Form assembly for forming an eave, a roof slab, and a perimeter beam in a monolithic structure and method of forming the same

Abstract

A form assembly for forming a sloped roof slab, an eave, and a peripheral beam in a monolithic structure and method for forming are provided. The eave portion of the form assembly is detachably attached to upright columns of a housing frame structure. A steel roof deck is used as the base of the form for the roof slab. The roof deck permanently binds to the poured concrete roof slab so the roof deck is never removed. As there are no large formwork, jacks or trusses that have to be removed after the formation of the roof slab, the method and apparatus saves time and money in forming the monolithic sloped roof slab and eave.

Description

CLAIM OF PRIORITY

[0001] This is a continuation-in-part of application Ser. No. 09/931,904 filed Aug. 20, 2001, incorporates the same herein and claims all benefits under 35 U.S.C. 120.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a form assembly for forming a roof slab, an eave, and a peripheral beam as a single, integrated monolithic unit, and more particularly, to a form assembly on housing frame for simultaneously forming the roof slab with the eave and the peripheral beam on the housing frame.

[0004] 2. Description of the Background Art

[0005] Homes, buildings and structures in a sub tropical or tropical region have special design considerations. These regions are plagued by frequent and heavy rain, high humidity, strong winds that occasionally reach hurricane strength and high, uncomfortable temperatures with high dew points. Therefore structures built in such a climate must be able to withstand the strong winds, be resilient to frequent rain and high moisture levels in the atmosphere and be able to deal with the hot, humid conditions by reducing the level of discomfort in such structures.

[0006] Structures built in these tropical and sub tropical climates are often constructed of steel reinforced concrete. The floors, the walls, and the roof are concrete and have steel reinforcing bars throughout the structure. The concrete can handle compressive forces while the steel reinforcing bars provide protection against tensile forces that act on the structure. Such forces often come from the hurricane strength winds that are regularly present throughout such climates. The walls, floor and roof slab have a cross-hatched steel bars throughout disposed at a pitch that depends on local zoning ordinances, upon the degree of strength desired for a building and the height of the structure. This results in the pitch ranging from 8 inches to 18 inches.

[0007] A drawback for using concrete as a roof slab is that concrete is inherently porous. If the roof slab is flat or almost flat, water can collect and remain on top of the concrete for a long period of time. In such a scenario, since the concrete roof slab is porous, the water will seep into the roof slab forming cracks in the roof slab leading to an early demise of the structure. One solution to this problem is to build a roof slab having an appreciable slope to enable rain water to rapidly drain off the concrete roof slab thereby minimizing the damaging effect of standing water on a concrete roof slab. In addition, having the concrete roof slab formed at an appreciable angle with the horizontal creates an attic space above the living quarters that collects and traps heat. Thus, having an appreciable slope in the concrete roof slab also provides a more comfortable living environment in the structure than if the roof slab were to be flat or nearly flat because hot air is able to rise above and away from the occupants.

[0008] Often the roof slab and eave are formed of poured concrete that solidifies. A problem occurs when the roof slab and the eave work are formed in piecemeal. If, for example, the concrete forming the eave is poured and solidified prior to the formation of the roof slab, a seem (or cold joint) would exist at the boundary of the two structures. This seem would act to absorb water and thereby promote the formation of cracks resulting in an untimely demise of the structure. Therefore, it is important that the roof slab, the eave and the peripheral beam are formed as a single integrated monolithic unit where the roof slab, the eave and the peripheral beam are poured and hardened at the same time to prevent the formation of a seem (or cold joint) in the concrete on the top side of a structure.

[0009] When forming these roof structures, the prior art requires numerous bulky formwork to be erected prior to the pouring of the concrete and to be removed after the solidification of the concrete. For example, in the formation of roof slabs, the prior art requires formwork underneath the roof slab to support the roof slab until the roof slab hardens. This bulky formwork must be removed after the pouring and solidification of the roof slab. The prior art also requires the erecting and removal of truss structures for roof formation. Such erection and removal of bulky formwork from the interior of a structure in order to pour and harden a roof slab is time consuming, labor intensive and very costly. For example, U.S. Pat. No. 4,490,729 to Luce et al. illustrates numerous form work panels and jacks in FIG. 2 that must be erected and then removed from the interior of the structure after the formation of the roof slab. U.S. Pat. No. 4,214,408 to Rich, Jr. illustrates, in FIG. 8 numerous bulky formwork components and jacks as well as the trusses that must be erected and then later removed from the interior of the structure after the form hardens. U.S. Pat. No. 3,847,521 to Stickler, Jr. illustrates, in FIGS. 2 and 3 elaborate and bulky formwork and jacks that must be erected and then removed after formation of the roof slab and eave. U.S. Pat. No. 3,405,903 to Sullivan illustrates in FIGS. 1-3 elaborate formwork and jacks that must be installed and then removed to produce the roof and eave. U.S. Pat. No. 3,630,479 to Sullivan illustrates in FIGS. 2 and 3 complicated formwork that must be installed and then removed to produce a coffred roof using a pan system.

[0010] In addition, if bulky formwork must be removed from the interior of a structure after formation of the roof slab, the structure cannot be enclosed by walls prior to the formation of the roof slab. Since the roof slab and eave are very heavy, the restriction on structures that at least one wall cannot be built prior to the formation of the roof slab severely restricts the strength of the remaining structure.

