THE MECHANISMS OF ABRASION OF ALUMINUM ALLOY CULVERT, RELATED FIELD EXPERIENCES, AND A METHOD TO PREDICT CULVERT PERFORMANCE

AN ANALYTIC APPROACH IS PRESENTED TO PREDICT THE BEHAVIOR OF ALUMINUM ALLOY CULVERT UNDER ABRASIVE FLOW CONDITIONS. SEVERAL YEARS OF EXPOSURE OF SELECTED ALUMINUM ALLOY CULVERTS NOW PROVIDE DATA THAT MAY BE USED AS A BASIS FOR SUBSTANTIATION OF A MATHEMATICAL HYPOTHESIS OF ABRASION PERFORMANCE. PRELIMINARY EVALUATION SUGGESTED THAT ABRASION MIGHT BE RELATED TO BED LOAD ENERGY, MASS, AND VELOCITY, WITH CONTRIBUTIONS FROM THE EFFECT OF THE REPETITIOUS CORRUGATIONS. THE SOURCE OF SURFACE ABRASION ON THE INVERT OF METAL CULVERT IS THE CUMULATIVE RESULT OF IMPACT OR RUBBING ACTION BY PARTICLES OF HARDNESS EQUAL TO OR GREATER THAN THE METAL SURFACE. THE ABRASIVE ACTION IS REDUCED TO A MATHEMATICAL HYPOTHESIS. WITH THE ABRASION RATING SYSTEM PRESENTED, AN ENGINEER CAN PREDICT PERFORMANCE BY EVALUATING THE CHANNEL TO BE DRAINED IN THE IMMEDIATE PROXIMITY OF THE UP-STREAM ENTRANCE TO A CULVERT AND ESTIMATING WHAT MAXIMUM ROCK SIZE CAN BE EXPECTED TO REACH AND PASS REPEATEDLY THROUGH THE CULVERT.