Abstract

Increased road traffic combined with heavy vehicle loads lead to deterioration and distress of pavements and consequently reduces the life span of the paved roads. As a result, large amounts of financial and labor resources are spent every year to improve and maintain road infrastructures around the world. Traditionally, vehicle and pavement dynamics are treated as two separate areas of research. However, they are strongly coupled together through their contact points. Thus, one of the major concerns is to develop a more reliable dynamic pavement-vehicle interaction model to investigate and evaluate accurately both vehicle and pavement responses, and also to examine the pavement distress due to the severity of traffic loads. One of the most important distress modes in pavements is fatigue cracking. Despite the fact that there have been considerable efforts in recent years in fatigue performance evaluation and the design of flexible pavements, there is still a need for further studies in predicting fatigue cracking in terms of damage distribution considering the uncertainty and variability associated with the input parameters of pavement-vehicle interaction and traffic load repetitions.

The main objective of this research study is to carry out an in-depth investigation of the dynamics of the pavement-vehicle interaction and the effect of coupling action on system response, as well as fatigue study of the pavement due to repeated traffic loads. The response of the pavement-vehicle coupled system supported by a linear visco-elastic foundation has been investigated. The vehicle is modeled as a two-degree-of-freedom quarter-vehicle model, and the pavement-foundation system is described by a simply supported Euler-Bernoulli beam resting on Pasternak foundation, while the tire is coupled to the flexible pavement with a single point contact. Galerkin method has been utilized to develop the governing differential equations of motion. Direct numerical integration approach based on implicit Newmark linear average acceleration technique has been used to solve the governing differential equations in order to evaluate the response of the coupled system. Results have been validated with previous research work and also compared with those of conventional uncoupled system. The effects of different parameters such as vehicle speed, road roughness, soil stiffness and suspension damping on the responses are then investigated. For the fatigue study of flexible pavements, a methodology, for modeling pavement damage and predicting fatigue cracking of flexible pavements is presented. The methodology is based on the combination of deterministic method and stochastic approach using Palmgren-Miner’s hypothesis in which Poisson process is employed to characterize the actual repetitions of traffic load. Different models are then presented to estimate the fatigue life of the pavement surface layer. The results are compared and discussed.