Long-Term Monitoring and Performance Assessment for Concrete Beam Bridge Based on Neutral Axis Index

Abstract:

A long-term monitoring index system based on neutral axis（NA) position and the corresponding performance assessment method were proposed. Based on a detachable viaduct in Hebei expressway, a health monitoring system based on monitoring indicators was established, and the structural strain information was collected. Static response caused by traffic loads was separated from original strain signals by the multi-resolution wavelet analysis. The peak-valley pairs were picked in accordance with the designated peak prominence. Then the strain amplitude distribution was fitted and the measured NA arrays were derived. Finally, the neutral axis index was extracted from the accumulated data, and the statistical characteristics of different evaluation periods were compared and analyzed. The results show that the proposed neutral axis index in daily periods is less disturbed by the environment, which can represent the performance degradation of the structure in the long-term monitoring.

Key words:concrete beam bridge;neutral axis index;long-term monitoring;performance assessment;structural health monitoring