Nonlinear vibration-based estimation of corrosion-induced deterioration in reinforced concrete

Abstract

The structural integrity of corroded reinforced concrete (RC) elements is commonly evaluated by the electrical resistivity method to estimate only the mass loss of reinforcement. It is also possible to evaluate overall deterioration induced by corrosion in the RC elements by examining their nonlinear dynamic behaviors. Therefore, herein, a nonlinear vibration-based diagnostic technique is investigated to measure the magnitudes of higher harmonics of resonance caused due to the corrosion-induced damage in the reinforced concrete. The developed diagnostic technique utilizes an adaptive higher order spectral analysis, which incorporates the wavelet transform instead of the Fourier transform, in order to suit the transit vibration signals generated under an impact hammer. Initially, the algorithm to extract a diagnostic feature, named the wavelet transform-based bicoherence (WTB), is developed on the synthetic vibration signals with different levels of nonlinearity. Then, the developed diagnostic method is demonstrated on two lab-scale RC columns. Comparison of the results obtained by the traditional Fourier-based and the proposed wavelet-based bispectra reveals up to 42.7% improvement in the discrimination of the damaged column from the intact one.