Edinburgh Napier University

  The laminated structural glass beam is a modern, transparent and innovative structural element, widely used in supporting floor and roof plates, glass walls and many other applications. Despite many favourable characteristics inherent in the material such as high compressive strength, flexibility, aesthetics and sustainability, there are shortcomings in the design of such glass elements: 1) glass is brittle in nature and fails instantaneously; 2) there is an absence of unified design codes. Engineers therefore must use scattered national codes for guidance with no set design procedure, causing hesitancy and over-design of elements. This ongoing research aims to provide new knowledge in the field by deriving the shear modulus, which is an important strength factor in structural elements, of multi-layer laminated glass beams. Currently the determination of the shear modulus is achieved through four-point bending tests which generally result in lateral-torsional buckling failure – a combination of bending and shear. Torsion induces a purer state of shear failure in such elements, yet there have been no torsion tests documented on glass beams so far. By taking inspiration from human and animal visual systems, binocular stereo-vision based algorithms can be applied to compute 3D disparities, distances and coordinates of any object. The aforementioned techniques are applied to this research in the form of an advanced photogrammetry method. This is comprised of a binocular stereo-vision experimental setup, which is a two-camera setup (left and right) that are fixated to specified target areas on a beam sample. As the beam is subjected to experimental torsion and rotation occurs, simultaneous images are taken at regular intervals. With the inclusion of machine-vision algorithms in MvTec HALCONs HDevelop programming environment, highly-accurate 3D distance measurements are attained from the specified target marks through camera calibration procedures and the reconstruction of 3D coordinates. The results from the aforementioned methods can be applied to existing analytical models to derive the shear modulus of laminated glass beams, and may help to provide knowledge that can support the development of a future structural glass Eurocode.