US2384464A - Graving or basin dry dock - Google Patents

Description

Sept. El, 19451 F. R. HARRIS 2,384,464

4 Sheets-Sheet 2 ATTORNEY Sept. 11, 1945.

F. R. HARRIS GRAVING OR BASIN DRY DOCK Filed March e, 194s 4 sheets-sheet s Sept. El, 3945a F. R. HARRls 2,384,464

GRAVING OR BASIN DRY DOCK Filed March 6, 1943 4 Shees-Sheet 4 zNvENToR afnam/GAMER@ ATTORNEY Patented Sept. 11, 1945 UNiTED STAES ATENT OFFICE GRAVI-NG 0R BASINDRY DOCK Frederic It. Harris, New York, N. Y., Application March 6, 1943, Serial No. 478,274

19 Claims.

This invention relates to. a dry dock and a method of building same; especially a basin or graving. dry dock which is a permanent structure on the shore adjacent the edge of a navigable body of water..

The principle of this invention is particularli7 applicable to the construction of docks of the socalled tremie type, in which the concrete is laid and allowed to set under water at the site of the dock. The invention has for its chief object to provide a treniie-.bu-ilt dock that is secure and durable and can safely be completed in a com-- paratively short time and at greatly reduced hazard and less expense.

Graving docks were formerly shorter, narrower andshallowerv because ships were previously smaller in length, beam and draft than they are today. But such docks were always hard to finish and del-iver in a useful and serviceable condition. Water in the soil near the shore, at great pressure,` and' other factors, often caused heavy damage; and sometimes even brought about the collapse of the dock itself in whole or in part. Often several contractors would go into bankruptcy beforeone finally succeeded; and occasionally the work was actually abandoned because the completion of it was believed to be too costly or vir tually impossible. Now, owing to the large size of ships, their increased'y length, beam, and draft and peculiar shape, much bigger docks are necessary and their construction is more difficult than ever. For example, a modern dock requires at the outset an excavation of' about 1,090 feet long, 150 feet wide and 60 or '70 feet dee-p. Such an operation is dangerous,y indeterminatebeforehand in cost and uncertain of outcome. To pump the water from the entire area of the basin, then lay the bottom and erect the Walls of the dock is not feasible; because the natural level of the navigable water nearby raises the hydrostatic pressure of the water in the earth on the site of the dock far too high to ber counterbalanced, especially at nthe gate end; or permit safe and certain operation.

Different modes ci proceeding still encounter problems of the most serious kind. It hasbeen proposed to build graving docks without unwatering the site; but plans of this nature have involved the formation of large masses 01' bodies of concrete and other materials on the surface of the earth and their subsequent removal and lowering into the exact places in the excavation prepared to receive them. In such cases, the concrete in a plastic. state was either not laid under water at all or was thus used only in a (Cl. (i1- 64) minor degree; because there has been no practical way of controlling the concrete when, spread over a large extent of ground under, water so as to avoid damage; or permit reinforclig it under 5 water in such measure, as to make it serve its4 intended purpose and keep the volume or quantityA within reasonable limits. This is particularly true of the bottom of the dock, whichl has to be a slab or bed of concrete many feet'l thick to enttbie the bottom to withstand hydrostatic pressure below it and the weight of the ship on top.

I have found that all obstacles can be o vercome with concrete laid by tremie on the bottom of the excavation of the, dock, without first unwatering thev site,` `and my invention resides in a new way of controlling the deposit of the concrete in the Wet, plastic state, so as to prevent damage or dilution;` and at this stage reinforce it; with the result that, as, the concrete, hardens, it is. bonded and otherwise joined to the reinforcing elements; increasing the strength thereof and adding to its own as well. I thus produce a bottom slab massive and, tenacious, firmly anchored to its foundation; and then the Walls of the docls can easily be reared` The entire dock can be located wet earth and complete at, a great` savingA intime and cost, and with virtually thetotal elimination 0i the usual risks. In its final stage it will have all the dependability, stability and security that are needed by an installation of this class.v

After the construction of the. bottom slab, the water can be pumped out over either the entire surface, or part thereof, to facilitate the erection of the walls; or the latter can be reared without the evacuation of the Water. During. this Step, any upward pressure beneath the bottom is successfully resisted and the foundations of the dock are in no Way impaired.

The ensuing description sets forth several embodiments of my inventionbut this disclosure is by way of demonstration only and variations in execution may, of course, be adopted even though not specifically mentioned herein, to, the full extent covered by the broad and general meanings `of the terms in which the claims appended hereto are expressed.

On the drawings:

Figure l is a top View showing a construction employed in the rst step of building a dock according to this invention..

Figure 2 is a side view mode of proceeding.

Figure 3 shows a view of, one part of, the mat terial employed in the` dQQk.

illustrating further the Figure 8 is in part a section on line 8-8 in Figure 7.

Figure 9 is a view of the framing employed in 'this method of proceeding, seen from one side.

Figure 10 shows another 'modification of my invention relating to the formation of the bottom slab and walls of the dock in cross-section.

Figure 11 is a plan of the construction of the side walls.

Figure 12 is a top view presenting the same method followed in constructing the inner or head end wall of the dock.

Figure 13 shows this method utilized in the construction of the gate end.

Figure 14 shows a portion of part of the frame-l work used with this embodiment of my invention.

Figure 15 is a cross-sectional View thereof; taken on line IST-l5 -n Figure 12.

Figures 16, 17 and 18 present structural details.

The same numerals of reference identify the same parts on all views.

In Figure 2,. the character F indicates the excavation for .the dock, on the bottom of which the concrete slab B is laid. The slab is presented in finished form at the left only, in Figure 2, but in practice it extends over the full Width of the dock. The right half of Figure 2 shows in side elevation part of one of the tremie mold forms for the bottom slab, with reinforcing elements that are put into the excavation before the concrete. 'I'hese forms 3 are laid side by side, but

Awith spaces between them, as illustrated in Figures 4 and 5. When the forms and spaces are lled with concrete, the result is a continuous layer of concrete of the same thickness as the depth of the forms, from one end of the dock to the other. The excavation is made by digging or dredging, to the required depth over the selected area. -Water collecting in this extensive pit, even to the point of filling the same, as shown at W, need not be removed when the concrete is poured.

