WO2009035452A1

WO2009035452A1 - Factory built basic durable dwelling having a structural thin concrete wall shell and horizontal foot element for installation directly on the soil of the building site

Info

Publication number: WO2009035452A1
Application number: PCT/US2007/078270
Authority: WO
Inventors: David L. Cohen
Original assignee: Intellectual Property LLC
Current assignee: Intellectual Property LLC
Priority date: 2007-09-12
Filing date: 2007-09-12
Publication date: 2009-03-19
Anticipated expiration: 2010-03-12

Abstract

The basic durable dwelling, which is designed for placement directly on the soil of the building site, has a structural thin concrete wall shell with a horizontal foot element to provide the required load bearing arrangement on the underlying soil. The bearing element of the factory produced structure is a downward extension of the wall element, where in effect this wall/foundation element then supports the floor and roof. Complete or near complete homes are capable of being manufactured in a factory environment at very high production rates with local, semi-skilled labor. In the preferred embodiment the thin concrete wall shell is poured as a monolithic casting and the horizontal foot element is integral to the monolithic wall shell casting. This eliminates the need for a site constructed foundation or floor slab.

Description

SUBSTITUTE PAGE

FACTORY BUILT BASIC DURABLE DWELLING HAVING A STRUCTURAL THIN

CONCRETE WALL SHELL AND HORIZONTAL FOOT ELEMENT FOR INSTALLATION

DIRECTLY ON THE SOIL OF THE BUILDING SITE

FIELD OF THE INVENTION

This invention relates to dwellings that are capable of being manufactured in their entirety in a factor₎ environment and that comprise a structural thin concrete wall shell that has an foundation element at the base to enable the dwelling to be installed directly on the soil at the construction site.

BACKGROUND OF THE INVENTION

It is a problem in the field of dwelling construction to consistently produce a basic dwelling that is low cost, yet durable in construction. The cost of the dw elling is a function of the cost of the materials used in the construction, the cost of the labor required to build the dwelling, the duration of time that the construction process requires, and the indirect costs of the construction. The durability of the dwelling is a function of the design of the home, the materials, and the production control that the production process offers.

Two different forms of construction practice are presently employed in residential housing construction. Both methods of residential housing construction have worked for many years, but each of them has inherent attributes that result in inconsistencies in the production of dwellings, excess cost, and compromised durability .

The most common residential housing construction practice produces the stick-built house that is built in the traditional field practice that occurs at the building site. Stick-built construction requires a sequenced building process of progressively affixing the constituent elements of a house together, piece by piece. Item A must be affixed before item B can begin, and in turn, item B must then be affixed before item C can begin, and so on. The framing system for a stick-built home may be sawn lumber or other wood-based framing materials, light-gauge or heavier sections of steel, masonry units, or a poured concrete frame which was formed in the field

The second general practice of dwelling construction produces homes through significant use of remotely-produced building systems or factory-built products. There are a variety of building systems or factory-built approaches that range from those that provide a limited scope

262668262668 of the home construction process to those systems that represent a comprehensive approach. A limited scope system is frequently one that provides a framing system or enclosure system. Examples of a framing system or enclosure system include wood framed wall panels, structural insulated panels (SIPS), pre-cut logs for a log home, or a framing system for a house which is comprised of pre-cast concrete elements produced off-site and assembled on-site. A comprehensive building system generally provides a factory-built wood or steel framed product that addresses the home more completely, including plumbing, electrical, and mechanical systems. An example of a comprehensive factory-built product is the "single wide" manufactured or modular home.

An alternative factory-built product is disclosed in U.S. Patent No. 3,973,365 which discloses a thin shell concrete cell consisting of a light weight non-load bearing wall/roof casting with steel reinforcing elements and optional external ribs which enable the construction of very thin (1 /4" - 2") shells which are sufficiently strong to be self-supporting yet lightweight enough to be transported to a construction site. The individual cells are used as a capsule to contain the internal finish that is applied to the interior walls of the cell and individual cells are placed side by side at the construction site in such a relationship that a complete multi-room building having intercommunication between rooms (cells) is formed. The cells are not load bearing structures and are arranged within a separate encompassing structure. The cells are transported to the building site where they are either placed on a foundation or affixed to the site poured slab floor. The house is supported by the floor and not the cell walls, which is structurally less sound and significantly more prone to failure. The addition of vertical and horizontal structural members makes the resulting structure rigid and vertical reinforced concrete columns formed at the intersections of adjacent cells provide support for cells in a two-story building.

All building systems or factory-built products are designed to accommodate the required shipment of the building systems or factory-built elements from the factory location to the house site. All building systems or factory-built approaches are designed for the eventual incorporation of the factory-built product onto a field-prepared foundation or onto other factory-built elements.

There are numerous disadvantages of the first, and the most common dwelling construction technique, the stick-built method. These disadvantages result in inconsistencies in the production of dwellings, excess cost, and compromised durability.

Stick building in a field environment is detrimental to maintaining consistent production. Job circumstances vary widely from house to house and include changing personnel on each job,

21) 262668262668 variable dimensions and details of the prior work which was performed, and the unpredictable availability of materials and tools required by each tradesperson. The production process occurs outside and is subject to the effects of weather, which degrades materials, allows mold to be introduced, affects the performance of workers, and delays schedules. All of these circumstances on a stick-built job result in a finished product with undesirable inconsistencies.

