CA2625897A1

CA2625897A1 - Reinforced concrete forming system

Info

Publication number: CA2625897A1
Application number: CA002625897A
Authority: CA
Inventors: Mootaz Sorial
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-10-12
Filing date: 2006-10-12
Publication date: 2007-04-26
Also published as: WO2007047441A2; WO2007047441A3; US20070079570A1

Abstract

A building system for a reinforced concrete floor includes forms made of foam plastic material such as expanded polystyrene for receiving liquid concrete.
The reinforcing steel bars are mutually connected to form trusses which are supported upon vertical, reinforced concrete columns at the corners of each bay, and in some cases upon one another. After the trusses are in place, the forms are lifted into position and supported by the trusses, following which the concrete is poured into or upon the forms and at least partially encloses the steel trusses. The invention is disclosed in the context of a flooring system of the type known in the art as One-Way Joist, but may be adapted to virtually any other system of reinforced concrete floor construction. In any event, the foam forms remain in place, effectively becoming part of the structure, after the concrete has hardened.

Description

f'NVENTION TITLE

Reinforced Concrete Forming System DESCRIPTION
PRIORITY CLAIM

[Para 1 ] The present application claims priority to United States Non-Provisional Patent Application Ser. No. 1 1/163,260 filed on October 12, 2005.
BACKGROUND OF THE INVENTION

[Para 2] The present invention relates to systems and methods of building construction, and more particularly to a combination of members collectively providing a system of forms for poured concrete wherein the forms become an integral part of the finished structure, and a method of constructing a building, or portion of a building, using such a system.

[Para 3] In the construction a typical building having reinforced concrete floors, wooden forms are constructed to accept the poured concrete, and .
reinforcing bars are placed within the forms. The forms are supported in the required positions by temporary shoring, which acts as main support for forms while concrete is fresh. As the concrete hardens, the shoring is removed progressively until finally, the forms are removed and, typically, discarded.
Metal forms may be used and removed after sufficient hardening of the concrete, and, in some cases, reused. In any case, the fabrication of forms for reinforced concrete floors, whether on or off site, and the erection and support of the forms is a major factor in the overall construction costs.

[Para 4] It is a principal object of the present invention to provide a novel and improved forming system for reinforced concrete floors.

[Pai'a"5] ' Another 6l5ject-is to provide a reinforced concrete tlooring system which eliminates, or substantially decreases the use of shores in the support of forms.

[Para 6] A further object is to provide a method of constructing a multi-story building having reinforced concrete floors which shortens the time required to complete the construction with many, attendant economic advantages.

[Para 7] Still another object is to provide a reinforced concrete floor forming system having a higher degree of sound and heat insulation compared to comparable prior art construction as well as to significantly enhance the blast resistance and fire resistance of the structural elements of the structure.
[Para 8] A still further object is to provide a building structure and method involving the use of reinforced concrete forming system which eliminates the use of wooden or metal forms which are removed after use, thus eliminating not only the materials and labor used in constructing the forms but also the stripping of the forms and their removal, as well as coatings, sealers and release agents.

[Para 9) Other objects will in part be obvious and will in part appear hereinafter.

Heading SUMMARY OF THE INVENTION

[Para 10] The invention is comprised of two major aspects..

[Para 11] The first is an innovative use of insulating plastic foam to act as a left-in-place reinforced concrete form. The traits of this form are as follows:
[Para 12] a. the plastic foam is formed into foam slabs and beams. The foams' own weight and the fresh concrete loads from pouring concrete are 'ca"r"ried by the foam slabs. The foam slabs are supported by foam beams. The foam beams are supported by the reinforcing steel instead of the vertical shores that rests on the lower floors as in traditional forming of concrete.

[Para 1 3] b. the forms being left-in-place, eliminates the stripping, removal and coating of the forms as in traditional wood concrete forming.

[Para 14] c. the left-in-place, plastic insulating foam form provide sound and heat insulation and fire and blast protecting for the structural elements of the floor in addition to the cost economy.

[Para 15] The second is an innovative way of assembling the reinforcing steel bars into structural steel trusses to carry loads during construction resulting in substantial cost and time savings through the following traits:
[Para 16] a. capacity of the truss to carry the foam form weight and the fresh concrete pouring loads by means of hangers from its lower chords.

[Para 17] b. capacity of the truss to carry the runways needed for concreting operations with all live loads imposed on the runways through coils attached to its upper chords.