To get the bottom slab down and anchor it,

piles l, made preferably of flanged steel beams of suitable length, are first driven into the subsoil at the bottom of the excavation to a sucient depth. These become embedded in the bottom slab B at their upper ends when the concrete sets, and are partially relied upon to resist the lifting of the dock by hydrostatic pressure in the soil when the surface water in the excavation is at last pumped out. A layer of stone or gravel 2 is also put down on the bottom, and when this layer and thel piles are in position, the piles I project about three feet above the layer. Sometimes the dock may have to be designed wholly without reliance on the piles l, as a precaution against the possibility that the piles might not gives the anchoring effect required. In such a case the piles might even be omitted.

Due to water in the soil as above described, the upward or lifting pressure against the bottom of the dock may be enormous, The retention of the water in the excavation at full depth balances this pressure. But with the water in the excavation the concrete must be laid under the water; and it is diflicult to prevent concrete in the plastic or fluid state from being diluted and damaged by the water before it sets. Docks of this general class have also been built by constructing large concrete sections, or caissons, each with bottom and high side walls, on the land adjacent the excavation; then floating them in the excavation, sinking them and connecting them together on the bottom; and nally removing the inside walls or partitions to give a single large basin; but this procedure and similar methods of making structural units of concrete on the land and then sinking them into place are very expensive and unwieldy. Laying concrete under water is, of course, easier and less expensive; but even when this can be done without damage in the construction of a basin or graving dock, the general nature of the work demands that the immense upward pressure on the extended surface of the bottom slab be transferred and concentrated, so far as possible, near the edges under the bulky and heavy side walls. Hence much reinforcement of the bottom slab is essential; but to deposit concrete under water and at the same time reinforce it, as with steel, has not heretofore been regarded as feasible. My invention successfully meets these requirements, for I have originated a method of laying concrete under water by the use of tremie or pouring equipment, and simultaneously reinforcing it; so that, as the concrete hardens, it develops full normal strength and reinforcing effect.

In practice, the tremie forms 3 are fully completed before laying them on the bottom of the excavation. They are lowered into the water and come to rest crosswise upon the stone or gravel 2. The forms have a Width of 12 to 15 feet; and are as deep as the thickness of the slab B; and they have the shape of closed troughs or pockets, the ends and sides, of which are provided by the reinforcing material to be combined with the concrete. The piles I project; up into the forms and spaces between them. In these molds and spaces between, the concrete can be poured without suffering damage before it sets; and in hardening, the concrete becomes so united to the reinforcing material that both are strengthened and stiffened in marked degree.

The troughs or forms 3, as illustrated separately in Figure 1, consist of steel side plates 4, with transverse or vertical corrugations, steel trusses 5 and corrugated metal end plates 6, with similar corrugations. The sides 4 may be relatively thin and exible but are sti'ened by trusses 5. Each truss includes two or more longitudinal beams 1, rigid with the sides along the outer faces thereof, and 'connected by vertical struts 8 and diagonal struts 9. Each truss is light but very strong, and all parts of the form are secured to one another by welding or otherwise. To the end plates S are fixed outside strips or battens l0. The end plates 6 are joined to the plates 4 and trusses 5 at the extremities of the latter, but project sideways beyond them. The battens serve to reinforce and stiften the plates 6. Preferably the beams 1 are angle-shaped in cross section with vertical flanges secured to the plates 4, and turned upward.

Before the tremie forms are put down into the dock excavation, the frames for bracing sheet piling, when my invention contemplates the erection of such piling on the bottom slab B all around the edges thereof, and for reinforcing the dock walls reared against; the inner face of such piling, are mounted on the tremie forms 3. The frames consist of uprights Il, inclined' braces I2, and struts I3. The uprights IA I project down far enough to be embedded in the concrete. These A-shaped frames arer aixed by welding or otherwise in, upright position to the trusses 5, at each end. Each tremie form., with four such vertical A-frames, isv then transferred to the excavation; and with a chain or cable attached. to each end and controlled by a crane on the surface near the excavation, lowered till it comes to. rest in the right position on the gravel or stone 2. The end plates project beyond the sides to such an extent that when the forms 3 are all down and the plates 6 at each end all in line. spaces I4, closed on all four sides, lie between the forms 3, and provide additional forms of slightly less width than the forms 3, as plainly appearsv in Figures 4 and 5. The four frames then rising from the ends of each formA 3 may be entirely submerged, with their tops under the surface of the water W. But straight pieces of timber or metal I5,A or other suitable members of sufficient height, may be detachably secured to the tops of the frames to project above the water and serve as markers to show the positions of the tremie forms and frames; and thus facilitate correct alignment when the forms. come to rest on the gravel 2. Oi course, underwater equipment and even the services of divers icould be used for this purpose if necessary.

The next step is to set up the sheet piling I6 around the four sides of the area supporting the tremie forms 3 and I4, andi thus erect a coiierdam on the bottom slab to enclose a space from which the water can be pumped out when the bottom slab has hardened. For the piling along the sides, horizontal wales or stringere` I1 are attached to the outer sides of the aligned A-frames; being bolted. welded or otherwise secured inv position. As, illustrated in Figures 4 and 5.-, a wale i1, is amxed to each pair of A-frames at the ends of the forms 3. projecting out sideways as far as the end plates 6 and stripsr Il); and is lowered into the water with the remainder of the structure. All the wales are in straight alignment when the forms and frames are on the bottom of the dock excavation. A single length could also be used and attached after the forms and A-frames are in place, as by lowering it separately intoy the water and securing it to all the A-irames by bolts or clamps. This, however, would require the use of underwater equipment and perhaps the services of divers. Therefore, the method of first attaching wale sectionsV in separate pieces o-r lengths is preferred.

This piling may be made up, for example, of members of the kind described in my Patent No. 1,937,738, covering Sheet piling, granted December 5, 1933, jointed or interlocked along their vertical longitudinal edges. They are preferably provided with hooks I8 on their faces. The wales f il. have upturned iianges with which the hooks engage. At their lower ends some of the piling members will t into recesses I9 in the side plates 4 of the forms; and thus the whole extent of sheet piling at each side will be kept in place'. For the sake of clearness only a few of such hooks are shown in Figures fi and 5, but are, of course, employed on each piling member. The piling is put up so as to be set back a bit from the endsr of the forms 3 and I4 for a purpose to be mentioned later'.

