Study on bridge weigh in motion (BWIM) system for measuring the vehicle parameters based on strain measurement using FBG sensors

•A BWIM system is proposed using two FBG based sensors.•The strain experienced by the bridge girder due to the motion of a loaded vehicle has been recorded and analyzed.•Different parameters of the vehicle like load, velocity and separation of the front and rear wheels (approximate length of vehicle) are measured.•The experiment is repeated with different angular orientations of FBG (0°, 45°, and 90°) with reference to the line of motion.•The experiment is repeated with different angular orientations of FBG.•Considering the system as a simply supported beam with concentrated load at a point, simulation study is performed with MATLAB too.. A Weigh in Motion (WIM) system is proposed, employing two fiber Bragg grating (FBG) sensors to evaluate the strain at a point on a prototype bridge due to a moving vehicle. The FBG's are fixed at two different longitudinal girders of bridge along the line of motion at different orientations. The parameters of investigation include strain developed in the proximity of FBG’s and speed of the vehicle. The response has been studied by arranging system of FBG sensors in the form of a rosette. It can be deduced from results that the suggested WIM structure could efficiently monitor variations in the load and speed of advancing vehicles over the bridge. The ideal arrangement of FBG’s in the sensor is found to be that oriented along the bridge axis due to a high sensitivity of 0.36μɛ/gram and linearity with a good coefficient of correlation of about 0.99 than other orientations of FBG. The principal strains obtained from the FBG rosette are in close correlation with the values simulated using numerical tool MATLAB.