[0011] What is therefore needed is a method and an apparatus for producing a sloped roof slab and eave as a monolithic unit where the amount of formwork that has to be erected and removed is minimized thereby reducing the time and costs needed to produce such a structure. In addition, what is needed is a form for a roof slab that does not require the removal of bulky forms that support the roof slab from the interior of the structure, thereby enabling the walls of the structure to be built before formation of the roof slab and eave.

SUMMARY OF THE INVENTION

[0012] It is therefore an object of the present invention to provide an improved method for producing a roof slab having an appreciable slope integrated with the eave.

[0013] It is also an object of the present invention to provide a structure and apparatus for producing a monolithic sloped roof slab and eave that is less labor intensive by not requiring the installation and removal of complicated, expensive and bulky formwork that supports the roof slab during construction to and from the interior of the structure.

[0014] It is further an object of the present invention to provide a roof slab having an appreciable slope and an eave and a peripheral beam formed with a sloped roof slab in a single monolithic structure where the peripheral beam has a reinforcing connection to the columns and the sidewalls of the structure.

[0015] It is also an object to provide a form for a roof slab, eave and peripheral beam where the formwork underneath the roof slab becomes part of the final structure and does not need to be removed.

[0016] It is another object to provide a method and a form assembly able to reduce construction time for forming a roof slab, an eave, and a peripheral beam on a housing frame structure.

[0017] It is yet another object to provide a method for forming and a formwork assembly able to form a monolithic roof slab preventing water leakage while drawing heat away from the living quarters.

[0018] It is yet another object of the present invention to provide a method for making and an apparatus for forming a roof slab and eave where the roof slab forms up to a 30 degree angle with the horizontal.

[0019] It is further an object of the present invention to provide a method and apparatus for making a roof slab having removable formwork only around the eaves of the structure.

[0020] It is also an object of the present invention to provide a method and apparatus for producing a concrete roof slab for a structure with walls completely surrounding the structure.

[0021] It is still another object to provide a form assembly capable of being detachably attached to upright walls of a housing frame structure to form a monolithic roof slab on the housing frame structure.

[0022] It is also an object of the present invention to provide a method and apparatus for forming a poured concrete roof slab and eave where the formation of the roof slab and eave can be done after formation of the walls of the structure thereby increasing the sturdiness of the resulting structure.

[0023] It is a further object to provide a form assembly able to provide a monolithic roof slab with a peripheral beam supporting the monolithic roof slab and an eave downwardly extended from the monolithic roof slab.

[0024] It is also an object to provide a form assembly able to form a peripheral beam enclosing an end portion of a housing frame structure for giving strength to a monolithic roof and eave structure.

[0025] These and other objects may be achieved by providing a form assembly attached to a housing frame structure in order to form a roof slab, an eave, and a peripheral beam in a monolithic structure. The housing frame structure includes pairs of upright columns, horizontal beams anchored on the upright columns, top beams placed on the horizontal beams, and a roof deck placed on the top beams as a roof formwork. Concrete is poured onto the roof deck and eave formwork and is hardened into a single monolithic unit. The roof slab may have an angle of 30 degrees with the horizontal. The formwork is absent any formwork inside the structure that must be removed after formation of the roof slab.

[0026] The form assembly includes removable eave formwork attached to the upright columns to form the eave, the roof formwork (the roof deck) forming on an underside of the roof slab, the roof deck becoming a permanent part of the structure when completed as there is no formwork inside the structure that needs to be removed after the concrete is poured and hardened thereby saving time and labor costs. The peripheral beam is placed on horizontal beams or on the upright column and encloses end portions of the top beams and the horizontal beams to support the eave and the roof slab. The form assembly about the eave is detachably attached to the upright columns of a housing frame structure and includes an eave formwork and a peripheral formwork. The eave formwork is mounted on the upright columns while the peripheral formwork is disposed between columns to be coupled to the eave formwork. The peripheral beam is supported by the upright columns.

[0027] This invention has two embodiments. The first embodiment is the method and apparatus used in the formation of the roof slab and eave without the presence of walls between the support columns. The second embodiment is the method and apparatus used in the formation of the roof slab and eave after concrete walls are in place about the structure. In the second embodiment, it is possible to pour and form the roof slab and eave even if the walls surrounding the structure were previously completed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] A more complete appreciation of this invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein:

[0029] FIG. 1 is a perspective view of a housing frame structure constructed according to the principles of the present invention;

[0030] FIG. 2 illustrates purlins stretched between top beams for supporting a roof deck;

[0031] FIG. 3 illustrates a close up view of a channel section of a typical purlin;

[0032] FIG. 4 illustrates roof decks disposed between top beams and on top of purlins;

[0033] FIG. 5 is a side view of the housing frame structure and a deck covering top beams of the housing frame structure;

[0034] FIG. 6 is a partial perspective view of the housing frame structure of FIG. 1 using rectangular beams;

[0035] FIG. 7 is a partial perspective view of the housing frame structure of FIG. 1 using “H” or “I” beams;

[0036] FIG. 8 is a perspective view of a form assembly constructed according to a first embodiment of the present invention where the roof, eave and peripheral beam are formed in the absence of a concrete wall about the structure;

[0037] FIG. 9 is a perspective view showing a form assembly mounted on a housing frame structure for forming a roof with an eave and a peripheral beam in a monolithic structure according to the first embodiment of the present invention;

[0038] FIGS. 10A and 10B are partial perspective views showing a portion A of FIG. 5 constructed according to a first embodiment of the present invention;

