effect further sinking in the river bottom.

Different constructions of the caisson or pier are described in my said previous application. The present improvement is applicabie to the several structures therein described and to various other analogous cellular masses of masonry which are to be sunk in mud. And the invention may be applied with considerable variations in the individual steps and in the timing of them.

Besides my previous application, reference is made to prior patents of Rush No. 1,079,517 of November 25, 1913, and Miller No. 1,899,346 of February 28, 1933, as showing caissons or similar structures with provisions for floating them to the desired site and sinking them. My present 5 invention provides improvements in such caissons and particularly in the carrying of them down into the mud of the river bottom.

The accompanying drawings illustrate embodiments of the invention. Fig. 1 is a plan of one end of a caisson; Fig. 2

is a vertical section of the same with its lower end entering the mud of the river bottom; Fig. 2

is a similar View showing the caisson out of plumb; Fig. 3 is a similar section with most of the water from the shaft at the right replaced by buoyant air to hold up this end of the caisson as the sinking proceeds; Fig. 3 is a similar view of a modification; Fig. 4 is a similar view with the right-hand shaft used for dredging; Fig. 5 is a partial plan of a modified construction of which Fig. 6 is a vertical section approximately on the line 6-6 of Fig. 5; Figs. 6 6 and 6 are enlarged details of Fig. 6; Fig. 7 is an enlarged vertical section of the upper part of the sump pipe and adjacent parts of Fig. 6; Fig. 8 is a part of Fig. 2, enlarged to indicate diagrammatically certain controlling devices.

In my previous application, I have illustrated an extraordinarily large caisson with five shafts across its width and ten along its length. For simplicity in the present case, I have assumed a structure with only three shafts across its width and of somewhat less depth than that shown in the previous case. Size is not a matter of importance. But generally the shafts are of such size and number as, when filled with air, to provide sufficient buoyancy to float the structure to the site and to control the level of it during flotation and during sinking in the water, and also to be subsequently used for dredging, all as described more fully in my previous application.

The principal parts of the structure are a sheet metal bell H at the bottom from which extend upward shafts l2 open at the bottom and closed by caps or domes i3 at the top, the shafts being extensible upward by removing the cap and adding new sections as desired; about which shafts is a body of concrete [4 providing the chief Weight for the sinking of the caisson. This in turn is surrounded by a cofferdam l5 extending upward beyond the top of the concrete and braced above the concrete by longitudinal braces 16 and cross-braces l1 against the great strains to which it is subjected when submerged.

An air line I? extends over the caps with branches leading into the several shafts'and with the usual control means by which air can be forced under compression into any shaft, or group of shafts, or can be similarly released from the shafts. For example, the valve Is Fig. ,8, may

- be moved from the admission position shown a quarter turnto a discharge position, or to an intermediate closed position.

When the cutting edge of the caisson enters the mud it will be forced up into the lower ends of the shafts as at is, Fig. 2, to a point somewhat above the level on the outer side of the caisson. This is because the mud displaced'by the entering caisson has roughly an area twice that of the open shafts. The tendency is to force mud outward -also, but since it is unconfined there it will not rise as it does within the shafts.

When the mud is forced outside there is a resulting .tendency'to lateral shifting andtilting of the caisson, which, of as faras possible.

The ideal condition would be I to withdraw through the shafts a quantity .of

7 cannot be removed from the dredging, which requires the opening of the tops" of the shaftsland invites a dangerous inflow of pressure balanced by mud or eeirthexactly equal to that displaced by the sinking caisson. V

In general it is desirable to have the external the internal pressure so that a particle under the cutting edge would not be subjected to an outward nor to an inward pressure. Under these conditions the caisson will penetrate the mud, and the mud entrapped within the cutting edge will be forced to rise in these circumstances to exert an increased lift in 7 one shaft,or group of shafts, so as to lift the corresponding part of the caisson.

In sinking through water, by exerting an increased pressure of air, the body of water within the shaft can be driven to a lower level and thus theidistanceor height between the levels 2] and 22 be'increase'd with a corresponding increase'in the lifting force.

