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TECHNICAL FIELD  
       [0001]     This invention relates to pre-manufactured concrete building structures, and more particularly, to building structures which can be attached to and removed from existing structures for repeated use.  
       BACKGROUND  
       [0002]     For background, reference is made to U.S. Pat. Nos. 4,171,596, 4,275,533, 4,573,292, 4,745,719, 5,265,384, 5,727,353, 5,845,441, and 6,330,771.  
       SUMMARY  
       [0003]     There is a need to provide portable structures to function as school classrooms, office spaces, and/or apartments in a economical and expeditious way. Readily adaptable and configurable building facilities are required to meet the rapidly changing requirements for facilities such as school classrooms. Structures according to the invention are formed from pre-manufactured modules which can be joined in many configurations for serving temporary or long term building needs.  
         [0004]     Structures according to the invention can be readily attached to an existing building or serve as a standalone structure. In addition, the structure can be used for a number of years after being delivered to the site. If and when the demographics again change and the additional space afforded by the structure is no longer needed, the structure can be detached and moved to a new site for expansion of a new school facility.  
         [0005]     Specifically in school applications, the total lead time from planning through commissioning, to building operation can take more than six years. With typical school expansion projects, an architectural firm will spend substantial efforts to develop and plan structures fitting the classrooms to the particular needs of the school. However, when specifying building modules according to the invention, the time required to plan and build the additional space is minimized. The necessity for numerous site specific shop drawings is also reduced because the specifications of the structure according to the invention are predefined. Through application of structures according to the invention, the delivery time and the costs of construction can be greatly reduced. Architects, engineers and school officials know building dimensions, specifications and costs in advance. Therefore, site specific planning and variability is vastly reduced. The total construction time is reduced because precasting of the building modules can be done concurrent with preparation of the existing school facility and adjacent construction site.  
         [0006]     In one aspect according to the invention, a building structure includes at least one building module for providing a temporary or permanent dwelling space, the module including wall, floor and ceiling members formed from reinforced precast concrete. The members are detachably coupled to one another to form an enclosed space, with adjacent members being spaced apart from each other a predetermined distance. A compliant pad spans this distance and couples adjacent members to accommodate relative movement between the members during transport and once the structure is located on the site.  
         [0007]     In one embodiment, the compliant pad is a synthetic rubber. In another embodiment, the structure includes a concrete form attached to the ceiling to accommodate fixtures, electrical conduit or suspending ceiling materials. The concrete form can include a channeled layer, such as a composite floor deck ceiling system, including EPICORE® (Epic Metals Corporation, Rankin, Pa.), for example. In another embodiment, the members of the structure are further adapted to detachably engage a second additional building module, comparable to the first module, to form a single larger structure. The modules can be arranged vertically to form a multiple-story building or connected along a horizontal orientation to form a larger single-story structure.  
         [0008]     The structure can also include a conduit extending through the members for accommodating building utilities including at least one of plumbing, electrical, heating, ventilating, and air conditioning. The structure can also be adapted for attachment to an preexisting structure. The structure can also include any of number of exterior facade surfaces, such as brick, stone, stucco, or any combination thereof.  
         [0009]     According to another aspect, of the invention, a portable pre-manufactured building includes a generally parallelepipal structure for releasable attachment to a pre-existing structure having vertical walls, a horizontal floor, and a horizontal ceiling. The walls and ceilings are formed from cast concrete including reinforcing steel rebar and include a connecting layer disposed between the top of the walls and the ceilings. Wall members can also include at least one conduit for uninterrupted passage of utilities.  
         [0010]     In a various embodiments, the connecting substrate is a synthetic rubber, such as neoprene, for example. A channeled layer, such as EPICORE® or equivalent, can be attached to the floor and ceiling members. The members of the structure can be further adapted to detachably engage a second additional structure, comparable to the first structure, to form a single larger structure. The structure can also include a conduit extending through the wall members for accommodating building utilities, including, for example, at least one of plumbing, electrical, heating, ventilating, and air conditioning.  
