The efficiency of the videogrammetric technique to detect the steel beams’ deflections under the vertical loads

Due to the great evolution in videogrammetric system, several studies have addressed the use of this system in different civil and close-range applications such as building structure monitoring. However, previous studies have not deeply discussed the ability of the videogrammetric system to detect the deflections of different types of steel beams under vertical load. Therefore, the aim of this study is to investigate the ability of the videogrammetric system to detect the deflections of different steel beam sections under the same vertical load. A Photo-Modeler (PM) software was used to derive a 3D stereo model of steel beams before and after applying the vertical load in order to find the values of the deflections in these beams. Two video cameras are fixed in the videogrammetric system used to capture the dynamic deformations of loaded beams. This study includes choosing and calibrating two same model video cameras (Canon IXUS 185) and three types of equal-length steel beam sections are used in the practical trials. The cross-sectional dimensions of these beams are (100x50) mm and they are selected with different thicknesses (2.5, 3.0, and 4.0) mm. Using the laboratory load equipment, a constant load is imparted to each one of the three beams. The video results are then analyzed according to the civil design calculations. The study demonstrates that videogrammetric system techniques can determine the amount of steel beam deflections with precision and efficiency of up to millimeters. Based on these findings, this technique can be implemented and utilized for destructive inspections of important civil structural elements.