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.

The International Roughness Index (IRI) is widely accepted as a measure of pavement condition. However it was developed as an indicator of passenger comfort as they travel in a vehicle on the pavement. In this paper, for the assumed failure model adopted, IRI is not found to be a good indicator of remaining pavement service life. The 3D continuous wavelet transform is proposed and shown to be a more effective indicator. Specific scales related to natural frequencies of the vehicle fleet, particularly the body mass frequency, are more significant than others. A weighted mean of the wavelet coefficients for these scales is used as an indicator of remaining life. One hundred randomly generated class A profiles are generated and their histories of damage progression throughout their lives are simulated. The new indicator is applied to the initial profiles to determine which ones are more vulnerable to damage than others. In numerical simulations using the assumed damage model, the wavelet based indicator is shown to be well correlated with service life.

Free-span occurs normally in a pipeline at uneven seabed, dynamic seabed and pipeline crossing. Free spanning in pipeline causes Vortex Induced Vibration (VIV) fatigue, fracture and bursting. In this paper, a pipeline located in South Pars Gas Field is assessed against local buckling and VIV fatigue using probability of failure theory based ...