Patent ID: 7251919

Claim:
A structural device for constructing ribbed concrete slabs, comprising: an elongate hollow tubular member having: two side walls; a top wall connected to said two side walls; a bottom wall connected to said two side walls, said bottom wall extending beyond said two side walls and forming two external wings; intermediate walls; said side walls, said top wall, said bottom wall, and said intermediate walls defining at least two interior chambers, said at least two interior chambers including upper and lower interior chambers; said intermediate walls forming two truss configurations disposed in one of said two interior chambers, said two truss configurations partially defining said one chamber; said truss configurations each being disposed in said lower interior chamber at a respective one of said two side walls; said two side walls being first and second substantially vertically disposed opposing parallel side walls, each of said side walls having an interior side wall surface, a top region and a bottom; said top wall being a substantially horizontal top wall connecting said top region of said first side wall to said top region of said second side wall and forming a top of said upper interior chamber; said intermediate walls including a substantially horizontal intermediate span connected to each of said first and second side walls and defining a boundary between said upper and lower interior chambers; said bottom wall being a substantially horizontal bottom wall connecting said bottom of said first side wall to said bottom of said second side wall; and each of said two truss configurations being connected to said intermediate span and to said bottom wall and being respectively connected to one of said first and second side walls.