This paper presents the vibration characteristics of a bridge with a wide clear width on the vibration generated by traffic loading. On the bridge with the wide clear width, it is apt to produce torsional vibration. Natural frequencies of bending vibration mode are similar in each girder, however their phases are not equal. Therefore, the rest institution vibrates in bridge axial direction and at right angle to its direction. By the results of this study, the effectiveness of tuned mass damper for buildings is about -5 -11dB on harmonic vibration, and -3-5dB on random waves . However a t the bu i 1 d i ng on the bridge with the wide clear width, the reduction o f the vibration level with a tuned mass daluper is no more than -1-3dB.