[0039] FIG. 11 is a partial sectional view along lines XI-XI′ of FIG. 5 constructed according to a first embodiment of the present invention;

[0040] FIG. 12 is a partial sectional view along lines XI-XI′ of FIG. 5 constructed according to a first embodiment of the present invention;

[0041] FIGS. 13A and 13B are partial views of the final product constructed according to a first embodiment of the present invention after the concrete is hardened and the formwork has been removed;

[0042] FIG. 14 illustrates the housing frame structure of FIG. 1 with a concrete wall formed prior to the formation of the roof slab and eave according to the second embodiment of the present invention;

[0043] FIG. 15 illustrates the steel reinforcements in place in the walls of the structure of FIG. 14 looking down in the concrete wall attached to a column according to the second embodiment of the present invention;

[0044] FIG. 16 illustrates the form used for forming the roof slab and the eave according to the second embodiment of the present invention;

[0045] FIG. 17 illustrates the structure of FIG. 14 with the formwork of FIG. 16 attached according to the second embodiment of the present invention;

[0046] FIG. 18 illustrates a closeup of the formwork attached to the structure at section “C” of FIG. 17 according to the second embodiment of the present invention;

[0047] FIG. 19 illustrates the a cross section of FIG. 14 along XIX-XIX′ according to the second embodiment of the present invention;

[0048] FIG. 20 illustrates the cross section of FIG. 14 along XX-XX′ according to the second embodiment of the present invention; and

[0049] FIGS. 21A and 21B are partial views of the final product constructed according to a second embodiment of the present invention after the concrete is hardened and the formwork has been removed.

DETAILED DESCRIPTION OF THE INVENTION

[0050] Turning now to the drawings, FIG. 1 illustrates a housing frame structure 100 built on a floor 101 for building a house. Pairs of upright columns 110 are spaced apart from each other and vertically anchored on floor 101 at the periphery of the house at a predetermined span. A horizontal beam 120 rests on top surfaces of each pair of columns 110, and two sloped top beams 130 are obliquely installed over each horizontal beam 120. Lower ends of sloped top beams 130 rest on a corresponding end portion of horizontal beam 120 while upper ends of sloped top beams 130 raised from horizontal beam 120 by a fixed distance meet each other in order to form a desired roof shape of housing frame structure 100. Concrete blocks or trusses may be used for top beams 130, horizontal beams 120, and upright columns 110. A space provided between sloped top beams 130 and horizontal beams 120 may be used as an attic to collect hot air within the structure thereby providing a more comfortable living space for the occupants. The angle of inclination between the sloped top beams 130 and the horizontal beams can be as high as 30 degrees. A plurality of auxiliary members 140, 141 are placed between two sloped top beams 130 and horizontal beam 120 to support sloped top beams 130 raised from horizontal beam 120.

[0051] It is to also be appreciated that “I” or “H” shaped steel beams may be used for columns 110. After construction of the frame structure 100, the columns can then be encased in concrete to form a column having a rectangular cross section. To encase the “I” or “H” beams in concrete, a rectangular form is used and then concrete is poured inside the form to produce an upright column 110 with a rectangular cross-section.

[0052] In the first embodiment of the present invention, it is also to be appreciated that no concrete walls are constructed between columns 110 prior to the formation of the roof slab, peripheral beam and the eave. Therefore, this first embodiment is employed when no wall is needed, such as for a garage, pavilion or gazebo. Instead, in the case of a pavilion or gazebo structure, a roof slab and eave are formed without the formation of any walls in the structure. The second embodiment of the present invention, to be discussed later, requires that steel reinforced concrete walls to be constructed between the columns prior to the erecttion of the formwork and the construction of the roof slab and eave.

[0053] The next step in the construction of the structure according to the first embodiment of the present invention is to assemble purlins 150 between the top beams 130 as illustrated in FIG. 2. These purlins are used to support roof deck 200 to be installed next. A close up view of an example of a purlin 150 is illustrated in FIG. 3. FIG. 3 is a channel section of purlin 150 used in FIG. 2. It is also to be appreciated that the present invention is in no way limited to the exact structure of a purlin 150 illustrated in FIG. 3.

[0054] After the purlins 150 are attached to top beams 130, roof deck 200 is attached to the purlins 150 and top beams 130. FIG. 4 illustrates the relationship between roof deck 200 and purlins 150 and top beams 130. In FIG. 4, purlins 150 are shown underneath roof deck 200. The roof deck 200 can be made of steel. Roof deck 200 serves as part of the formwork for the roof slab to be later formed. Roof deck 200 is a lower or bottom boundary for the roof slab. Unlike the prior art, roof deck 200 remains in the structure after the concrete is poured and hardened and the roof slab and eaves are formed. Therefore, roof deck 200 is not lubricated with vegetable oil as roof deck 200 is never removed from the structure.

[0055] FIG. 5 illustrates roof deck 200 in place. As purlins 150 are completely covered by roof deck 200, the purlins 150 are not visible in FIG. 5. However, it is the purlins 150 along with top beams 130 that support roof deck 200. On the underside of the structure in FIG. 5, the purlins 150, the top beams 130 and the roof deck 200 are visible. After completion of the structure, the purlins 150, top beams 130 and roof deck 200 on the underside of the roof are covered by either drywall or wooden boards to provide a more aesthetic appearance.

