Abstract
Damping characteristics are significant factors for seismic design of a cable stayed bridge. It is general in seismic design to assume a damping ratio of approximately 2-5% of critical for superstructure. However, damping ratio which has so far been estimated from field observation such as forced vibration test is generally much smaller than those values. This study presents an analysis on the damping characteristics of a cable stayed bridge where strong motion records have been accumulated. Damping characteristics are analyzed through analytical simulation for the measured response by varying the damping ratio assumed in the analysis. It is concluded from the analysis that the damping ratio which gives the best correlation in response analysis simulation is 2% and 0-1% of critical in longitudinal and transverse direction, respectively, for the tower, and 5% in both directions for the deck.
