Concrete formwork system for forming cast in place horizontal slabs

Abstract

A system for forming Cast In Place horizontal concrete slabs, having multiple embodiments together comprising: plywood support modular elements, mounted on joists and/or joist sections, having flanges protruding beyond the joist edges and supporting top plywood sheathing; perpendicular joist support modular elements engaging with plywood support modular elements and providing vertical support to one end of a perpendicular joist and/or joist section; a first set of rows and a second perpendicular set of rows of joists and/or joist sections forming a grid structure for supporting top plywood sheathing further comprising use of the said modular elements to reduce plywood deflection; shoring means; means for rendering a level top horizontal surface of the formwork; means for setting the camber at each intersection perpendicular joists; and means for disassembly of the second set of rows and joists and/or joist sections after the formed slab has partially cured.

1 . A formwork system for forming Cast In Place horizontal concrete slabs, comprising:
 a. one, or a plurality, of plywood support modular elements, each said plywood support modular element mounted on top of, and depending for vertical support on, a first joist section, and,   b. one, or a plurality, of perpendicular joist support modular elements, each said perpendicular joist support modular element engaged with, and depending on vertical support from, a plywood support modular element, and,   c. each said perpendicular joist support modular element enclosing, and providing vertical support for, one end of a second joist section perpendicular to the said first joist section supporting the said engaged plywood support modular element.   
   
   
       2 . The formwork system of  claim 1 , further comprising plywood support modular elements having central protruding nails that abut top plywood sheathing. 
   
   
       3 . The formwork system of  claim 1 , further comprising a grid of rectangles formed by joists and/or joist sections. 
   
   
       4 . The formwork system of  claim 3 , further comprising one, or a plurality, of shoring members, vertically supporting the intersection of one, or a plurality, of intersections of the said joists and/or joist sections. 
   
   
       5 . The formwork system of  claim 4 , further comprising means of setting the camber of one, or a plurality, of the said intersections of joists and/or joist sections. 
   
   
       6 . The formwork system of  claim 3 , further comprising one, or a plurality, of plywood support modular element mounted at a point between the points of intersection of one, or a plurality, of the said joist and/or joist sections. 
   
   
       7 . The formwork system of  claim 6 , further comprising fastening means for attaching each plywood support modular element to its supporting joist and/or joist section. 
   
   
       8 . The formwork system of  claim 3 , further comprising one, or a plurality, of plywood support modular elements mounted at the midpoint between the points of intersection of one, or a plurality, of the said joist and/or joist sections. 
   
   
       9 . The formwork system of  claim 7 , further comprising a fastening means for attaching the bottom of each perpendicular joist support modular element to the joist and/or joist section supporting the said engaged plywood support modular element. 
   
   
       10 . The formwork system of  claim 3 , further comprising one, or a plurality, of vertically dimensioned support shims beneath one or a plurality of the said plywood support modular elements, such that the upper surfaces of a plurality of plywood support modular elements are in the same horizontal plane. 
   
   
       11 . The formwork structure of  claim 3 , the said plywood support modular element(s) further comprising a top plate, the said plywood support modular element further comprising two side support structures, each of the said side support structures having an upper notch, each of the said side support structures forming together with the said top plate, a plywood supporting flange structure perpendicular to the said first joist section, extending outward from the upper side of the said first joist section, and supported horizontally by the vertical side of the said first joist section, each of the said flange structures having a central slot beneath the top plate, the said central slot having a perimeter delineated by the bottom surface of the said top plate, and the peripheral edges of the said notch. 
   
   
       12 . The formwork structure of  claim 11 , the said perpendicular joist support modular element(s) further comprising a downward flange section, the said perpendicular joist support modular element(s) further comprising a gap between the said downward flange section and the joist side vertical face of the said perpendicular joist support modular element(s), the said gap being dimensioned to the thickness of the said side support structure. 
   
   
       13 . The formwork structure of  claim 3 , further comprising one, or a plurality, of vertically dimensioned plywood support modular element supporting shim pads. 
   
   
       14 . The formwork structure of  claim 3 , further comprising one, or a plurality, of vertical shoring to grid engagement means. 
   
   
       15 . The formwork structure of  claim 3 , further comprising means for disengagement and immediate reuse of one or a plurality of the said perpendicular joist support modular elements, and formwork elements supported by them. 
   
   
       16 . A formwork structure for forming Cast In Place horizontal concrete slabs, comprising a plywood support modular element, mounted on, and depending for vertical support on, a first joist section, the said plywood support modular element further comprising:
 a. a top plate, and   b. two side support structures, each having an upper notch, and   c. a central joist enclosing cavity, and   d. the said notch of each of the said side support structures, forming together with the said top plate, a slot, and,   e. each of the said side support structures forming together with the said top plate, a flange structure perpendicular to the said first joist section, extending outward from the upper side of the said first joist section, and supported horizontally by the vertical side of the said first joist section.   
   
   
       17 . The formwork structure of  claim 16 , further comprising a nailing hole through the top plate, and adjoining the said first joist section. 
   
   
       18 . The formwork structure of  claim 16 , further comprising an outer peripheral nailing hole through one or both of the said side support structures.