Low-Cost Load Monitoring System for the Force Redistribution Assessment in Civil Structures by Means of Fiber Optic-Based Transducers

Civil structures are designed to withstand loads from multiple sources; however, design is achieved based on several hypotheses, which in some cases do not occur. Phenomena such as differential settlements, damage or failure of structural elements, overloads, etc., cause buildings to behave differently than expected. When any of these phenomena occur, due to multiple factors, it is not possible to determine precisely the distribution of stresses in the building and therefore, it is difficult to establish with any degree of reliability if there are elements that may be subjected to stress levels that could cause a critical failure of the structure. In this paper, the development of a low-cost fiber optic-based transducer intended to force/stress measuring in civil structure pillars within the SHM context is presented. Test transducers were embedded in scale reduced columns, which were submitted to compression loads using a testing bench rig. Transducers successfully measured strain levels up to 200 mu epsilon under compression load with an accuracy of +/- 1 mu epsilon. Strains and applied force were linearly related. Through finite element analysis (FEA), a sensing scheme was designed for the first floor of a 32-story-tall building composed of 32 columns where each column includes one embedded transducer. The constructive phase of building will start by April 2022, when transducers will be embedded within the structure. It is expected to detect load redistribution during the construction phase of the building and its operational phase.