Similar frames and piling are erected along the two ends 0f the dock. At the entrance and the inshore endsA are A-trames 20 put up` along the inner sides of the end tremie forms indicated at 3^', and aflixed crosswise to the tops of the trusses 5 thereof'. These frames support a. single long Wale Illia at each endof the dock, torbe engaged by hooksl 8 on the inner faces of the pile members and mount the latter. The lower ends of these pile members wil-1 be within the outer corrugated side walls 4 of the tremie forms 3^, as appears in Figures 4, 5 and 6. The inclined braces I2' of these frames are in contact with the uppermost beam I of the truss 5' along the inner side or each 'form 3 and securedv thereto by Welding or otherwise. The uprights II also extend down into these forms. Cross struts 2lV may be aflixed to both sides of the tremie forms 3' at the bottom to give the frames 210 more rigidity. Any other suitablev method of fabricating and mounting these frames may be adopted; and as much transverse or horizontal strut work between the plates 4, as may be needed' to prevent deformation may be used with the forms 3 and 3". The lower ends of the piling, as before, will hangl down far enough to be embedded when the terminal forms 3" arev filled, These lowerendsgmay be free, or a second Wale I1' may be attached to the uprights It', below the level ofthe truss beams 1; and addittional hooks I8 employed to engage these lower wales and4 support'the piling I6. Each end form 3 also mounts an A-frame at each end above its inner side plate 4, and this frame supports a short wale length Il connected to the long Wale I'I-a. Each end form 3 with its A-frame and wales is lowered to the bottom or the excavation as a unit.

The concrete is deposited by means of pipes of relatively large diameter held with their ends relatively close to the bottom of the forms in the excavation, while through these pipes the concrete is poured till the forms 3 and spaces |14 are filled to their tops. One of these pipes is shown at 22 in Figure 2, but several will be simultaneously employed to fill each form at a number of points between the end plates 6; and one or more formsv may be lled together. First the tremie forms 3 and 3' are filled and then the intervening spaces I4. The center forms may be taken rst, and the pipes shifted towards the forms at the ends. Any suitable meansfor connecting, supporting, and moving the pou-ring pipes 22 may be employed. As the concrete rises in the forms or troughs 3 and 3', the vertical grooves in the corrugations of the metal plates 4 and' are occupied by it. The subsequent nlling of the spaces VI4 covers the trusses 5, and the concrete embeds all of the metal parts. The various blocks orv sections in the forms 3 and 3', and spaces I4, become rigidly connected to all the metal work, and immovably joined together. The nal result is a' continuous monolithic stratum of concrete as thick as necessary, fully reinforced crosswise, and well calculated to resist bending moments due to either pressure underneath, or theweight of a ship on top. Owing to the closeness of the joint between the concrete and the metal, because of the recessed surfaces afforded by vertical corrugations of the plates 4 and 6, a great reinforcing eiiect is assured. Hence, the plates and trusses can even -be comparatively light in size and weight. The trusses and plates are, therefore, easy to makey up, and move into position, and the tremie forms, each of which constitutes a separate reinforcing member, can be readily constructed and at relatively low cost. No large concrete bodies or units have to be first made and then sunk into position.

As the pouringv ofthe concrete into the forms is finished it engages the lower ends of the A- frames and piling I1 land secures them in place as it sets. v.

The vertical corrugations in the plates 4 and 6. greatly increase the surface of adhesion and produce a most efficient union between the concreteand the metal. Even if the concrete did not fully bond with the metal under water, the concrete after hardening assumes along the sides and ends of the forms, ridges and grooves and other recesses corresponding to the corrugations in the metal plates 4 and other recesses. When both the forms 3 and 3' and intervening spaces I4 are filled and the concrete sets, the plates 4 and 6 and the trusses 5 are tightly embedded in the bottom and the latterA receives `all the strength and ruggedness which could be desired.

A preferred kind of corrugations is illustrated in Figure 3. Here the side plates 4 are shown with large transverse ribs 23 alternating with grooves 24. In the tops of the ribsare small grooves 25 and at the bottoms of the grooves 24 are small transverse ribs 26. This design increases the surface of adhesion between the concrete and the metal, besides further stilfening and strengthening the latter.

When they pouring of the concrete is thus completed and hardened, earth or back fill is dumped against the sheet piling along the two sides and at the head end. It is heaped on the shoulders 2'I` of the bottom slab B, outside of the piling and assists in holding the bottom slab in place against upward pressure under it.

Figures 4 and 5 respectively show the bracing framework, the sheet piling andthe tremie forms for approximately half f the dock at the inshore end and the entrance end. The dock need not be square but its ends may be rounded or trapezoidal; that is, the sides near the ends may converge somewhat to make the dock narrower thereat than in the middle. In that event the tremie or moldforms near said ends will be .shortened and otherwise modified in shape, as

required.

When the bottom forms and A-frames have thus been put into place, the sheet piling added .and the bottom slab has been poured and set,

the head end wall and the side walls can be erected in the dry because the piling I6 makes a closed coferdam from which the water can be pumped out. The necessary forms are then built around the inside of the sheet piling and the walls poured in place on the floor of the slab B. Part of one side wall is indicated at 28 on Figure 5, in dot-and-dash lines, and the head end wall will be the same. The side walls at the entrance will have projections 29 with shoulders 30 and a similar sill on the bottom slab for the steel pontoon gate 3I.

When the dock is emptied of water, the weight and strength of the bottom slab, the weight and pressure of the earth on the shoulders 21 and against the piling I6 and the eifect of the piles I, are suiiicient to resist any upward pressure on the bottom of the dock. The bottom with its embedded reinforcements has sufficient beam strength to withstand the weight of a ship; and,

when not in use, to resist effectively any water pressure beneath and to offset this pressure by itsown weight and the weight of the walls at the sides and ends, when the walls are added.

The A-frames, having their lower ends em-V bedded in the` concrete ofthe bottom slab, serve as reinforcements for the side walls and inner end wall intoA which they are incorporated. After the side walls are completed at the entrance end, the piling I'along this end and its frames are removed.

The side walls contain the usual chambers, passages or conduits for water, pumps, electric wires, and other purposes. Two such spaces are indicated on Figure 2 at 32 and 33. Other types of construction for the side walls are described below. Thev finished dock, over the floor of the bottom and entire inner surface of the walls, may receive a cement lining.

This design is very satisfactory for docks of less than maximum size and depth; and favors expeditious building and nishing. The back lling can be undertaken at an early stage of the work, thus making it possible to complete .some of the crane tracks and other work strucslab in the forms 3, 3 and I4. This result can be gained by inclining th'e braces I 2 at a greater angle. They may even project somewhat from the inside faces of the concrete walls adjacent the floor of the dock. Such an arrangement increases the beam strength of these blocks after the Water is pumped out from with'in the area enclosed by the sheet piling, and while the side walls are in course of erection.

