US2179429A - Cofferdam construction - Google Patents

Description

Nom 7, 1939. vl scH|Av| 2,179,429

COFFERDAM CONSTRUCTION Filed Feb. 4, 1959 2 Sheets-Sheet 1 l juan-Hor, x A .uf Tf je hz D J6 h# @Zaai/fge 51) )7Z /g ,l

Nov. 7, 1939. v scHlAvl 2,179,429

COFFERDAM CONSTRUCTION Filed Feb. 4, 1939 2 Sheets-Sheet 2 mmm Patented Nov. 7, 1939 UNITED STATES PATENT @ENCE 4 Claims.

rlhis invention relates to an improved cofferdam and method oi constructing same.

Drainage structures, tunnels, aqueducts, foundations, and the like, require a relatively deep trench in their construction. While trenches for the placement of aqueducts, foundations, and the like may readily be constructed in dry hard soils, and the construction work carried out therein without any attendant danger of the trench walls falling in or the construction work being shifted from its intended position, nevertheless, many soils are soft, damp, and mobile and accordingly they present many handicaps in the formation of trenches for the accurate laying of construction work and for the safety to workmen engaged therein. Heretofore, in the construction of aqueducts, foundations, and the like in soft, wet and mobile soils it has been the practice to provide submerged housings generally known as coerdams .for preventing caving in of the sides of the trenches during construction as well as for assuring working room and safety to workmen engaged in the work.

Cofferdams as heretofore constructed or proposed, however, were not' dependable in the building of trenches in soils, particularly when in a semi-fluid condition and possessing a heavy sub-surface pressure such as is found in bogs and mud areas for the reason that they were not capable oi withstanding such sub-surface pressure. This not only resulted in bending, twisting or crushing the structures of the cofferdams but also endangered the accurate and intended position of the construction work in the trenches. Furthermore, coierdams as heretofore used or proposed were not of a character adapting them for expeditious placement, nor did such coerdams offer maximum working space without materially weakening their pressure resisting proporties.

It is accordingly a primary object of this invention to provide a method of expeditiously constructing cofferdams whereby aqueducts, foundations, and the like, may be accurately built without any attendant danger of displacement thereof and with assured safety to, and unobstructed working space for workmen engaged therein.

A further object of the invention is `the provision or a cofferdam comprising relatively few strong and durable cooperating parts and which eiiectively resists sub-surface pressures and provides maximum working space therein.

A still further aim is the provision oi a coerdam comprising bracing elements, trench side wall retaining panels held by the bracing ele- (Cl. (i1-34) ments, and a base seal for preciuding the entrance of soil before, during or after removal of the soil conned by the panels.

Yet another purpose of the invention resides in a method of constructing a cofferdam whereby soil is positively sealed against admission to a trench during or after construction thereof by removal of the soil within the cciierdam.

Further objects and advantages will appear upon consideration of the following detailed description taken in connection with the accompanying drawings, wherein:

Fig. l is an end elevational View or" a coiierdam construction in accordance with one of the embodiments of the invention, the View being taken in a direction as indicated by the line i in Fig. 2 and the concrete seal and sub-floor being in transverse section.

Fig. 2 is a top plan view of the structure illustrated in Fig. 1 with. the top transverse bracing bars omitted for the sake of clarity.

Figs. 3 and 4 are views similar to Fig. l on a smaller scale and respectively disclosing modiiied forms of construction.

Fig. 5 is a transverse section of a portion of the construction in a plane represented by the line 5 5 in Fig. 3.

Fig. 6 is asimilar transverse section in plane as represented by the line in Fig. 3.

Referring now in detail to the drawings by reference characters, and 'wherein like characters designate like parts, and referring iirst to Figs. l and 2, B designates bracing devices, P designates panels, S designates a concrete seal, F designates a concrete sub-floor, p designates piles and G and G', respectiveiy, designate the ground surface prior to and in preparation ior construction of the coierdam.

The bracing devices B each comprise a pair of laterally spaced vertical members il), a top driving transverse brace bar i I, a transverse brace bar l2 adjacent the bar il and similar bars i3 and lil adjacent the lower ends of members it. A steel rod i5 preferably extends through. the members l@ adjacent each of the transverse brace bars I2, I3 and ld for reinforcing the brace device B an r: lr maintaining the bars l2, i3 and lli in rigid Contact with members lil, the brace bars being otherwise secured to members iii as by nailing, boiting or welding.

As indicated in Fig. 1, the coiferdam is constructed prior to the removal of all the soil in providing the trench and accordingiy the bracing devices B are driven into the soil by any suitable power means and as the coierdam is intended for loose mobile soils substantially little resistance will be oiered in driving these devices into place.

The position of the required trench is first determined by excavating the soil from the original level G to the level G after which the bracing devices B are driven into position in accurate alignment and in uniformly spaced position as determined by the panel sections later ref-erred to and which may be driven subsequently to or With the device B.

