Load Testing Measurements for Structural Assessment Using Geodetic and Photogrammetric Techniques

SUMMARY The methodologies used for the design of large manmade structures are mainly based on information about the materials, which is obtained experimentally using small-scale specimens and simplifying assumptions with regard to the geometry and the behaviour of structural elements and structural components. Displacement measurements in structural elements, like beams, in laboratory-controlled conditions constitute a very useful tool for the validation of the theoretical design models and material behaviour. These measurements are usually taken at specific positions on the structural element. In this paper the behaviour of a timber beam under five-point bending conditions is examined both theoretically and experimentally. The objective of this research is to use geodetic techniques, specifically conventional surveying and digital photogrammetry, to describe a beam undergoing controlled loading. Whilst both the above geodetic techniques provide non-contact measurement systems, photogrammetry has the advantage of rapidly recording detailed and definitive threedimensional information over the entire surface of the beam as opposed to traditional sparse point-wise structural displacement observation techniques (e.g. dial gauges, LVDTs). Measurements of displacements are taken for a number of load levels. The test results are compared with analytical results using the finite element method for orthotropic behaviour of the timber beam. occur