US3305612A

US3305612A - Method for forming a prefabricated truss deck

Info

Publication number: US3305612A
Application number: US372796A
Authority: US
Inventors: Woodrow W Frantz
Original assignee: Conodec Inc
Current assignee: Conodec Inc
Priority date: 1964-06-05
Filing date: 1964-06-05
Publication date: 1967-02-21
Anticipated expiration: 1984-02-21
Also published as: GB1115227A; DE1584412B1; US3349457A; FR1445745A

Description

Feb. 21, 1967 w. w. FRANTZ 3,305,612

METHOD FOR FORMING A PREF'ABRICATED TRUSS DECK Filed June 5. 1964 5 Sheets-Sheet 2 BY W M,.

Feb. 21, 1967 w. w. FRANTZ 3,305,612

METHOD FOR FORMING A PREFABRICATED TRUSS DECK Filed June 5, 1964 5 Sheets-Sheet :5

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IIIHIIHIIIIIIIIIIIHHHI H H l' 3} 0/ 36 17 ml 96 i3} r H m i /0/ 70 l. c." H x\.' U H K68 R70 68 as United States Patent 3,305,612 METHOD FOR FORMING A PREFABRICATED TRUSS DECK Woodrow W. Frantz, Nazareth, Pa., assignor, by direct and mesne assignments, to Conodec Inc., Easton, Pa., a

corporation of Pennsylvania Filed June 5, 1964, Sen. No. 372,796 4 Claims. (Cl. 264-69) This invention relates to a method for producing a prefabricated truss deck.

Prefabrication of structural components for a building has become widespread. It has been found that structural components can be more economically shop fabricated and assembled at the construction site.

This invention relates to the shop fabrication of a floor or roof component. In particular, this invention deals with the fabrication of a floor or roof component comprising a pair of substantially parallel open web steel joists embedded within a precast concrete slab.

Accordingly, it is an object of this invention to provide a method for forming a prefabricated truss deck.

A more specific object of this invention is to provide a method for forming a prefabricated truss deck in a more economical manner.

Yet another object of this invention is to provide a method for forming a plurality of prefabricated truss decks in a single continuous operation.

Another object of this invention is to provide a method for forming a plurality of prefabricated truss decks in a single continuous operation which can easily be joined to each other at a construction site for forming a roof or floor.

Other objects will appear from the disclosure which follows hereinafter.

For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIGURE 1 is a top plan view of a portion of the apparatus used in carrying out the method of the instant invention and illustrates a casting bed and a hopper mounted thereon for selectively dispensing a cementitious mixture into the casting bed.

FIGURE 2 is an end view in elevation of the apparatus illustrated in FIGURE 1 as seen substantially along the plane indicated by the line 2-2 of FIGURE 1.

FIGURE 3 is a fragmentary cross sectional view taken substantially along the plane indicated by the line 33 of FIGURE 2.

FIGURE 4 is an end view in elevation of the structure illustrated in FIGURE 3 as seen from the plane indicated by the line 4-4 of FIGURE 3.

FIGURE 5 is a fragmentary perspective view of one end of the casting bed illustrated in FIGURE 1.

FIGURE 6 is a perspective view of a preassembled truss structure comprising a portion of the end product formed by the method and apparatus of the instant invention.

FIGURE 7 is an enlarged fragmentary plan view of one end of the truss illustrated in FIGURE 6.

FIGURE 8 is a fragmentary cross sectional view taken substantially along the plane indicated by the line 8-8 of FIGURE 7 and also showing in phantom the manner in which the truss is adapted to be located relative to the casting bed in accordance with the method of the instant invention.

FIGURE 9 is a fragmentary enlarged plan view of the other end of the truss illustrated in FIGURE 6.

FIGURE 10 is a fragmentary cross sectional view taken substantially along the plane indicated by the line 10-10 of FIGURE 9 and also illustrating in phantom the manner in which the truss is adapted to be located with respect to the casting bed when carrying out the method of the instant invention.

FIGURE 11 is a top plan view similar to FIGURE 1 but showing the hopper carriage moved along the casting bed and a first truss member disposed within the casting bed.