[Para 18] c. this dual capacity of the truss eliminates or greatly reduces the shoring needed for forms support while concrete is fresh as in traditional wood forming operations, thus freeing the floors lower than the one being poured form the maze of shores obstructing their use by other building trades. Such earlier access to the floors allows the shortening of the construction schedule, the earlier occupancy of the building and earlier cash flow proceeds.

Heading SEQUENCE OF CONSTRUCTION

[Para 19] In furtherance of the foregoing objects, the invention contemplates a building system wherein a plurality of vertical, reinforced concrete columns "are erected in the usual manner at selected positions. Although, as will be pointed out later, the construction system and method may be applied to many generic types of flooring design, the disclosed system and method are in the form of the well-known "One Wayjoist" design. In the preferred sequence of construction, a truss is assembled from reinforcing bar and lifted into position for connection at opposite ends to a pair of laterally adjacent columns. This is repeated until all laterally adjacent columns are connected by such a girder truss. joist trusses are then assembled and lifted into position for attachment to longitudinally adjacent columns and girder trusses until attachment of all joist trusses has been completed. Slab trusses are then assembled, lifted into position and connected to the joist trusses, thereby completing the basic structural steel skeleton necessary for support of the forms. Additional reinforcement for the floor elements above the assembled skeleton is connected to the skeleton as required by the particular design of the project, following which all reinforcement is in place.

[Para 20] The forms of the building system of the invention are fabricated from a material such as Modified Expanded Polystyrene Plastic, the preferred material being Preformed, Cellular Polystyrene Thermal Insulation, e.g., EPS
Insulation, ASTM C578-87a Type IX. The forms are designed in several cross-sectional configurations, each suited for use at a specified place in the composite system. Two such foam forms are used in the girder forms per span and are simultaneously lifted to a position below the girder truss and temporarily supported in place as they are connected to one another and to the columns and girder trusses. This is repeated until all girder forms have been installed. Four foam form modules per span are used for every joist, and are temporarily supported in place as they are connected to one another, to the coi"urnns and girder forms, and to the joist trusses. Ties are then installed to prevent the girder and joists forms from opening up under pressure from the poured concrete. The slab foam form modules are then lifted up and temporarily supported as they are connected to their slab trusses through steel hangers. Now all forms are assembled in their intended locations, all steel and foam components are in place and ready to accept the loads to be applied to them.

[Para 21 ] Metal runway frames are then assembled and connected to the joist trusses. Wood planks are placed on the runway frames then plywood sheets are connected to the wood planks in a pattern allowing the concrete pouring operation to begin. Plywood sheets, planks and runway frames may be progressively removed when they are no longer required until, at the completion of the concrete pouring operation, all plywood sheets, planks and runways are removed. Upon hardening of the concrete, if architecturally required tie and hanger connections and bolting assemblies may be dismantled and removed. The foam forms, however, remain permanently in place.

[Para 22] The foregoing and other features of the building system and sequence of construction will be more readily understood and fully appreciated from the following detailed disclosure taken in conjunction with the accompanying drawings.

Heading BRIEF DESCRIPTION OF THE DRAWINGS

[Para 23] Figure 1 is a top plan view of an entire flooring system constructed in accordance with the present invention, with a circled portion indicating a part of the structure which is shown in Figure 2;

õ ..
Para 2'41 Figure 2 is __ a . to.p plan view of the portion of the flooring system indicated in Figure 1 ;

[Para 25] Figure 3 is a perspective view of the columns at the four corners of the portion of the flooring system shown in Figure 2 with the girder trusses positioned in preparation for attachment to laterally adjacent columns;

[Para 26] Figure 4 is a perspective view showing the girder trusses mounted to the columns and the joist trusses positioned for attachment to the columns and girder trusses;

[Para 27] Figure 5 is a perspective view showing the girder and joist trusses fully mounted and the slab trusses in position for attachment to the joist trusses;

[Para 28] Figure 6 is a perspective view showing all trusses fully mounted, forming a completed structural skeleton, and additional reinforcement elements in position for attachment to the skeleton;

[Para 29] Figure 7 is a perspective view showing the steel skeleton and reinforcement in place with the girder foam forms positioned for mounting to the girder trusses and columns;

[Para 30] Figure 8 is a perspective view showing the girder forms in place and the joist forms in position to be mounted;

[Para 311 Figure 9 is a perspective view showing the girder and joist forms fully mounted and the slab forms positioned for mounting;

[Para 32] Figure 10 is a perspective view showing all forms assembled with the steel skeleton and reinforcement in place and the runways' steel frame in position for attachment to the joist trusses;

