Deflection-based multilevel structural condition assessment of long-span prestressed concrete girder bridges using a connected pipe system

Several long-span prestressed concrete (PSC) girder bridges have exhibited excessive deflection over time that can affect their normal use and safety. Thus, monitoring the time-dependent deflections of PSC girder bridges is required to ensure a timely warning of deficient bridge conditions. This study measured the deflections of a PSC box-girder bridge using a connected pipe system to provide health monitoring and condition assessment. A deflection-based, multilevel assessment approach was proposed wherein the individual deflection components (traffic-induced, temperature-induced, and long term) were used to evaluate the bridge state. The assessments of each component were fused using the Dempster–Shafer evidence theory to achieve an integrated outcome. Results show that a connected pipe system can accurately monitor the real-time deflection of long-span girder bridges. The proposed multilevel assessment approach makes full use of the structural condition information from the acquired deflection data, demonstrating the effectiveness and practicality of the fusion algorithm.