[0056] FIGS. 6 and 7 are close up views of area “A” in FIG. 5. FIGS. 6 and 7 illustrate a close up of where top beams 130 are joined with horizontal beams 120 and columns 110 when roof deck 200 has been installed on top beams 130. FIG. 6 illustrates the case where columns 110, horizontal beams 120 and top beams 130 are concrete blocks having a square or rectangular cross section. FIG. 7 illustrates portion “A” of FIG. 5 in the embodiment where horizontal beams 120 and top beam 130 are “I” or “H” steel trusses. FIGS. 6 and 7 illustrate joint “A” prior to the erection of the eave formwork and prior to the pouring of the concrete to form the roof slab, the peripheral beam and the eaves.

[0057] FIG. 8 illustrates a form assembly 300 constructed according to the first embodiment of the present invention where no wall is formed between columns 110. Form assembly 300 is provided with an eave formwork 400, peripheral formwork 500, and side plates 550. Roof decks 200 are included in form assembly 300 as roof decks 200 form the bottom surface for the roof slab. Eave formwork 400 is provided with an eave panel 410 for supporting an overhanging of the eave extended from the roof slab, an end panel 420 upwardly extended from a longitudinal side of eave panel 410 for forming an end of the overhanging of the eave, a beam coupler 430 downwardly extended from a longitudinal opposite side of eave panel 410 and attached to a vertical outer side of columns 110, a plurality of eave supports 440 disposed between a distal portion of the eave panel 410 and beam coupler 430 to support eave panel 410 of eave formwork 400 during pouring the concrete onto eave panel 410 of form assembly 300.

[0058] Peripheral formwork 500 in this first embodiment includes a vertical panel 510, a horizontal panel 520 horizontally extended from a longitudinal lower side of vertical panel 510, a lower coupler 532 downwardly extended from horizontal panel 520 and coupled to an inner surface of beam coupler 430 of eave formwork 400 and a vertical inner side of column 110, and an upper coupler 531 obliquely upwardly extended from an upper side of vertical panel 510 and coupled to a bottom of roof deck 200. Holes 542 and 541 are provided for coupling peripheral formwork 500 to the bottom of roof deck 200 and the inner surface of beam coupler 430, respectively. Horizontal panel 520 disposed between vertical panel 510 and lower coupler 532 and forms a lower boundary for peripheral beam 752, the peripheral beam being about as wide as the cross section of columns 110. Therefore, holes 541 of lower coupler 532 are attached to holes in the surface of beam coupler 430. Reinforcing plates 460 with holes 464 can be used to couple lower coupler 532 to beam coupler 430. Horizontal panel 520 is required in this first embodiment to serve as a lower boundary for the poured concrete for the peripheral beam 752 in the absence of a wall formed between the columns 110. A rectangular longitudinal space is provided by vertical panel 510, horizontal panel 520, and a portion of the inner surface of beam coupler 430 for forming the longitudinal peripheral beam 752 which is one of major features of the present invention when lower coupler 532 is coupled to beam coupler 430 of eave formwork 400 and upper coupler 531 is coupled to the bottom of roof deck 200. A plurality of side plates 550 having a predetermined height (approximately 3½ inches high) are disposed to be attached to each side portion of top beams 130 and roof deck 200. The thickness of the roof slab depends on the height of the side plates 550. Generally, the roof slab is poured to be about 3½ inches thick. On the overhanging eave, the thickness of the poured concrete is about 6 inches thereby requiring end portion 420 to be at least 6 inches high.

[0059] FIG. 9 shows form assembly 300 illustrated in FIG. 8 mounted on housing frame structure 100 of FIG. 5. Each peripheral formwork is disposed between two top beams 130 and between two horizontal beams 110 to be attached to beam coupler 430 of eave formwork 400. A first space 601 for pouring the concrete to form a roof slab 751 is provided by roof deck 200 and side pates 550, and a second space 602 for pouring the concrete to form the longitudinal peripheral beam 752 is provided by vertical plate 510 of peripheral formwork 500 and beam coupler 430 of eave formwork 400 and horizontal plate 520. A third space 603 for pouring the concrete to form the overhanging of the eave 753 is provide by eave portion 410 and end portion 420 of eave formwork 400. The monolithic roof structure having the roof slab, the eave, and the peripheral beam is made by a single concrete pouring operation into spaces 601, 602 and 603.

[0060] FIGS. 10A and 10B show enlarged housing frame structures of “B” portion of FIG. 9. A “H”shaped steel beam used for top beam 130 as shown in FIG. 10A. Vertical plate 510 and horizontal plate 520 of peripheral formwork 500 are modified to have a shape corresponding to the shape of “H” shaped steel beam 130. A portion of vertical plate 510 is cut out to accommodate the top beam 130. In FIG. 10A, protrusion 511 of vertical plate 510 of peripheral formwork 500 is inserted between two extensions 131, 132 of top beam 130 in order to prevent leakage of the concrete between vertical plate 510 and “H” shaped beam 130 when the concrete is poured into space 602 for the peripheral beam. FIG. 10A illustrates support eave panel 410 having the same slope as roof deck 200 to form an eave thereon.

[0061] FIG. 10B again illustrates section “B” of FIG. 9 with eave formwork 400 removed. It is noted that vertical panel 510 is perforated by a hole to accommodate an end of horizontal beam 120 and an end of top beam 130. In FIG. 10B, top beam 130 and horizontal beam 120 are “H” or “I” beams thereby requiring vertical panel 510 to be cut out to accommodate the shape of these beams while preventing the leakage of the poured concrete. Horizontal panel 520 is also perforated by a hole to accommodate horizontal beam 120. In FIG. 10B, since horizontal beam is “H” shaped, the horizontal panel 520 is cut out to accommodate the lower protrusion 122 of horizontal beam 120 while providing a tight enough fit so that the poured concrete does not leak out during the hardening process.

