Abstract
For the Yokohama Bay Bridge, Rainbow Bridge and Tsurumi Tsubasa Bridge, long-span cable-supported bridges on the metropolitan expressway, seismic records have been collected intensively using numerous seismometers since their construction. This study examined how the modal parameters and seismic response parameters estimated from the acceleration records collected on the three bridges during the 2004 Chuetsu-Niigata earthquake could be reproduced by a seismic retrofit dynamic analytical model. Normal mode of vibration existed that could not be reproduced by the analytical model unless the effect of friction at bearings was taken into consideration. The periodicity of acceleration response was reproduced generally well despite variations in response level in the direction transverse to the bridge axis. Along the bridge axis, however, periodic elements existed that could not be reproduced by the dynamic analytical model used for seismic retrofit although corresponding seismic records were available. It was revealed that the existence of such periodic elements was ascribable to the effect of friction at bearings.
