Now showing 1 - 5 of 5
  • Publication
    The Influence of Statistical Spatial Repeatabiliy on Remaining Pavement Life
    (Research Publishing Services, 2010-08) ;
    A road develops permanent deformation and fatigue damage because of the strains induced in its structure by surface loading and environmental change. A mechanistic-empirical approach is implemented here to simulate the deterioration of a pavement. A quarter car model is used to simulate pavement/vehicle dynamic interaction and a feedback mechanism is implemented after each run to update the pavement profile after the passage of each axle. In this way, the influence of Statistical Spatial Repeatability (SSR) is incorporated into the pavement damage model. The model is run for two sample profiles. The first is a simple step profile which demonstrates that the patterns of damage relate to the two natural frequencies of the quarter car. An initially random profile is also investigated. A complete history of the surface profile during its life demonstrates how the peaks and troughs migrate in response to the evolving pattern of SSR.
  • Publication
    The Influence of Subgrade Subsidence on Train Track Dynamic Interaction
    This paper reports results from a numerical model to calculate subgrade settlement in railway tracks due to repeated dynamic loading. The trains are modelled as rigid body 2-axle carriages on two layers of springs. The track is modelled as a beam supported on three layers of springs. Permanent deformation of the subgrade layer is calculated on the basis of a power law assumption. Patterns of dynamic forces are calculated on a smooth track and on a track subject to an initial subgrade ‘pothole’. The latter is shown to grow with repeated loading and to change the mean patterns of applied force.
      586Scopus© Citations 2
  • Publication
    Numerical integration approach to the problem of simulating damage in an asphalt pavement
    (Taylor and Francis, 2011-06-13) ;
    A road develops permanent deformation or fatigue damage because of the stress and strain induced in its structure by surface loading and environmental change. Dynamic tyre forces generated by the vibration of moving heavy vehicles excited by the road surface profile are strongly influenced by vehicle speed and dynamic properties. A mechanistic-empirical approach is implemented here to simulate the deterioration of a pavement, taking account of dynamic excitation of the axles. This paper highlights the importance of statistical spatial repeatability in damage evolution during the pavement life. Numerical integration of the distribution of forces at each point is shown to be sufficient to predict the changing road surface and elastic modulus. This results in an approximate 100-fold increase in computational efficiency. Finally, the pattern of the forces generated by the axles of a half car is found to be a little less damaging than that of independent quarter cars. In the examples considered, the quarter car reduces calculated pavement life by an average of 6%.
      367Scopus© Citations 5
  • Publication
    Pavement damage model incorporating vehicle dynamics and a 3D pavement surface
    (Taylor and Francis, 2012-02-16) ; ;
    This paper proposes a mechanistic-empirical pavement damage model to predict changes in 3D road profiles due to dynamic axle loads. The traffic is represented by a fleet of quarter cars which allows for statistical variability in model parameters such as velocity, suspension stiffness, suspension damping, sprung mass, unsprung mass and tyre stiffness. The fleet model generates statistical distributions of dynamic force at each point which are used to predict pavement damage. As the pavement deteriorates, the distributions of dynamic axle force are changed by the changing road profile. This paper introduces a 3D approach – the transverse position of the wheel is represented by a Laplace probability distribution. This influences the extent to which the force patterns are spatially repeatable. Differences in the range of 10–30% are found between 2D and 3D predictions of pavement life.
      349Scopus© Citations 9