Sometimes, further, under some conditions, the bottom pressure against the dock, after the water hasbeen pumped out and before the side walls have been put up, may be counteracted in great part by gravel h'eaped on the floor of the dock in suiiicient quantity to act as ballast. As the side walls are built up and their weight becomes more and more effective, the gravel ballast can be removed for use as coarse aggregate in the wall concrete. However, docks may be built by the above method without such transverse bracing or gravel ballast.

To lay down the tremie forms with th'e A- frames at each end in the excavation for the dock, floating derricks may be employed and, in some places, shore-supported gantries have been useful.

For larger docks, to meet more unfavorable conditions at the bottom of the excavation, the walls can be built without removing th'e water on the top of the slab B. In such constructions colerdams may be built along the sides of the slab, one for each of the side and back walls. Such a method will render entirely unnecessary stone or gravel ballast and transverse bracing; for the greater portion of the water is retained in th'e dock and only the areas whereon -the side walls are built are pumped out. But it does require a great deal of sheet piling. A more advantageous method is to proceed to erect the side walls in sections with spaces in between. A coiferdam can then be put up for each section; and after the various sections are completed, th'e intervening spaces can easily be iilled. This method of procedure is'illustrated in Figures 7, 8 and 9.

These views show how, after the bottom is laid, as above described, the wall sections are reared on areas 34, separated by spaces 35, without unwatering the partly completed dock. For this purpose,

coff'erdams are put up around the periph'ery of each area 34. The spaces 35 are filled in later to make the walls continuous.

In this method, the places 34 for the wall sections and the spaces 35 are delineated by laying down channel beams 36 along the edges of the bottom B. They must be in contact with and set into the floor over their` entire lengths, tight at the joints, and become fixed as 4the concrete hardens. Wherever there are corners, angleshaped sections are used, and T-sections between the areas 34 and 35. The channel beams can be laid and finished by divers; or axed to the tremie bottom forms in position to match and assume their proper places in the floor of the slab. The channel beams may have feet or lugs 3l which project down into the concrete.

These beams receive the lower ends ofpile members joined along their vertical edges to make sheet piling I6', providing a cofferdam fora wall section as appears at the left in Figures "I and 8. Inside the coierdam is a bracing framework, comprising uprights' 3B at 'the ends, uprights 39 between them, longitudinal struts40 along the sides at top and bottom and in between; and cross struts 4| joining the struts 40. Diagonal struts 42 are put in the spaces enclosed by the struts 40 and the uprights 33 and 39 and similar struts 43 horizontally between the cross struts 4I. The construction of the framework may be of iron or other suitable material with the various parts detachably bolted or otherwise secured together. The framework may have any suitable design, the details of which need not be'enlarged upon here. When the framework has been put together it is lowered asa whole -into the water, and th'e lower ends o'f the corner uprights Vcome to rest at the cornersvof the area-35 over which a wall section is to be built. Then the piling is put into place. Suitable seats, such as lare illustrated and described below in connection with' Figures 14 and l5, may -be provided 4to engage the lower ends of the uprights when the framework is let down. The uprights '38 and 39 serve as guides for some of the pilemembers into the recesses of thechannel beams, which serve as seats for the lower ends; the remainder of the piling being easily managed. When the piling is complete it is held in line by horizontal wales 44 lon all foursides, at the top and several points inthe height thereof about onfa level with the lintermediate cross struts 4l. These wales may be separate beams of any chosen shape, held together at their ends, and some of them put into place under water and bolted to the piles or to one another. I-f desired, they may be frames lowereddown over th'e piling, and made in such a way that the ends of ythe beams can be adjusted to make them enclose the coferdam snugly. It is believed such frames need not be more `fully illustrated, as they can be of different types in practice. The 4cofferdams, comprising piling and wales, might also be completely nished in unitary form on land and loweredas-a unit over the frameworkafter the latter has been sunk. i

When the coiferdamsare in place they will appear as in Figures '7 and -8, the latter showing at the left a cross-section of the colerdam with .part of a wall in course of erection; and indicating in elevation a, cofferdam enclosing the 'finished wall section at Athe right. The cofferdam is first pumped out, The concrete forms, consisting'of steel sheets'or plates, are then set up on the slab B, at th'e bottom-of the coierdam. For this Apurpose, the struts "43 and --41 at the bottom, their piling and the wallapart. Finally, when the wall lowermost wales 44, .are removed. The concrete` is -then poured and lower part 2'9 of the wall section is thus built. Wh'en it has set, more struts are detached above it'and the forms put in for the next addition. Thus the wall section'rises, and .the framework except for the uprights is removed part by 'part Afrom the bottom up. Between th'einner face of the wall section and colerdam compensating blocks 45 are inserted, to keep the is nished the Aup'rights and Apiling are removed. The bottom slab is laid as before, except that the A-fframe at sides and ends are not used.

Whenevertwo adjacent wall sections are finished, 'the intervening places '35 are built upon. Framework maybe set up thereon and piling added Ato cover it alongfits inner and outer sides only; overlapping onthe adjacent ends of wall sections 34. The piling may be held at a slant along the inner iacesof the side walls as these are inclined. VThen the conc-rete forms can be putin, and the "space between these sections filled in stages from bottomt'o top, as already described. 4

'To ymake the `piling leakproof at the bottom, grout may/be'laid'through lpipes'. along the outside of the .piling at the bottom; thus covering also the channel seats v3B.

When 'the walls are nished at the sides and the head end, the piling is removed. Backfill can then be heaped around'the walls and down on the outside shoulders n2.1 of the bottom and the head ends of the side walls with their shoulders 30 as shown in Figure 5 are ready for the gate. The latter vis now floated into .place and'closed. All the water inside the dock can now beevacuated. A f

'It is oftenV advantageous to Verect the wallsas a unit from the bottm of the excavation to `the top of the dock; instead of lconstructing the walls on the top face of the bottom slab and thus obtaining a horizontal joint between the slab and the Walls. Such a joint or Yseam in a large, deep dock may allow leakage of water into the dock and require special measures to prevent this. A more eicient and durable union can be produced by connecting the opposite ends of the blocks in the `tremie bottom forms to the inner sides of the walls by starting the walls at the bottom of the excavation, as indicated on Figures V10 to 18 inclusive. .Both the bottom and the walls are then constructed under water.`

In these views, and particularly Figure 10, the bottom slab B is indicated as being of a width no greater than the distance between the vside walls valong theirinner faces, except as will later appear, along the entrance end. The transverse concrete sections or blocks b of the bottom slab terminate yat -cross plates v.45 having transversely extending inclined shoulders 4l..` The concreteat the ,two ends 0f thebottom slab sections or blocks and in the lower portions -of the side walls hardens against the .plates 46. Thus, in effect, a wedging or Yinclined `rabbetted ,.joint is made. Underground pressure exerted upward on the bottom slab will `now `hold the ends'of the blocks b more forcibly against these shoulders 41 and the seal there will be/ very tight. A similar result is obtained-at thehead endof the dock.

