Bridge Load Rating Using Dynamic Response

Proposed herein is a method for load rating of prestressed box beam (PSBB) bridges based on their dynamic response collected using wireless sensor networks (WSNs). The hypothesis states that the health of a bridge is associated with its vibration signatures. Two WSNs were deployed on a 25-year-old PSBB bridge, and trucks were run with variable loads and speeds for collecting its real-time dynamic response at current condition. Also performed were finite-element (FE) simulations of 3D bridge models under vehicular loads to acquire the representative dynamic response at its newest condition. The bridge model was validated by field testing and numerical analysis. The fast Fourier transform and peak-picking algorithms were used to find maximum peak amplitudes and their corresponding frequencies. The inservice stiffness of the bridge was calculated to determine its load rating, which resembles the actual load rating of the bridge. The application software developed from this research can instantly determine the load rating of a PSBB bridge by collecting its real-time dynamic response. The research outcome will help reduce bridge maintenance costs and increase public safety. (C) 2014 American Society of Civil Engineers.