Pavement Response to Moving Loads

University dissertation from Stockholm : KTH Royal Institute of Technology

Abstract: The response of flexible pavements at vehicle-road interaction has been studied in this thesis. A quasi-static and a dynamic framework for analysing the pavement structure under moving load has been developed. Both frameworks are general, robust and computationally efficient.The quasi-static procedure is based on superposition principle and is computationally favourable, as it requires only reduced incremental problem to be solved numerically. Using the developed framework the effect of vehicle configuration and traffic characteristics on the damage induced in pavements is investigated numerically. It is shown that the developed numerical model provides a more accurate explanation of different distress modes. Moreover the conventional analysis and design methods with layered linear elastic behaviour assumption for asphalt layer are unable to capture several important aspects of pavement response.In the dynamic analysis approach the pavement roughness and vehicle suspension system is linked to a dynamic pavement model in order to account for the dynamic effects at vehicle-road interaction on pavement response. A finite element method is relied upon in order to establish the response function for a linear viscoelastic pavement structure with dynamic effects taken into account. The computational procedure developed is applied to evaluate the effect of the pavement surface roughness on the pavement structure response to truck traffic loading. Stress field parameters governing fracture initiation in asphalt layers are reported for two measured road roughness profiles. It is shown that the dynamic effects at vehicle-road interaction may have a profound influence on the stresses induced in flexible pavements; therefore these effects need to be taken into account for accurate prediction of the road performance in the field.