Citation

Gillespie TD, Karamihas SM. Proc. Int. Tech. Conf. Enhanced Safety Vehicles 1992; 1992: 102-108.

Copyright

(Copyright © 1992, In public domain, Publisher National Highway Traffic Safety Administration)

DOI

unavailable

PMID

unavailable

Abstract

This paper summarizes key findings from a study whose objective was to use simulation methods to systematically investigate the relationship between truck properties and pavement damage. Pitch plane models of 13 basic truck configurations were developed. The trucks were "run" on roads with generalized roughness properties designed to represent the characteristic spectral content of each road type, with the amplitude varied. The dynamic loads along the pavement were calculated for each axle of the truck combination and stored in such a way that they could be simultaneously applied to the pavement in their respective positions. The pavements were analysed from pavement structural models by computing influence functions for the response at each point to a unit load imposed anywhere else on the pavement. The rigid pavement model for Portland cement concrete roads was ILLI-SLAB, and the flexible pavement model was derived from VESYSDYN. Time varying stresses and strains due to the combined loads of all wheels of the truck as it passed by were calculated. The time history of stress at each point was used to estimate the cumulative damage caused by the truck. A power law relationship was used to estimate fatigue damage resulting in cracking. For rutting damage, permanent deformation in each layer was computed using a visco-elastic model. Computations were made over road sections approximately 400 m in length. The potential for fatigue damage was found to have a first- order relationship to truck axle loads and is consistent across a range of pavement designs. Closely-spaced tandem axles have a beneficial interaction that reduces fatigue damage on rigid pavements. On flexible pavements, the tire properties of size, configuration (single vs. dual), and inflation pressure are important to both fatigue and rutting damage. Truck dynamic loads, which are affected by suspension properties, road roughness, and operating speed, act to increase pavement fatigue damage. The road damage performance of several generic truck suspension designs is compared.