Fotogrametrično merjenje deformacij pri preizkusih mehanske odpornosti konstrukcijskih elementov ( = Photogrammetric measurement of deformations in tests of mechanical resistance of structural elements)

Abstract

Methods of close-range photogrammetry, which can be efficiently used to supplement the conventional measurements of displacements during the investigation of the mechanical capacity of structural elements, are presented. In the first part of the paper, an overview of photogrammetric procedures employing automatic measurements that enable the acquisition of measuring data in real time is given. The focus is placed on the single-image photogrammetric methods that use successive images taken with a camera for deformation measurements in the object plane. A description of the photogrammetric workflow follows, which assures precise measurements of deformations, as well as a demonstration of the proposed procedure by means of the cyclic test of the reinforced concrete wall, which was loaded with the prescribed cycles of the horizontal displacements and a constant axial force. The results of the measurements are the displacement field of the measuring points and the deformations, which are calculated on the basis of the single-image photogrammetric method applying projective transformation. We have demonstrated that the pattern of calculated deformations fits very well with the damage observed in the wall.

Keywords

• camera calibration
• image correlation
• least squares matching
• projective transformation
• cyclic test of lightly reinforced concrete wall
• deformation