Similar to other corrugated metal pipes, helical corrugated metal pipe has also the corrugation shape. Corrugations add the structural strength and stiffness to culverts. More over, helical corrugated metal pipe has the special corrugation - annular pattern corrugations, which not only make the culverts more strong and stiff, but also reduce the roughness of flow through the pipe.
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Helical corrugated steel pipe Images