Evaluation of Rutting Depth in Flexible Pavements by Using Finite Element Analysis and Local Empirical Model

The objective of this research is to predict rut depth in local flexible pavements. Predication model in pavement performance is the process that used to estimate the parameter values which related to pavement structure, environmental condition and traffic loading. The different local empirical models have been used to calculate permanent deformation which include environmental and traffic conditions. Finite element analysis through ANSYS computer software is used to analyze two dimensional linear elastic plane strain problem through (Plane 82) elements. Standard Axle Load (ESAL) of 18 kip (80 kN) loading on an axle with dual set of tires, the wheel spacing is 13.5 in (343 mm) with tire contact pressure of 87 psi (0.6 MPa) is used. The pavement system is assumed to be an elastic multi-layers system with each layer being isotropic, homogeneous with specified resilient modulus and Poisson ratio. Each layer is to extend to infinity in the horizontal direction and have a finite thickness except the bottom layer. The analysis of results show that, although, the stress level decrease 14% in the leveling course and 27% in the base course, the rut depth is increased by 12 and 28% in that layers respectively because the material properties is changed.