In following this-method, tremie bottom forms are constructed with lcorrugated side plates stiff-` ened by trusses 5, andend -plates `l5; projecting as 'before k(see Figurevl) the same distance beyond the sidefplate's. The plates 46 are affixed to'these bottom forms between the side plates, within the end plates 6. The plates 46 make transverse partitions in the forms; and the trusses extend beyond said plates. The partitions 46 are as long as the end plates 6 and project beyond the sides of the bottom forms as far as these plates 6 and battens I0. These partitions may be prepared in one piece or in parts, welded or otherwise secured to the inner and outer sides of the trusses and side plates to make in eiect a single plate of the same length as the end plates 6. The bottom tremie forms are shown mostly in outline on Figures 11, 12 and 13, but are constructed essentially the same as presented in Figures 1, 2, 4 and 5, with the partitions 46 added and the A-frames omitted. Some of them, further have no corrugated plating along part of one side between the partitions 46 and end plates 6.

For the method now being set forth, each bottom tremie form also has at horizontal plates or seats 48 on the top; for example, one at each corner and two adjacent the plate 46, to support upright beams or columns 491 which hold the tremie concrete mold formsr for the wall sections. These sections are put up by pouring concrete into the wall forms Without unwatering the excavation. Each wallsection along most of the length of the sides will be as long as the width of three bottom tremie forms. (See Figure 11.)

The wall forms for the side walls are indicated at 50, alternating with wall forms 5I. The former will'cover the ends of two bottom tremie forms and one space I4 between them. The others cover the ends of one bottom tremie form and part of the width of an intervening space at each side. The wall forms 56 will have four sides. The wall forms 5I each will have two sides only extending across the bottom of the forms. 'I'his arrangement is utilized along each side walll of the d ock from the head end to a point near the entrance.

With reference to Figurell, each wall form 5U may be considered as adapted to cooperate with two bottom tremie forms, marked 3a, and the space I4 between them. Each wall form 5I stands upon a similar form 3b, which has similar spaces I4 between it and the forms on both sides. Several wall forms 50 and 5I may be needed along each side of the dock. Each row of wall forms will start with a wall form similar to that marked 5| near the entrance end and terminate with a wall form 5I at the opposite end as shown in Figures 13 and 12 respectively. The ends of the bottom forms will be designed so as to cooperate with the wall forms fully Vwhen the `wall sections concrete is poured in.

In Figure 11, the two adjacent bottom forms 3a to be considered are shown at the left. Their end plates 6 are in alignment and so are their partitions 46. A wall form 56, ofv metal plating with vertical corrugations, assembled on land and made rigid with bracing, is lowered into place so that it will come to rest with the plating of one long side in the same vertical plane as the upper portions of the partitions 46, and the plating of its opposite long side in the plane of the end plates 6. of the two tremie bottom forms 3a. (See Figure 14.) Its plating at the ends will be in the planes of the corrugated side plates 4, of the bottom forms; but the plating of the long sides of the wall forms will project beyond the cross-plating at its ends to the same distance as the plates 6 and partitions 46 project from the sides of the two tremie forms 3a. The outside vertical beams 49 are adjacent the transverse end plating of each wallform 5 0, and horizontal wales 52 are welded to the columns 49 and to the outer faces of each wall form 50. The cofferdams thus can be easily hoisted and lowered. The internal bracing of each wall form, shown diagrammatically at 56a and 5019, can be of any design suiicient to serve my purpose; and need not here be set forth in detail.

The mold forms 3a have the corrugated plates 4 along their adjacent or opposed sides, which delineate the spaces I4, terminating at the partitions or plates 46. This construction is indicated in Figure 14, which is a view ofV the end of the form 3a at the extreme left of Figure 11, viewed from the left. The side plate 4 in line with the cross-plating at the adjacent end of the wall form 50 (the left end in Figure 11) is illustrated as extending past the partition or plate 46 to the end plate 6; but is broken away to show no side plating between said partition and end plate on the opposite side of this form 3a. On the remaining or far side of the other form 3a there is plating 4 between the plates 6 and 46. This design is clearly indicated at the right of Figure l1, which shows the sides of the two forms 3a in line with the cross-plating at the ends of the next wall form 50 in full lines to signify that the plating 4 continues to the plane of the outside face of said wall form 50; while the remaining or adjacent sides of these two forms appear in full lines only up to the inner side of the tremie wall form above the partitions 46; to show that the plating 4 on these two sides terminates at the plates 46. The dashed lines 5 signify that only the truss work of said two sides is continued out to the extreme ends of these forms. It is to be understood, of course, that the next wall form 50 at the right of Figure 11 is ofthe same construction as at the left. No side plating 4 is needed in the bottom forms 3a below the wall forms 56 at points between the ends of the latter. Therefore, when the concrete is poured in the forms 3a and forms provided by spaces I 4 between, it lls these forms from the shouldered plates 46 at one end to those at the other. When a wall form 56 is poured full of concrete, the latter lls the entire'space at the ends of the three forms 3a and I4, under the wall form 50, from the bottom of the excavation up to the top of the wall form. `'I'he plates 46 of the forms 3a extending laterally from each of said forms half way out to bridge the intervening space I4, like the end plates 6 of the two forms 3a, are thus entirely embedded.