[0062] If space 602 is provided to include an end portion of horizontal beam 120, vertical panel 510 is modified to form a second protrusion 522 inserted between two extensions 121, 122 of horizontal beam 120. Vertical plate 510 is provided with an extension 523 to cover between end portions of horizontal beam 120 and top beam 130. If the concrete is poured into space 602 as shown in FIG. 10B, the peripheral beam formed within space 602 encloses end portions of horizontal beam 120 and top beam 130. Lower coupler 532 protrudes toward beam coupler 430 in line with the vertical outer surface of column 110 while horizontal plate 520 is placed on the same plane as a top surface of column 110 to support the peripheral beam formed in space 602 as shown in FIG. 10B.

[0063] FIG. 11 is a partial sectional view along lines XI-XI′ of FIG. 9 to show peripheral formwork 500 attached to beam coupler 430 of eave formwork 400 at a portion of the eave formwork away from section “B” in FIG. 9 (i.e., away from the juncture of column 110, horizontal beam 120 and top beam 130). Horizontal plate 520 forms a lower boundary for space 602 to become peripheral beam 752. Lower coupler 532 of formwork 500 is attached to beam coupler 430 of eave formwork 400 via bolts 545 and nuts 546. Bolts 545 go through hole 541 in lower coupler 532 and through a hole in beam coupler 430. Support 440 extends from beam coupler 430 to a distal portion of eave panel 410 (i.e., near end panel 420) to support the 6 inch thick poured concrete that is poured to form eave 603. Space 601 is disposed above roof deck 200 to form roof slab 751 which is to be 3½ inches thick. As can be seen from FIG. 11, the spaces 601, 602 and 603 are continuous so that the entire structure of roof slab 751, peripheral beam 752 and eave 753 are formed by a single concrete pouring and a single hardening step thereby forming a single integrated monolithic structure that is not easily weakened by moisture and rain and does not contain seems and/or cold joints. End panel 420 of the eave formwork extends at least 6 inches high as eave 753 is to be 6 inches thick.

[0064] FIG. 12 is a partial cross sectional views along lines XII-XII′ of FIG. 9 to show form assembly 300 attached to the structure near the juncture of column 110, horizontal beam 120 and top beam 130. The lower end of top beam 130 and one end of horizontal beam 120 is enclosed in the peripheral beam of the monolithic structure. The peripheral beam 752 is supported by column 110 because peripheral beam 752 contains the end portion of horizontal beam 120 which rests on an upper surface of column 110. A roof slab 751 formed above roof deck 200 is supported by roof deck 200 while eave 753 and peripheral beam 752 are formed with roof slab 751 as a single, integrated monolithic unit. As can be seen from FIG. 12, column 110 is never perforated by a hole to hold the formwork 500 in place as this would severely weaken column 110. At the juncture of column 110, horizontal beam 120 and top beam 130, the horizontal beam 120 forms the lower boundary of the formwork instead of horizontal plate 520. A hole is formed in horizontal plate 520 to accommodate horizontal beam 120. This hole in horizontal plate 520 must fit tightly with horizontal beam 120 to prevent poured concrete from leaking out during the hardening process.

[0065] It is further noted that FIGS. 11 and 12 could, but does not illustrate a cover 700 as in Ser. No. 09/931,904 as the upper boundary for the formwork. It is to be appreciated that the use of cover 700 is not necessary and has thus been omitted in FIGS. 11 and 12. When used, cover 700 is perforated by at least one hole to enable concrete to be poured into the formwork. However, even if the slope of the roof slab with respect to the horizontal is 30 degrees, it is not necessary to use cover 700. When cover 700 is not used, the concrete may be poured on top of the formwork. If less water is used in making the poured concrete, the concrete may be poured to make the roof slab and eave even if the roof slab is at a 30 degree angle with respect to horizontal beam 120. This is because a more thicker mixture of poured concrete using less water will result in the concrete not flowing down off the roof slab and into the eaves. A uniform thick roof slab can be formed without use of cover 700 by pouring concrete onto a roof deck having a 30 degree angle with the horizontal if the concrete mixture is thick enough.

[0066] After formwork 500 is attached to the structure, the concrete is then poured to form the roof slab, the peripheral beam and the eave. Because formwork 500 must be removed after the hardening of the poured concrete, portions of formwork 500 must be lubricated prior to the pouring of the concrete so that the formwork 500 will not stick to the concrete when hardened. It is preferred to lubricate the interior portions of formwork 500 with vegetable oil prior to the pouring of the concrete. Vegetable oil enables formwork 500 to be easily removed from the eave 753 and the peripheral beam 752 after the concrete is hardened and vegetable oil can be easily washed off using water. It can be appreciated that other lubricants can be used such as diesel oil. In any scenario, roof deck 200 is not to be lubricated as roof deck 200 binds to roof slab 751 and remains bound to roof slab 751 after the structure is complete.

[0067] As mentioned earlier, it is to be appreciated that all concrete structures in the building are reinforced by steel bars. These steel bars are cross hatched throughout all poured concrete structures. The pitch between bars can vary from about 8 inches to 18 inches, depending on local ordinances, the strength of the building desired and the design of the structure. For example, the higher the structure, the closer together the spacing or pitch between adjacent reinforcing bars.

