Disposable formwork for columns having a circular section

Abstract

A perfectly cylindrical column is structured from a rigid plastic flat sheet, high impact polyethylene or the like, having a length which coincides with the envisaged height of the column and a width which coincides with the size of the section of the column. The flat sheet is wound on a mounting core with the purpose of adopting a tubular and cylindrical configuration by connecting its longitudinal edges, the connection being temporarily stabilized with the aid of an adhesive tape extending throughout the entire connecting line. The assembly is then provided with an outer rigidizing envelope in the form of a strip that is helicoidally wound on the tubular body, the strip consisting of a fiberglass mesh or mesh of fiberglass fibers longitudinally embedded in a paper support or the like. The envelope will bear the radial strains generated by the casting of the concrete into the tubular body.

1 . Disposable formwork for circular section columns of the type incorporating a tubular body constituting the surface of the formwork, stabilised by an external casing consisting of a helicoidal band, either materialised in fibreglass mesh or in a series of fibreglass threads arranged longitudinally and equidistantly in a support of paper or similar, characterised in that said tubular body consists of a smooth plate ( 1 ) of rigid plastic, such as, for example, rectangular high impact polyethylene or similar, with a length that coincides with the envisaged height of the column and a width in turn corresponding to the development of the circular section of said column, a plate that is arched and closes in on itself along its longitudinal or vertical edges ( 3 - 3 ′) with the help of an adhesive external tape ( 4 ) that joins said edges, configuring a tubular and cylindrical body, which is stabilised by means of the external fibreglass.  
   
   
       2 . Disposable formwork for circular section columns, according to  claim 1 , characterised in that optionally on the closing line ( 3 - 3 ′) of the smooth plate on itself, there is an external strip ( 5 ) of the same rigid plastic, of about 4 or 5 cm wide, of a length coinciding with the length of the formwork, which reinforces said closing line and is fixed to the smooth plate also with the help of one or two adhesive tapes ( 4 - 4 ′).  
   
   
       3 . Disposable formwork for circular section columns, according to  claim 1 , characterised in that the smooth and initially flat plate ( 1 ) is transformed into a cylindrical element with the help of an assembly core ( 2 ), cylindrical, formally and dimensionally coinciding with the column to be produced and inflatable in order to facilitate its subsequent disassembly.  
   
   
       4 . Disposable formwork for circular section columns, according to  claim 2 , characterised in that the smooth and initially flat plate ( 1 ) is transformed into a cylindrical element with the help of an assembly core ( 2 ), cylindrical, formally and dimensionally coinciding with the column to be produced and inflatable in order to facilitate its subsequent disassembly.