FIGURE 12 is a fragmentary cross sectional view taken substantially along the plane indicated by the line 1212 of FIGURE 11.

FIGURE 13 is an enlarged detail of the lefthand portion of FIGURE 12 indicated by the circle 13.

FIGURE 14 is a fragmentary cross sectional view taken substantially along the plane indicated by the line 1414 of FIGURE 12 and showing in phantom the location of a second truss element on the casting bed with respect to a first truss element.

FIGURE 15 is a top plan view as seen substantially along the plane indicated by the line 15-15 of FIG- URE 14.

FIGURE 16 is an end view in elevation illustrating the manner in which a pair of identical truss decks formed by the apparatus and method of the present invention can be joined to each other in constructing a roof or floor.

FIGURE 17 is an enlarged detail view, partly in section, of the central portion of FIGURE 16 indicated by the circle 17.

The apparatus of the instant invention includes a casting bed generally designated by the numeral 20.

The casting bed 241 includes a floor 21. The floor 21 is mounted on the top flanges of a pair of parallel I-

beams

40 and 44 running the length of the casting bed. Mounted between the opposed webs of the I-

beams

40, 44 adjacent their ends, are a pair of parallel,

rectangular beams

41 and 42. The I-beams 4t) and 44 are supported by

transverse beams

23 and 24 at their respective ends.

A side wall 48 is pivotally connected to the web of the I-beam 40. Similarly, a side Wall 50 is pivotally connected to an I-beam 44.

Side walls

48 and 50 extend the longitudinal length of the I-beams.

The

side walls

48 and 50 include a plurality of longitudinally spaced triangular shaped brackets 60. Secured to the webs of the I-

beams

46 and 44 are a plurality of pairs of triangularly shaped brackets 62. Each of the

brackets

60, 62 include a hinge collar 64. The hinge collar on the bracket 60 is disposed between the hinge collars on a pair of brackets 62 and a hinge pin is inserted within the collars.

End walls

46 and 52 are supported at remote ends of the casting bed 20 upon the top flanges of the I-

beams

40 and 44. The

end walls

46 and 52 are pivotally mounted to the

rectangular beams

42 and 41 respectively. A plubrackets 54 are disposed between a pair of adjacent hinge collar 58 are secured to the

end walls

46 and 52. Pairs of spaced triangular brackets 56 are secured to the

rectangular beams

42 and 41. The brackets 56 also terminate in a hinge collar 58. The hinge collars on the brackets 54 are disposed betwen a pair of adjacent hinge collars on the brackets 56 an a pivot pin is run through the aligned collars.

A pair of

rails

26 and 28 are supported on top of the

transverse beams

23 and 24 and run the length of the casting bed 20. Mounted on the

rails

26 and 28 in overlying relation to the casting bed floor 21 is a hopper 22 for dispensing cementitious material. The hopper 22 includes a plurality of wheels 30 in enga ement with the 32, as shown in FIGURE 2, about which is entrained an endless chain 38. A bracket 34 extends in cantilever fashion from the side of the hopper 22. An electric motor 36 is supported upon the bracket 34. A sprocket is mounted upon the motor shaft and engages the endless chain 38. Therefore, upon actuation of the electric motor 36, the wheels 30 of the hopper 22 will be rotated and the hopper can be caused to selectively move along the casting bed 20.

In the fabrication of the truss deck by the method of the instant invention, a preassembled truss 66 is provided. The truss 66 includes a pair of spaced, substantially

parallel joist sections

68 and 70. The

joist sections

68 and 70 are connected by a steel joist web 72. The outer portions of the joist web 72 are inclined away from the bottom chord of the

joists

68 and 70.

The top chord 74 of each joist section includes a pair of sloping

extensions

76 and 82 at its opposite ends. The

extensions

76 and 82 terminate in

horizontal portions

78 and 84 respectively. The horizontal portion 78 includes an aperture 80. Similarly, the horizontal extension 84 includes an aperture 86.

