Continuous Health Monitoring of Reinforced Concrete Bridge Deck based on Traffic Load-induced Acoustic Emission

This paper presents continuous bridge deck monitoring based on b-value obtained from traffic load-induced acoustic emission (AE) signals. Using the self powered AE system that we developed, we have observed traffic load-induced AE on an actual bridge for five years. The developed self-powered AE system demonstrated that long-term traffic load-induced AE measurements over five years could be performed without an external power source. Traffic load-induced AEs measured irregularly by event-driven measurement were accumulated, and b-values were calculated. We used an additive regression model that accounts for piecewise linear trends and seasonality to extract long-term trends accurately. Over the past five years, the bridge has deteriorated. In addition, repairs were made during the period. As a result of this monitoring, we determined the relationship between the damage condition of the bridge and the b-value trend obtained from the traffic load-induced AEs. The results confirmed that the b-value based on traffic load-induced AE corresponds well with the damage conditions on the underside of the deck slab or in a shallow area inside it.