Plastic rotation and tension stiffening effect analysis in beams using photogrammetry

Abstract

Innovative procedures for monitoring experimental tests using photogrammetry and image processing have been recently proposed. This manuscript aims at providing a practical demonstration of the advantages of using these new techniques in experimental tests up to failure. In this scope, focus is given to the curvature, rotation and to the tension stiffening effect, i.e., the contribution of the concrete between cracks to increase the bending stiffness. These parameters are crucial to describe the structural behavior of reinforced concrete beams both in serviceability and in ultimate limit states. These new techniques allow monitoring a high number of points, enhancing the traditional monitoring methods and providing more information which would be impossible to obtain using the traditional methods.

FlɛX: a computer vision program to evaluate strain in flexible crystals

“…By applying imageprocessing techniques, it is possible to, at least in part, fill the gap arising from the lack of mechanical testing. Imageprocessing techniques have already been successfully applied for macroscale samples (Kromanis & Kripakaran, 2021;Carmo et al, 2019Carmo et al, , 2013 and can be adapted for smaller sized samples. Specifically, image-processing techniques applied to macroscale samples rely on a preliminary marking of the sample, which is not possible for subcentimetric samples.…”

Assessing steel strains on reinforced concrete members from surface cracking patterns

“…These techniques can be applied to a significant number of surface points and enable more refined measurements, which would be extremely difficult to obtain using other traditional methods. Photogrammetry and image processing are also non-contact and non-destructive techniques for characterising crack patterns and deflections ( was shown the feasibility of measuring bending moments in structural members using this approach [2,3].…”