Pavement Strength Rating Methods as Viewed by Airframes Manufacturers

The effects of allowable aircraft payload of variations in tire pressure, axle spacing, and wheel spacing were explored using four important pavement design/rating methods. The methods used were the California Bearing Ratio (CBR) (SEFL165A variation) method (flexible pavement), the Load Classification Number (LCN) method (flexible and rigid pavement) and the Portland Cement Association method (rigid pavement). The effects on payload were determined for both dual and dual tandem type loading gear on pavements of an assumed strength. This analysis was followed by a study of the payload effects of variations on pavement parameters such as subgrade strength or pavement thickness in allowable aircraft payload given a particular aircraft configuration. Based upon the foregoing analysis five airframe manufacturer's objectives for new pavement design methods were stated.