[Para 33] Figure 1 1 is a perspective view showing runway frames installed on the trusses and wood planks positioned for attachment to the runway frames;

[Para s4a Figure 12 is a perspective view showing the wood planks attached to the runway frames and the plywood sheets in position for attachment to the wood planks;

[Para 35] Figure 13 is a perspective view showing the plywood sheets attached to the wood planks and the power buggy being lifted to be positioned on the runway;

[Para 36] Figure 14 is a perspective view showing the completed floor forming structure after pouring of concrete and partial removal of runway frames, planks and plywood sheets;

[Para 37] Figures 15 through 21 are elevational views of foam forms in cross section at the positions of lines 1 5-1 5 through 21-21, of Figure 2, respectively;

[Para 38] Figures 22 and 23 are fragmentary, elevational views showing the relationship of the joist and slab forms and trusses; and [Para 39] Figures 24 and 25 are fragmentary, elevational views showing the relationship of the joist and girder forms and trusses.

Heading DETAILED DESCRIPTION OF THE DRAWINGS

[Para 40] Referring now to the drawings, in Figure 1 is shown a concrete floor plan for a building constructed according to the present invention. The illustrated plan includes sixteen sections or bays, four rows of laterally adjacent bays in each of four longitudinally adjacent bays, a bay being defined as a section of the floor plan having a pair of laterally adjacent, and a pair of longitudinally adjacent, vertical columns at its four corners. The columns at each corner of the floor are denoted by reference numeral 10, the laterally adjacent columns between corner columns 10 along the ends of the floor are indicated by reterence numeral I L, and the longitudinally adjacent columns along each side edge of the floor are denoted by numeral 14. All internal columns, i.e., the columns which are neither at the corners, ends or side edges of the floor, are denoted by reference numeral 16. Corner and laterally adjacent columns 10 and 12, respectively, are connected to one another by end girders 18, while internal columns 16 are connected to one another and to side edge columns 14 by intermediate girders 20. Edge joists 22 extend between corner and side columns, and edge joists 24 extend between longitudinally adjacent girders. Although all elements are shown in solid lines, it will be understood (and will be shown later in more detail) that the completed floor system would be covered by a continuous layer of concrete.

[Para 41 ] One of the floor bays is circled in Figure 1 and appears as Figure 2.
The vertical columns at the four corners of the bay of Figure 2 are denoted by reference numerals 16a, 16b, 1 6c and 1 6d. Laterally adjacent columns 16a and 6b, and laterally adjacent columns 16c and 6d, are con'nected by girders 20a and 20b, respectively. Edge joists 22a are connected between longitudinally adjacent columns 1 6a and 1 6c and to one another along one edge of the module, and connected between columns 16b and 16d along the other edge. Intermediate joists 24a are connected between girders 20a and 20b. The trusses and forms which will be described in the following paragraphs are shown in Figure 2 in hidden lines, the floor being shown in its final condition with the trusses and forms covered by concrete.

[Para 42] The successive steps in carrying 'out the construction method of the invention, and in fabricating the structure of the invention, with respect to the module of Figure 2 are illustrated (somewhat diagrammatically) in Figures through 14, to which attention is now directed. Vertical columns 16a - 16d nave been constructed ot reintorced concrete in the usual manner. Girder trusses are fabricated on grade or on the floor below that is shown in the drawings. A pair of girder trusses, assembled by connecting together reinforcing bars of appropriate lengths and diameters, is shown in Figure 3 as they are lifted into position for attachment to the vertical columns. Girder truss 26a will be connected at opposite ends to stirrups 27a anchored in the concrete columns and girder truss 26b will likewise be connected to stirrups 27b in columns 1 6c and 1 6d. Although the girder trusses may take a variety of structurally acceptable forms, a preferred form is that shown in Figure 3 wherein each truss includes a pair of upper chords and a pair of lower chords, all upper and lower chords being connected to one another by stirrups and diagonal members.

[Para 43] The elements are shown in Figure 4 after girder trusses 26a and 26b have been permanently affixed to stirrups 27a and 27b, respectively, and joist truss 28 is being lifted into position for attachment at its opposite ends to girder trusses 26a and 26b. joist trusses 28, similar in design to girder trusses 26a and 26b, continue to be positioned between and attached to the girder trusses at equally spaced intervals until all required joist trusses are in place.
Two joist trusses 28 are shown in Figure 5 connected between the girder trusses, although it is assumed that all joist trusses are in place when slab trusses, one of which is shown in Figure 5 and denoted by reference numeral 30, are lifted into position for attachment at opposite ends between two laterally adjacent joist trusses. In Figure 6, all of girder trusses 26a and 26b, joist trusses 28 and slab trusses 30 are shown in their fully erected positions (only two joist and three slab trusses being shown) with any additional reinforcing members which may be required in the particular design shown aiagrammatically and indicated by reference numeral 32 positioned for attachment to the trusses.

