Patent ID: 6840491

Claim:
A prefabricated footing form for molding a footing of concrete material at a bottom end of a concrete column, comprising a substantially tapered rigid hollow body having a vertical axis, a circular top end of a first diameter D T , a bottom end of a second diameter D B larger than the first diameter, the top and bottom ends being concentrically aligned along the vertical axis, the top and bottom ends being vertically spaced apart at a height H, and an integral side wall extending between the top and bottom ends, at least a portion of the sidewall being inclined at a sidewall angle below 45° with respect to the base plane, the sidewall having a length S from the top to the bottom end; a circular top flange on the side wall for fittingly supporting a prefabricated tubular column form, and a bottom flange for supporting the footing form on a suitably prepared substrate; whereby the dimensions of D T , D B , H and S are selected such that S≦2.4 H for reducing the amount of material used to manufacture the footing form, S≧0.55ΔD, with ΔD=D B -D T for preventing cave-in of the form upon exterior backfilling prior to molding of the footing, D B ≧1.8D T for lateral stability of the footing form, ½ΔD≧H≧¼ΔD for D B ≧24 inches for preventing excessive footing form heights, and D T ≧0.5 D B -H for ensuring proper filling of the footing form with a concrete mixture of about 3000 psi to 4000 psi.