Long-term SHM (Structural Health Monitoring) of continuous rigid frame bridge reinforced by external prestressing

Abstract

The SHM (Structural Health Monitoring) system deployed for an external prestressing tendon and steel plates rehabilitated continuous rigid frame bridge is introduced in this paper. Damages and deterioration of the large box girder was described as well as the rehabilitation plan. Data that were collected for 6 monthes were analyzed. Performance of the rehabilitated bridge, pattern of the collected data as well as investigation of the correlation between different types of data were the research focus. Temperature was considered as a major issue in the monitored data, the effort has been made to eliminate the effect of temperature in deformation and strain data. The best outlier detection method for deformation data is determined to be IQR analysis, for strain data a thresholding method of the empirical value 200 με was used, and lastly for tension force a thresholding method of 85% tension force was determined to be the best and most reasonable for outlier removal. The variation range of deflection and strain can help determine whether the vehicle load is over the limit.

Keywords

• continuous rigid frame bridge
• rehabilitation
• long-term monitoring
• external prestressing tendon