Health monitoring of concrete bridges and vehicle loads correlation analysis based on acoustic emission

Abstract

In recent years, with the development of digital acoustic emission (AE) systems and the improvement of signal processing technique, acoustic emission technology has been more and more widely used in the research of dynamic processes of compression, tension, impact, fatigue, crack, and fracture of materials and structures. Since correlation analysis of vehicle loads during the monitoring period is lacking in previous concrete bridge structure health monitoring with AE, it is hard to identify the form of AE signals when vehicles cross the bridge. This paper is the first study to combine acoustic emission technique with dynamic monitoring of vehicle loads in bridge structure health monitoring. It studies the feasibility of applying AE technique to existing concrete bridges and discusses characteristic forms of acoustic emission when vehicles pass the bridge. The monitored bridge is a typical highway concrete bridge with small box girders. AE sensors were located on the web, deck plate, and bottom plate of the box girders; a weigh-in-motion system (WIM system) was located in the pavement of bridgehead. The clocks of the two systems were synchronized in order to coordinate the relationship between AE and the weight and velocity of vehicles when they pass the bridge. Based on the analysis of recorded data in 24 hours, the forms of AE signals and the influencing factors were studied; the response characteristics of AE in different locations of the box girder were detected. Then, the correlation between vehicles' dynamic loads and AE features was studied. Reference datum of healthy concrete bridges under the vehicle loads was established, which laid the foundation for further monitoring and evaluation of concrete bridges by AE.