7 But in the situation of Fig. 2 this will not work. The mud in the bottom of theshaft cannot'be forced out by any practicable air pressure, so thatthewater cannot be forced out of the bottom of the shaft; and if this could be done, it is not advisable because the mud would probably be forced out under the cutting edge of the caisson with the disadvantages above stated, It is not generally possible to correct the trou ble by opening the shaft at the high end and dredging out the mud therein. There is apt to be and'has been, in such cases, a flow of mud.

from the shafts on the low side through the bell l i to those on the high side. If at anytime during the sinking it be found that the weight on the mud bottomcauses too rapid asettlement or an outward and lateral flow of 'must' be reduced. It'is mud, the weight impracticable to cut the weight of the caisson itself. The mud generally shafts except by to so great a height.

' the caisson tilts, as in Fig. 2

course, is to be avoided 7 reaches .a dangerous limit.

apparatus, such as the clamshell'digger at the top'of the shaft.

lower end' 28 leading to the central portionof mud. I propose to meet these emergencies by lessening the'weight of'water in the shafts on the low side, replacing it at thesame time with air.

The invention therefore provides for removing the Water in the selected shafts, forcing it through outlets which are above the mud. Various arrangements of conduits may be provided.

In Figs. 1, 2 and 3, for example, there'are pipes 23extendingdownward through the caps I 3 of 1 the shafts and upward to a common pipe 24 which discharges through the coiferdam at a point outside of the water level. Of course, the usual fixtures and valves are assumed for handlingfea'ch shaft separately, such as the valve 1" 24 Fig. 8, for each shaft and the common valve 24 for the group of three shafts.

for this purpose The pipes 23 extend downward to a level above which the mud is not apt to penetrate. When the load at the 2 low side should be lessened. 'To do this the water in the right hand shaft (or a group of shafts on the low side) is evacuatedrsufiiciently to right the caisson. Generally the water is expelled as far as possible. 1 e

The further sinking operations involve the re moval of the caps and the excavation of the mud through the shafts. Under some circumstances this might be objectionable because of its permitting a rush of mud into the shafts, and the present invention contemplates the relieving of the air pressure gradually, permitting the mud to rise at a corresponding rate, in shafts in different locations so as to maintain the caisson level until, even with the air pressure entirely off, the 3 mud ceases to move up, Thismay be done before the removal of water from the space above the mud, but the pressure control is better if the water is first removed. The shafts may thenlbe uncapped and dredged out. in proper order.

-Before removing the caps and dredging, however, I propose as shown in Fig. 4, to introduce an additional body .of water 25 within the shaft to be dredged. 'Any usual or suitable dredging be used. And during dredging the mud should be progressively replaced bywater and the water 26 may 45 should be kept up to about the outside level 2!.

This is advantageous in that it avoids a bad distribution of the pressure on the mud below the 5 sinking caisson. l r The arrangement for removing water in Figs. 1 to 4 is practicable but offers mechanical dis-' advantages, particularly, in the removal of the cap'for dredging, or for the addition of sections 5 The arrangement illustrated in Figs; 5 to 7- inclusive, has certain advantages. In this case the water is expelled through a r sort of sump 27 of which there maybe one for 3 each shaft 12, or a common sump for several shafts. Each sump is a vertical tube which passes clear through the caisson and has an open the partition between the entrances to two ad-c jacent shafts.

air as it is introduced through the lower .end. At its upper end itihas a branch 7 This sump is connected at in tervals by lateral branches 29 to the shafts, and

pressure of top willforce the water out downito the level if is a water discharge pipe iii) Though size is not a matter of importance in explaining the principle, yet the invention finds its greatest utility in caissons of the largest size and in sinking operations of the greatest depth.

What I claim is:

1. In the sinking of caissons and similar structures having a number of shafts open at the bottom and closed at the top, the method of controlling the rate of sinking and the level of the caisson which comprises the varying of the quantity of buoyant air in said shafts, while sinking through water, by expelling and admitting water through the bottoms of the shafts and, while sinking through mud Which enters the shafts, by forcing water out of said shafts at levels above the mud.

