Debonding detection of FRP-strengthened reinforced concrete using a novel amplitude modulated vibro-acoustic method

Abstract

This paper presents a novel Amplitude Modulated Vibro-Acoustic (AMVA) method for debonding detection in reinforced concrete strengthened by fibre-reinforced polymer (FRP) composite laminates. This study also compares the behaviour of AMVA method with the conventional Vibro-Modulation (VM) method. The comparative analysis is based on sidebands measurements related to different debonding sizes. A theoretical framework is used to obtain the nonlinear parameter β of Contact Acoustic Nonlinearity (CAN), utilized in both AMVA and conventional VM methods to characterize varying debonding levels. In addition, the Sideband Peak Count (SPC) and Sideband Peak Count-Index (SPC–I) approaches are employed to evaluate damage levels by counting and comparing the number of sideband peaks above a moving threshold level. The results show that using SPC-I technique has a better behaviour to characterize damage levels since it is more accurate than SPC technique and it is easier to implement compared with calculating nonlinear parameters β. In addition, the AMVA method demonstrates greater sensitivity than conventional VM method, improving its capability to identify damage and making AMVA method as a promising tool for debonding detection in FRP strengthened concrete.