Estimating Deformations of Laboratory Structures Subjected to Loadings Using Images Collected with Phone Camerase

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Estimating Deformations of Laboratory Structures Subjected to Loadings Using Images Collected with Phone Camerase

Journal Title: Trends in Civil Engineering and its Architecture - Year 2018, Vol 1, Issue 3

Abstract

A Fundamental civil engineering knowledge is the ability to understand, explain and calculate deformations of/in civil structures. New civil engineers acquire this knowledge at universities in material science, engineering mechanics and introduction to structural engineering modules. Structural deformations can be calculated when knowing material properties, geometry and boundary conditions of a structure and loads that are applied on/to it. Inverse engineering can be employed if deformations of a structure are known, but some other parameters are not known. Theoretical formulae are then tested using laboratory test beds, usually beams. Laboratory technicians are responsible for the acquisition of deformation measurements of laboratory tests. Their time is often limited and so is the number of available measurement collection devices such as dial gauges and strain gauges. If devices that do not log measured deformations are employed, information of structural deformations or response might be lost or readings might not be collected at required intervals. However, all laboratories do not offer luxury of sensors that are available at hand and technicians, which would have time to install sensorsand collect data when needed, especially if this as to be done with a short period of notice. This paper introduces a low-cost vision-based system for deformation estimations of laboratory structures. Significant research is done in the image processing and photogrammetry fields, which is reviewed in recently published paper [1]. Ho et al. [2] demonstrated that two camcorders when used simultaneously can capture displacements of civil structures. Ye at el. [3] employed high-resolution industrial digital cameras with extended-range zoom lenses to collect dynamic movements of long- span bridges and derived structural displacements from collected images. In above examples, camcorders or high-resolution cameras were employed. This study shows that mobile phone cameras can be used to do the above. DefoMonit- software introduced in this paper and developed at Nottingham Trent University (NTU) [4], can analyse consecutively collected images of structures subjected to loadings and estimate structural deformations. DefoMonit, in contrast to proprietary software, is free for students and academics. The next sections provide general introduction to the vision-based system and a laboratory case study. An illustration of the proposed system using a phone for deformation monitoring of a cantilever beam is shown (see Figure 2). Markers are drawn on the face of the beam. A phone is placed at a preferred distance from the laboratory structure. Setting the correct distance, at which images are taken, has a direct impact on the resolution of images and calculated structural deformations. Understanding of structures is required to provisionally estimate expected movement of the laboratory structure. The collected images are analysed using DeforMonit, and time series of estimated deformations are generated.

Authors and Affiliations

Rolands Kromanis

Keywords

Lupine Publishers Lupine Publishers Group lupine publishers indexing Journals lupine publishers indexing list lupine publishers indexing sites Indexed Journals indexed journals list List of Indexed Journals lupine publishers impact factor lupine publishers open access journals lupine publishers indexing Lupine group Lupine online open access open access journals open access journals publishers lupinepublishers civil civil engineering Phone Cameras laboratory Laboratory technicians sensors camcorders photogrammetry

EP ID EP605057
DOI 10.32474/TCEIA.2018.01.000111
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