         [0011]     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the detailed description, which refers to the following drawings, in which: 
     
    
     DESCRIPTION OF DRAWINGS  
       [0012]      FIG. 1  is a perspective view of a pre-manufactured concrete building module according to the invention;  
         [0013]      FIG. 2  is a perspective view of two of the building modules shown in  FIG. 1 , arranged in a vertical configuration;  
         [0014]      FIG. 3  is a floor plan view of a pre-manufactured concrete building module attached to an existing building;  
         [0015]      FIG. 4  is a section view of the building module of  FIG. 3  through line A-A;  
         [0016]      FIG. 5  is a floor plan view of the structure of  FIG. 1 ;  
         [0017]      FIG. 6  is a cross-section elevation view of the typical wall and foundation construction;  
         [0018]      FIG. 7  is a cross-section elevation view of wall, floor, and foundation construction;  
         [0019]      FIG. 8  is a detail cross-section view of the junction between ceiling and wall members and floor and ceiling members;  
         [0020]      FIG. 9  is another detail cross-section view of the junction between ceiling and wall members and floor and ceiling members;  
         [0021]      FIG. 10  is a detail cross-section view of the junction between floor, ceiling, and wall members which depicts the attachment to the building foundation;  
         [0022]      FIG. 11  is a detail cross-section view of a junction between adjacent floor members and a wall member;  
         [0023]      FIG. 12  is a detail cross-section view of a window installed in a wall member; and  
         [0024]      FIG. 13  is a detail view of an exterior door and an attached folding stair. 
     
    
       [0025]     Like reference symbols in the various drawings indicate like elements.  
       DETAILED DESCRIPTION  
       [0026]     This invention relates to a system of pre-manufactured concrete modules that can serve as a freestanding school classroom, expand a preexisting school, apartment units, small office of other commercial space. Construction details permit the option of readily adding exterior facades such as brick, stucco, stone or lapboard, for example, to architecturally blend the new structure with the existing structure. Individual modules can be connected horizontally and/or vertically stacked to form multi-story structures. The room sizes may vary as to need and desire so that the rooms can be versatile and the only thing that will be required is that the room sizes can be engineered economically and safely. The modules forming the building structure can be constructed to withstand hurricanes, rainstorms, windstorms, snowstorms, and if geographic conditions warrant, seismic activity.  
         [0027]     For classroom applications, the modules can readily provide additional student capacity when demographic changes require it. The modules can be attached to and integrated with the existing school and not an isolated “portable” style classroom. The modules can be delivered to the construction site and furnished with interior features, desks, chalkboards. The modules can be located to form hallways and bathrooms, for example. In commercial applications, the modules can be arranged in various horizontal and vertical configurations to meet the particular building requirements.  
         [0028]     With reference now to the drawings and more particularly to  FIG. 1 , there is shown a concrete building module  20  according to the invention. The module  20  can be pre-manufactured in a factory to desired specification and include all building facilities, such as bathrooms, closets, hallways, interior wall furnishings, and lighting fixtures, for example, and ready for use after placement and installation at the construction site. Alternatively, if practical, the module can be cast onsite. The module  20  is a single story building having a generally rectangular floor plan and is formed from steel reinforced concrete floor member  22 , wall members  24  and roof member  26 . Other floor plan dimensions are contemplated to meet individual building requirements. The floor, wall, and roof member  22 ,  24 ,  26  can be formed from reinforced concrete slab having a thickness of six inches. In one embodiment, the roof member  26  extends beyond an exterior wall member  24  in one direction to form an overhang  28 . The concrete roof member  26  can be coated with a waterproof layer or membrane, such as a thoroseal material, for example. The roof member  26  can also be flat or pitched along the lateral dimension of the module  20  at a suitable pitch, such as ¼-inch per foot for improved drainage.  
         [0029]     The module  20  can also include preinstalled windows  30  and doors  32 . Cutouts  34  in wall members  24  adjacent the roof members  26  form conduits for continuous piping  36  from one module  20  to another adjacent module, comparable to module  20 , or to a preexisting building. The floor, wall, and roof members  22 ,  24 ,  26  are cast individually in appropriately sized forms and then joined together as described below. The interior surfaces of the wall members  24  can be covered with drywall or painted plywood. Optional facings  38  can be attached to the exterior surfaces of the wall members  24 , such as brick, stone, stucco, or lapboard for example, to conform the building module  20  to the preexisting building to which it can be attached.  
