Patent ID: 7887735

Claim:
A method of forming a void in a mass of hardened concrete, the method comprising the steps of: obtaining a void former, the void former comprising an elongate tubular body having a closed inner end and an open outer end; a wall of said body defined by coextensive inner and outer surfaces; and a groove formed in said wall and extending from one of said inner and outer surfaces thereof toward, but not through, the other of said inner and outer surfaces, such that a web of material substantially thinner than said wall is retained between said groove and the other of said inner and outer surfaces; positioning the body in a mass of plastic concrete having a substantially horizontal upper surface and an edge surface extending substantially perpendicular to the upper surface, with the open outer end of said body positioned adjacent the edge surface of said mass, by inserting said closed inner end of said body into the edge surface of said mass of plastic concrete; allowing said mass to harden; and applying a force to said body adjacent the open end, the force being effective to rupture said web of material and permit said body to collapse inwardly, wherein said void former contracts to a size permitting withdrawal from the hardened mass.