CA2673876A1 - Shoring free excavation and basement construction apparatus and method - Google Patents

Abstract

Posts are made by drilling holes around a perimeter, the exact placement of forms and reinforcement steel within those holes, as well as similarly drilled and formed interior bearing posts, each formed with adequate footings and reinforcement prior to mass excavation, when pre-formed reinforced concrete parabolic wall panels with optional waterproofing and insulation are placed and fixed between the perimeter posts as the posts uncovered by mass excavation. When excavation reaches a pre-determined depth, beams may be laid between facing perimeter walls post-to-post across the excavated hole to brace the walls against pressures exerted by the earth. Each panel's parabolic curves "outward", with each layer of wall-panels mating with the layer below with a pre-designed joint and a watertight seal, also with each post, continuing downward until the desired depth is attained, when wall footings and lowest floor may be poured.

Description

SHORING FREE EXCAVATION AND BASEMENT CONSTRUCTION APPARATUS AND
METHOD
FIELD OF THE INVENTION
[0001] The present invention relates generally to the excavation and construction of basements for buildings. More particularly, the present invention relates to a set of components which used together provide for a shoring-less excavation and relatively simultaneous construction of finished basement structures, and a system for their use in practice.
BACKGROUND OF THE INVENTION

[0002] In large construction projects, it is common to make large preliminary excavations in the earth to provide for suitable foundations and parking or basement facilities within a planned building. During excavation, it is usual to drive pilings around the perimeter of the site, and then as earth is removed from the site, to place planks or panels between the pilings to shore up the walls of the excavated hole. It is also usual to put aggregate material such as gravel into a space between the shoring planks and the newly excavated face in the earth and to provide drainage of that aggregate, in order to avoid water entering the excavation site within the shored area. Once excavated and shored to a designed depth, foundation footings are poured, flooring is poured, and bearing and interior walls are formed and poured, alongside interior bearing pillars. Floor slabs are poured at various heights from the bottom floor, and a basement is formed which can bear the weight of the building and resist the forces applied by the earth surrounding the hole. Shoring and piles can sometimes be removed. This results in the costly step of adding shoring while excavating which does not provide any finished foundation or walls, costly and time-consuming provision of drainage around the shoring, and loss of valuable real estate in that the outside 12-15 inches of the perimeter of the excavation cannot be part of the useable land, being taken up by the shoring and related items which must by their nature be outside of the outside wall of the poured perimeter bearing and other walls.
Examples of the prior art in the field are described in the following paragraphs:

[0003] US 6,220,789 B1-- This method uses SLIDING panels that must be standing vertically , pressed against the exterior wall columns. For this method, the panels must be flat.

WSLegal\064560\00001\ 5430245v2 - 1 -[0004] The panels are installed on the back side of the columns.

[0005] The panels must be designed to withstand a bending moment generated by the lateral earth pressure.

[0006] This method requires building additional support beams to provide lateral stability and doesn't contemplate any mating feature between the panels, so, appears to have ONE PIECE panel, which is extremely difficult and expensive.

[0007] Using this method, the provision of a waterproof membrane on the outside face of the panel is not useful because friction with adjacent earth will damage any membrane or waiting as the panel slides and thereby defeat the waterproof feature. The deeper proceeds the excavation, the lateral earth pressure increases and increases the difficulty to maneuver or slide the panel downward into place, because it is being pushed against the backside of the columns. The necessary strength to slide the panel downward will cause damage to the panel or the columns. This force on the columns will move the centered position of the column; therefore, the use of lateral brackets is mandated.

[0008] US 7,048,471 B2 -- This method is intended for use for trenches and pitsand is not for use for perimeter walls, columns or any other permanent structural but as instructive of the industry's approach to shoring.

[0009] US 6,981,686 B2 -- This invention relates to modular wall assemblies of the type used for earth excavations, concrete forms and temporary enclosures. More specifically, the invention relates to a set of parts and materials that facilitate the assembly and disassembly of such walls in the widest possible variety of shapes and layouts with a minimum number of different parts. It describes a temporary assembly, and while not directly relevant, shows the prior art appraoch to modular wall assemblies.

