Improvement of vehicle axle load test method based on portable WIM

Abstract

An improved portable weigh-in-motion test method was proposed based on the polyvinylidene fluoride piezoelectric sensor. Four different kinds of installation method were compared and the optimal installation method was confirmed. The influence of vehicle speed on the accuracy of axle load was studied and result showed that the maximum relative error was less than 14% under the same pavement temperature with constant automatic adjustment factor. At the same vehicle speed, the integral value of axle load increased linearly with the increase of temperature and an improved axle load calculation method was proposed to reduce the influence of temperature. The self-developed portable WIM system was compared with a portable WIM product in the real road test. Result showed that the deviation of the two systems was less than 13% and most of the deviations were under 8%, which showed the self-developed system can meet the requirement of the real road test.