Health monitoring data in assessing critical behaviour of bridges

Abstract

A baseline finite element model has been developed and used for system identification of the Confederation Bridge in Canada. The model was calibrated using the test data collected by the health monitoring system during two field tests. The frequencies and mode shapes obtained from the modal analyses were in good agreement with the values obtained from the tests. The model was used to simulate the bridge responses to the field tests. Continuity of the bridge model beyond the baseline model is essential in analysing its behaviour under moving truck loads. Coupling of the longitudinal movements of the pier tops with vertical movement of the deck and rocking vibration of the drop-in girders were observed in modal analyses of the extended model, which was then used for seismic analyses. The possibility of slippage of the drop-in girder as well as its separation from the bearings during strong ground motions should be considered in designing and future extension of the instrumentation program and the analyses of the recorded data for similar structures.

Keywords:

• Health monitoring
• System identification
• Modal analysis
• Seismic analysis
• Finite element analysis
• Bridges

Acknowledgement

The authors wish to thank Mr Yui-Bun Chan of the Department of Civil Engineering of the Hong Kong University of Science and Technology, for his assistance in carrying out some of the numerical calculations.