Measuring Time-Dependent Pavement Deflection Profiles Under Drive-by Conditions with a Portable System.

摘要

Measuring pavement deflections on secondary roads permits assessment of their performance upon passage of an Army convoy. On secondary roads traffic volume is low enough to permit drive-by conditions. The system was designed accordingly. For sensing pavement deflections, linear variable differential transformer (LVDT) sensors were chosen. The investigation showed that in order to credibly extrapolate from sensors away from the tires to deflection underneath the tires, a laterally separated pair of sensors at each longitudinal location would be necessary. The investigation also turned up options and trade- offs regarding different methods for end-supports of the lightweight aluminum beam which would support the sensor array. Sideways-looking ultrasonic sensors for detecting tire positions both laterally and longitudinally, independently of the LVDT's, were also selected and evaluated. Overall design philosophy was not to try to zero in on the optimum right away, but to permit reasonably maximum latitude for field experimentation.