Stick building represents problems from a cost standpoint. Stick-built cost is a function of the cost of the materials, labor, time, and indirect expenses. Stick building is wasteful of materials because job-site production inherently generates excess or unnecessary materials waste (theft, over ordering to avoid shortages, weather damage, poor utilization, etc.). Materials cost more on a stick- built job because they are frequently delivered though multiple steps in a material supply chain that each has costs including overhead, handling, breakage, etc. Both of these factors drive up material costs. Labor is costly in stick-built circumstances because work output per hour worked is significantly less than work output per hour in a factory setting. This reduction in work output is attributable to the difficulty of a field environment when compared to the advantages of a predictable and well- coordinated factory environment. Labor costs in stick building also are elevated because wage rates are often higher in stick building because the field requires a higher skill level of employee. Time costs money in stick building because work-in-progress must be financed over extended production schedules of three to eight months for each home. Lastly, stick building is costly because the indirect cost of construction is significant, such as the accumulated overhead and profit associated with the stick building company and all of that company's subcontractors on an aggregated basis. The aggregated overhead and profit of all companies involved in the field production of housing is a surprisingly high 25% to 28% of sales price.

Stick building represents problems from a durability standpoint. Durability of a dwelling is a function of the design of the home, the materials, and the production control that the production process offers. Stick-built durability is a problem primarily due to the difficulty in controlling the production process in a field environment. A stick-built home can be designed to be durable and materials can be specified for whatever level of durability is desired, but it is extremely difficult to build the home in the field with consistent control of the installation process. This lack of control of the production process introduces unplanned variations and defects which significantly compromise long-term durability.

23D

262668262668 There are similar disadvantages with the second method of residential construction, the building system or factory-built approach. These disadvantages also result in inconsistencies in the production of dwellings, excess cost, and compromised durability.

A building system or factory-built environment offers a great deal of consistency for what is produced within that environment. Therefore, in some measure, a building system or factory-built setting is more advantageous than stick building from the consistency standpoint. Unfortunately, however, the building systems or factory-built products need to be connected to something in the field which is outside of the controlled factory environment. Limited scope systems such as wall panelization require extensive connecting of individual factory-built components in the field, and then field applying other building elements and finishes. As a result, limited scope building systems and factory-built approaches become significantly inconsistent. Comprehensive building systems, such as the "single-wide" manufactured or modular home, also need to be connected to a foundation and utility infrastructure. The connection of comprehensive factory produced elements to field built foundations again introduces an appreciable level of inconsistency. In summary, consistency remains a significant challenge with all present building systems or factory-built residential techniques.

There are also problems with building systems and factory-built residential methods from a cost standpoint. The following incremental costs are introduced in a building system or factory-built setting: the cost associated with the retail dealer distribution network for the factory manufacturer, the shipping cost for the factory-built products from the manufacturer all the way through the system to the home site where the products will be utilized, the cost of cranes and other material handling equipment required to place the factory-built elements, the cost of travel for required personnel who are involved in the placing or fit-up of the factory-built components, the labor cost of the fit-up and finish of the home in the field that was partially constructed from factory-built elements, and the incrementally higher service and support costs associatede with products installed in a widely dispersed setting. In summary the existing factory environment does offer significant cost advantages within the plants, but the use of factory production in the home building industry has unintentionally imbedded a significant amount of cost inefficiency into the building process.

Building systems and factory-built residential practices introduce significant durability problems. The durability issues are mostly related to the design of the home and the production control that the production process offers. Building systems and factory-built products are designed

20 262668262668 to be connected to something else. This inherent design attribute means a lack of continuity and a series of interconnection details that do not bode well for long-term durability. Structural integrity may be compromised over time at the interface points. Water intrusion can occur at the interface points. Stress concentration in high wind or earthquake settings will occur at interface points, resulting in localized over-loading that would not have occurred in a more homogeneous structural environment. Further, durability suffers because the overall production process for a home offers limited production control when the building systems or factory-built program progresses to the field environment. In the factory, there was outstanding production control. Unfortunately, the factory did not produce the object in its totality (such as an automobile from an automobile factory), and the factory-built element had to be manipulated in the field environment subject to weather where sub-optimal process control significantly degrades durability.

Both forms of present construction practice for homes, the stick-built method and the building system or factory-built approach, share a common characteristic that is costly and compromises durability. They both rely on a design approach where the unstable earth and soils on which the house will rest are designed to be substantially restrained from movement in the vicinity of the home via a heavy foundation element which is often poured concrete. This allows a somewhat fragile home to be successfully deployed over time on unstable earth. This design approach could be referred to as "restraining mother earth". This design approach is costly, time consuming, adds little to the functional utility of the home, and it can be the source of durability problems if not successfully performed. Performance problems can occur if either the foundation itself does not perform properly or if the house is not successfully attached to the foundation (e.g. an earthquake displacement).

BRIEF SUMMARY OF THE INVENTION

The above-described problems are solved and a technical advance achieved by the present basic durable dwelling which is designed for placement directly on the soil of the building site. This basic durable dwelling has a structural thin concrete wall shell with a horizontal foot element that provides the required load bearing arrangement on the underlying soil. This bearing element of the factory produced structure is a downward extension of the wall element, where in effect this wall/foundation element then supports the floor and roof. Complete or near complete homes are capable of being manufactured in a factory environment at very high production rates with local, semiskilled labor. In the preferred embodiment, the thin concrete wall shell is poured as a monolithic

25) 262668262668 casting and the horizontal foot element is integral to the monolithic wall shell casting. This eliminates the need for a site constructed foundation or floor slab as in the prior art.

The present basic durable dwelling is described below. It is then compared to the construction practices presently in use in the home building industries from the standpoint of its superior attributes related to consistency, cost efficiency, and durability. These were the characteristics of the existing housing industry that were examined earlier. In addition, the present basic durable dwelling is examined from the standpoint of its relationship to the earth underneath it, where superior results are also produced.

