Comprehensive Model for Fatigue Analysis of Flexible Pavements considering Effects of Dynamic Axle Loads

Abstract

A comprehensive model for the fatigue analysis of flexible pavements that considers the effects of dynamic axle loads is presented in this paper. The main objective of this work is to quantify the reduction in the structural service life of the pavement resulting from the rise of the dynamic axle loads exerted by traffic as the progressive deterioration of the road profile occurs. First, the procedure for the fatigue analysis of flexible pavements, as defined in the Spanish Standard 6.1-IC, is explained in detail. The implementation presented here is specific for this standard, but the underlying concepts are not restrictive and the model can be easily adapted to fit the distinctive features of other regulations. Second, the concepts of accumulated damage and structural service life are formalized in mathematical terms. Next, the introduction of dynamic axle loads leads to the definition of a suitable accumulated fatigue damage indicator that takes into account these effects. Dynamic axle loads are introduced in this formulation by means of the dynamic load amplification factor. For the quantification of this factor, the quarter-car model is extended to allow for computing the time evolution of the dynamic axle load exerted by a heavy vehicle on the pavement. The model is completed by adding a simple procedure for simulating how the road profile deteriorates over time. Finally, an application example is presented.