Development of Fiber Optic Dynamic Weigh-in-Motion Systems

摘要

Flexible fiber optic sensors were successfully developed in both flexible andrigid pavements subjected to heavy truck traffic. Vehicles were classified and weighed in both pavement types. The sensors, manufactured in any desirable lengths are about 0.25 inches (7 mm) wide by 0.0625 inches (1.7 mm) thick. For vehicle classification and weigh-in-motion (WIM) sensors are typically constructed 6 to 7 feet (1.8 to 2.1 m) long. These sensors were epoxied into pavement grooves, covered with a flexible filler material and the leads were connected to a specially designed optical-electronic box. The optical-electronic interface contains light emitting diodes that focus the light into the core of the optical fiber and photodetection equipment that converts light intensity to voltage. Voltage can then be used either for WIM or vehicle classification. Sharp, clear signals were obtained using the system developed. They show changes in light intensity for each single or dual tire assembly that passes over the sensor. The intensity changes vary according to the load on the tire and the vehicle speed. The fiber-optic system can be manufactured for costs comparable to piezoelectric sensor systems. It is noncorrosive and unaffected by power surges.