An Inexpensive Method for Measuring Deformation of Corrugated Cladding Using Close Range Photogrammetry

Close range photogrammetry is becoming more popular as the availability and affordability of photogrammetry software increases and could be used to great effect in a number of civil engineering applications. Close range photogrammetry can be used to create detailed Digital Surface Models (DSMs) of objects that have deformed under applied loads. In addition to capturing the nature of the deformation, the deflection of the object subjected to load can be inferred from the same DSM. This paper presents an inexpensive method for measuring the deformation and displacement of corrugated steel cladding using a single digital camera and low cost software programs. The development of this method has been documented in detail, including an assessment of its accuracy which was determined to be +/- 0.1 mm for a 142 mm x 350 mm section of corrugated cladding. In addition, this paper demonstrates how DSMs are particularly useful for evaluating the performance of a numerical model. The DSM created using photogrammetry was compared directly to the deformed mesh predicted by a numerical model, enabling an expansive and quantitative validation of that numerical model. It was found that the current numerical model of corrugated cladding can predict the deformation of the cladding under an applied load of 800 N to within 96 % of that documented during experiments.