         [0030]     Referring to  FIG. 2 , the modules  20  can be stacked to form the two-story structure  40  as shown. Up to the three modules can be stacked vertically. The modules can also be attached horizontally (not shown), to form a larger, single-story structure. Junctions (discussed below) disposed between adjacent members of the modules  20  connect the first and second modules together. The structure  40  is supported by concrete pilings  42  or concrete footings spaced along the underside of the floor member  22  of the first-story module. Along the mating surfaces between the modules, filler strips  44  consisting of elongate decorative metal or plastic panels, can be attached.  
         [0031]     The structure  40  can serve as a standalone classroom, with interior facilities including blackboards/whiteboards, clocks, closets and cabinetry and desks, for example. As shown in  FIGS. 3 and 4 , the structure  40  can function as an addition to an existing school building. Preferably, the structure  40  is attached to the existing school building and integrated into the design of the school.  FIG. 3  depicts an aggregation of structures  40  to form a wing  41  extending from an existing building  43 . In this example, the wing  41  includes two sets of two structures  40   a,    40   b,    40   c  and  40   d,  connected by a hallway section  45  spanning the adjacent units. The wing  41  is attached to the building  43  by vestibules  47  extending therebetween. As shown in  FIG. 4 , floor member  49  extends from a first structure  40   a  to a second structure  40   c,    40   d.  One end of the member  49  bears on notch unit  51 . A roof extension member  53  spans the roof members of structures  40   a  and  40   c.  In one example, the roof is arcuate and includes a skylight (shown in phantom). Alternatively, the structure  40  is located proximate to the school for ready accessibility. In the classroom application, the structure  40  can also be assembled and installed on site to meet the needs of increased enrollment at a particular school and later, if enrollment drops, detached and reinstalled for use in a different school district. The structure  40  can also serve individually or collectively, as apartment units, office space, or commercial retail space.  
         [0032]     A representative floor plan shown in  FIG. 5 , shows exterior dimensions of about 20 by 30 feet. Although the floor plan shown is rectangular, other dimensions, as dictated by the site, the specifications, and the existing structure (if an expansion), are contemplated. The floor member  22  is formed from one or more slabs of reinforced concrete, similar to roof member  26 , with a thickness of six inches. Flat beams  46  extend beneath the floor member  26  to support the module  20  on pilings and/or footings  42  ( FIG. 2 ). Interior spaces such as closets  50  are formed with internal, non-load bearing walls  52 , framed with metal or wood studs, having a thickness of six inches.  
         [0033]     As shown in  FIG. 6 , steel rods  52  extend vertically between upper and lower horizontal steel beams  52 ,  54 , respectively, for reinforcing the wall member  24 . The module  20  is supported by pilings  42  positioned along the span of floor member  22  and corresponding to the flat beams  46  ( FIG. 5 ). The ceiling height is nominally 9 feet.  
         [0034]     Referring now to  FIG. 7 , the floor, wall, and ceiling members  22 ,  24 ,  26  are joined together along wall-to-roof member junctions  60 , wall-to-single floor member junctions  62 , wall-to-two floor member junctions  64 , a and floor-to-floor junctions  66 . The wall and roof members in junction  60 , the wall and floor members in junction  62 , and the wall and floor members in junction  64  are separated a vertical gap or distance D 1 . This distance is filled by a compliant pad  70  disposed between the concrete members. The pad  70  can be formed from a commercial available synthetic rubber compound, such as neoprene. A sealant  72  is applied along the peripheral edges of the pad  70  to substantially seal the connection against infiltration of weather and debris. Adjacent floor members  22  at junctions  64  and  66  are separated by a horizontal gap of distance D 2  filled with sealant  72  to bridge the gap. The vertical and horizontal gaps defined by D 1  and D 2 , respectively, in junctions  60 ,  62 ,  64 , and  66 , spanned by pad  70  or filled with sealant  72 , permit relative movement between wall, floor, and roof members during transport and after installed at the site to accommodate building settling, while also mitigated cracking and other damage to concrete members  22 ,  24 , and  26  of the structure  40  ( FIG. 2 ).  