[Para 44] All of the members making up the steel skeleton and reinforcement have been fully erected in Figure 7 and the foam forms which will accept the poured concrete will be attached thereto. Two configurations of such forms, referred to as end and lateral girder forms, numbered 34a and 34b, respectively, cooperatively mal<e up the girder forms. A single end girder form 34a is shown in Figure 7 adjacent column 1 6c, it being understood that one such form would be installed adjacent each side column. A first intermediate girder form 34b is shown adjacent columns 16a and 16b and a second adjacent columns 16c and 1 6d. One portion of each lateral girder forms 34b faces inwardly, toward the bay described, and the other portion, indicated by reference numeral 34b', faces away from this bay, when it is at the edge of the floor. The foam forms are lifted upwardly, from below the steel skeleton, end forms 34a being bolted to the columns and lateral forms 34b being supported from the girder trusses by hangers.

[Para 45] In Figure 8 the girder forms are shown fully installed and the joist forms 36 are being lifted into position from below the joist trusses 28 and slab trusses 30, respectively. Joist forms36 are supported by hangers from joist trusses 28, as indicated in Figure 9 which also shows tie rod 38 extending across one of joist forms 36, through the spaced walls of the form with plates affixed on each exterior side of the form in order to reinforce the latter so that it does not open up when, at a later stage, the concrete is poured into the form. A similar tie rod 40 is shown in Figure 8 installed on one of the girder forms. Joist forms 36 continue to be lifted into place until a joist form is provided for each joist truss.

[PaYa'46] S I'abf6rni 47'1s"sh6wn in Figure 9 being lifted into place for placement between the spaced walls of laterally adjacent joist forms. This is continued until a slab form is mounted between each pair of joist forms. Slab forms 42 are shown mounted upon joist forms 36 in Figure 10, which also shows "U-head" 44 being positioned for temporary assembly through coils on joist trusses 28. In Figure 1 1 a pair of U-heads are shown mounted upon joist trusses with wooden planks 46 (e.g., 4"x4") being positioned for placement on the U-heads. Planks 46 are in place and plywood sheets 48 are being positioned for placement upon the planks in the illustration of Figure 12. The runway platform provided by the U-heads, wooden planks and plywood sheets is shown in complete form in Figure 13 and power buggy 50 is being lifted for placement on the runway. Fresh concrete in fluid form is supplied to buggy 50 and the latter is maneuvered across the runway platform as required to deposit the concrete into the foam forms, as seen in Figure 14 where a portion of reinforced concrete floor 54 is seen in cross section.. When concrete pouring is completed, the buggy and runway platform are removed for use on the next floor. All forms remain in place and become part of the finished structure.
[Para 47] Although the foam forms may take a wide variety of dimensions and configurations to suit the requirements of a particular structural design, examples of typical girder, joist and slab forms, in cross section as indicated in Figure 2 with the section lines numbered to correspond to the Figure numbers (1 5- 21). A girder form, denoted generally by reference numeral 34b, is shown in Figures 1 5, 16 and 1 7, at the different positions along its length indicated by the section lines. When mounted in its final position and supported by one of the girder trusses, form 34b has a horizontally disposed surface 62 upon which the fluid concrete is to be poured. At the position of cross sect'i'ori 15=1 5, form 34b has a pair of side members 64 with spaced, opposing surfaces 66 defining, with horizontal surface 62, an essentially U-shaped cross section with open top 68. Also, beams 70 extend along the lower side, and beam 71 extend outwardly from side walls 64 at this position. At the position of cross section 16-16 the form does not have side members, but rather communicates with the joist forms, as discussed later in more detail.
At the position of cross section 17-17, form 34b includes side members 64, but not the lower beams which are present at the Figure 15 and positions.

