Internally trussed monolithic structural members

Abstract

A prefabricated, monolithic, structural building panel of box-like configuration includes face, side and end members, all constructed of fiber reinforced concrete, the panel having a plurality of internal truss members, also constructed of fiber reinforced concrete, extending angularly between the panel face members. Forms for the casting of the structural components making up the panel are fabricated from a light weight, insulative material that is left in place within the panel after casting to provide heat and sound insulation.

1 . An internally trussed, unitary, structural member comprising:
 a first and a second face member, each said member consisting essentially of fiber reinforced, Portland cement concrete, said face members being generally planar and parallel one to the other;   a first and a second edge member, each said member consisting essentially of fiber reinforced, Portland cement concrete, said edge members extending between the face members at a border thereof to define an enclosed space; and   a plurality of truss members extending between said first and second face members, each said truss member consisting essentially of fiber reinforced Portland cement concrete.   
   
   
       2 . The structural member of  claim 1  including truss members that extend between said first and second edge members. 
   
   
       3 . The structural member of  claim 1  wherein the combined volume of said face members, said edge members, and said truss members is less than 25% of the volume of said enclosed space. 
   
   
       4 . The structural member of  claim 1  wherein the volume that is not occupied by said face members, edge members, and truss members comprises a light weight, solid material shaped to form a mold assembly that defines said truss members. 
   
   
       5 . A unitary mold assembly for fabrication of an internally trussed structural member manufactured entirely of fiber reinforced, Portland cement concrete comprising:
 a plurality of form billets arranged in a planar and parallel relationship to create a form assembly, all of said billets having the same shape and size, each said billet connected to the next adjacent billet through a plurality of spacer means, said spacer means arranged on the billet surfaces to define a plurality of channels, each said channel extending from one side of said form assembly to its opposing side.   
   
   
       6 . A method for fabricating a structural member comprising:
 providing an open-topped box mold sized to the desired length and width of the structural member, said mold having a depth equal to the thickness of said structural member;   pouring a slurry of fiber reinforced Portland cement concrete into said box mold and leveling said slurry in the box mold bottom to form a first member face;   placing a form assembly atop the first member face, said form assembly comprising a plurality of form billets, all of said billets having the same shape and size, each said billet connected to the next adjacent billet through a plurality of spacer means, said spacer means arranged on the billet surfaces to define a plurality of channels, each said channel extending from one side of said form assembly to its opposing side;   adding additional concrete slurry into said mold box to fill the channels between billets, to cover the mold assembly, and to form a second member face; and   allowing the concrete to cure to thereby produce a single piece, unitary structure having the mold assembly encased therein.   
   
   
       7 . The structural member of  claim 1  wherein the fibers employed to reinforce said Portland cement concrete are stable in a strongly alkaline environment. 
   
   
       8 . The structural member of  claim 7  wherein the fibers employed to reinforce said Portland cement concrete are selected from the group consisting of zirconia glass, corrosion resistant metal fibers, and graphite and wherein the fiber concentration in the Portland cement concrete is in the range of 1% to 5% by volume. 
   
   
       9 . The structural member of  claim 1  wherein said truss members are disposed parallel one to another, and extend between said face members. 
   
   
       10 . The structural member of  claim 9  wherein each said truss member includes an upper truss beam and a lower truss beam, each of said truss beams extending the length of said truss member, said upper and lower truss beams connected by a plurality of rib members that extend between said upper and lower truss beams. 
   
   
       11 . The structural member of  claim 10  wherein alternate ones of said rib members are disposed parallel one to another and extend diagonally between said truss beams to form a triangular rib lattice. 
   
   
       12 . The structural member of  claim 10  wherein said upper and lower truss beams are integral with said upper and lower face members respectively. 
   
   
       13 . The mold assembly of  claim 5  wherein said billets and said spacer means comprise a foamed plastic. 
   
   
       14 . The mold assembly of  claim 13  wherein said foamed plastic is selected from the group consisting of polystyrene, polyurethane, and isocyanurate. 
   
   
       15 . The mold assembly of  claim 5  wherein said billets and spacer means are fabricated of a light weight mineral aggregate in an adhesive matrix. 
   
   
       16 . The mold assembly of  claim 15  wherein said light weight mineral aggregate is selected from the group consisting of perlite, vermiculite, and mixtures thereof. 
   
   
       17 . The mold assembly of  claim 5  in which the mold assembly has a top side and a bottom side and wherein said billets are triangular in cross-section, each billet having a base and two sides, said billets disposed such that a first billet is positioned with its base plane and generally parallel with the mold assembly top side and the adjacent billet positioned with its base plane and generally parallel with the mold assembly bottom side. 
   
   
       18 . The mold assembly of  claim 17  wherein the cross section of each said billet is in the shape of an isosceles triangle having a base angle ranging from about 30° to about 75°. 
   
   
       19 . The mold assembly of  claim 18  wherein said base angle ranges from 45° to 60°. 
   
   
       20 . The mold assembly of  claim 17  wherein said spacer means are triangular is shape, are of uniform size and thickness, and are equally spaced along said billets. 
   
   
       21 . The mold assembly of  claim 20  wherein the bases of adjacent triangular spacers are shaped such that they fit flush and level with the bases of adjacent billets. 
   
   
       22 . The method of  claim 6  wherein said form billets are triangular in cross section, each billet having a base and two sides that meet at an apex, said billets being disposed such that a first billet is positioned with its base plane and generally parallel with the bottom of said box mold, and the next adjacent billet positioned with its apex plane and generally parallel with the top of said box mold. 
   
   
       23 . The method of  claim 22  wherein said spacer means are triangular in shape, are of uniform size and thickness, and are equally spaced along said billets to form channels of uniform cross section. 
   
   
       24 . The method of  claim 23  wherein the total volume of said mold assembly is more than half of the total volume of said structural member. 
   
   
       25 . The method of  claim 23  wherein the total volume of said mold assembly is more than three-quarters of the total volume of said structural member. 
   
   
       26 . The method of  claim 6  wherein the fibers employed to reinforce said Portland cement concrete are stable in a strongly alkaline environment. 
   
   
       27 . The method of  claim 6  wherein the fibers employed to reinforce said Portland cement concrete are selected from the group consisting of zirconia glass, corrosion resistant metal fibers, graphite, and mixtures thereof, and wherein the fiber concentration in the Portland cement concrete is in the range of 1% to 5% by volume.