EFFECT OF DESIGN PARAMETERS ON PERFORMANCE OF ROAD PROFILOGRAPHS

Road profilographs are commonly used to measure roughness of new and newly surfaced pavements. Because new pavements are usually smooth, profilographs must have high measuring sensitivity, particularly in the range of profile wavelengths responsible for dynamic pavement loading applied by heavy trucks and for ride comfort. Simple analytical and computer models were developed to examine the effects of basic design parameters on the performance of California and Rainhart profilographs. It was found that the quality of measurements obtained with the two profilographs can be improved by modifying some of the design parameters (e.g., length of main truss and number and spacing of supporting wheels). The improvement should be more significant for the California profilograph. The design parameters of the existing Rainhart profilograph are close to the values recommended in the paper.