摘要: |
The current AASHTO Guide for the Design of Pavement Structures was derived from the large-scale Road Test conducted by AASHTO in the 1950s. Being empirical in nature, the AASHTO pavement design guide reflects only the truck technology prevalent at the AASHTO Road Test. However, truck technology has advanced in many areas since the AASHTO Road Test. In that road test, average tire pressures of 75 to 80 psi were used, and the tires were of bias-ply construction. However, trucks today are normally operated with tire pressures of about 100 psi, and radial tires have essentially replaced bias-ply tires as the commonly used tire types. Moreover, in response to the increased trucking loads, a new truck fleet with different truck classes, new axle configurations, different axle spacings, different tire widths, and new truck suspension systems has emerged. To characterize the current truck configurations on Texas highways, in late 1999 and early 2000, a truck survey was conducted on major trucking routes throughout Texas. In this report, the newly collected truck configuration data are analyzed and presented. Mathematical models and theories employed for the survey design and data analysis are introduced. In-depth analysis of truck tire pressure is also conducted to identify the significant factors affecting tire pressures. Findings and conclusions based on the data analysis are presented. |