The thin concrete wall shell and horizontal foot element may be produced from a number of specialized concrete products including Self-Consolidating Concrete, which is a new concrete technology whereby the Self-Consolidating Concrete mix can be placed in forms containing dense rebar and other inserted building components without the need for any vibration to settle the concrete. The Self-Consolidating Concrete mix flows to fill the voids in the forms that are used to define the walls and/or the horizontal foot element, surrounding and flowing through the reinforcement and block-outs in the forms without leaving significant air pockets or voids. The resultant concrete structures are extremely strong, and thinner concrete sections can be used which reduces cost and weight. For example, the walls of the dwelling can be constructed using Self- Consolidating Concrete, with the thickness of the walls typically being between 0.05 meters and 0.18 meters in thickness. The walls are combined with an integral horizontal foot element in the preferred embodiment, and the resultant monolithic wall-horizontal foot element combination can be constructed in a factory environment. The resultant dwelling can then be equipped with a floor and substantially completed in the factory with interior and exterior finishes and then transported to the home site for installation.

In the present basic durable dwelling, utilities are typically brought to the home site via an underground feed and stubbed into a termination box that is located within the extent of the dwelling's final location to simplify utility hookup and maintenance. The prefabricated dwelling (including the horizontal foot element, which is a part of the home) is placed on the building site over the termination box and the utilities are attached from their termination in the termination box to the corresponding interconnects that are manufactured into the dwelling.

The dwelling may also typically include an intermediate floor support beam that is supported on both ends by the horizontal foot element. This intermediate floor support beam spans the middle portion of the horizontal foot element opening to provide midspan support for

21) 262668262668 the floor joists or floor slab. The floor can then be installed and inside finishes also can be installed in the factory. Utilities within the factory-built home are terminated at a point that can be field interconnected to site utilities in the termination box. There is an access door built into the floor of the home near this utility termination location. The home, including the horizontal foot element, is placed directly on the soil in such a manner that the access door and utility stubs within the home are located near the termination box. It is a straight forward matter to then open the access door and connect all the utilities. Another primary activity that needs to be undertaken for installation is to push a small amount of dirt against the exterior wall of the dwelling to achieve the proper grade and drainage. A second story can be added to the basic dwelling by building a scond floor, second floor walls and a roof on top of the vertical exterior walls of the first floor, either in the factory or in the field.

Consistency of production is fully realized by the present basic durable dwelling. Structural, thin concrete wall shells are cast in a repetitive fashion from pre-prepared molds in the factory environment. This results in homes that are consistent in dimension, squareness, plumbness, production schedule, absence of weather defects, cost, and their adherence to pre-established plans and specifications. All of the home, including a horizontal foot element that is integral to the home, can be factory constructed with controlled processes and quality control procedures which elevate product consistency and quality to a higher level than what can be achieved in any existing practice of dwelling construction.

Excess cost is the second problem experienced in the present home building industries.

The cost of dwellings is a function of the materials used in the construction, the labor required to build the dwelling, the duration of time that the construction process requires, and the indirect costs of the construction. The present basic durable dwelling lowers cost significantly when compared to the two existing home building industries in each of these four cost elements. The material cost for a thin concrete wall shell and a horizontal foot element are a bare minimum, and waste can be optimally managed in a factory setting. The cost of the other finishing materials to complete the home can be similarly optimized in a factory environment. Labor, in both hours worked and cost per hour, is very efficient in the present basic durable dwelling built in a factory setting. There is very little unnecessary labor expenditure. Production time is compressed to typically four to eight working days per home, so excess time has been removed from the cost equation. Indirect expenses of production are similarly optimized by providing a consistent production process where products are built on a consistent schedule in a controlled factory environment. There are indirect

20 262668262668 costs of production, but they are significantly less per unit than what occurs in the present homebuilding industries.

The present basic durable dwelling is highly durable; in fact, it is more durable than homes built using the present construction practices. This durability is a result of the following factors. The design of the dwelling in the present basic durable dwelling in its preferred embodiment results in a monolithic structure including both the walls and the horizontal foot element; there are no joints or discontinuities in either the external wall shell of the home or its connection to the horizontal foot element. The absence of joints and discontinuities is particularly important because product life is shortened by water intrusion and by failures induced by earthquake conditions which concentrate loads and damage at points of discontinuity. The material that comprises this combination wall shell and horizontal foot element is inherently durable and lasts for 50 to 100 years even when subjected to sun, water, wind, earthquake, and other conditions that normally result in more rapid degradation of a home's structure. The use of a novel manufacturing process using self-consolidating concrete also enhances the consistency, cost efficiency, and durability of the resultant dwelling because it is an ideal form of concrete for this application.

The use of construction based on higher performance concrete products including Self- Consolidating Concrete provides a high quality, durable dwelling that is thin, affordable, and lighter weight than typical concrete. The elimination of the need for a foundation, the use of Self- Consolidating Concrete, and the use of a factory environment are major factors that provide the benefits listed above.

The present basic durable dwelling with a horizontal foot element enables a low cost, durable home to be produced without the need to restrain the earth under the home with a separate, expensive, field-built foundation. This novel configuration is a very important attribute of the present basic durable dwelling and results in significant cost reductions without compromising durability when compared to the existing homebuilding industry. The present basic durable dwelling can be factory built and then placed directly on the ground in one event, which greatly simplifies the housing production process and lowers cost. If the ground moves at a later date, the present basic durable dwelling with a horizontal foot element has sufficient inherent structural integrity that it can be jacked and re-leveled directly on the ground with very little effort. Flexible design of utility interconnects also enable home movement to occur without damage to utility lines.