The wall forms 5I are of a little different type; consisting of metal plating at the two long sides only. They also have outside columns 49'connected by wales 52 to which thecorrugated plating is afxed. There will be the necessary bracing between the corrugated plating along the opposite sides. The wall forms 5I, as stated above, cover the end of one bottom tremie form indicated at 3b on Figure 11, and project about half way across the adjacent spaces I4. The plating 4 along both sides of this form 3b runs only out to the shouldered plates 46; and the end plates 6 and shouldered plates 46 of this form project out into the two adjacent yspaces I4 to bridge half of these spaces; the end plates 6 and partition plates 46 of the adjacent `forms 3a under the wall forms 5U bridging the other half. Only the trusses 5 of the forms 3b run from the plates 46 therein outto the'extremities or end plates 6 of said form. The side plating of the two neighboring wall forms 50 extends out, beyond the 4cross-plating of their ends, about half way over the two spaces I4 at each side of the bottom form 3b. Thus, each of the wall forms l will also contain the forms or concrete for a wall section long enough to cover three blocks in thebottom. A

With this construction the bottom tremie forms can be lle'd with concrete poured through the pipes 22 (Figure 2) into them over their entire lengths between the partitions 4S. To build a wall vsection in the wall forms, concrete is poured into the wall forms until the wall rises from the bottom of the excavation to the top of the wall form. None of the water in the excavation is pumped out till later.

To `bridge the gaps between theplating on the long sides of the wall forms 50 and 5l, the side plating is provided on the vertical edges with closures 53, hinged on in any suitable manner. One or more springs 54 normally tends to pull these closures shut. The springs 53 may be long helical springs, aixed at their extremities to v the inner faces of the closures and the sides of the wall forms 5I. Cords 55, attached to the closures, pass through eyelets 5S on the wall forms to the top, and hold the closures in the positions shown in Figure 17 when the wall forms are sunk down into position. The cords are then cut or released and the springs 54 then pull all the closures 153 shut.

Each ltremie viorm 3a and 3b can be made up as a complete unit, as before, on the land; with all parts secured rigidly to the trusses the plates 4 extending along the inner sides of the trusses from one partition 46 to the other, in t e case of the forms 3b; and continued along one side only out to the end plates 6, in the case of the forms 3a. The partitions 46 are welded or otherwise fastened in place and so are the end plates 6, vas before; and additional corrugated plating 4, will be extended along and be afxed to the inner face of the trusses "between the end plates 5 and partitions 4B along the one proper side of each form 3a. When the wall :forms 50 and 5l are sunk into the 'water in the excavation, the vertical plating of their longer sides will be separated in practice by `gaps lof about six inches. These gaps are bridged by the closure panels 53 above described. The next wall form 50 is followed by another like the Wall form 5l set upon a form '3b. "Suitable bracing indicated at 51, is secured vbetween the projecting ends of the side plating of wall forms 50, and the ends of the plates 6 and 46 under them. Plates 46 are usually corrugated vertically from the yshoulders il down to their lower edges.

Panels like those shown at 53 may also be used with the bottom tremie forms to bridge the gaps between the plates 46, 'and between the end plates 6 in every dock containing any of these plates. rIA'he spaces between the bottoms of the wall forms and the mold forms of the bottom slab are small and need no closures.

Reference is now made to Figures 12, 15 and 16. Each of the side walls shown in Figure 11 terminates at the Vhead end of the dock in the section set up by means of a wall form 5l spanning a bottom form 3b, as above described. The tremie bottom form at the inner end of the dock beside this form 3b, is indicated on Figure 12 at 3'. This terminal form 9.' will have corrugated plating 4 along the full length of its outer side; but along the 'opposite side, adjacent the form 3b, this plating will be replaced by a shouldered plate 46a extending from the line of plates 46 in one -endof the other forms to the line of the same .-platesfin the opposite ends. At its extremities, the .plate or `partition 46a will be 'bent at an angle as shown in Figures 15 and 16. The rightangled ends of this plate 46a, will line up with the same plates -in the forms 3a and 3b. When the tremie wall forms are now reared over the terminal form "3 under water and concrete is poured into same, the head'en'd walll can be built up from the bottom of the excavation to the top of the 'wall 'forms and make the same kind of joint between'the end wall and the bottom of the dock as is shown Figure 10. 'The plate 46a will be :corrugated only below the shouldered portion 41.- The terminal form 3" `will comprise trusses 5 along its 'two sides, made up of beams 'l and such struts as may be necessary. Some similar to the wall forms 5|.

of these struts are indicated in horizontal position at 58 in Figure 15. The 'top of the plate 46a will of course be more distant from the corrugated side plate 4 in the -form 3' than the bottom portion of plate 46a, which bears the corrugations. Vertical struts or braces 59 rnay be extended from the top portion of the plate 45a downward and be made rigid with the trusses yFl and braces 58. All the mold forms in fact 'maybe braced across wherever necessary; y Flat plates lill on supports 48 will besecured in lplace above the four corners ofthe form v3' and at suitable points along the two sides of this form to support "the columns 49 of the wall for'rns. The form 3" may be braced inside in any manner required.

lThe wall forms 'for the corners shown at 6'0 will consist of 'plating forming two long sides, and cross-plating at the ends as indicated in Figure l2. The plating at one "end will be extended sideways as indicated at '62; above each en'd 'plate 'of the form v3', like plates 6 above described, vbut here projecting out to one side only towardsthe like end plate rof adjacent form 3b and similar plating 63 will project out at the same side; to line up with the side -plates'of the iadjacent wall forms '51 for the side walls of the dock. The plating at the opposite 'end 'of this wall form 60 away from the corner of the dock willllie in the same plane as transverse corrugated plating "6' put across the extreme end form 3 under all of the wall form ends. This plating "6 will 'project at one side of the form as 'far as the side 4of' the adjacent form 3b.

The wall forms 6l between the wall forms 60 need comprise only'two long sides of sheet plating y Closure members 53 may be included, though not shown in Figure l2. Each wall form 6| will likewise have columns 49 to support its sides and rest upon the plates or seats 443', as in Figure 15. This construction will be continued over to the opposite side wall of the dock where a wall form 60 will be used at the corner in conjunction with the side wall forms 5l thereat. The wall forms 60 and Bl, too, will be braced inside and concrete may be poured into them and the form 3 from the bottom of the excavation to thetop, without removing any water. Bracing or truss-work indicated at 64 and 65 is attached to the tremie form 3 in position to extend towards the yform 3b, being rigidly connected to the adjacent truss 5, plate 45a and the plating 6'. This bracingwill be embedded in the block which fills the intervening space' I4, thereby making the yinner end of the bottom slab more rigid and immovable, obviating'a tendency of the concrete to cause creeping of the form V3' away from said block when the end Wallis poured. As before, the bottom slab is laid by pouring concrete rst into the various forms 3a betweenfthe plates Vt6; and then into the spaces 14; andthen p the walls are made by lling the forms at the mold form marked 3b. Beyond this there will be 10 two bottom forms 3c and 3c' separated by a space I4. Sheet piling 66 will be driven into the bottom of the excavation along the side of the form 3c' at the left, across the whole width of the dock.