[Para 48] A typical joist form 36 is shown in Figures 18 and 19 at the cross sectional positions indicated by section lines 18-18 and 19-19, respectively, of :Figure 2. Form 36 has a lower surface 74, bounded by spaced, opposing, side surfaces 76, forming a U-shaped enclosure with open top 78. The open ends of joist forms 36 communicate with the interior of girder forms 34b at positions such as that of Figure 16 where the girder forms do not have side members, as mentioned earlier. Joist form 36 includes slab portion 77 and beam portions 79. Slab form 42 is shown in Figures 20 and 21 at the positions of the correspondingly numbered section lines in Figure 2. Slab form 42 includes integral slab 80 and beam 82 portions.

[Para 49] Assembled joist and slab forms 36 and 42 are shown, together with joist and slab trusses 28 and 30, respectively, in Figures 22 and 23 at the positions indicated in Figure 2 by section lines 22-22 and 23-23, respectively in Figure 2. The vertical members of joist trusses 28 are in the form of stirrups 84 for the side joist truss and hangers 86, which extend through and support the foam joist forms, for intermediate joist trusses. As seen in the enlarged detail of Figure 23, in a preferred system for supporting slab trusses30 on joist trusses 28, one slab truss has a horizontal member resting upon a portion of the joist truss to torm a roller support 88 while the adjacent slab truss has a n end portion of the horizontal member bent around the joist truss to provide simple support 90, thereby allowing for relative horizontal movement of the joist and slab trusses. The same type of system for supporting joist trusses upon girder trusses 26 is shown in Figures 24 and 25 at the positions indicated by section lines 24-24 and 25-25, respectively, in Figure 2. That is, in Figure 24 an upper horizontal member of joist truss 28 extends over a horizontal member of the girder truss to form a roller support 92 and, in the adjacent joist and girder trusses, the upper horizontal member of joist truss 28 is bent to form a hook passing around a horizontal member of girder truss 26 to provide simple support 94. The horizontal members of joist trusses 28 pass over, and are supported by, two horizontal members of girder trusses 26 at the position of Figure 25.

[Para 50] There will be some variation in the design of the foam forms at side or end locations, as opposed to the intermediate positions shown, but the range of possible designs to suit the requirements at the various positions will be apparent to those skilled in the art. For example, in the joist form shown extending along the left-hand side of the floor of Figure 14 (and the same joist form shown at the left side of Figure 22), outer wall member 36a is higher than wall member 36b so that the fluid concrete can form a continuous slab.
Another dimensional consideration is the necessity to make the relative dimensions of slab forms 42, joist forms 36 and slab trusses 30 such that the slab forms can be lifted into place to be supported on each side by beam portions 79 of joist forms 36..

[Para 51] While the detailed description of the invention has taken the form of the well-known One Way joist pan system, it will be apparent that the principies or tne invention may ae encompassed in other types of cast-in-place and precast concrete floor systems in current use such as Flat Plate, One Way Slab, Two Way Slab, Banded Beam, Two Way Joist and Flat Slab constructions.

Claims

[Claim 1] A form having a surface upon which fluid concrete is poured, said form, including said surface, being composed at least partially of a plastic foam material.
[Claim 2] The form of claim 1 wherein said form is composed entirely of said plastic foam material.
[Claim 3] The form of claim 1 wherein said foam material is expanded polystyrene.
[Claim 4] The form of claim 3 wherein said form is composed entirely of expanded polystyrene.
[Claim 5] The form of claim 1 wherein said form is elongated along an axis and essentially U-shaped in cross section transverse to said axis, having an open side through which said concrete may be poured.
[Claim 6] The form of claim 5 wherein said form includes at least one slab and at least one beam portion.
[Claim 7] The form of claim 5 wherein said form is composed entirely of expanded polystyrene.
[Claim 8] A reinforced concrete floor comprising;

at least one form composed at least partially of a plastic foam material;
a plurality of elongated reinforcing bars positioned in predetermined relationship to said form; and a layer of hardened concrete having at least one surface contacting an opposing surface of said form and at least partially enclosing said bars.
[Claim 9] The concrete floor of claim 8 wherein said form is composed entirely of said foam material.
[Claim 10] The concrete floor of claim 9 wherein said plastic foam material is expanded polystyrene.
[Claim 11] The concrete floor of claim 10 wherein said form is entirely composed of expanded polystyrene.
[Claim 12] The concrete floor of claim 8 wherein said bars are mutually interconnected to form a truss.
[Claim 13] The concrete floor of claim 12 wherein said truss is connected to and supports said form.
[Claim 14] The concrete floor of claim 13 wherein said truss is positioned vertically above a portion of said form, and further comprising a hanger connecting said truss to said portion of said form.
[Claim 15] A reinforced concrete floor having an upper surface in a substantially horizontal plane, said floor comprising:

