The first step in structural evaluation of pavements (when using the analytical-empirical approach) is the determination of layer thicknesses, moduli, and types of materials. Based on this the structural performance is normally predicted by calculating the number of loads to cause a certain amount and severity of cracking. Most procedures do not predict the changes in the structural condition, i.e. in the layer moduli. This paper presents two methods of calculating the damage, one based on the actual stress, i.e. the stress in the intact part of the cross sectional area, and another based on the peak internal energy. With both methods the changes in moduli and the fatigue life may be calculated for either controlled stress or controlled strain testing.