It will be continued across the ends of the two bottom forms 3c and 3c' as far as the rst side wall form 5Ia, and from this point it will be continued across the excavation again to the opposite side.

On the outside of said wall `form 51a, a rib 20 66a (Figure 18) will be welded to the plating and a similar rib 66h will be on the outer face of the end plate 6 on the end of the form 3b beneath. To these ribs the last memberof the sheet piling 66 can be jointed as' the pile members are forced 25 down into the subsoil of the excavation. This piling will enable corrugated plates 6 to be dispensed with across the ends of the two forms 3c and 3c'; these ends being open, with only crosstrusswork or bracing; and will also render unnecessary any side plating for the bottom form 3c along the entrance end of the floor of the dock. This form, therefore, will have along its outer side only the truss-work indicated by the` dashed line 5. Along its opposite side and the adjacent side of the other form 3c, plating 4 extends up only to the shouldered cross-plates 46, in the same position as the corresponding plates of other forms. These plates project as illustrated half way out from the opposing or adjacent sides of the two forms 3c and 3c into the intervening space I4; while at their other ends they terminate flush with the sides of the forms bearing them. The remaining side of the inner form 3c, has corrugated plating 4 along its full 45 length, past the plates 46, rout to its extreme ends. This plating 4 bridges the space between the plate 46 and end plate 6 of the adjacent form 3b, both of which are extended out across the full width of the intervening space I4.

Thus the bottom forms 3c and 3c can be filled under water bypouring concrete into them between and up to the partitions 46, and then lling the space I4 between. Then the ends of the forms 3c and 3c' and space I4 between them 55 are filled by pouring concrete between the plates 46 and piling 66. The adjacent formb and space I4 between it and the'form 3c are Vfilled likewise between and up to the cross-plates 46.

With all the bottom forms in place in the ex- 60 cavation, from 3c' to 3.', all the bottom forms and spaces I4 can be' poured at the same stage in the construction of the dock. Then the side walls and end walls are put up by pouring concrete in the wall forms' 50, 5I, 5Ia, 60 and 6I 65 as above described. Each wall form Sla. at the entrance end has its inner and outer side walls extended as far as the side of the form 3c, and there connected by end orcross-plating in the vertical plane of the platingA 4 of said 70 form 3c. These wall forms Sla are filled like the others by pouring them full from the bottom of the excavation to their tops.

A line of temporary sheet piling 61 is now erected across the full width of the dock and engagement with the floor.

side walls, and is connected to the piling 66 near the sides of the dock by two lines of temporary piling 68. Thus coierdams 69 are built at the entrance ends of the side Walls, and a large central enclosed space 1I). 'I'he cofferdams 69 are then pumped out, and the outshore ends of the side walls erected to their full height in the free space thus obtained. These ends will be formed with inside shoulders 1I for the pontoon gate. When they are finished, they receive a lining on their inner faces. The floor of the bottom between said ends receives a similar lining and the space 10 between the two lines of piling 68 can be pumped out for this purpose.

The tops of the walls are illustrated in Figure l0 at 12. T erect them, the head end Wall and side walls up to the piling 61 after the tremie wall forms are lled with the concrete, receive lines of sheet piling 13. These may be attached to the wall forms by bracing 14 and 15, and the lower ends of the pile members are embedded in the concrete. The bracing may be secured in any suitable manner. When the wall forms have been lled and the concrete has set, the dock may be pumped out to lower the water level down a little below the tops of these forms. All the work to make the tops 12 of the walls can then be done above water. Back fill is nally heaped into the sides of the excavation up to the level of the earth and the columns 49 and plating and piling on the outside faces of the walls completely interred. The nish lining 16 similarly embeds and covers the metal work on the inner faces.

The piling 66, 61 and 68 is as high as the finished walls. The piling 61 extends across the tops of the wall forms 51a, consisting of shorter members there and embedded in the concrete; and it can be jointed to the sides of the piling i3 and to the inner side of the wall form 5|a by means such as shown in Figure 18. Between the side walls the temporary piling 61 and 68 is sealed on the floor of the dock by means of troughs put down under the water and in water-tight The lower ends of the 4piling are sealed in said troughs. To set the piles 61 and 68 into place, wooden frames are built and sunk down into the water to brace the piling and facilitate its erection. After the completion of the dock the piling 61 and 68,' with framing and other appurtenances are removed, and so is the piling 66 across the entrance end, the remaining piling 66 being covered with earth. The piling 66 and 68 can be taken away first to enable the pontoon gate to be oated into position, the dismantling of the piling 61 then following as the final step.

This dock too, can be made narrower at its ends by building the walls so that they converge somewhat, and making the bottom forms of less length away from the middle of the dock.

By lining with plywood the inside of any of the mold forms for the walls of the dock, a surface can be obtained smooth and iinished to such an extent as to make a lining unnecessary.

The tops of the walls 12 have chambers indicated at 11 therein, a roadbed 18 on top for crane tracks, and agallery or walk 19 for workmen.

The corrugated plates attached to the framework for the sidewall forms and bottom molds must of course hold and confine the concrete and prevent escape. Even if the plates were made with openings or slits instead of corrugations for bonding of the concrete to the metal, such open- Vings would have to be small or restricted enough to prevent the passage or leakage of the concrete through them, leaving the plates substantially imperforate in use and effect.

Having described my invention, what I believe to .be new and desire to secure and protect by Letters Patent of the United States is:

1. The method of constructing a basin dry dock in a Water-bearing soil which consists in excavating a site, spanning the bottom thereof with transverse, metal reinforcing members having substantially imperforate recessed surfaces, pouring tremie concrete under water over said members to embed said members under Water, thereby forming a continuous bottom slab consisting substantially Wholly of concrete hardened under water and forming transverse blocks united to said members and to one another when the concrete sets, and rearing the Walls for the dock along the sides of said site.