Removably secured to the horizontal extension portion 78 is an angle iron positioning bar 88. Core pins 90 connect the positioning bar 88 to the horizontal extension 78 by being inserted within the apertures 80.

A Z-shaped cut-off bar 92 is removably supported upon the horizontal extensions 84. Core pins 94 attached to the cut-off bar 92 are inserted in the apertures 86 in the horizontal extensions 84.

As shown in FIGURES l2 and 13, a continuous upstanding flange 98 is provided along the opposite longitudinal edges of the floor 21 of the casting bed 20.

The method of the present invention is carried out with the previously described apparatus, substantially as follows:

The side and end walls of the casting bed are disposed in their upper positions to close the casting bed. A light oil film is applied to the inside flanges of the

side walls

48 and 50 and the

end walls

46 and 52 of the casting bed 20. The oil film is also applied on the floor 21 of the casting bed.

The motor 36 is actuated to cause movement of the hopper 22 along the

rails

26 and 28. As the hopper 22 moves along the casting bed above the floor 21, cementitious material is dispensed through a door in the bottom of the hopper onto the floor 21 of the bed 20.

As soon as the hopper 22 reaches a position as substantially shown in FIGURE 11, the truss 66 is immersed within the cementitious material 96 deposited on the bed 21. The truss 66 is lowered into the cementitious material 96. An oil film is applied to the positioning bar flanges and the cut-off bar flanges. The truss 66 is vibrated by means of jack hammers or the like as it is immersed.

As shown in FIGURES 11-15, the positioning bar 88 is lowered until its horizontal flange seats upon the

side walls

48 and 50 and the edge of the horizontal flange abuts the upstanding flange on the end wall 46. The cutoff bar 92 is lowered until the bottom edge of one of its vertically extending flanges seats on the

side walls

48 and 50 and its other vertically extending flange seats on the floor 21 of the bed 20. The lateral dimension of the floor 21 is such that the angularly extending portions of the joist web 72 are seated between the upstanding flanges 98 on the floor 21.

The core pins supported by bar 88 and bar 92 are also dimensioned to seat upon the floor 21 of the casting bed.

Meanwhile, the hopper 22 is continuing its travel along the casting bed 20. More cementitious material 96 is deposited upon the floor 21. As soon as space allows, a second truss 66 is immersed within the cementitious material 96. The positioning bar 88 on the second immersed truss is seated upon the

opposed side walls

48 and 50. An edge of the horizontal flange of the positioning bar 88 is placed in abutment with the horizontal flange of the cut- 4 off bar 92 on the previously immersed truss. shown in phantom in FIGURES l4 and 15.

The process is continued as previously described until the casting bed 20 is filled and a desired number of trusses 66 have been immersed. In practice, the casting bed is approximately 80 feet in length.

The cementitious mixture is then allowed to harden. The hopper 22 is removed from the

tracks

26 and 28.

Side walls

48 and 50 are then pivoted away from the hardened mixture on the floor 21. The

end walls

46 and 52 are also pivoted away from the hardened mixture.

The individual trusses 56 and cementitious material attached thereto may then be elevated from the floor 21 of the casting bed 20. A plurality of truss desks have been formed because of the plurality of chambers defined by the cut-off bars 92 when they were disposed within the cementitious material 96. The resultant truss deck is inverted and supported upon the chords 74. The truss decks may be stacked one on top of each other for ready transportation or storage at the construction site.

Each truss deck includes the open web

steel joist sections

68 and 70 and a concrete slab reinforced by the joist web 72. Due to the inclusion of the upstanding flanges 98 on the floor 21 of the casting bed, longitudinally extending notches 101 are formed along the opposed longitudinal edges of the slab. As shown in FIGURE 17, the ends of the joist web 72 are exposed by the notches 101.

The last mentioned construction lends itself to easy assemblage of the truss decks at the construction site.

As shown in FIGURE 16, the inverted truss decks are adapted to have their longitudinal edges placed in abutment to form a roof or floor at the construction site. The juxtaposed notches 101 form a longitudinal opening 100. The exposed ends of the joist web may be Welded together as shown at 102. Hence, each truss deck may be easily joined to another at the construction site to form a prefabricated floor or roof element.