[0010] US 7,309,191 B2 -- This shoring system is in the category of slide rail shoring systems, including rails, panels and strutting assemblies . It applies to shoring of excavations of various shapes such as trenches, rectangular and polygonal pits of great or lesser depth. This is provided as another example of the prior art's approach to shoring in excavation sites.

[0011] US 7,500,807 B2 -- This method intend to use metal sheet piling sections also referred to herein as "sheet piles" or "sheet piling" ), preferably AZ
series sheet piling, to form a wall around the perimeter of a structure that is being built in place of a traditional concrete foundation wall, and is provided as an example of a prior art method of finished-wall excavation.

WSLegaI\064560\000011 5430245v2 -2-[0012] US 6,616,380 B1 -- This method includes excavating soil to form a downward sloping ramp, and forming soil to form a downward sloping ramp, and forming a concrete slab on the downward sloping ramp. The method further includes continuing to excavate soil to extend the downward sloping ramp to a location under the concrete slab, and continuing to form the concrete slab on the downward sloping ramp so that a subterranean structure is formed having an essentially continuous concrete slab with a first portion which is above, and spaced-apart from, a second portion of the slab.
This reference is provided to show an example of subteranean excavation-while-building methods in the industry's prior art.

[0013] US 6,402,435 B1 -- This invention relates to a system and method for constructing a pre-stressed modular construction for supporting an applied load. In particular, the present invention relates to a system and method for pre-stressed modular walls. The system comprises a plurality of header stacks constructed from a variety of header units. The header stacks are coupled by structural members. Active reinforcement elements are used to induce a pre-stressing force into the header stacks to support or retain the applied load. This is provided as an example of modular construction techniques in the prior art.

[0014] US 6,299,386 B1 -- This invention relates to a method for a wall that retains earthen material, and more particularly to a shoring wall for below-grade excavations. This invention relates to a temporarily system.

[0015] It is, therefore, desirable to provide a system and apparatus for overcoming the obstacles in the prior art, reducing materials costs, time to build and associated time-dependent costs, and increasing useable lot space for medium to large-scale construction projects involving excavation and provision of useable basement structures which may also form foundations for the upper building structure, among other deficiencies.
SUMMARY OF THE INVENTION

[0016] To mitigate some of the problems with the prior art, this system provides for the drilling of holes around the outer perimeter wall, then the exact placement of forms and reinforcement steel within those holes, as well as similarly drilling and placing interior bearing posts. Each post is relatively exactly formed with adequate footings and reinforcement, while covered by the earth, prior to excavation. During excavation, pre-formed parabolic wall panels of reinforced concrete, which may also include extra waterproofing and insulating materials, are placed and fixed between the perimeter posts as those posts are uncovered WSLegal\064560\00001\ 5430245v2 -3-by the excavation. When the hole reaches a pre-determined depth, beams are laid between facing perimeter walls (post-to-post across the excavated hole) in order that the perimeter walls will be braced against pressures exerted by the earth behind them. The parabolic curve is placed "outward" from the posts. Each layer of wall-panels mates with a new panel below it, preferably with a lap joint and preferably with a watertight seal along that joint and the joint with the each post. This continues downward until the desired predetermined depth is attained, at which stage wall footings and lowest floor may be poured in place. Simultaneous with this construction, building may proceed above ground, as the interior posts and perimeter posts form bearing structures to support the construction above grade. The invention comprises the method, as well as the apparatus of the curved formed concrete panels with pre-formed lap joints between them, and with the preferred mechanism of attachment of each panel to each post. That attachment is provided by a bolt system through the post to a steel plate which is bonded to each back-side corner of each post. The bolt holds the panels from downward movement during excavation, and from moving away from their attachment to the post prior to backfilling behind the newly created wall. The system provides a finished interior wall without further work, the interior wall capable of having decorative or functional features embedded during manufacture.

[0017] differences and/or advantages for sfs system Vs. US 6,220,789 B1 patent:

[0018] The SFS system doesn't need to slide any element.

[0019] SFS system doesn't use flat panels. SFS system uses curved panels, leading the system to work in a compressive status.

