Numerical methods for shakedown analysis of pavements under moving surface loads

Failure of pavements associated with moving repeated traffic loads are typically caused by gradual deterioration rather than sudden collapse. This type of failure behaviour is mostly due to the accumulation of plastic strains under repeated loadings. There are different from the geotechnical engineering solution of the stability problems of soil masses under simple loading programs. It can be shown theoretically that there is a load magnitude below which a protective residual stress will develop in the road, and above which the pavement will undergo an incremental failure. This load is known as the 'shakedown limit load' and the protective residual stresses associated with this shakedown limit load are the optimal residual stresses for the life of the pavement. This thesis thus aims at describing a general numerical method for the shakedown solutions of pavements subjected to repeated moving traffic loads. To achieve this goal, a novel numerical formulation based on Bleich-Melan shakedown theorem is developed by making use of finite element techniques and mathematical programming. The proposed numerical procedure can be used to solve for the shakedown limit load and the associated developed residual stresses for both two- and three- dimensional continua under complex load distribution and boundary geometry, layered material, and inhomogeneous soil deposit.