Drainage Wall System And Method Of Erecting Same

Abstract

A drainage wall system and method of erecting same which may be constructed substantially along property lines without encroachment exteriorly of the property lines and without requiring thick beams of struts within the property lines as are requisite with steel sheet piling or other impermeable cofferdams. A permeable cofferdam is associated with a series of vertical column members and is provided with means for guiding water which seeps therethrough to a drainage system which removes the water and thereby the water pressure from the cofferdam. A reinforced concrete wall is alter added without impairing the effectiveness of the drainage system.

Description

This invention relates to a drainage wall system and method and more particularly to such a drainage wall system which may be constructed substantially along property lines without encroachment exteriorly thereof.

In the construction of buildings such as multi-story buildings where open excavations are required, it is frequently required that vertical cuts in the ground be made and a provisional or permanent cofferdam be erected around the substructure to be constructed, thereby maximizing use of the available property area. Such cofferdams must be able to resist lateral soil pressure as well as water pressure. Because of this it has been customary to use a cofferdam of steel sheet piling along with massive strut and beam supports when the excavation is originally made in order to support the earth and water or hydrostatic pressures until a permanent substructure is erected.

In instances where the water infiltration or seepage is not a serious factor, it is customary to permit the water to seep into the excavation and then be pumped out. This procedure is applicable even when operating below the water table provided that the soil has a sufficiently low permeability. In this case the cofferdam is required only to resist earth pressure, as water pressure does not build excessively. A cofferdam of less demanding strength is used which permits water infiltration, and consists of horizontal timbers laterally bridging vertical supported columns known as soldier beams. In both the sheet steel and the timber cofferdam structures, however, it is customary to cast the permanent walls of the building substructure against the cofferdams.

The need for the drainage wall system of the present invention exists when it is necessary or desirable to continue and maintain dimunition of water pressure on walls of the permanent sub-structure, or to provide a clean and dry surface for casting the permanent walls, or to provide an efficient water barrier to the building basement.

Additionally, the need for the drainage system of the present invention is especially evident when space requirements on the sub-structure call for relatively slender walls against water-bearing strata.

Further, the need for the drainage wall system of the present invention exists even where the land is relatively dry and where the excavation is made above the water table. The reason for this is that rainfall which occurs while the excavation is being undertaken finds its way to such man-made depressions creating a water-handling problem at the excavation site. Furthermore, the problem may become acute after a permanent concrete sub-structure is erected at the excavation site. Thus many basements have been constructed on so-called dry sub-soil only to find that rains cause a saturation of the upper soil profile walls which absorb moisture, begin to drip, and develop objectionable water infiltration. Many such walls or floor slabs which have not been designed to resist such added water pressure caused by this accumulated water result in structural failure.

In accordance with the present invention, the foregoing problems and failures of the prior art structures are effectively overcome by providing a system which will drain water from the walls and thereby reduce the hydrostatic pressure. The foregoing is accomplished in a drainage wall system which not only permits full utilization of the available property by building right up to the property line but also avoids the requirement for heavy, and therefore, thick supporting beams or struts which would, for example, restrict the available area of parking within the property lines and within the below-grade structure.

The inherent advantages and improvements of the present invention will become more readily apparent upon considering the following detailed description of the invention and by reference to the drawings in which:

FIG. 1 is a fragmentary perspective view illustrating the salient features of the drainage wall system of the present invention; and,

FIG. 2 is a typical plan view of an excavation site, drawn to a reduced scale, and illustrating various stages of the erection of the drainage wall system. For clarity purposes, no indication of provisional beams and struts to support the walls is shown.

Referring now to FIG. 1 of the drawings, there is illustrated a cofferdam, indicated generally at 10. Cofferdam 10 is shown to comprise a series of horizontally disposed timber members 12 stacked one above the other with a small separation in between. Members 12 are suitably attached to one of a series of vertical column members indicated generally at 14. These vertical column members are also known in the trade as soldier beams. Each vertical column 14 is shown to comprise an I-beam construction having a central web 16 and flanges 18 with the latter being substantially parallel to the cofferdam 10.

One of a series of vertically extending conduit members 20 is attached to the timber members 12 of cofferdam 10 by any suitable means at 22. Each vertically extending conduit member 20 is preferably channel-shaped in accordance with the present invention, the opening of which faces the cofferdam 10. Means 24 is provided with guiding seepage water laterally toward conduit members 20. Means 24 preferably comprises a flexible water impermeable membrane, one end of which is attached as required to the vertically extending conduit members 20 at 26 and the other end of which may be attached to a next adjacent vertical column member 14, not shown, or to the next adjacent conduit 20, as necessary. The means 24 may be continuous and extend over one or more conduits 20 without being attached to each conduit at 26.