[0020] SFS system connects the panels with columns on the lateral faces.

[0021] SFS system doesn't require steel reinforcement to absorb the bending moment. The panels will be working in a total compressive status. SFS system doesn't require additional beams. SFS system doesn't require lateral brackets.

[0022] SFS system doesn't require wooden blocks or clips.

[0023] SFS system is less expensive than this method .

[0024] SFS system allows to start the precast manufacturing several weeks prior to clean the site.

[0025] DIFFERENCES AND/OR ADVANTAGES FOR SFS SYSTEM VS. US
7,500,807 B2 PATENT:

[0026] The SFS system doesn't work with metal sheet panels.

WSLegal\064560\00001\ 5430245v2 -4-[0027] Any metal sheet system is not allowed to work as a bearing wall. SFS
system provides a bearing perimeter wall at the same time is a retaining structure to keep undisturbed the surrounding soil.

[0028] Any comparison for this invention vs. SFS system, doesn't make sense, since are totally different concepts and targets.

[0029] This invention is much more expensive than SFS system and the use of concrete panels allows the insulation prior to installation.

[0030] Also, the use of precast concrete panels combined with columns is not contemplated [0031] DIFFERENCES AND/OR ADVANTAGES FOR SFS SYSTEM VS. US
6,402,435 61 PATENT:

[0032] Any comparison for this invention vs. SFS system, doesn't make sense, since are totally different concepts and targets.

[0033] Also, the use of precast concrete panels combined with columns is not contemplated, therefore, is a total different concept.

[0034] DIFFERENCES AND/OR ADVANTAGES FOR SFS SYSTEM VS. US
6,616,380 B1 PATENT:

[0035] This invention intends the stabilization of the surrounding soil.

[0036] This is not intended to be part of the structure.

[0037] This method goes beyond the perimeter of the foundation. Consequently, the property owner had to either build further in from property line to allow room for the installation of the anchors or receive permission from adjoining property.

[0038] SFS system doesn't go beyond the property line.

[0039] SFS system will be a permanent part of the future structure.

[0040] SFS system is a permanent bearing wall and uses precast concrete panels and precast concrete columns.

[0041] In a first aspect, the present invention provides a [0042] In a further embodiment, there is provided a [0043] In further aspect, the present invention provides a [0044] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

WSLegal\064560\00001\ 5430245v2 -5-BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Embodiments of the invention will now be described, by way of example, with references to the attached Figures, which are briefly described below:
Figure 1 is a set of cross-sectional drawings of various prior art retaining wall systems used in shoring excavations.
Figure 2 is a fictional structural drawing or site plan showing placement of exemplar pile/column on an imaginary plot of land.
Figure 3 is a is a cross-sectional drawing on a horizontal plane through two adjacent pillars and their enclosed panel.
Figure 4 is a is an architectural rendering of the inner surface of an assembled wall portion.
Figure 5 is an exploded view of 3 interlocking panels.
Figures 6a, b, c, and d are architectural drawings of different perspectives of an example panel.
Figure 7a is a cross sectional elevation of a pile/column bisected along a vertical plane midway and perpendicular to its inner face.
Figure 7b is a cross-section of an exemplar pillar/column along a horizontal line at some point mid-way its height showing reinforcing elements.
Figure 8 is a cross-section of a pillar and panel combination along a horizontal plane showing details of the joint and fastening means between panel and pillar/column.

DETAILED DESCRIPTION

[0046] Generally, the present invention provides a method and system for the excavation and construction of basement structures in a relatively simultaneous fashion without separate shoring systems.

[0047] One of the targets of this method is to eliminate the construction of a temporary shoring system, which as a general rule, is conformed of cut-off caisson walls or timber lagging and soldier piles. This temporary shoring system will be replaced with a permanent concrete wall, that will be formed with precast concrete rectangle piles-columns with dimension 300 mm x 400 mm as a typical piece. Every pile-column will be provided concrete footings 1.0 m to 2.0 m below the basement's grade level ( accordingly to WSLegal\064560\00001\ 5430245v2 -6-geotechnical report ) , poured on site, with tremie tube or concrete pump.
Concrete placed by tremie tube should have a slump of not less than 150 mm.