25)

262668262668 BRIEF DESCRIPTION OF THE DRAWINGS

Figures IA and IB illustrate a plan view of a typical basic durable dwelling having a thin wall concrete shell and integral horizontal foot element;

Figure 2 illustrates a perspective view of the typical basic durable dwelling having a thin wall concrete shell of Figure 1 with the roof removed therefrom;

Figure 3 illustrates typical floor construction details for the typical basic durable dwelling having a thin wall concrete shell of Figure 1; and

Figure 4 illustrates a typical implementation of the various staging areas contained in a typical embodiment of the dwelling manufacturing facility used to manufacture a typical basic durable dwelling having a thin wall concrete shell.

DETAILED DESCRIPTION OF THE INVENTION

The present durable basic dwelling is manufactured in a factory environment, and uses an integral horizontal foot element with a monolithic thin wall concrete shell as the basic exterior wall structure. The elimination of the need for a foundation, and the use of a novel manufacturing process using Self-Consolidating Concrete ensures the durability of the resultant dwelling and produces an affordable dwelling.

As shown in Figures IA, IB, 2, and 3, the durable basic dwelling 100 consists of an integral horizontal foot element 101 that substantially defines an exterior perimeter of the dwelling and a plurality of vertical walls 102, each attached at one end 102B thereof to the integral horizontal foot element 101, to form an exterior shell inside of which is a living space. The plurality of vertical walls 102 and the integral horizontal foot element 101 are monolithically formed, typically in a factory location, using Self-Consolidating Concrete. There are no joints between the integral horizontal foot element 101 and the associated vertical walls 102, and the distinction between these two elements is one of function rather than separate structures. In addition, the plurality of vertical walls 102 do not necessarily completely enclose the living space, in that the exterior shell formed by the plurality of vertical walls 102 can include voids or sections where the vertical walls 102 are not continuous; but the inclusion of some voids in the vertical walls 102 does not impact the stability or transportability of the resulting durable basic dwelling 100.

2D

262668262668 A roof 105 is installed on the second end 102T of the plurality of vertical walls 102, and the ceiling joists hold together the tops 102T of the plurality of vertical walls 102 to prevent wall spreading at the top of the durable basic dwelling 100. As shown in Figure IB, a second story can be added to the durable basic dwelling 100 by simply replicating the wall structure 102N of the first floor on top of the vertical exterior walls 102 of the first floor. The second floor can be simply the extension of the vertical walls 102 to a two-story extent where the floor of the second story is attached to the vertical walls 102 at the height defined by the ceiling of the first story. Alternatively, floor supports for the second story can be placed on the top of the vertical walls 102 of the first story and the second story is formed on top thereof, with one option being that the floor supports are formed in whole or in part as part of the second story walls.

Utilities typically are brought to the home site via an underground feed 106 and stubbed into an enclosure 103 that is located within the extent of the durable basic dwelling 100 to simplify utility hookup and maintenance. The prefabricated durable basic dwelling 100 is placed on the building site, and the utilities are attached to the corresponding interconnects that are manufactured into the durable basic dwelling 100. The horizontal foot element 101 is backfilled with soil 107 and graded to provide proper surface drainage. As shown in Figure 3, the durable basic dwelling 100 typically also includes a support beam 104 that is supported on both ends by the integral horizontal foot element 101 and spans the middle of the foundation opening to provide support for the floor joists 108. The floor 109 can be installed over the floor joists 108 once the utilities are connected. If floor joists are not used, floor decking can be used in its place to comprise the floor or to provide the structure on which the floor is poured or installed. If the interior dimensions of the basic durable dwelling are properly sized, it may be possible to install decking that spans the interior space and is supported only at its ends by the integral horizontal foot element 101.

Integral Horizontal Foot Element Architecture The integral horizontal foot element 101 is that structural element which is integral to the base of the durable basic dwelling 100 and provides the base upon which the floors 102 and vertical framing elements for the durable basic dwelling 100 are attached, as shown in Figure 2. The integral horizontal foot element 101 allows the durable basic dwelling 100 to be created in its entirety and moved prior to being located at a permanent location. The integral horizontal foot element 101 typically is provided at the base of the outside bearing perimeter walls 102, at interior load bearing walls, and at selected other locations and may be contained within a floor subassembly.

20 262668262668 The footer 111 portion of the horizontal foot element 101 is oriented perpendicular to the associated vertical wall 102 and braces the wall at its base 102B for movement in the direction that is perpendicular to the major surface of the wall 102, as shown by the arrows 102A. The footer 111 also distributes the vertical load of the house onto the earth via the width of the footer 111. The vertical walls 102 brace the durable basic dwelling 100 in a vertical direction as shown by the arrows 102V. The corners of the durable basic dwelling 100 brace the wall ends where they join with adjacent wall ends for movement along the face of the walls as shown by arrows 102L. The midpoints of the tops of the walls are the only unrestrained elements and these are braced by the roof 105 or the second story, which is attached to the tops 102T of the walls and which provides an added element of stability and rigidity.

In a factory manufacturing environment, the durable basic dwelling 100 is built with an integral horizontal foot element 101 to enable the simple relocation of the partially built durable basic dwelling 100 within the manufacturing facility and eventually to a permanent dwelling site. The durable basic dwelling 100 also can be moved later without significant complexity, since the structure incorporates the integral horizontal foot element 101 and can be relocated to another permanent location. The integral horizontal foot element 101 is typically L-shaped with a footer 111 section facing into the interior space circumscribed by the walls 102 or away from the walls 102. Alternatively, the horizontal foot element can be an inverted T-shape, with the footer 111 having one leg facing into the interior space circumscribed by the walls 102 and one leg away from the walls 102. The shape and dimensions of the integral horizontal foot element 101 are selected to spread the load of the walls 102 over a larger area than the footprint of the walls 102, and typically is engineered as a function of soil conditions at the permanent dwelling site. The integral horizontal foot element 101 also ties the walls 102 together to prevent wall spreading. In order to create the monolithic wall structure, the rebar used to reinforce the integral horizontal foot element 101 and walls 102 is also curved around the corner wall joints to provide lateral rigidity and prevent wall separation at the corners. Furthermore, the ceiling joists of the roof or second story hold together the top of walls 102 to prevent wall spreading at the top.

