| 摘要 |
A prefabricated concrete form for the pouring of a footing for a structural pillar is disclosed. The form is preferably constructed from a thermoplastic such as a high density polyethylene or ABS and is molded as a single disposable unit. The form is bell-shaped and has dimensions which render it useful in industrial size applications with large footprints. The dimensioning of the form also reduces the amount of material used for the manufacture of the form, allows the form to be backfilled without cave-in and to reliably support a tubular form for the pillar without an additional bracing or supporting structure. The form is in particular a low profile form wherein the sidewall is inclined at an angle below 45° relative to the bottom edge. A top flange of the form is preferably adapted to accommodate two or more different diameters of the tubular form for the structural pillar. The sidewall may include integral ribs which open inwardly to facilitate evacuation of air as the form is filled and to lend rigidity to the sidewall. The sidewall may further include vent openings for the escape of air which is possibly temporarily entrapped during filling of the form. The advantage is an inexpensive form which does not have an excessive height despite large footprints, fills reliably and supports a tubular form for a pillar without the need for cross-pieces, even at sidewall angles below 45°.
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