Curvature assessment of reinforced concrete beams using photogrammetric techniques

Innovative procedures have been proposed recently for monitoring laboratory tests using photogrammetry and image processing. In spite of the growing interest, most existing research is still highly focused on the theoretical development of the procedures, being experimental tests only performed for validation. This manuscript aims at providing a practical demonstration of the advantages of using these new techniques in laboratory tests up to failure. In this scope, focus is given to the assessment of the curvature of reinforced concrete beams, since this parameter is crucial for characterising the structural response both in service conditions and in ultimate limit states. In conclusion, it can be stated that these new techniques can be used in combination with, or even as a replacement of, more traditional methods (such as LVDTs and DEMECs), monitoring a significantly higher number of points and without placement restrictions. The limitation is mostly related to the strain precision that is not adequate for monitoring serviceability conditions. Nevertheless, the curvature can be assessed in short time intervals and lengths, respectively of few seconds and centimetres, independently of the presence of cracks and the plastic hinge location, in this case circumventing several of the drawbacks presented by traditional methods.