[0068] In the case of forming the roof slab 751, a steel reinforcing gridwork needs to be put in place upon steel roof deck 200 prior to the pouring of the concrete. Since it is desired to have the steel reinforcing bars near the center of the roof slab rather than at the bottom, plastic spacers and seats are disposed on roof deck 200 in order to raise the steel reinforcing gridwork off the roof deck 200 prior to the pouring of the concrete. Since the roof slab is about 3½ inches thick, the spacers and the seat must raise the steel gridwork off the roof deck by at least 1 inch and preferably almost two inches off steel deck 200. The horizontal steel bars are twisted at junctures with vertical steel bars thereby further reinforcing the structure prior to the pouring of the concrete.

[0069] After the formwork 500 is attached to the structure as in FIG. 9, the interior portions of formwork are lubricated with vegetable oil. Then, the spacers and seats are placed on roof deck is 200 and on appropriate portions of the formwork prior to the pouring of the concrete. Then the concrete mixture is prepared where less water is used so the concrete will not run off the roof when poured. Then the concrete is poured to form a roof slab 751 of 3½ inches thick and eave 753 of 6 inches thick and peripheral beam 752. The concrete is poured at once to form roof slab 751, peripheral beam 752 and eave 753 by filling in spaces 601, 602 and 603 respectively. Then the concrete is allowed to harden and dry. When the poured concrete is dried, the formwork 500 is removed leaving a structure as illustrated by FIGS. 13A and 13B.

[0070] FIG. 13A is a cross section of the concrete in the vicinity of the eave and in the vicinity of the juncture of column 110, horizontal beam 120 and top beam 130 after the concrete is hardened and the formwork is removed. The space between horizontal beam 120 and top beam 130 is filled with hardened concrete that forms the peripheral beam 752 of the structure. Eave 753 and roof slab 751 are sloped at a slope of up to 30 degrees. Roof slab 751 is attached to roof deck 200 in the final structure. Roof slab 751, peripheral beam 752 and eave 753 form a single integrated monolithic unit that are all formed by one concrete pouring and one hardening thereby preserving the length of life of the structure. Roof slab 751 is about 3½ inches thick while eave 753 is 6 inches thick. It is also noted in FIG. 13A that roof deck 200 forms part of the final structure and is never removed.

[0071] FIG. 13B illustrates a cross section of the concrete in the vicinity of the eave but away from the juncture of the top beam 130, the column 110 and the horizontal beam 120 after the concrete is hardened and the formwork is removed. FIG. 13B pertains to the first embodiment of the present invention where no wall has been formed between the columns (i.e., under peripheral beam 752). In this figure, peripheral beam 752 is unsupported but is joined with roof slab 751 and eave 753. Since roof slab 751, peripheral beam 752 and eave 753 are all poured at once and are all hardened at once, there is no cold joints or seems in the resulting structure in FIG. 13B.

[0072] Formation of the roof slab, the cap beam and the eave will now be described according to the second embodiment of the present invention. Unless otherwise noted, the method and structure according to the second embodiment is the same as for the first embodiment. Starting with FIG. 1, a frame structure 100 is built onto floor slab 101. Concrete walls 160 are then formed on the floor slab 101 between columns 110 as illustrated in FIG. 14. Then, the purlins 150 and the roof deck 200 are attached to the top beams 130 as in the first embodiment. Purlins 150 and roof deck 200 can be installed on top beams 130 either prior to or after the formation of concrete wall 160. It is to be appreciated that a modification of the second embodiment would be to also form walls between concrete walls 160 thereby enclosing the structure prior to construction of the roof slab 751, cap beam 754 and eave 753. Cap beam 754 is similar to the peripheral beam 752 in the first embodiment except concrete wall 160 instead of horizontal plate 520 serves as a lower boundary in this second embodiment.

[0073] FIG. 15 is a cross section of concrete wall 160 in the vicinity of column 110. In addition to the vertical and horizontal steel reinforcing bars in the concrete wall 160, the structure further contains rebars 170 that are welded to the column 110 and extend about 12 inches on either side of the column into the concrete blocks 160 in order to form a stronger attachment between concrete wall 160 and column 110. The rebars and the reinforcing steel meshwork are made from galvanized steel. After the concrete blocks with steel reinforcement and the rebars 170 are assembled and welded, concrete is poured into the wall to fill in voids within the concrete blocks and to fill in spaces between column 110 and the blocks and the rebars. Then the concrete is allowed to harden resulting in the structure of FIG. 15.

[0074] FIG. 16 illustrates the formwork 800 that is attached to the structure of FIG. 14 to form the roof slab, the cap beam and the eave for the second embodiment of the present invention. Formwork 800 is different than formwork 300 of FIG. 8 in that horizontal plate 520 and lower coupler 532 are not present in formwork 800 but were present in formwork 300. This is because the presence of concrete wall 160 serves as a lower boundary for the formation of peripheral beam 754 in the second embodiment and thus the horizontal plate 520 is not needed.

[0075] FIG. 17 illustrates formwork 800 attached to the structure of FIG. 14. As mentioned above, the top of concrete wall 160 serves in the second embodiment as a lower boundary for the formwork of the peripheral beam or cap beam. Bolts and nuts are driven through concrete wall 160 to attach plate 430 of eave formwork 400 to the structure and vertical plate 810 of formwork 801 to the structure. After the formwork is attached, the concrete is poured, the concrete hardens and then the formwork is removed leaving the roof deck 200 attached to the structure. The cap beam, the roof slab and the eave are formed as a single integrated monolithic unit.

