Novel Application of PVDF Sensors for Vehicle Weight Identification in Reinforced Concrete Deck Steel Bridges

Abstract

Identification of overweight vehicles has been increasingly important due to the need for accurate information of actual live load, which is required for fatigue assessment of highway steel bridges. This study proposes a first-time application of polyvinylidene fluoride (PVDF)-based strain sensors for identification of vehicle weight using bridge weigh-in-motion (BWIM) algorithms in steel bridges. A portable sensor module consisting of a PVDF sensor, a charge amplifier circuit, a low-pass filter circuit, a gain amplifier, and a power supply circuit is developed. Performance of the sensor module was evaluated through laboratory experiments. Applicability of the sensor module for vehicle weight identification was validated through identification of a calibration truck during actual running tests in a RC deck steel bridge. Accuracy of vehicle speed and axle spacing identification by a pair of transverse sensors located on the same lane was verified using the measurement data of longitudinal sensors as a reference. In-lane transverse sensors exhibit sensitivity to individual axle passages; thus, they can be used for both axle-detecting and weighing sensors for a vehicle weight identification algorithm based on influence line method.