Removal of the core pins 94 from the hardened mixture results in the formation of a plurality of anchor holes. The prefabricated roof or floor can then be secured to other structural components of, the building.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

1 claim:

1. A method of fabricating building slabs comprising the steps of pouring a cementitious mixture into a casting bed substantially longer than the desired length of a slab, providing a preassembled reinforced truss of a length less than the length of the casting bed and having two spaced susbtantially parallel joists, immersing a portion of said truss into a portion of said mixture with the major portion of the joists above and spaced from the mixture, immersing a cut-off bar into said mixture to separate said portion from the remainder of said mixture, vibrating said truss while it is immersed in said mixture, providing a second pre-assem bled reinforced truss having two spaced substantially parallel joists, immersing a portion of said second truss into the remainder of said mixture, vibrating said truss while it is immersed in said mixture; permitting said mixture to solidify into slabs integral with said trusses, separating the trusses and their solidified slabs from said bed and cutoff bar, and then turning said slabs and trusses over so that the slabs are supported by the trusses.

2. A method in accordance with claim 1 including using a casting bed having a longitudinally extending protrusion along the side edges of its floor, immersing said trusses so that portions on the trusses abut said protrusions, so that the solidified slabs will have a notch at the upper corner along their lengths exposing the said portions of the trusses.

3. A method in accordance with claim 1 including providing at least one core pin on at least one end of one of This is said trusses with the pin extending to the floor of the bed, and removing said pin after the mixture has solidified into slabs and the sla'bs have been separated from the bed, thereby providing an anchor hole adjacent an end of the slab.

4. A method in accordance with claim 11 wherein said preassembled reinforced truss of a length less than the length of the casting bed and having two spaced substantially parallel joists has the cutoff bar connected thereto at one end, including immersing said preassembled rein- 10 References (Iited by the Examiner UNITED STATES PATENTS 2,705,886 4/ 1955 Annett 52723 2,948,947 8/ 1960 Berg et a1 26442 2,979,801 4/1961 Gasmire 264-42 3,173,193 3/1965 Grebner et al. 29155 ROBERT F. WHITE, Primary Examiner. ALEXANDER H. BRODMERKEL, Examiner. I. A. FINLAYSON, Assistant Examiner.

Claims

1. A METHOF FABRICATING BUILDING SLABS COMPRISING THE STEPS OF POURING A CEMENTITIOUS MIXTURE INTO A CASTING BED SUBSTANTIALLY LONGER THAN THE DESIRED LENGTH OF A SLAB, PROVIDING A PREASSEMBLED REINFORCED TRUSS OF A LENGTH LESS THAN THE LENGTH OF THE CASTING BED AND HAVING TWO SPACED SUBSTANTIALLY PARALLEL JOISTS, IMMERSING A PORTION OF SAID TRUSS INTO A PORTION OF SAID MIXTURE WITH THE MAJOR PORTION OF THE JOISTS ABOVE AND SPACED FROM THE MIXTURE, IMMERSING A CUT-OFF BAR INTO SAID MIXTURE TO SEPARATE SAID PORTION FROM THE REMAINDER OF SAID MIXTURE, VIBRATING SAID TRUSS WHILE IT IS IMMERSED IN SAID MIXTURE, PROVIDING A SECOND PRE-ASSEMBLED REINFORCED TRUSS HAVING TWO SPACED SUBSTANTIALLY PARALLEL JOIST, IMMERSING PORTION OF SAID SECOND TRUSS INTO THE REMAINDER OF SAID MIXTURE, VIBRATING SAID TRUSS WHILE IT IS IMMERSED IN SAID MIXTURE; PERMITTING SAID MIXTURE TO SOLIDIFY INTO SLABS INTEGRAL WITH SAID TRUSSES, SEPARATING THE TRUSSES AND THEIR SOLIDIFIED SLABS FROM SAID BED AND CUTOFF BAR, AND THEN TURNING SAID SLABS AND TRUSSES OVER TO THAT THE SLABS ARE SUPPORTED BY THE TRUSSES.