Abstract
The objective of this paper is to show the influence of local damage in steel truss bridge on its vibration characteristic. In particular, this paper presents the results of modal analysis using vibration data of a truss bridge in damaged and repaired condition. This results show that the influence of local damage on natural frequency is small. On the other hand, influence of local damage on modal damping ratio is large and the result shows that damage detection might use it. This qualitative trend of change in modal damping ratio is also observed in the result of numerical modal analysis.
