A novel fast and low-cost masonry monitoring strategy for masonry arches

This work proposes a novel non-destructive, vision-based measurement strategy to identify and quantify mechanical deformations between rigid blocks, which can be applied to the long-term real-time monitoring of masonry arches with a single camera that is not necessarily with high resolution. First, the possible motions between the two rigid blocks were identified and measured, under the utilization of a perpendicular, parallel and symmetrical 4x4 points grid around the masonry joint line. Repeated calculations from different rows and columns of the grid improved the precision of measurements. Then, this method was verified via photographic images with 2D holography, and tests on an in-scale arch, showing good adaptability and precision. Finally, this strategy was performed on a video recording of a full-scale arch model under tilting tests until failure. With the dimensions of the points grid being the only known parameters, the mechanical joint, the type, and the amount of the rigid block movement were successfully determined.