La misura di deformate dinamiche su ponti in esercizio mediante correlazione digitale di immagini

In the last years the digital image correlation (DIC) measurement technique is becoming very popular in experimental mechanics in order to perform measurements of deformation fields on structural components under static and dynamic loads. The goal of this work is the development of a measurement chain, based on this measurement principle, to detect dynamic deformations of concrete highway bridge under normal operating conditions. To choose a proper digital recording camera for this application, a first series of tests has been peformed on the surface of a concrete specimen in the lab. This was fundamental to choose the proper optical configuration of the recording system taking into account the typical deformations of this kind of material and to choose the optimal spekle pattern of the surface. Using also previous dynamic measurements of bridge deflections performed by a laser Doppler vibrometer, it was possible to setup and validate the measurement technique on a highway bridge loaded by the normal traffic of truks.