Structural Health Monitoring of FRP-Reinforced Concrete Bridges Using Vibration Responses

Abstract

This paper evaluates the feasibility of using vibration-based structural damage detection methods to identify potential damage in FRP-reinforced concrete (FRP-RC) bridges. A series of dynamic load tests were conducted immediately after construction on a continuous three-span FRP-RC bridge deck to capture its dynamic responses under intact conditions. A detailed finite element (FE) model was developed and validated against the experimental results. This model allows for the simulation and study of the bridge dynamic behavior after cracking develops at different locations along the deck. The effects of cracking severity and location on the bridge were investigated using natural frequency and mode shapes changes. The numerical results showed that natural frequency and mode shape changes are sufficiently sensitive for detecting cracks in the FRP-RC bridge deck. Additional dynamic load tests are scheduled for this bridge so that experimental data, possibly obtained from a cracked deck, can be used to calibrate the FE model after some damage. While recognizing that corrosion is a non-issue for FRP-RC structures, the ultimate question that this research attempts to answer is how the deck flexural stiffness changes over time as the result of traffic loads and possibly predict a service life expectation based on stiffness degradation.