This paper demonstrates bridge deflection measurement using digital image correlation technique during bridge load testing. A bridge is loaded by a heavy cargo truck on the bridge road. Then, the deflection distribution is measured by digital image correlation. The applicability of digital image correlation to bridge deflection measurement is investigated by comparing the results obtained by digital image correlation with those obtained by displacement transducers. The effect of random pattern on an object surface is also investigated by measuring with and without random pattern. Results show that the deflection distributions of the bridge obtained by digital image correlation agree well with those obtained by displacement transducers when random pattern is attached on the bridge surface. In addition, it is found that deflections can be measured even if artificial random pattern is not applied to the surface of bridge girders. It is emphasized that noncontact displacement measurement is possible by simple and easy procedure with digital image correlation for the structural evaluation of infrastructures.
