Vibration-based condition monitoring of a stress-ribbon pedestrian bridge

Operational modal analysis is performed on a stress-ribbon pedestrian bridge supported on butterfly arch. A highly-synchronous tri-axial wireless sensor network is deployed on the bridge deck to record the ambient vibration responses of the structure excited by wind and low-density walking pedestrians. Operational modal data are extracted by using stochastic subspace identification method. It’s found that the experimental mode shapes are characterized by symmetric and anti-symmetric vertical bending and several torsion modes. On the basis of the experimental results, an improved FE model that considers the abutment is built in order to simulate the structure as the self-balanced system. The new model is then updated with a sensitivity-based approach. The calibrated model can serve as the baseline model for long-term monitoring of the life-cycle performance of the bridge.