2023 Volume 79 Issue 15 Article ID: 22-15054
In the displacement measurement of railway bridges, optical measurement without a target is widely studied in recent years because it does not require access to bridges. However, the estimation accuracy of displacement depends on the surface condition of the structure, and there are some points where the displacement response cannot be obtained. In this study, the authors conducted displacement measurement using the digital image correlation method for a RC and a steel I girder bridges, and develop the subpixel estimation accuracy estimation method using the second-order differential value. The accuracy estimation results revealed that the horizontal errors affect to the vertical displacement estimation. Considering this finding, a practical improvement method that removes the horizontal effect is proposed, and can expand the applicable areas, which were mainly limited to the stiffener positions in the previous study.