A horizontally extending conduit is shown at 28 in FIG. 1. The horizontally extending conduit is also preferably channel-shaped the opening of which faces the cofferdam wall 10. Conduit 28 is provided with a cut or burned-out and welded section 30 at which point communication is made between conduit 28 and the vertically extending conduit member 20. The horizontally extending conduit 28 is attached to one of the timber members 12 as at 32. In order to connect the drainage system longitudinally through soldier beams 14, a horizontally extending splice member 34 is provided. A portion of the beam central web 16 is burned clean at 36 in order to provide an aperture for the splice member 34. The latter is also provided with an end cap at 38. In order to afford communication between conduit 28 and splice member 34, the web of conduit 28 is burned through at 40. Preferably, the membrane 24 extends over conduit 28 as well as along the outer face of wall 44 between members 14.

A collector pipe 42 is welded to the horizontally extending conduit 28 in order to direct the water which accumulates in conduit 28 to be piped through a concrete wall indicated in phantom at 44 in FIG. 1 and shown in position in portions of FIG. 2. This drainage water passes to a central sump pit and a suitable sump pump. The wall 44 may be erected on a sub-basement slab indicated in phantom at 46 in FIG. 1.

Referring now specifically to FIG. 2, the drainage wall system of the present invention is indicated to be positioned substantially in line with the property lines, as is designated at 48 and 50, for example. As is also illustrated in FIG. 2, the flanges of the vertical columns 14 may effectively provide vertical edge molds for portions of the basement wall 44 which is poured after the cofferdam structure is associated with the vertical columns 14.

In order to prevent later clogging of the drainage wall system, foraminous cover members, such as screens, are added at 52 and 54 between cofferdam 10 and each of the vertically extending conduit members 20 and horizontally extending conduit member 28. In addition, a plate cover 56 is placed atop each of the vertically extending conduit members 20.

While it is believed that the function and purpose of the drainage wall system will be apparent from the foregoing description, the method of erecting the drainage wall system will not be described. With the vertical column members 14 in place, the cofferdam 10 is attached exteriorly of the vertical column members 14 which are spaced any suitable distance, such as 7 feet. The vertically extending conduit members 20 with screens 52 covering the openings thereof are then fastened to the inside of the cofferdam wall. Then the means 24 for guiding water which may seep through the cofferdam wall is attached to the vertically extending conduit members 20 and to the vertical columns 14. The means 24 comprises a flexible, water-impermeable membrane which covers the entire inside wall of cofferdam 10 and also prevents clogging of the spaces between the members 12 of the cofferdam 10 by the concrete wall 44. Thereafter, the bottoms of the vertically extending conduit members 20 are attached to a collector means for receiving water from the vertically extending conduit members 20 and removing it from the cofferdam. This collector system comprises the horizontally extending conduit member 28 with screen 54 covering its opening and the collector pipe 42 which leads to a central sump pit and sump pump.

After the foregoing is completed, it is possible to pour a concrete basement wall 44 which preferably is a reinforced concrete wall. It is convenient in so doing to utilize the flanges 18 of vertical columns or I-beams 14 as vertical edge molds for the basement wall 44, although thicker walls completely enclosing the flanges may be cast, if desired.

If desired, the collector pipe 42 may be placed through the sub-basement floor slab 46 after it leads from the horizontally extending conduit 28.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention, the form hereinbefore described being merely a preferred embodiment thereof.

Claims

What is claimed is:

1. In a drainage wall system, the combination which comprises:

a. a cofferdam wall construction provided by a plurality of horizontally disposed members stacked one above the other,

b. a plurality of vertically extending conduit members placed on one side of said cofferdam wall construction,

c. means for guiding water which may seep through said horizontally disposed members of said cofferdam to said conduit members,

d. and collector means for receiving water from said plurality of vertically extending conduit members and for removing said water from said cofferdam.

2. A drainage wall system as defined in claim 1 wherein said means for guiding water which may seep through said horizontally disposed members of said cofferdam to said plurality of vertically extending conduit members is a flexible water impermeable membrane.

3. A drainage wall system as defined in claim 1 wherein said plurality of vertically extending conduit members are substantially U-shaped channel members the opening of which faces said cofferdam wall construction.

4. A drainage wall system as defined in claim 1 wherein said plurality of vertically extending conduit members are positioned on the inside of said cofferdam wall construction whereby the outside wall surface of cofferdam wall construction may be positioned substantially coincident with a given property line without encroachment on property exterior to said property line in the erection of said cofferdam wall construction.

