Identifying Traffic-Induced Vibrations of a Suspension Bridge: A Modelling Approach Based on Full-Scale Data

The present paper introduces a procedure to identify traffic-induced vibrations from full-scale acceleration records from a long-span suspension bridge. First, an outlier detection algorithm coupled with a cluster analysis is applied to detect when a vehicle crosses the bridge. Then, the mass and average speed of each identified vehicle are estimated using a moving mass model. The current identification procedure requires a low wind speed and a low traffic density to isolate the background component of the displacement response from its resonant component. Eleven months of records from high-accuracy three-axial accelerometers were used to systematically identify traffic-induced vibrations and estimate the mass and speed of numerous vehicles. The computation of the combined effects of wind and traffic loading on the vertical bridge displacement response indicates that the study of the wind-induced vibrations of the Lysefjord bridge should account for traffic loading, even for wind speed above 10 ms(-1).