Thus, the durable basic dwelling 100 built in the dwelling manufacturing facility substantially is built "in space" rather than "in place." For this to be possible, the initial step in the manufacturing process requires the use of the integral horizontal foot element 101, and its associated monolithic vertical walls 102, which establish a solid point of beginning and provide a dimensionally stable foundation. The integral horizontal foot element 101 thereby provides

2Φ 262668262668 structural integrity to the base of the durable basic dwelling 100, which enables the durable basic dwelling 100 to exist in space without continuous additional support to enable the durable basic dwelling 100 to be manufactured, transported, and placed on a permanent site as an integral, self- supporting and rigidized structure. The integral horizontal foot element 101 distributes vertical loads downward from the wall 102 sections to the ground. The integral horizontal foot element 101 also provides a dimensionally stable flat surface on which the floor and interior wall elements can be added and is manufactured from Self-Consolidating Concrete.

Self-Consolidating Concrete

Self-Consolidating Concrete, also known as Self-Compacting Concrete, is a highly flowable, non- segregating concrete that can spread into place, fill the formwork, and encapsulate the reinforcement without any mechanical consolidation. An additional advantage of Self-Consolidating Concrete is that it produces an improved and more uniform architectural surface finish with little or no remedial surface work. It also consolidates around and bonds with the reinforcement elements used in the structure.

Self-Consolidating Concrete consists of cement conglomerates whose fluidity in the fresh state is such that they can be used without any need for vibration or consolidating stress. The self-consolidating concrete must have excellent properties when fresh (fluidity, cohesion, and absence of segregation) and in the hardened state (mechanical resistance and durability). The main characteristic of Self-Consolidating Concrete is an extremely high fluidity.

Self-Consolidating Concrete is a new concrete technology whereby concrete can be placed in forms containing dense rebar and other inserted building components without the need for any vibration. The concrete flows to fill all of the voids in the form, completely surrounding and flowing through the rebar without leaving air pockets or voids. No segregation or bleed occurs with the concrete during placement or during the time it remains in the plastic state. The self- consolidating concrete flows like a viscous liquid rather than exhibiting the traditional slump of a high slump concrete. The Self-Consolidating Concrete is made flowable by altering the mix proportions and through the use of additional admixtures that prevent segregation.

Self-Consolidating Concrete is not a specific concrete mix design, but instead is a continuum of mixes that exhibit similar flow characteristics. The rheologic properties are developed by altering the mix design and by the use of admixtures. For example, a high-range, water-reducing admixture (super plasticizer) is used to provide the high flowability of the mix and the aggregate

20 262668262668 content is proportioned. The size and shape of the coarse aggregate are very important to the successful manufacture of self-consolidating concrete, with the coarse aggregate being typically less than ¹A inch to Va inch in diameter. In addition, a rounded aggregate is preferred over an angular aggregate, since the angular aggregate has a tendency to lock together. The sand and aggregate ratio used is typically 0.50 or greater. Finally, the fluid properties of the mix are altered to provide a cohesive mix that keeps the aggregate and paste together. The water reducing admixtures typically used include polycarboxolate super plasticizers, such as Glenium, Adva, Viscocrete 5000, and Superflux, manufactured by Master Builders, Grace, Sika, and Axium, respectively.

The viscous properties of a Self-Consolidating Concrete mix are achieved through one of three components:

1. Higher fines content, using materials such as: cement, fly ash, limestone screenings, finely ground glass, and granulated ground blast furnace slag;

2. The addition of viscosity modifying admixtures with lower fines; or

3. The addition of a combination of the above two components.

In addition, special purpose admixtures can be added to the Self-Consolidating

Concrete, such as air entraining agents, retarders or hydration control agents, corrosion inhibiting admixtures, and the like.

Rheologic Properties Of Self-Consolidating Concrete

Traditionally, high-slump concretes have been plagued by the tendency to bleed and segregate. In contrast, a Self-Consolidating Concrete mix has the following properties:

1. Non-Segregating — The aggregate stays in suspension in the Self- Consolidating Concrete mix as it flows into the forms;

2. Non-Bleeding — Water does not rise to the top of the Self-Consolidating Concrete mix or is observed on the outer edges of a flow test;

3. Vibration — No vibration is required during placement, since the Self-

Consolidating Concrete mix flows around rebar and other inclusions in the form under its own weight;

20 262668262668 4. Flow Spreads — Flow spreads of and 18-inch diameter or greater can be obtained; and

5. Set Time — The initial set time in many Self-Consolidating Concrete mixes increases upwards of 90 minutes, depending on the admixtures used and the water content of the Self-Consolidating Concrete mix.

The most significant problems addressed by thin wall construction with vertical concrete placement are:

1. Concrete delivery in very tight spaces, where tremie pipes or pump hoses typically cannot fit;

2. Concrete casings in vertically standing framework intended for thin reinforced concrete walls, if done from the top of the wall, have a significant potential for segregation; and

3. In such construction, concrete vibration also becomes an issue due to lack of available space.

Thus, the final product can be insufficiently consolidated with reduced strength and durability, and contain aesthetic defects due to surface honeycombing.

