Continuous Box-Girder Bridge Condition Assessment Based on Structural Health Monitoring System: A Case Study

Fu-Sui Bridge is a continuous box-girder bridge located in mainland China, crossing the Songhua River and connecting two towns: Fu Jin and Sui Bin. The entire construction of Fu-Sui bridge lasted three years from 2008 to 2011. In the bridge location region, the temperature in winter is extremely cold, exceeding down to -30 oC. A long-term structure health monitoring system has been designed and installed to monitor the behaviour of the bridge with the enormous fluctuation of temperature between the summer and the winter. During one-year field monitoring, strain and displacement sensors of the bridge have been identified and addressed giving valuable information for the long-term evaluation of the behaviour of Fu-Sui Bridge. The following conclusions are obtained in this study: (1) the influence of low temperature on the observation is more dominant than the high temperature; and (2) the strain variation and deflection corresponds to a typical thermal coefficient of expansion of concrete with different slopes and the temperature effect may not produce in a short term while reflection of the cumulative effect on the cross sections of bridges.