[0048] The precast concrete curved panels of this invention will be of total dimension 3600 mm x 1000 mm x 150 mm, with an are length of 33425mm, and radius of 112872 mm.
The curved formed concrete panel system will include pre-formed lap joints between each panel, and the panels will be attached to the piles-columns . That attachment is provided by a bolt system through the panel to a steel plate which is bonded to each back-side corner of each post, extending laterally parelled to the excavated face. The bolt holds each panel from downward movement during excavation, and from moving away from their attachment to the post prior to backfilling behind the newly created wall. A "concrete welding joint" will be constructed in order to integrate the piles-columns with the concrete panels and the three elements will be working together at this time , as one piece, achieving an integral system working in compressive forces to retain the integrity of the basement space formed by the walls. This is not a "sliding system". The concrete panels are installed after the piles-columns installation and after the excavation is already done as it is done.
Backfilling behind the newly created wall is then done, putting the lateral soil against the new wall, keeping the static state of the surrounding earth.

[0049] Customized shape piles-columns and panels will be used accordingly the architectonic and structural features of each specific project. The necessary rebar to avoid the bending moment for the piles-columns will be determined for the maximum height required without lateral supporting ( interior beams ) and the specific weight of the confined soil acting on the outside of the wall system, through the concrete panels system . Specific steel reinforcement design verification must be performed according to the soil characteristics for each site.
COMPRESSIVE STATUS

[0050] As above mentioned, an important feature of this system is the concept that the arrangement is conceived to work in total "compressive status". This means a very important saving on the cost for main reinforcement steel bars. To Inhibit the formation of plastic shrinkage and plastic settlement cracking or prevent temperature cracking, an engineered graded macro-synthetic fiber can be used for secondary reinforcement for the concrete . For piles-columns and panels the fiber can preferably be added at a rate of 2 kg/m3.

WSLegal\064560\00001\ 5430245v2 -7-[0051] The "concrete welding joint" will be a chamfer shaped fillet, in a preferred emodiment with dimensions of 367mm x 508mm x 448 mm. The concrete to be used for this joint may contain fiber with a minimum addition rate of 3 kg / m3 .

TYPE OF CONCRETE

[0052] The properties of concrete either for panels piles, or welding chamfer shall preferably meet the Canadian Standards Association (CSA) A23.2-04, Table 2, Class C-2 exposure, as minimum . water / cement ratio Of 0.45 , air entrainment of 4% to 7% , maximum size of aggregate = 16 mm and a minimum specified 28-day compressive strength of 32 MPa. The standard curing time would then be 7 days with normal wetting procedure. Otherwise, proven and authorized alternate curing process may be used .

[0053] For further specifications regarding concrete in contact with sulphates, refer to CSA Standard A23.1-04, Tables 2,3, and 4.

WATERPROOFING

[0054] The waterproof feature of the system will be provided in several ways:
a) - From the factory, the panel surface that will be in contact with the soil, can be made with a final polished finish. This means that all the texture will be completely closed, doing away with the porosity of the exposed surface, and then not allowing water penetration. A mineral waterproof hardener may also be used at the final polishing process.
b) - The use of an alloy polymer macro-synthetic fiber facilitate and guarantee to keep free of cracking the outside surface and the inside surface of the panels.
c) - Prior to installation (on site ), two layers of waterproof membrane should preferably be applied to the panels' exterior-facing surface.
d) - The concrete panels should preferably have a special interlocked system (between vertically adjacent panels as they are stacked into place) that will be caulked and the joints will be covered on the back or earth-facing side with another extra membrane to avoid water penetration, assuring waterproofing for the entire system.
e) - Note that these procedures may be applied either to the piles or the concrete panels.
The above will allow the elimination of the filtration material fill normally used on the back or earth-facing side of the usual retaining walls in a shoring system or a panel-wall or other conventional system.

