Patent ID: 7300610
Filing Date: 2007-11-27
Classification: E02B,E04G,Y02E

Abstract:
1. A method of forming a cavity within a concrete structure comprising the steps of: providing a plurality of rigid section members each comprising a flexible mold skeleton member and a polymer-aggregate concrete panel member joined to said mold skeleton member, said concrete panel member imparting rigidity to said flexible mold skeleton; each of said section members created by forming a mold skeleton member comprising a tubular wall portion, a pair of annular flanges and a pair of longitudinal flanges, with said annular flanges and said longitudinal flanges extending internally and externally relative to said tubular wall portion; spraying polymer-aggregate concrete onto the exterior of said three-dimensional form to completely fill the space between the externally extending portions of said annular flanges and the externally extending portions of said longitudinal flanges, and planing said sprayed polymer-aggregate concrete using said annular flanges and said longitudinal flanges as planing guides to produce a said smooth-walled exterior surface on said section members; joining said section members to each other to create a three-dimensional tubular form having a smooth-walled tubular exterior surface; pouring concrete onto said exterior surface of said form and allowing said concrete to cure to form a concrete structure; disassembling and removing said section members such that a smooth-walled tubular cavity is present within said concrete structure.