Centrifugal molding of prestressed piles

Claim 1

A method for centrifugally forming prestressed piles, comprising steps of providing a mould comprising two semicylindrical half-shells with ends bounded by respective headpieces having apertures therein, said half-shells further having lateral apertures therein, disposing a spiral within a first of the two half-shells of the mould for the pile to be formed, securing within said spiral a plurality of strands, each strand extending along an axis parallel to that of the mould, each having at least one end emerging from a mould headpiece, and at least some of said strands having one end thereof terminating within the mould, in the vicinity of respective ones of said lateral apertures, affixing a first block to each of those strands terminating within the mould, in proximity to a respective one of said lateral apertures, pouring concrete into said first half-shell, joining the two half-shells together, then inserting elements for axially restraining the blocks through said lateral apertures provided in the half-shells, tensioning the strands at those ends which emerge from the headpiece, and centrifuging the mould prepared in this manner.

Claim 2

A method for centrifugally forming prestressed piles, comprising steps of providing a mould comprising two semicylindrical half-shells with ends bounded by respective headpieces having apertures therein, said half-shells further having lateral apertures therein, disposing a spiral within a first of the two half-shells of the mould for the pile to be formed, securing within said spiral a plurality of strands, each strand extending along an axis parallel to that of the mould, each having at least one end emerging from a mould headpiece, and at least some of said strands having one end thereof terminating within the mould, in the vicinity of respective ones of said lateral apertures, affixing a first block to each of those strands terminating within the mould, in proximity to a respective one of said lateral apertures, pouring concrete into said first half-shell, joining the two half-shells together, then inserting elements for axially restraining the blocks through said lateral apertures provided in the half-shells, tensioning the strands at those ends which emerge from the headpiece, and centrifuging the mould prepared in this manner.