Application of seismic surface-waves in concrete bridge-deck evaluation

Accurate and timely condition assessment of bridge decks is essential for economic management of aging highway bridges. The ability to evaluate concrete modulus profile in a bridge deck can help the detection of early signs of deterioration and optimize the bridge maintenance procedures. This study presents a new method for modulus profiling of concrete bridge decks. The stiffness matrix method is used to simulate wave propagation in a layered media. The results are compared to numerical finite element models. Dispersion analysis is done using the multi-channel analysis of surface waves (MASW) and phase-shift methods. The characteristics of dispersion surface are analyzed and the effects of model parameters on dispersion surface are examined through a series of parametric studies. An inversion technique is proposed for a fast inversion of surface-wave data collected on bridge decks. This technique utilizes a database of pre-calculated dispersion surfaces and takes advantage of the observed patterns in the parametric study as a priori information for the inversion process.