5. A drainage wall system as defined in claim 1 wherein said collector means includes a horizontally disposed substantially U-shaped channel member the opening of which faces said cofferdam wall construction.

6. A drainage wall system as defined in claim 3 including screen means to prevent clogging of said U-shaped channel members.

7. A drainage wall system as defined in claim 5 including screen means to prevent clogging of said U-shaped channel member.

8. In a drainage wall system, the combination which comprises:

a. a plurality of vertically extending column members,

b. a concrete wall supported by said plurality of column members,

c. a cofferdam wall construction provided by a plurality of horizontally disposed members stacked one above the other,

1. said cofferdam wall being secured to said vertically extending column members exteriorly of said concrete wall,

d. a plurality of vertically extending conduit members positioned between said cofferdam wall and said concrete wall,

e. means for guiding water which may seep through said horizontally disposed members of said cofferdam to said plurality of vertically extending conduit members,

f. and collector means for receiving water from said plurality of vertically extending conduit members and for removing said water from said cofferdam.

9. A drainage wall system as defined in claim 8 wherein said column members are substantially I-shaped in cross section whereby said column members have flanges which serve as vertical edge molds during the pouring of said concrete wall.

10. A drainage wall system as defined in claim 8 wherein said means for guiding water which may seep through said horizontally disposed members of said cofferdam to said plurality of vertically extending conduit members is a flexible water-impermeable membrane.

11. A drainage wall system as defined in claim 8 wherein said plurality of vertically extending conduit members are substantially U-shaped channel members the opening of which faces said cofferdam wall construction.

12. A drainage wall system as defined in claim 8 wherein said collector means includes a horizontally disposed U-shaped channel member the opening of which faces said cofferdam wall construction.

13. A drainage wall system as defined in claim 12 including screen means to prevent clogging of said U-shaped channel members.

14. A method of erecting a drainage wall system comprising the steps of:

a. erecting a series of vertical column members,

b. attaching a cofferdam wall exterior of said vertical column members,

c. fastening a plurality of vertically extending conduit members to the inside of said cofferdam wall,

d. attaching to said vertically extending conduit members means for guiding water which may seep through said cofferdam wall to said vertically extending conduit members,

e. and interconnecting the bottoms of said vertically extending conduit means with said collector means for receiving water from said vertically extending conduit members and removing said water from said cofferdam.

15. A method of erecting a drainage wall system as defined in claim 14 wherein said vertical column members are substantially I-shaped in cross section with the flanges thereof extending generally parallel to said cofferdam wall and said method further comprises the step of pouring a concrete wall interiorly of said cofferdam wall using the flanges of said column members as vertical edge guides for portions of said concrete wall.

16. A method of erecting a drainage wall system as defined in claim 14 wherein said plurality of vertically extending conduit members are substantially U-shaped in cross section with the longitudinal openings thereof facing said cofferdam wall and said method further comprises the step of covering the longitudinal openings of said U-shaped conduit members with a foraminous member to prevent said U-shaped conduit members from becoming clogged.

17. A method of erecting a drainage wall system as defined in claim 15 wherein said collector means includes a horizontally disposed member having a substantially U-shaped cross section with the longitudinal opening thereof facing said cofferdam wall and said method further comprising the step of covering the longitudinal opening of said U-shaped conduit member with a foraminous member to prevent said U-shaped conduit member from becoming clogged.

18. A method of erecting a drainage wall system as defined in claim 15 wherein said method further comprises erecting a series of vertical column members closely adjacent a property line whereby said cofferdam wall attached to said vertical column members is positioned substantially coincident with said property line without encroachment on property exterior to said property line during the erection of said cofferdam wall.

19. A drainage wall system for an excavation comprising in combination,

a water-infiltratable vertical wall constituting a cofferdam along a peripheral area of the excavation, and,

drainage conduit means affixed to said cofferdam for receiving and leading away infiltrate water,

thereby to provide a clean and dry form for subsequent construction of basement walls thereat while avoiding use of massive space-occupying supporting structures requisite for substantially impermeable cofferdams.

20. An infiltratable excavation cofferdam having permanent drainage means associated therewith comprising,

a plurality of spaced ground-embedded beams along a peripheral area of said excavation,

a plurality of timber-like means stacked one upon another to comprise a vertical wall and spanning said beams outwardly thereof with respect to the excavation,

said timber-like means permitting liquid infiltration therebetween toward said excavation,

and drainage means disposed upon and inwardly of said timber-like means for guiding and collecting seepage liquid passing therebetween,

thereby providing a dry form inwardly of said cofferdam for construction of permanent walls thereat and wherein said drainage means also prevents buildup of water pressure against said permanent walls.