WSLegaI\064560\00001\ 5430245v2 -8-[0055] GENERAL PROCEDURE
1. The first step is to drill all holes for columns / piling.
2. After drilling holes columnn / piles are centered, aligned and placed in position.
3. This hole drilling and column / piling placing takes place prior to mass excavation.
4. Perimeter columns / piles are placed on site and central columns / piles are placed at the same time.
5. Mass excavation does not commence until after all columns / piles are installed into their exact location.
6. The hole will be filled with crushed gravel with a size not bigger than 4.75 mm, surrounding every pile-column in order to maintain the vertical position.
7. Concrete wall panels are installed as mass excavation proceeds.
8. At the point excavation to the depth of 1.5 metres is completed, the first row of concrete panels will be installed.
9. The concrete panels will be provided with the mechanism of attachment of each panel to each post.
10. After mass excavation proceeds downward about one panel height, the next row of concrete curved panels will be placed, with the same procedure above explained.
11. At the time the walls reach a depth defined by the capability of the piles /
columns to withstand lateral pressures exerted by the earth inward on the panels, a beam system installation can be performed, conecting perimeter columns with central columns (for each level of basement, for example).

[0056] In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments of the invention. However, it will be apparent to one skilled in the art that these specific details are not required in order to practice the invention. In other instances, well-known structures and elements are described in order not to obscure the invention. For example, specific details are not provided as to whether the embodiments of the invention described herein are implemented with specific dimensions or materials.

[0057] The above-described embodiments of the invention are intended to be examples only. Alterations, modifications and variations can be effected to the particular WSLegal\064560\00001\ 5430245v2 -9-embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.

WSLegal\064560\00001\ 5430245v2 -10-

Claims (10)

1. A pre-cast concrete panel with parabolic cross-section along a plane horizontally intersecting the panel for use as a wall in a shoring-free construction of a basement during excavation.

2. The panel of claim 1 with a pre-configured joint along its upper and lower perimeters formed to mate a similar panel when stacked together in the wall.

3. The panel of claim 1 with a coating on its outer surface.

4. The panel of claim 3 where the coating is waterproofing.

5. The panel of claim 3 where the coating is insulating against heat transfer.

6. The panel of claim 2 where an element of the joint is a lapping layer of waterproofing membrane affixed to the earth-facing side at its lower edge and temporarily held wrapped around its lower edge and extending up its opposite side during excavation, for release just prior to placement of a next-adjacent panel beneath the panel.

7. A plurality of posts cast in place in holes along a perimeter of a building site's planned excavation spaced and formed to substantially exactly mate post-side edge to panel-edge to form a wall during mass excavation which when completed will be a finished bearing wall for the structure for which the excavation was made.

8. A post of claim 7 adapted with a receiver for affixation of an adjacently-placed panel during assembly during mass excavation.

9. The affixation means of claim 8 being cementing by waterproof concrete formed in a chamfer between the post and panel on the side inside the void formed within the formed wall.

10. A system of shoring-free mass excavation and construction of a walled basement structure comprising the steps of:
a. drill a plurality of holes along the perimeter of the planned basement, the holes of sufficient depth to be adequately footed beneath the basement's planned floor and of diameter sufficient to permit reinforcement and forms for later pouring of concrete;
b. if internal posts are required for foundation of a structure planned for construction on the site, either the basement or a structure above ground, the drilling of similar holes sited for such internal posts;
c. placing forms, reinforcing elements and pouring concrete into the holes to form posts;

d. prior to mass excavation, the manufacture of pre-cast concrete panels e. mass excavation is started and continued to about the depth of a panel's height;
f. placement and affixation of panels between the perimeter posts to form a wall section;
g. continuation of mass excavation for a further depth of about a panel's height;
h. placement and affixation of panels below the previously placed panels between posts, these next layer of panels being fitted to the previously placed panels such that there is a sealable joint between the bottom edge of the first level of panels and the top edge of the next-lower vertically adjacent level of panels, continuing to form the wall;
i. mass excavation and panel placement steps are repeated until a desired basement depth is reached;
j. if the depth is appropriate for the installation of cross-beams, such as may be required to provide lateral bracing between sides of the excavation's cavity, cross-beams may be installed while excavation ceases, after which the excavation and wall assembly continues;
k. if the depth is the planned bottom on which the basement's floor is to be laid, footings and other castings are installed as required using conventional construction methods.