The Rational Use of Finite Element Method in the Analysis of Flexible Pavements

Abstract

The environment, traffic loading, material properties and construction practices are main factors influencing pavement performance. Traffic loading with different wheel configurations is simultaneously moving on highways. Moreover, the pavement boundary conditions affect pavement behaviour. To predict pavement responses and performance, traffic loads with different characteristics are considered to estimate stresses and deformations through pavement. These responses in case of layered pavement system are less than those obtained for the ideal homogeneous case depending upon the stiffness of the layers. Semi-analytical solutions are available to analyze the behaviour of elastic layered pavement subjected to traffic loads. For more complex cases of layered pavement or loading conditions, it is necessary to perform numerical analysis using finite element technique. In addition, most of pavement materials do not linearly perform under the action of traffic loading. Therefore, linear and non linear analyses were preformed for first series of the investigation, which take in account the effect of tyre pressure, axle load, asphalt layers rigidity and pavement layers properties. Also, the influence of state of loading, tyre type and some boundary conditions on pavement responses is considered in the second series. Furthermore, for moving traffic loads, the effects of viscous damping, and load frequency on the deflection and stress have been investigated. In this paper, the ANSYS programs version-8 and version-10 are used to analyze in three dimensions the behaviour of layered pavement systems under static and moving vertical loads and to obtain stresses and deflections through it considering the realistic properties of the pavement layers indicating load transmission issues for a wide variety of materials stiffness. In this research, the pavement is modeled as a multilayered elastic system composed of a subgrade assumed to be an infinite medium upon which layers of finite thickness infinitely extended horizontally are laid. Discussing and analyzing of obtained results are presented and the main conclusions are drawn out.

The Influence of Base Layer Thickness in Flexible Pavements

“…Factors such as material properties, geometry of pavement structures, environment, traffic loading and construction practices affect the pavements. Furthermore, vehicle characteristics, load axle, and wheel configuration may cause damage to the pavements [2]. If the induced strains due to the external load are relatively small, stresses and deformations are usually estimated using the theory of elasticity.…”

“…Semi-analytical and analytical solutions are available to analyze the behavior of elastic layered pavements subjected to surface loads. In solutions concerning the analysis of the pavement layer system under traffic load, the pavement layers are considered homogeneous, isotropic, and linear elastic [2].…”