Ultrasonic methods implemented in various types of integrated seismic devices can be successfully used in quality control and condition assessment of bridge decks. Of special interest are three ultrasonic techniques: ultrasonic body-wave (UBW), ultrasonic surface-wave (USW) and impact echo (IE). While the first two are used in a deck material characterization, the IE method is primarily used in evaluation of a corrosion induced delamination. The biggest advantage of the IE method over a curent practice of chain dragging is that it allows detection of zones of delamination at various stages: from initial to progressed and developed, thus enabling better prediction of deterioration processes in the deck. To improve automation, accuracy and interpretation of results of the IE technique, the testing is simulated by the finite element method. Numerous finite element results confirm the ability of the IE method to accurately measure theposition, extent and the stage of delamination. The finite element method was successfully used in simulation of two probable scenarios of delamination progression: expansion\growth of a single small delamination, and progressive linking of several smaller delaminations. Elements that can be used in recognition of the two processes are described and can be used in long term monitoring and prediction of deterioration processes. Issues related to finite element modeling of wave propagation in bridge decks and finite element analysis results interpretation are discussed too.