Acoustic emission monitoring of conventionally reinforced concrete highway bridges under service conditions

Abstract

Acoustic Emission (AE) monitoring offers the unique possibility to monitor structural bridge components in real-time and detect sudden changes in the integrity of the monitored element. AE are stress waves initiated by sudden strain releases from within a solid such as crack formation and propagation, material crushing, or bond fracture of two materials in a composite due to over-loading. The present study focuses on methods for in-service monitoring of conventionally reinforced concrete (RC) bridges. Extensive laboratory experiments on two full-scale reinforced concrete bridge girders were carried out to study existing evaluation methods and to identify potential applications that will also work for in-service bridges. A novel evaluation approach based on the well-known b -value analysis that worked particularly well was developed and is proposed. It was found that this new method can help estimate operating load conditions and detect overloading of existing bridges. Additionally, an in-service highway bridge was monitored during structural load testing and while experiencing ambient traffic to collect real service-level AE data for comparison. Preliminary data from both the laboratory experiment as well as the in-service test are presented and compared. © RILEM 2013.