Progressive finite element model calibration of a long-span suspension bridge based on ambient vibration and static measurements

Abstract

A two-phase model updating approach is presented to develop a baseline model for the Runyang Suspension Bridge (RSB), which is the longest bridge in China with a main span of 1490 m. In this approach, the model updating is divided into two phases of free-standing tower phase and full-bridge phase according to the construction procedure, so that the model updating of the long-span suspension bridge can be greatly simplified. The physical meaning of sensitivity and the penalty function concept is employed in the iterative calculation. The structural model is updated by modifying the parameters of design, and validated by structural natural vibration characteristics and static responses. The design parameters used for updating are bounded according to measured static results and engineering judgments. After ambient vibration measurements were carried out to obtain the eigenfrequencies, damping ratios and mode shapes of RSB based on the monitored acceleration records, the FE model is then updated by using the measurements come from field tests during construction of the bridge and after the completion of the bridge. The calibrated FE model is proved to have a good correlation with the static and dynamic measurements and is then used for the continuous structural health monitoring of the bridge.