Patent ID: 7874540

Claim:
A method for making a concrete form for pouring a column having a non-round cross-section, comprising the steps of: (a) providing an outer tube having a cylindrical inner surface and a length L; (b) providing a first plurality of pre-fabricated cellular material pieces each having opposite first and second surfaces, the first surface of each cellular material piece being configured to form a portion of the non-round cross-section desired for the column and the second surface of each cellular material piece being formed substantially as an angular section of a cylinder, each cellular material piece having a width defined between opposite side edges and a length defined between opposite ends of the cellular material piece; (c) providing a first pre-formed polymer liner sheet having a length approximately equal to L; (d) providing a first pre-formed polymer backing sheet having a length approximately equal to L; (e) arranging the first plurality of cellular material pieces on the first liner sheet in a plurality of laterally adjacent rows with the first surfaces of the cellular material pieces against the first liner sheet and affixing the first liner sheet to the first surfaces of the cellular material pieces, each row having a length approximately equal to L; (f) affixing the first backing sheet to the second surfaces of the first plurality of cellular material pieces to form a first insert assembly, the first liner sheet and first backing sheet together substantially fully enveloping the cellular material pieces; (g) repeating steps (c) through (f) with a second pre-formed polymer liner sheet, a second pre-formed polymer backing sheet, and a second plurality of cellular material pieces to form a second insert assembly having a plurality of rows of the cellular material pieces substantially fully enveloped by the second liner sheet and second backing sheet; and (h) inserting the first and second insert assemblies into the outer tube and arranging the insert assemblies such that the backing sheets abut the inner surface of the tube and the liner sheets on the first surfaces of the cellular material pieces of the first and second pluralities of cellular material pieces define the non-round cross-section desired for the column.