Feasibility study on evaluating surface opening cracks in concrete by multi-channel instrumented surface rayleigh wave propagation

In the present paper, numerical simulations of wave propagation were conducted for concrete containing surface opening crack. The purpose is to examine the behavior of surface Rayleigh wave (R-wave) components when impinged by the crack and to identify wave parameters that could be utilized to characterize the crack, including depth (length) and degree of inclination. In the study, cracks with varying inclination angle were investigated. By changing the frequencies of source, the change in amplitudes and velocities of R-waves that propagate from one side to another side of the crack were extracted from the observed waveforms. The change of R-wave parameters (velocity, amplitude and frequency) with respect to crack depth as well as the inclination angle was analyzed. The simulation results revealed that promising relationships can be established between velocity or amplitude with the crack characteristics, leading to the suggestion that simple methodology based on R-waves could be developed for assessing surface opening cracks in concrete structures.