         [0035]      FIGS. 8, 9 , and  10  show the junctions  60 ,  62 ,  64  and  66  in greater detail. Generally the detailed view of a typical joint, depicted in  FIG. 11 , shows the ends of adjacent floor members  22  positioned proximate one another and separated by a horizontal gap of distance D 2  filled with sealant  72 . A compliant pad  70  is interposed between the wall member  24  and the two floor members  22 , spanning the vertical distance D 1 . A layer of sealant  72  also extends along the periphery of the compliant pad  70  to substantially seal the connection against infiltration of weather and debris. Reinforcing steel rebar  52  extends vertically through the wall members  24  to strengthen the wall members in tension, as is commonly known in the art. For those areas of steel rebar  52  which are exposed, a layer of anticorrosive paint can be applied to resist oxidation of the rebar. A channeled layer  78  is attached to the lower surface of the floor members  22 . The channeled layer  78  can include metal decking for supporting ceiling fixtures, containing insulation or concealing pipes and ventilation components, for example. A second complaint pad  80 , spanning a vertical distance D 3 , is disposed between the channeled layer  78  and the flat beam  24 .  
         [0036]     The compliant pads  70 ,  80  can be made from commercially available synthetic rubbers, such as neoprene, for example. Collectively, pad  70 , extending along the distance D 1 , second pad  80  extending between the layer  78  and the flat beam  24 , and horizontal gap of distance D 2 , filled with sealant  72 , prevent direct contact between the wall and floor members  22 ,  24 , which accommodates relative moment therebetween for transport and settling while still maintaining sufficient dimensional stability and rigidity of the structure. Referring to  FIG. 10 , the wall section  24  is supported by piling  42 . The flat metal beam  46  is rigidly connected to the concrete pile  42  (or footing) beneath it, by a steel strap  82 , for example.  
         [0037]      FIG. 12  shows a typical window section. A window  100 , bounded by a window frame  102 , is installed within corresponding open of wall member  24 , according to standard, accepted installation techniques. A concrete teat  104  or 1-inch pressure-treated wood beam is positioned along the top of the window  100 . About all sides, the window frame  102  is secured in place with screws fastened to lead shields  106  which are attached to the opening in the wall member  24 . Pressure treated wood trim  108  and window sealant  110  are attached along the outside perimeter of the opening in the wall section  24  along the window  100 . The decorative facade  38 , attached to the exterior surface of the wall member  34  can extend proximate the lowest edge of the window  100  to form a window sill  112 . The sill  112  can be pitched downward away from the window  100  to facilitate drainage of rain water. An interior wall  114 , attached to the inside surface of the wall member  24 , can be ⅝-inch drywall or painted plywood  112 , for example.  
         [0038]      FIG. 13  shows a detailed view of the lower edge of door  32 . The door can be solid wood, fiber glass-composite heavy-gauge, galvanized steel over a core of rigid foam, for example. If the doors  32  open to the outside, an exterior door sill  118  extends from the floor member  22  to engage the lower edge of the door  32  and provide a tight seal. Folding stairs  120  can be attached to the inside of the door  32  for emergency egress from the structure  40 . The stairs  120  can include a rope  122 , attached to the stairs, for extending the stair  120  away from the door  32 .  
         [0039]     A number of embodiments have been described herein. Other embodiments are within the scope of the following claims.

Summary:
A pre-manufactured building structure including at least one building module for providing a temporary or permanent dwelling space. The module includes wall, floor and ceiling members formed from precast concrete and configured for detachable engagement to one another to form an enclosed space. Adjacent wall, floor and ceiling members are spaced apart from each other by a predetermined distance. A compliant pad spans this distance to couple adjacent members and accommodate relative movement between the members during transport and after installation of the structure.