Self-Consolidating Concrete is highly flowable, which allows for placement from the bottom of the forms and consolidation under its own weight, thus eliminating the need for vibration. From a rheological perspective, Self-Consolidating Concrete is characterized by its low yield value, i.e., high fluidity. The Self-Consolidating Concrete also is characterized by a moderate viscosity, which ensures homogenous dispersion of solid particles and retention of water until hardening. Such viscosity is required to slow down the rate of sedimentation of solid particles and enhance the suspension and dispersion of solids in the plastic state to reduce bleeding, segregation, and settlement. High fluidity is achieved with the use of high range water reducing admixtures, especially in the case of low water cementitious materials ratio (w/cm). Moderate to high viscosity of the Self-Consolidating Concrete can be secured by lowering the free water content, increasing the concentration of fine particles (cement and fly ash), and/or incorporating a viscosity modifying admixture (VMA). The mixes typically contain the following proportions:

1. 20% by weight replacement of cement with Fly Ash type F;

2§ 262668262668 2. High content of cementitious materials (476 kg/m³ or 800 lb/cu yd);

3. Smaller size coarse aggregate (max size 10 mm or 3/8 in); and

4. High content of fine aggregate (typically 895 kg/m³ or 1500 lb/cu yd).

Dwelling Manufacturing Facility Configurations Figure 4 illustrates a typical implementation of the various staging areas and manufacturing areas contained in a typical embodiment of the dwelling manufacturing facility 400 used to manufacture a typical durable basic dwelling 100 having a load bearing thin wall concrete shell. By collapsing the linear structure of traditional residential housing production into a substantially volumetric process, and relocating the partially completed structure within the dwelling manufacturing facility 400 from one location to another, a significant amount of flexibility in the scheduling of the work can be attained by intermixing finished, roughed-in, and feature work into concurrently extant operations within the same structure.

Figure 4 illustrates a typical layout of the various staging areas and manufacturing areas contained in a typical embodiment of the dwelling manufacturing facility 400 and the linear flow of the manufacturing process where the durable basic dwelling 100 is assembled in a plurality of stages, with each location C1-C2, F1-F2 in the dwelling manufacturing facility 400 being able to access an assembly alley AA, as shown in Figure 4. In addition, hoisting apparatus, such as a traveling crane, whose bases 401-404 are shown in Figure 4, serves the dwelling manufacturing facility 400 and functions to transport the exterior shell of the durable basic dwelling 100 as well as interior walls, the roof, and other components and materials within the dwelling manufacturing facility 400.

In this process, the roof subassembly is shown as being manufactured on site at the dwelling manufacturing facility 400, rather than being delivered as a complete subassembly, due to the typical size of a roof subassembly. There need not be a dedicated assembly alley, and the location of the dwellings in their various stages of completion can be determined by the availability and implementation of the various hoisting apparatus used to move, lift, and place the foundation element, floor subassemblies, wall subassemblies, prefabricated kitchen/bathroom modules, roof subassembly, and any other components or materials. Thus, the use of a dwelling assembly alley AA is simply an illustration to demonstrate a typical configuration and is not a limitation on the implementation of the dwelling manufacturing facility.

2Θ 262668262668 The sequence of process steps (described below) and the siting of the various functions illustrated in Figure 4 are for illustration and not intended to limit the concepts disclosed herein. Furthermore, the roof subassembly construction may be implemented external to the building that houses other portions of the dwelling assembly, with the roof being installed on the partially assembled dwelling either within or external to the building that houses other portions of the dwelling assembly, with the external installation reducing the height requirement of the building. Similarly, the finish work shown as being implemented at location L4 can be done within another building, external to a building, and possibly at a site distant from the building that houses other portions of the dwelling assembly.

In all of these configurations, and others naturally derived from these configurations, hoisting apparatus are used to move, lift, and place the foundation element, floor subassemblies, wall subassemblies, prefabricated kitchen/bathroom modules, roof subassembly, and any other components or materials. The following description of the various staging areas refers to the specific configuration illustrated in Figure 4, although the concepts articulated therein are applicable to other configurations.

First Staging Area

The first staging area Sl of the dwelling manufacturing facility 400 is primarily used to receive, store, and process the materials used to create the exterior shell subassembly, which as a minimum includes the integral horizontal foot element 101 and integral vertical walls 102. The SeIf- Consolidating Concrete can be produced in the first staging area Pl from the raw materials that are stored in the first staging area Pl, or it may be delivered to the dwelling manufacturing facility 400 from a processing area that is located external to or even remote from the dwelling manufacturing facility 400.

Casting Areas The casting area(s) Cl, C2 of the dwelling manufacturing facility 400 are located juxtaposed to the First Staging Area Sl and Assembly Area AA and primarily are used to create the exterior shell of the durable basic dwelling 100 which, as a minimum, includes the integral horizontal foot element 101 and the integral vertical walls 102. The vertical walls 102 can be one story or two stories and are manufactured using Self-Consolidating Concrete. Thus, the forms, rebar, and other materials used to pour the integral horizontal foot element 101 and the integral vertical walls 102 are placed in the Casting Areas Cl, C2 as are the necessary tools, such as rebar cutting saws and rebar bending presses.

26 262668262668 First Assembly Area

Once the exterior shell is cast and the forms removed, the hoisting apparatus relocates the assembled exterior shell from the Casting Areas Cl, C2 into a First Assembly Area Al. The First Assembly Area Al can be used to partially finish the floors of the durable basic dwelling 100 with the final connection to utilities remaining to be performed on site via an access port in the flooring. This process includes installing the floor joists and associated subflooring or floor decking to provide the interior floors, on which the interior walls and other finish components are installed.

Second Assembly Area

Once the exterior shell is cast and the flooring installed, the hoisting apparatus relocates the assembled exterior shell into a Second Assembly Area A2 where the interior walls are installed. At this juncture, to increase the speed of manufacture and reduce the handling of materials, cabinet assemblies, doors, windows, floor coverings, etc. can be pre-stocked in the shell of the durable basic dwelling 100 to enable the workers to perform finish work concurrently with the optional second story and the roof being assembled and installed on the durable basic dwelling 100. In addition, prefabricated modules, such as bathroom modules or kitchen modules, can be installed to simplify the assembly of the durable basic dwelling 100.