at least a first truss formed from a plurality of interconnected reinforcing bars;
at least one pair of vertically extending, horizontally spaced, first columns to each of which said truss is connected;

at least one form defining a cavity for accepting fluid concrete, said form being connected to and supported by said truss; and a layer of concrete at least partially enclosing said truss and having a first surface in contact with an opposing surface of said cavity and a second surface in said horizontal plane.
[Claim 16] The concrete floor of claim 15 wherein said truss, form and concrete collectively form a first girder extending between said first columns.
[Claim 17] The concrete floor of claim 16 and further comprising a second truss formed from a plurality of interconnected reinforcing bars, a pair of vertically extending second columns horizontally spaced from one another and from said first pair of columns, said second truss being connected to each of said second columns, a second form defining a cavity for accepting fluid concrete, said second form being connected to said second truss, and a second layer of concrete at least partially enclosing said second truss and having a first surface in contact with an opposing surface of said second form cavity and a second surface in said horizontal plane, said second truss, second form and second layer of concrete collectively forming a second girder extending between said second columns.
[Claim 18] The concrete floor of claim 17 and further comprising a third truss formed from a plurality of interconnected reinforcing bars, said third truss being connected to each of said first and second trusses, a third form defining a cavity for accepting fluid concrete, said third form being connected to said third truss, and a third layer of concrete at least partially enclosing said third truss and having a first surface in contact with an opposing surface of said third form cavity and a second surface in said horizontal plane, said third truss, third form and third layer of concrete collectively forming a joist extending between said first and second girders.
[Claim 19] The concrete floor of claim 18 wherein all of said forms are composed entirely of a plastic foam material.
[Claim 20] The concrete floor of claim 19 wherein said plastic foam material is expanded polystyrene.
[Claim 21] The method of constructing a reinforced concrete structure, said method comprising:

preparing at least one form composed at least partly of a plastic foam material;
supporting said form in a predetermined position with at least one surface of said form disposed to receive thereon fluid concrete; and pouring fluid concrete onto said at least one surface and allowing said concrete to dry.
[Claim 22] The method of claim 21 wherein said form is composed entirely of said plastic foam material.
[Claim 23] The method of claim 22 wherein said plastic foam material is expanded polystyrene.
[Claim 24] The method of claim 21 wherein said form is allowed to remain in place after said concrete hardens to effectively become a part of said structure.
[Claim 25] The method of claim 21 and further comprising preparing at least one truss from interconnected reinforcing bars and supporting said truss in a predetermined position, and wherein said form is supported by said truss.
[Claim 26] The method of claim 25 and further comprising preparing a pair of spaced, vertical columns, and supporting said truss upon said columns prior to supporting said form by said truss.
[Claim 27] The method of claim 26 wherein said truss and said form are so relatively oriented that said truss is at least partially enclosed by said concrete after the latter had been poured.
[Claim 28] The method of constructing a reinforced concrete floor having a surface in a substantially horizontal plane and extending between a pair of first, vertically oriented, laterally spaced columns and a pair of second, vertically oriented columns laterally spaced from one another and longitudinally spaced from said first columns, said method comprising:
forming a pair of first trusses and at least one second truss of interconnected reinforcing bars;

supporting one of said first trusses upon and extending between said first columns, and another of said first trusses upon and extending between said second columns;

supporting said at least one of second truss upon and extending between said one and said another of said first trusses;

forming first and second concrete forms;

supporting a pair of said first forms upon respective ones of said first trusses;
supporting one of said second forms upon said second trusses; and pouring fluid concrete into said first and second forms to enclose at least portions of said first and second trusses.
[Claim 29] The method of claim 28 and further comprising allowing said first and second forms to remain in place after said concrete hardens, whereby said first trusses, first forms and concrete become girders of said floor and said second truss, second form and concrete become a joist of said floor.
[Claim 30] The method of claim 29 wherein said first and second forms are composed of a plastic foam material.
[Claim 31] The method of claim 30 wherein said foam material is polystyrene.
[Claim 32] The method of claim 28 and further comprising supporting at least two of said second trusses upon and extending between said first trusses, forming a third truss and a third form, supporting said third truss between said second trusses, supporting said third form upon said second forms below said third truss, and pouring said fluid concrete over said third form to enclose at least a portion of said third truss.
[Claim 33] The method of claim 32 where said concrete poured into said first and second forms and over said third form has a substantially continuous upper surface in said horizontal plane.