The panels P comprise a plurality of inner sections i6 and a plurality of outer sections I1 in overlapping relation to the inner sections I6. Each of the sections le, l'l is formed in any suitable manner but as shown each comprises a plurality of horizontal sheets i 8 and a plurality of superposed vertical sheets i9 which are secured together in any suitable and desired manner. The inner sections I6 are provided with vertical guide strips 20 for engagement with opposite sides of member lll for properly positioning the panels relative thereto. Panels P may be constructed from any desired material and may be of any size or shape for best accomplishing the desired results.

When the bracing devices B have been driven into place andthe panel sections i6 and Il positioned as indicated particularly in Fig. 2, the sid-e Walls of the required trench will be effectively spaced irrespective of the sub-surface pressure, which is great in loose mobile soils, and the overlapping panels l6 and I1 will prevent loose mobile soils from seeping in from said side walls.

In the constructions requiring thempiles p are driven after the placement of the bracing devices and the panels. The piles are driven in downwardly diverging relation as indicated for maximum bracing effect.

After the driving of the piles the concrete base seal S is positioned as by means of a tremie fuse or by chuting or dumping. This concrete will harden after being introduced and will form a bottom sea-l thereby preventing mud, ooze, r other uid or liquid material working upward before, during, or after excavation. It will now be seen that the panels P and bottom seal S will effectively enclose the soil within the panels against ingress of other soil or liquid whereby after excavation the resulting trench will be dry and its walls eiectively braced in xed and immovable position. The concrete seal will also aid in materially bracing the devices B and panels P and will also lock the piles p permanently together. I-Iaving placed the seal S the soil is excavated from between the panels P to the seal S. The piles p are thereafter cut oil? at positions substantially as represented by the dotted lines l after which' the concrete sub-oor F is laid in readiness for the particular construction work within the trench.

Thus it will be seen that a cofferdam is provided by a relatively simple method and its formation is such as to effectively brace the walls of the trench and positively preclude the ingress of soil or moisture and by cutting the piles off at the lines l unobstructed working space is available. The assembly shown in Figs. 1 and 2 is preferably left in place.

As the construction of the cofferdam may be materially reduced in expense upon removal of the assemblies for use in subsequent coierdam constructions, the invention includes a form of construction as illustrated in Fig. 3 wherein provision is made for ready removal of the assemblies.

As indicated in this gure the transverse brace bars l2', I3 and I4 are all positioned above the concrete seal S as well as the sub-door F and an additional transverse brace bar 22 is disposed adjacent the lower ends of the members I0. Also added intersecting braces 23 are provided and reinforcing brace members 24 are secured to members l0 and the top transverse brace bar Il.

Due to the position of brace bars I2', I3 and lf3 and in view of the fact that the two latter preclude available working space in the trench, such bars are removable and for this purpose are constructed and assembled with the members I0 as indicated in Fig. 5. A strip 25 extends vertically along the inner wall of each of the members l and is interrupted at each of the cross bars I2', i3 and I Il and each cross bar is laterally positioned Within the resulting channels provided by such interruptions and each bar has an extension 26 seated in a depression in member lil and removably secured to the member as by a bolt 2l'. Thus when the assembly is in position and the excavating completed the bolts 21 may be withdrawn and the brace bars laterally removed to provide for maximum working room in the resulting trench. The braces 23 are also preferably removably secured in position as by bolts 28 whereby they may also be withdrawn. The lower brace bar 22 being below the seal S would preclude removal of the braces B if said bar 22 is permanently secured to members I0.

As indicated, the brace bar 22 is positioned for positive assembly and bracing action during driving of the bracing devices and while such devices remain in position, but will readily admit of removal of the devices B minus only the brace bar 22. To accomplish this, (see Fig. 6), the strips 25 are reduced at their lower ends for a length substantially equal to the thickness of bar 22 as indicated at 29. The bar 22 is provided with vertical end channels 30 to removably receive these reduced portions whereby the members l0 may be elevated and leave the bar 22 in position and while driving the shoulders on strips 25, dened by the reduced portions 29, woill urge the bar downwardly with the members In the form according to Fig. 4 no concrete seal is required as same is replaced by a wood floor 3l resting upon and secured to stringers 32 extending longitudinally between the piles p.

It will be obvious that various modifications and changes may be made in the invention as disclosed as will be apparent to those skilled in the art. It is contemplated to cover all such and to be limited in this respect only as may be necessary the scope of the claims hereto appended.

What I claim and desire to secure by Letters Patent is:

1. A method in sub-surface construction comprising the following steps: driving vertically disposed brace members into the ground in longitudinally spaced relation, inserting continuous linings at each side of the brace members, driving piles into the ground within the connes of the brace members, and providing a bottom seal adjacent the lower ends of the piles.

2. The method according to claim l, comprising the additional steps of cutting 01T the piles adjacent the bottom seal and providing a subfloor on top of the bottom seal.

3. A coferdam construction comprising vertically disposed and longitudinally spaced brace members driven into the ground, lining panels positioned on opposite sides of the brace members, a bottom seal adjacent the lower edges of the lining panels, a sub-floor disposed upon the bottom seal, and piles positioned within the connes of the panels intermediate the brace members and extending downwardly through the suboor and seal.

4. The structure of claim 3, in which the top of the piles are substantially ush with said sub-Hoor.

VINCENT SCHIAVI.

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