Ribbed pipe

A substantially rigid pipe particularly for use in buried storm drain and sanitary applications, said pipe comprising a cylindrical metal wall having a helically extending lock seam and defining a plurality of outwardly projecting walled structural supporting ribs extending helically about and along the length of said pipe and being integrally formed therewith, said ribs defining a corresponding plurality of open channels formed interiorly thereof, the walls of said ribs converging inwardly toward the open end of said channels thereby reducing the transverse dimension of said open end of said channels, said cylindrical wall being of constant radius between said channels and said open channels being sized and relatively spaced from one another to render the pipe substantially rigid and possess sufficient structural strength to withstand the stresses of being buried underground, a filler material disposed within said channels and held therein by the reduced transverse dimension of said open end of said channels, and a protective liner interfacing the interior sides of said cylindrical wall of said pipe, said liner being secured to said filler material within said channels thereby anchoring said liner to said filler material and against said cylindrical wall of said pipe.