This paper presents the experimental studies performed to investigate the feasibility of the proposed photogrammetric system for torsion tests. In this study, two binocular stereo systems were used to measure the surface rotation of timber glulam beams under torsional loading. The first stereo system was employed to monitor the
photogrammetric pattern painted on the left sides of the timber samples whereas the second system was employed to monitor the pattern painted on the right sides of the timber samples. This test result has revealed how to provide more details on the surface deformation of timber samples as this may assist in understanding their torsional behaviour during loading. Several test series were conducted with twelve timber samples under torsional loading. The proposed approach was validated by comparing its angular measurements with those measured by inclinometers placed
above the photogrammetric patterns. The results showed that the optical systems not only allowed assessing performance and reliability of inclinometers but also allowed monitoring the shear modulus of the samples at various locations by providing more information which would not be possible to obtain using the traditional techniques.