SENSITIVITY ANALYSIS OF THREE FLEXIBLE PAVEMENT DESIGN TECHNIQUES

To better understand the art and science of pavement design, three highway design techniques were studied to determine the relative effects of various design parameters on pavement thickness. The analysis phase of this investigation consists of formulating each technique into a comprehensive mathematical or graphical thickness model. An evaluation of the infleunces on thickness of the major design factors was accomplished by a sensitivity analysis with a theoretical and two practical measures of parameter importance. The theoretical measure of parameter importance reveals considerable differences among techniques as to the process of resolving design thicknesses and to the relative theoretical influence of various parameters that estimate the same major design factors. However, the practical parameter importance measures, which account for variations in parameter values as well as the formulated parameter-thickness relationship, demonstrate a greater similarity in the importance of generic factors among the design methods. For flexible pavement design, traffic load and subgrade support are the more influential factors in the determination of pavement thickness.