The long-term vibration monitoring of a steel girder bridge in the cold region was performed to investigate the temperature dependency on the dynamic characteristics of the bridge structure. The predominant frequency varied depending on the daily and seasonal fluctuation of the bridge temperature. A FE model with different elastic modulus based on each assumed temperature gave the natural vibration frequencies analytically. These natural frequencies have the same tendency with the measured result that means the main cause of the variation of the predominant frequency is the thermal dependencies of the elastic modulus of the structural members.