Interior Wall Framing Area

The Interior Wall Framing Area Fl is the area where the interior walls are constructed and also optionally where finish is applied to the first floor interior walls of the durable basic dwelling 100. A wall panel assembly staging area is included in the First Framing area Fl to store subassemblies of interior walls, with insulation, wiring, plumbing, windows, and doors installed therein as desired. Workers can tape drywall seams, finish the drywall, and paint the wall subassembly, if not already done. The Interior Wall Framing Area Fl can also be used to stock cabinet assemblies, doors, windows, floor coverings, etc. for placement into the shell of the durable basic dwelling 100 to enable the workers to perform finish work concurrently with the optional second story and the roof being assembled and installed on the durable basic dwelling 100. In addition, prefabricated modules, such as bathroom modules or kitchen modules, can be assembled in the Interior Wall Framing Area Fl and/or installed in the shell of the durable basic dwelling 100 to simplify the assembly of the durable basic dwelling 100.

As noted above, the hoisting apparatus can transport the completed interior walls and prefabricated modules into the exterior shell of the durable basic dwelling 100, which is placed in the Second Assembly Area A2.

20 262668262668 Roof Framing Area

The Roof Framing Area F2 is used to fabricate the roof subassembly of the durable basic dwelling 100. The roof fabrication optionally can be implemented external to the building that houses the dwelling manufacturing facility. The equipment and work areas of the Roof Framing Area F2 typically comprise at least one raw material processing stage. In particular, standard lengths of framing members and roof truss members are delivered to the Roof Framing Area F2. The roof subassembly then is manufactured and hoisted into place on top of the framed shell of the durable basic dwelling 100 located in the Second Assembly Area A2; thus, it must be constructed somewhat differently from existing roof designs. In particular, since a crane (such as an overhead crane) "picks and places" the entire roof subassembly, the trusses used to fabricate the roof subassembly must be designed to support both dynamic and static traditional roof loads, supported by the frame of the house, as well as to be capable of supporting the weight of the assembled roof when it is being hoisted. Therefore, the roof trusses must be designed to account for compression and tension loads in all conditions. The overhead crane transports the completed roof subassembly from the Roof Framing Area F2 to the Second Assembly Area A2 where it is placed on the exterior shell of the durable basic dwelling 100, which is placed in the Second Assembly Ares A2.

The fabrication of the roof subassembly in the Roof Framing Area F2 results in a reduced assembly time, since working on ground level is easier, safer, and more efficient than constructing the roof in place on the exterior shell of the durable basic dwelling 100 as is presently done in the stick building technology.

Finish Assembly Area

Once the exterior shell is cast and the flooring and interior walls installed, the hoisting apparatus relocates the assembled exterior shell into a Third Assembly Area A3 where the interior and exterior finishes are installed. This typically is the last stage of the construction of the durable basic dwelling 100, but further work can be optionally done at the permanent dwelling site if necessary or desired.

Second And Third Staging Areas

The second and third staging areas S2, S3 of the dwelling manufacturing facility 400 are used as staging areas since no subassembly is produced therein; instead, in the preferred embodiment of the dwelling manufacturing facility 400, these areas are used as storage and staging areas where the pre-stocking materials, such as floor coverings, are stored and cut to size for insertion into the partially competed dwelling located in the Third Assembly Area A3. The materials

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262668262668 can be stored in a plurality of rows of high bay storage racks. The materials handled in the second and third staging areas S2, S3 of the dwelling manufacturing facility 400 may be more adapted to processing using a forklift truck rather than an overhead crane.

At this juncture, the durable basic dwelling 100, located in the Third Assembly Area A3, substantially is completed and ready to be transported to the permanent dwelling site.

Summary

The present durable basic dwelling is comprised of a monolithic thin wall concrete shell as the basic load bearing exterior wall structure, where an integral horizontal foot element is incorporated at the base of this shell. The durable basic dwelling is manufactured in a factory environment, and the use of a load bearing thin wall concrete shell as the basic exterior wall structure enables the transportation of the durable basic dwelling from the factory to the permanent dwelling site for placement. The use of a novel manufacturing process using self-consolidating concrete ensures the durability of the resultant dwelling and produces an affordable dwelling.

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Claims

CLAIMSWhat is claimed as new and desired to be protected by Letters Patent of the UnitedStates is:

1. A durable dwelling for placement directly on soil at the dwelling installation site, comprising: an integral horizontal foot element that substantially defines an exterior perimeter of said dwelling; a plurality of vertical walls, structurally connected at one end thereof to be part of said integral horizontal foot element, to form an exterior shell inside of which is a living space.

2. The durable dwelling of claim 1 further comprising: floor support means, having a first end and a second end, supported at each of said first end and said second end by said integral horizontal foot element, said floor support means spanning a space between two parallel oriented opposed ones of said plurality of vertical walls.

3. The durable dwelling of claim 2 further comprising: a plurality of floor joist means, each having a first end and a second end, supported at said first end by said integral horizontal foot element and at said second end by said floor support means, and oriented to provide a floor substructure.

4. The durable dwelling of claim 2 further comprising: at least one floor decking means, each having a first end and a second end, supported at said first end by said integral horizontal foot element and at said second end by said floor support means, and oriented to provide a floor substructure.

5. The durable dwelling of claim 2 further comprising: at least one floor decking means, each having a first end and a second end, supported at said first end and said second end by said integral horizontal foot element, and oriented to provide a floor substructure.

6. The durable dwelling of claim 1 wherein said integral foundation element is of a width greater than said vertical walls and extends in a direction perpendicular to said vertical walls to

20 262668262668 thereby brace said vertical walls at the junction of said vertical wall and said integral horizontal foot element.

