CORRUGATED METAL PIPE COMPARISON STUDY

Over 100 uncoated galvanized steel and alclad aluminum culverts were inspected during the course of this six-year study. Environments varied from coastal with rain fall exceeding 110 inches per year to semiarid range lands of Eastern Oregon where rainfall averages only 10 inches per year. Test culverts ranged in age from 60 years to two years with most in the range of four to ten years. It was found that the only significant variable influencing the performance of uncoated galvanized steel and alclad aluminum culvert was their location east or west of the Cascade Mountain Range which is the north-south divider of the State into wet and dry regions. In Eastern Oregon where the climate is dry both materials have performed satisfactorily while in Western Oregon where the climate is wet, aluminum has performed well but galvanized steel corrodes quite rapidly when unprotected.