Displacement monitoring of a pedestrian bridge using 3D digital image correlation

Using computer vision methods for monitoring the behaviour of structures in urban environments, especially if it is intended to be a long term operation, requires the vision system and the preparation of the structure to be set up with minimal disruption to the surroundings and the use of the structure itself With this concept in mind, 3D digital image correlation was used to evaluate the deflection caused by a static load on a pedestrian bridge, using cameras installed by windows in different floors of an adjacent building. The measurements were performed using IP cameras designed for video surveillance and security applications, capturing the bridge's surface from above. Rather than preparing the surface with a custom speckle pattern, the DIC processing was performed using the pattern appearing naturally due to the irregularities on the surface. A 2D DIC test was performed simultaneously with an industrial camera capturing the same section of the bridge from a horizontal position inside a lower floor of the same building. The results from the 3D and 2D tests were in close agreement with each other and with the expected displacement profile. (C) 2022 The Authors. Published by Elsevier B.V.