2. In the sinking of caissons and similar structures having a number of shafts open at the bottom and closed at the top, the method of controlling the rate of sinking and the level of the caisson of regulating the sinking through the river bottom which comprises the removal of Water trapped in said shafts by mud entering their lower ends, the gradual release of air pressure above the mud to permit the mud to rise until an approximate balance is obtained, restoring water in the shafts above the mud and subsequently opening the upper ends of the shafts and excavating the mud through said shafts by dredging while maintaining the water therein at approximately the outside water level.

3. In the sinking of caissons and similar structures having a number of shafts open at the bottom and closed at the top, the method of controlling the rate of sinking and the level of the caisson of regulating the sinking through the river bottom which comprises the gradual release of air pressure above the mud to permit the mud to rise until an approximate balance is obtained and the subsequent opening of the upper ends of the shafts and excavation of the mud through said shafts by dredging.

4. In the sinking of caissons and similar structures having shafts open at the bottom and closed at the top, the method of regulating the rate of sinking and the level of thecaisson during the sinking through the river bottom which comprises the removal from said shafts separately of Water trapped in said shafts by mud entering their lower ends.

5. In the sinking through mud of caissons and. the like having a shaft open at the bottom, the method of controlling the level of the caisson which consists in controlling the quantity of mud entering the lower end of said shaft by changing the weight of water superimposed on such mud.

6. In the sinking through mud of caissons and the like having a shaft open at the bottom, the method of controlling the level of the caisson which consists in controlling the quantity of mud entering the lower end of said shaft by reversibly imposing a water load or a water load and a compressed air load on such mud.

7. A caisson or the like having a number of shafts therein open at the bottom. and closed at the top and means for controlling the level of the caisson, said controlling means comprising devices for removing from said shafts separately water trapped therein by mud entering the bottom.

8. A caisson or the like having a number of therewith shafts therein open at the bottom and closed at the top airtight so as to permit the expulsion by compressed air of water entering at the bottom and separate discharge conduits from a point above the bottom of said shafts for the removal from separate shafts of water trapped therein by mud in the bottom.

9. A caisson or the like having a shaft therein open at the bottom and closed at the top and means for removing from said shaft water trapped therein by mud entering the bottom, said means comprising a sump parallel to the shaft and communicating therewith at different levels.

10. A caisson or the like having a shaft therein open at the bottom and closed at the top and means for removing from said shaft water trapped therein by mud entering the bottom, said means comprising a sump parallel to the shaft and communicating therewith at different levels and a drain pipe in said sump communicating therewith and extending upward to discharge the water.

11. A caisson or the like having a shaft therein open at the bottom and closed at the top and means for removing from said shaft water trapped therein by mud entering the bottom, said means comprising 'a sump parallel to the shaft and communicating therewith at different levels and a drain pipe in said sump communicating and extending upward to discharge the water, said drain pipe being removable so as to leave the sump open from end to end through the caisson and to permit the introduction of a tool to loosenthe material below the caisson.

12. A caisson or the like having a shaft therein open at the bottom and closed at the top and means for removing from said shaft water trapped therein by mud entering the bottom, said means comprising a sump parallel with the shaft, a cofierdam extending above the body of the caisson andhaving interior braces, said braces being supported by the sump.

13. A caisson or the like having a shaft therein open at the bottom and closed at the top and means for removing from said shaft water trapped therein by mud entering the bottom, said means comprising a sump parallel to the shaft and communicating therewith and being made in detachable sections to permit upward extension.

14. A caisson or the like having a shaft therein open at the bottom and closed at the top and means for removing from said shaft water trapped therein by mud entering the bottom, said means comprising a sump parallel to the shaft and communicating therewith and being made in detachable sections to permit upward extension in combination with a drain pipe therein made also in detachable sections to permit upward extension with the sump.

15. A caisson or the like having a shaft therein open at the bottom. and closed at the top and means for removing from said shaft water trapped therein by mud entering the bottom, said means comprising a sump parallel to the shaft and communicating therewith and being made in detachable sections to permit upward extension and branched fittings connecting such sections and serving to form lateral connections with the shaft at different levels.

DANIEL E. MORAN.

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