2. The method of constructing a basin dry dock in a Water-bearing soil which consists in excavating a site, spanning the bottom thereof with transverse, metal reinforcing members having substantially imperforate recessed surfaces, pouring tremie concrete under Water over said members to embed said members under water, thereby forming a continuous bottom slab consisting substantially wholly of concrete hardened under water and forming transverse blocks united. to said members and to one another when the concrete sets, unwatering at least a portion of said site by means of sheet piling in coiferdam arrangement, and rearing Wall construction for the dock upon said blocks.

in a water-bearing soil which consists in excavating a site, spanning the bottom thereof with transverse, substantially imperforate metal reinforcing members, placing sheet piling around the excavation with the lower ends of the piling in the space between said members, pouring tremie concrete under water over said members to embed said members under water and anchor said piling thereto, thereby forming a continuous bottom slab consisting of transverse blocks'united to said members and to one another and to the piling walls when the concrete sets, unwatering the space enclosed by the piling, and rearing the walls of the dock along the sides of said bottom slab.

4. The method of constructing a basin dry dock' in water-bearing soil which consists in excavating a site, spanning the bottom thereof with metal reinforcing members having substantially imperforate recessed surfaces, pouring tremie concrete under water over said members to embed said members under water, thereby forming a continuous bottom slab consisting of blocks united to said members and to one another when the concrete sets, rearing cofferdams enclosing portions at the sides of the slab, unwatering said portions and rearing Wall construction within said cofferdams.

5. The method of constructing a basin dry dock in a Water-bearing soil which consists in excavating a site, spanning the bottom thereof with transverse, metal reinforcing members having substantially imperforate recessed surfaces, pouring tremie concrete under water over said members to embed said members under water, thereby forming a continuous bottom slab consisting substantially wholly of concrete hardened under water and forming transverse blocks united to g 3. The method of constructing a basin dry dock Y '7. The method `of' said members and to one another when the concrete sets, and rearing walls for Y'the dock on the bottom ofesaid site atthe ends of said blocks.

6. The method of constructing a basin dry dock in a water-bearingV soilwhich consists in excavating a site, spanningl the bottom tnereorwith transverse, metal reinforcing members having substantially imperforate recessed surfaces, pouring tremie concrete under water over saidmembers to embed said members under water, thereby forming a continuous bottom slab consisting` substantially wholly .of` concrete hardened `under `waterand forming transverse blocks united to said members and to one another whentheconcrete sets, fitting sheet piling in place allaround the sides of the slab to enclose the water thereon, and removing vthe water within the area enclosed by the piling, ,Y

constructing a basin dry dock in a water-bearing soil which consists,` in excavating a..site,.spanning the bottom thereof With i metal reinforcing members having substantially imperforate recessed surfaces, pouring tremie 'water over said members to embed said members in the concrete under water.' -therebyf forming a continuous bottom slab consisting substantially -wholly of concrete hardened under water and forming transverse blocks united to said members and to one another when the concrete sets, and rearing the Walls for the dock upon said bottom slab.

9. The method of constructing a basin dry dock in a Water-bearing soil which consists in excavating a site, spanning the bottom thereof with transverse, metal reinforcing members having substantially imperforate recessed surfaces, pouring tremie concrete under water over said members to embed said members under water, thereby forming a continuous bottom slab consisting of transverse blocks united to said members and to one another when the concrete sets, erecting separate cofferdams adjacent the sides of the slab, unwatering said cofferdams, rearing sections of wall therein, and filling the gaps between said sections.

10. The method of constructing a basin dry dock in a Water-bearing soil which consists in excavating a site, spanning the bottom thereof with transverse, metal reinforcing members having substantially imperforate recessed surfaces, pouring tremie concrete under water over said members except at their ends to embed said members in the concrete under Water, thereby forming a continuous bottom slab consisting of transverse blocks united to said members when the concrete sets, rearing cofferdams over the ends of said reinforcements adjacent the sides of the slab, and rearing side wall construction within said cofferdams.

11. A basin dry dock in a Water-.bearing soil comprising side walls and a bottom, the latter having reinforcing plates therein,` said jplates having sloping shoulders to forma rWedger joint with the lower parts ofthe walls which is made tighter by upward pressure'onthe bottom. y

12. A basin dry dock in a water-bearing soil having a wall and a bottom containinga concrete fblock abutting the Ylower part of the Wall, said block having a reinforcing plate therein with a. shoulder sloping outward anddownward for wedging engagement, with said wall. 0

13. In a. basin-dry dock a pluralityvof bottom forms having sides including reinforcing members, elevated seats at lthe tops of some of said forms, and wall forms having supportingrcolumns resting upon said seats. .Y

14. The method of-building a dock which consists in digging an excavation, laying reinforcements comprising plates having sloping shoulders adjacent the sides of the bottomf of the excavation and constructing a bottomLslab therein with' wedge-shaped sides formed bysaid. plates, rearing walls on the Vbottom ofthe 'excavation around the edges of the slab invwedging engagement with the sides of 'said slab. 1 z

15. The method of constructing a basin dryi dock in water-bearing soil, .which consists in excavating a site, spanning the bottom thereof with transverse metal reinforcing members which divide said bottom into a r'plurality 'of transverse sections, pouring vtremie concrete under waterfo over and between all saidmerrnbers to embed same in concrete hardened underwater, thereby forming a continuous reinforcedV bottom slab with said members fast therein, and rearing walls along the sidesof said slab.v Y l J g "-535 16. The method of constructing a basin dry dock in water-bearing soil, whicnconsists in excavating a. site, spanning the bottom thereof with sides of said slab.

- transversemetall reinforcing# members,A securing substantially*v upright plates between-l said 'members at-a distance from the'endsthereofypouring rearing concrete Walls on thebottom ofthe excavation at the sides ofthe bottomY slab land si- 1 -lmulta'neouslyembedding the ends of said l'reinforcements beyondsaid plates Yin the lower fparts ofsaid-walls. vi@ '.n

`17. A dry dock in a Water-bearing soil, comprising a concrete bottomslab yand side walls,.said bottom' `having transverse reinforcing members therein, and vertical plates having shoulders-adjacent the ends of said members, 4the side walls Yextending-along said plates and resting upon said Y shoulders; so that pressure acting upward on said bottom is resisted bysaid-walls. V'18. The method of constructin'ga basin `dock f in waterbearingsoil, which consists in excavating a site, spanning the bottom` thereof with: transverse `metal reinforcing `members including verticalplates delineating sections in said bottom, pouring' tremie concrete under water over and between said members to embed same inconcrete f hardened under water, thereby yforming, a `conltinuous reinforced bottom slab with said members fast therein, and rearing walls along the I19. The method of building a dock whichfcon-` sists in constructing a bottom slab with reinforcements therein, and bevelling the upper corner of the slab at the side edge thereof, and rearinga 'side wallon theslab overhanging said bevelled side edge. f

FREDERIC. n. HARRIS.

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