Field Verification of Simplified Bridge Weigh-in-Motion Techniques
Journal of Bridge Engineering
Volume 21 Issue 10 - October 2016
Navid Zolghadri, S.M.ASCE; Marvin W. Halling, F.ASCE; Nephi Johnson, S.M.ASCE; and Paul J. Barr, A.M.ASCE
This study addresses the feasibility of using a single-span bridge as a weigh-in-motion (WIM) tool to quantify the gross vehicle weights (GVWs) of trucks inexpensively with a small number of sensors and without using axle detectors. Field testing was performed on an interstate without any lane closures. Four preweighed trucks with different axle configurations traveled over a bridge at three different speeds and in two separate lanes. Measured strain data were used to implement bridge weigh-in-motion (B-WIM) algorithms and calculate the corresponding velocities and GVWs. A comparison was made between calculated and actual measured static weights, and between the calculated and specified speeds of the trucks. In addition to field testing, a finite-element (FE) model of the tested bridge was created and calibrated based on the measured strains at different locations. This calibrated FE model enabled the acquisition of the influence values for the bridge at any location (influence surface). Ten different points were selected to calculate the influence surface values, and a comparison was made between calculated strains from the influence surface and the actual response of the bridge recorded by strain gauges. The comparison showed that the updated FE model was capable of providing the influence surface values at different locations. The validated influence surfaces were then used to simulate the passing of common types of trucks with various weights and axle configurations over the bridge. The measured GVWs based on simulated strain measurements provided by the FE model and validated influence surfaces verified the applied method.