Nondestructive evaluation of defects in concrete structures based on finite element simulations of ultrasonic wave propagation

Concrete structures require periodic inspections and quality control to assess their structural integrity. For this task, several methodologies based on the use of different technologies have been previously proposed. In particular, nondestructive evaluations, based on the use of ultrasonic wave propagation, have proved to be attractive due to the possibility to perform reliable assessments of concrete structures. In this paper, an approach exploiting ultrasonic propagation characteristics is proposed. This approach is developed by using data obtained from numerical simulations, whereas proper simulation settings to perform the diagnosis are obtained by preliminary studies. Subsequently, an automatic inspection method to determine the position of defects is developed. The aim of the method consists of determining the position of a defect by the computation of flight times related to signals reflected by anomalies in the structure. Such computation is based on a preliminary classification of defect positions that combines a genetic algorithm for a feature selection and a statistical approach for classification. The performances of the proposed method are evaluated in a specific study case, showing satisfactory numerical results, which show that this approach can be used to identify the position of defects.