Effect of Uphill Flexible Pavements on The Damaging Effect Of Full-Trailer Trucks With Tandem Front Axles

Abstract

The effect of traffic on flexible pavements can be expressed in terms of truck equivalence factors. This paper presents a study on the effect of uphill pavements on the damaging effect (truck equivalence factors) of two types of full-trailer trucks with tandem front axles. Axle load and geometrical characteristics survey on the two types of full-trailer trucks were carried out for determining the data needed in this study. In addition, uphill slope survey in Kerbala city was done and the data of uphill slope of other Iraqi cities were obtained from previous surveys. The paper reveals that the uphill pavement gradient causes significant increase in truck equivalence factors. In addition, the research reveals that there are many factors affecting the truck equivalence factors on uphill flexible pavements, including the total weight of full-trailer, H/B ratio (height of center of gravity to the wheel base of the truck), magnitude of uphill slope, and the structural number (SN).This work shows the importance of considering the effect of uphill slope in the design of flexible pavements on steep uphill slopes.