ULTRASONIC TOMOGRAPHY TO APPRAISE REINFORCED CONCRETE STRUCTURES

Abstract

Ultrasonic tomography in recent years has had a great advance as a non-destructive test (NDT) for the diagnosis of the pathologies of civil works, since it allows to obtain an image of the environment with a great resolving power that responds to the heterogeneities or discontinuities of the material. In the present research, an ultrasonic tomography was performed in a case study using conventional ultrasonic pulse velocity (UPV) equipment, instead of an ultrasonic tomograph. 15 measurements were made on three sides of a beam using different configurations of direct and semi-direct shots, and by solving a linear inverse problem an image was obtained with the distribution of slowness (inverse of velocity). For the solution of the inverse problem of ultrasonic tomography, the algorithm designed by Blanco (2015) in MATLAB was used, capable of treating a general discrete linear inverse problem, from the data of the observation system through the general method of Singular Value Decomposition (SVD). The case study consisted of a beam, which had previously been subjected to loads, through the design of the observation system and the tomographic inversion, areas of high values of slowness (decreased speeds) corresponding to fault zones were identified and the fence steels were identified by the low values of slowness (increased speeds). The quality of the system was evaluated high with an error of 6.27 %.