[0076] FIG. 18 illustrates a close up of portion “C” of FIG. 17 according to the second 11 embodiment of the present invention. FIG. 18 is identical to FIG. 10B except that horizontal plate 520 is replaced by the top of concrete wall 160. The top of concrete wall 160 serves as the lower boundary for cap beam 754.

[0077] FIG. 19 is a cross section of the formwork about the eave for the second embodiment of the present invention. Vertical plate 810 is perforated by holes 811 and beam coupler 430 is perforated by holes. Bolts 545 with nuts 546 screw through concrete wall 160 to bind vertical plate 810 to beam coupler 430. Bolts 545 and nuts 546 are then removed after formation of the roof slab 751, eave 753 and cap beam 754.

[0078] FIG. 20 is a cross section of the formwork about the eave in the vicinity of the juncture of the column 110, the horizontal beam 120 and the top beam 130 for the second embodiment of the present invention. FIG. 20 is identical to FIG. 12 with the exception of peripheral beam 752 is replaced with cap beam 754.

[0079] FIG. 21A is a cross section of an eave at the juncture of column 110, horizontal beam 120 and top beam 130 according to the second embodiment of the present invention after the concrete is poured and hardened and the formwork is then removed. Note that roof deck 200 is part of the final structure and is never removed. FIG. 21A is similar to FIG. 13A except that the peripheral beam is now the cap beam 754.

[0080] FIG. 21B is a cross section of an eave away from the juncture of column 110, horizontal beam 120 and top beam 130 according to the second embodiment of the present invention after the concrete is poured and hardened and the formwork is then removed. Note that roof deck 200 is part of the final structure. FIG. 21A is similar to FIG. 13B except that the peripheral beam is now the cap beam 754 and now the cap beam is supported by concrete wall 160.

[0081] It is to be appreciated that the second embodiment of the present invention is preferred over the first embodiment of the present invention. Therefore, the second embodiment is employed except in cases where wall 160 is not wanted, such as to build a garage, pavilion or gazebo. As is often the case, a structure can be made using both the first and the second embodiment in one structure, like in a garage where only on side of the structure is open.

[0082] After formation of the roof slab, peripheral beam and the eave, when the eave formwork is removed, clay tiles can be placed on the roof slab for aesthetics. In the interior of the structure, the purlins, beams and roof deck are still visible. Therefore, after construction of the roof slab, peripheral beam and the eave, wooden panels and/or drywall can be assembled over the purlins, the steel deck and the top beams to provide a more aesthetically pleasing interior.

[0083] After construction of the roof slab, peripheral beam and eave, formwork needs to be removed only from areas about the eave. Thus, the installation and removal of heavy elaborate formwork inside the structure to support the roof and/or walls is eliminated by the present invention. Since installation and removal of bulky equipment inside the building to support the roof slab is not required, the present invention provides a much less expensive, less labor intensive and less complicated method and apparatus for forming a sloped roof slab, eave and peripheral beam in a monolithic structure. Since the formwork about the eaves is much less bulky and much less heavy than prior art formwork inside the building to support the roof slab, removal of the formwork about the eaves in the present invention is relatively simple, quick and inexpensive. Also, since the formwork about the eave in the present invention is exterior to the structure as opposed to inside the structure, the removal of the formwork in the present invention is much simpler than removal of formwork from the interior of the structure.

[0084] In addition, in the second embodiment of the present invention, walls are formed around the structure prior to forming the roof slab, eave and cap beam. Since it would be nearly impossible to remove bulky formwork from the interior of the structure if the walls around the structure are build first, the present invention provides a method and a structure of a roof deck, cap beam and eave that is well supported compared to the prior art, thereby enabling the structure to be more resilient to harsh weather.

[0085] The above method and apparatus provides for a stronger roof slab and eave as the entire roof slab, eave and peripheral beam are poured at once and hardened at once thereby preventing the formation of seems or cold joints between concrete elements in the structure. The roof slab can be formed to have a 30 degree angle with the horizontal thereby causing water to run off the roof preventing water filtration through the roof slab providing a roof slab that lasts longer. Also, the slope of the roof slab allows heat to rise above the occupied portions of the structure thus providing a more comfortable structure in warm, humid climates.

[0086] Although the preferred embodiments of the present invention has been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims

1. A method for forming a structure having a roof with an appreciable slope wherein a roof slab and an eave form a single monolithic unit, said method comprising the steps of:

forming a horizontal, unsloped floor slab;

building columns spaced apart from each other on said floor slab, said columns defining a perimeter of said structure;

forming horizontal beams connecting tops of pairs of columns, said horizontal beams being parallel to the floor slab and being unsloped;

forming top beams having a slope with respect to the horizontal beams, one end of the top beams being at tops of said columns;

attaching purlins between said top beams;

attaching a steel roof deck to said purlins on said top beams, said steel deck having an angle of at least 10 degrees with the horizontal;

attaching eave formwork at edges of said roof deck along said perimeter of said structure;

pouring concrete over said roof deck and said eave formwork;

allowing the poured concrete to dry and harden forming a roof slab on said roof deck and forming an eave on said eave formwork, said concrete being permanently bound to said roof deck but not being permanently bound to said eave formwork, said eave and said roof slab being a single monolithic unit absent cold joints; and

removing said eave formwork.

