Mechanistic Code for Asphalt Pavements Loaded by Farming Vehicles

Farming vehicles are relatively heavy and slow-moving machines, typically equipped with rubber tracks or flotation tires (or both). The objective of this study was to develop, validate, and openly share a new mechanistic code for calculating asphalt pavement responses under the loading conditions of such vehicles. For a given farming vehicle, the loading geometry was modeled by exploiting symmetry considerations and representing tread contact areas as groups of rotated rectangular patches. For the purpose of calculating responses, the pavement system was modeled as a layered elastic half-space, loaded vertically by many small identical circular areas—collectively approximating the patches. Computational efficiency was sought by solving the layered model for one circular area and executing a series of coordinate transformations, interpolations, and translations, to represent the entire vehicle loading. The new code is named LynFarm; it was validated through its ability to reproduce mechanical responses generated by farming vehicles as they were driven over an instrumented asphalt pavement section. LynFarm is openly shared on GitHub for further verification, validation, and improvement by the pavement engineering community.