Delamination detection in concrete plates using output-only vibration measurements

Abstract

This paper addresses delamination detection of concrete slabs by analyzing vibration data from dynamic tests. Four concrete decks with different delamination sizes were constructed and experimental tests were conducted on these concrete slabs. Traditional peak-picking (PP), frequency domain decomposition (FDD) and stochastic subspace identification (SSI) methods were applied in the modal identification from real measurements of dynamic velocity responses. The modal parameters identified by these identification methods matched very well. The changes in modal frequencies, damping ratios, and mode shapes that were extracted from dynamic measurements were correlated to delamination size and can indicate presence and severity of delamination. Finite element (FE) models of reinforced concrete plates with different delamination sizes and locations were established. The modal parameters computed from FE models were compared to those obtained from real measurements and FE models were validated.