2. The method of claim 1, said roof slab and said floor slab being formed around steel reinforcing bars.

3. The method of claim 1, wherein a wall is built along said perimeter of said structure prior to the pouring of concrete step.

4. The method of claim 3, said columns being steel trusses, said wall being attached to said columns by steel rebars disposed within said wall and welded to said column trusses.

5. The method of claim 1, wherein a wall is build along said perimeter of said structure after the pouring of concrete step.

6. The method of claim 1, said method being absent the step of removing formwork for said poured concrete from inside said perimeter of said structure.

7. The method of claim 1, said method being absent removal of any formwork forming a bottom boundary for the roof slab.

8. A structure under construction, said structure comprising:

a horizontal concrete floor slab containing steel bar reinforcement;

a plurality of columns extending up from said floor slab, said columns defining a perimeter of said structure;

horizontal beams and sloped top beams connecting pairs of said plurality of support columns;

a plurality of purlins connecting adjacent top beams;

a steel, unlubricated roof deck disposed on said purlins, said roof deck having an angle with the horizontal of at least 10 degrees;

lubricated eave formwork disposed around unsloped edges of said roof deck;

side plates disposed along sloped edges of said roof deck; and

poured concrete that has hardened forming a roof slab and an eave as a single monolithic unit, said poured and hardened concrete covering said roof deck and said eave formwork, said poured and hardened concrete being absent of cold joints, said hardened concrete binding permanently to said roof deck, said hardened concrete not binding to said eave formwork.

9. The structure of claim 8, said structure being absent any removable formwork disposed inside said perimeter of said structure.

10. The structure of claim 8, further comprising concrete walls disposed along said perimeter and underneath said eave formwork, said concrete walls supporting said eave formwork.

11. The structure of claim 8, said roof slab having steel reinforcement bars formed therein.

12. The structure of claim 8, said poured concrete forming a beam along said perimeter of said structure connecting said eave with said roof slab, said hardened concrete being absent of cold joints between said eave and said roof slab.

13. A method for forming a sloped, monolithic roof slab and eave on a structure having support columns, horizontal beams connecting said columns and top beams inclined at an angle with said horizontal beams, said concrete columns joining with a floor slab around a perimeter of said structure, the method comprising the steps of:

attaching a roof deck to said top beams of said structure, said roof deck being inclined at an angle with the horizontal, said roof deck being formwork for a roof slab and forming a lower boundary for said roof slab;

attaching eave formwork around said perimeter of said structure, said eave formwork being exterior to said perimeter of said structure;

pouring concrete on said roof deck and said eave formwork;

allowing said poured concrete to dry and harden forming an eave and a roof slab as a single monolithic structure, said roof slab permanently binding with said roof deck; and

removing only said eave formwork.

14. The method of claim 13, said roof slab having an angle with the horizontal of at least 10 degrees.

15. The method of claim 13, said roof deck not being removed from said structure, said roof deck forming part of a final structure.

16. The method of claim 14, said roof deck serving to support said roof slab, said method being absent of removal of any formwork, including said roof slab, from an interior of said perimeter of said structure.

17. The method of claim 13, wherein end plates are installed at edges of said roof deck that are not bordering said eave formwork prior to pouring said concrete.

18. The method of claim 13, said eave formwork forming a beam along said perimeter of said structure on top of said columns, said beam being a single monolithic unit with said eave and said roof slab, said roof slab, said eave and said beam being absent of any cold joints.

19. The method of claim 13, further comprised the step of building permanent walls around said perimeter of said structure prior to said pouring concrete step.

20. The method of claim 13, further comprised the step of building permanent walls around said perimeter of said structure after said pouring concrete step.

21. A structure, comprising formwork for forming a sloped roof slab and eave as a single monolithic unit on said structure, said structure comprising:

a roof deck placed on a top of a frame of said structure;

an eave formwork disposed at edges of said roof deck; and

poured and then hardened concrete disposed over both said roof deck and said eave formwork to form said roof slab and said eave respectively as a single monolithic unit absent cold joints, wherein, only said eave formwork is removed after hardening of said concrete and said roof deck is permanently bound to said roof slab and is never removed.

22. The formwork of claim 21, said roof deck and said roof slab have at least a 10 degree angle with the horizontal.

23. The structure of claim 21, said structure having a perimeter, said eave formwork being exterior to said perimeter, said roof deck being disposed within said perimeter, said structure being absent any removable formwork from an inside of said perimeter.

24. The structure of claim 21, further comprising formwork disposed between said eave formwork and said roof deck along a perimeter of said structure resulting in a peripheral beam formed monolithically with said eave and said roof slab, said beam joining together tops of columns of said structure wherein bottoms of said columns are secured to a horizontal floor slab.

25. The structure of claim 21, wherein a form for said roof slab being said roof deck.

26. The structure of claim 23, said eave formwork being removable formwork disposed exterior to said perimeter, said eave formwork being lubricated to be removed from said hardened concrete.

27. The structure of claim 21, said structure being absent any walls joining said roof slab to a floor slab, said structure having only spaced apart columns joining said roof slab to a floor slab.

28. The structure of claim 24, said structure further comprising concrete walls supporting said peripheral beam.

29. The structure of claim 21, said roof deck being made of steel.

30. The structure of claim 21, portions of said roof deck along said perimeter of said structure and not in contact with either said peripheral beam or said eave having side plates.

31. The structure of claim 21, further comprising side plates disposed along edges of said roof deck not adjacent to said eave formwork.