7. The durable dwelling of claim 1 wherein said plurality of vertical walls comprise a thin wall concrete structure with walls of a thickness less than 0.15 meters.

8. The durable dwelling of claim 1: wherein said plurality of vertical walls and said integral horizontal foot element are formed together using self-consolidating concrete.

9. The durable dwelling of claim 8 where said self-consolidating concrete consists of cement conglomerates whose fluidity in the fresh state is such that they can be used without any need for vibration or consolidating stress.

10. The durable dwelling of claim 1 further comprising: roof means, attached to said plurality of vertical walls at an end thereof opposite of said junction of said vertical wall and said integral horizontal foot element, to cover said living space.

11. A method of constructing a durable dwelling for placement directly on soil at the dwelling installation site, comprising: forming an integral horizontal foot element that substantially defines an exterior perimeter of said dwelling; structurally connecting a plurality of vertical walls, each attached at one end thereof to said integral horizontal foot element, to form an exterior shell inside of which is a living space.

12. The method of constructing a durable dwelling of claim 11 further comprising: installing a floor support having a first end and a second end, supported at each of said first end and said second end by said integral horizontal foot element, said floor support spanning a space between two parallel oriented opposed ones of said plurality of vertical walls.

13. The method of constructing a durable dwelling of claim 12 further comprising: installing a plurality of floor joists, each having a first end and a second end, supported at said first end by said integral horizontal foot element and at said second end by said floor support, and oriented to provide a floor substructure.

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14. The method of constructing a durable dwelling of claim 12 further comprising: installing at least one floor decking, each having a first end and a second end, supported at said first end by said integral horizontal foot element and at said second end by said floor support, and oriented to provide a floor substructure.

15. The method of constructing a durable dwelling of claim 12 further comprising: installing at least one floor decking, each having a first end and a second end, supported at said first end and said second end by said integral horizontal foot element, and oriented to provide a floor substructure.

16. The method of constructing a durable dwelling of claim 11 wherein said integral horizontal foot element is formed of a width greater than said vertical walls and extends in a direction perpendicular to said vertical walls to thereby brace said vertical walls at the junction of said vertical wall and said integral horizontal foot element.

17. The method of constructing a durable dwelling of claim 11 wherein said plurality of vertical walls is formed using a thin wall concrete structure with walls of a thickness of less than 0.10 meters to 0.13 meters.

18. The method of constructing a durable dwelling of claim 11 : wherein said plurality of vertical walls and said integral horizontal foot element are formed together using self-consolidating concrete.

19. The method of constructing a durable dwelling of claim 11 where said self- consolidating concrete consists of cement conglomerates whose fluidity in the fresh state is such that they can be used without any need for vibration or consolidating stress.

20. The method of constructing a durable dwelling of claim 11 further comprising: constructing a roof, in a factory location, attached to said plurality of vertical walls at an end thereof opposite of said junction of said vertical wall and said integral horizontal foot element, to cover said living space.

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21. A method of constructing in a factory a durable dwelling for placement directly on soil at the dwelling installation site, comprising: forming in said factory an integral horizontal foot element that substantially defines an exterior perimeter of said dwelling; forming in said factory a plurality of vertical walls, each attached at one end thereof to said integral horizontal foot element, to form an exterior shell inside of which is a living space; installing in said factory a floor supported by said horizontal foot element; and installing in said factory interior finish in said durable dwelling to substantially complete construction of said durable dwelling.

22. The method of constructing a durable dwelling of claim 21 wherein said step of installing a floor comprises: installing a floor support having a first end and a second end, supported at each of said first end and said second end by said integral horizontal foot element, said floor support spanning a space between two parallel oriented opposed ones of said plurality of vertical walls.

23. The method of constructing a durable dwelling of claim 22 wherein said step of installing a floor further comprises: installing a plurality of floor joists, each having a first end and a second end, supported at said first end by said integral horizontal foot element and at said second end by said floor support, and oriented to provide a floor substructure.

24. The method of constructing a durable dwelling of claim 22 wherein said step of installing a floor further comprises: installing at least one floor decking, each having a first end and a second end, supported at said first end by said integral horizontal foot element and at said second end by said floor support, and oriented to provide a floor substructure.

25. The method of constructing a durable dwelling of claim 22 wherein said step of installing a floor further comprises: installing at least one floor decking, each having a first end and a second end, supported at said first end and said second end by said integral horizontal foot element, and oriented to provide a floor substructure.

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26. The method of constructing a durable dwelling of claim 21 wherein said step of forming a integral horizontal foot element comprises: forming said horizontal foot element of a width greater than said vertical walls and extending in a direction perpendicular to said vertical walls to thereby brace said vertical walls at the junction of said vertical wall and said integral horizontal foot element.

27. The method of constructing a durable dwelling of claim 21 wherein said step of forming a plurality of vertical walls comprises: forming said plurality of vertical walls using a thin wall concrete structure with walls of a thickness of less than 0.10 meters to 0.13 meters.

28. The method of constructing a durable dwelling of claim 21 : wherein said plurality of vertical walls and said integral horizontal foot element are formed together using self-consolidating concrete.

29. The method of constructing a durable dwelling of claim 21 where said self- consolidating concrete consists of cement conglomerates whose fluidity in the fresh state is such that they can be used without any need for vibration or consolidating stress.

30. The method of constructing a durable dwelling of claim 21 further comprising: constructing a roof, in a factory location, attached to said plurality of vertical walls at an end thereof opposite of said junction of said vertical wall and said integral horizontal foot element, to cover said living space.

31. The method of constructing a durable dwelling of claim 21 further comprising: transporting said substantially completed durable dwelling to an installation site; and siting said substantially completed durable dwelling directly on the soil of said installation site.

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