Deflection estimation of reinforced concrete beams using long-gauge optic sensors

• DOI: 10.1016/j.istruc.2024.107249
• Publication Date: 2024-09-14T18:29:52Z
• Authors: Haoran Lin; Wan Hong; Zhihong Yang; Zhaowen Xu; Yixin Wang; Bing Li
• Keywords: Engineering; Deflection distribution estimation; 624; Shear deformation; 620

Deflection is a crucial indicator in structural health monitoring, directly impacting the service life, safety, and economic viability of structures. However, current indirect methods for measuring deflection, such as multi-element FBG sensors or accelerometers, often have limitations. While they may be suitable for flexure-dominated reinforced concrete (RC) specimens in the elastic stage, they neglect the significant influence of nonlinearity and shear deformation. This paper introduces a new approach for estimating the deflection of reinforced concrete (RC) beams using distributed long-gauge optic sensors. The method tackles the limitations of current methods by incorporating the crucial factors of shear deformation, neutral axis position variation and shear stiffness degradation. Experimental studies are first conducted to validate the accuracy and stability of long-gauge optic sensors in small-scale RC members. Algorithms are then utilized the measurement data to estimate the deflection. The results demonstrate the excellent performance of long-gauge optic sensors in measuring shear deformation and vertical deflection of RC beams, as evidenced by comparisons with LVDT measurements. Additionally, a method for decoupling flexural and shear deformation is proposed. This method offers a preliminary assessment of the reinforced concrete (RC) beam type by quantifying the relative significance of shear deformation. ; Housing & Development Board ; Ministry of National Development (MND) ; National Research Foundation (NRF) ; This research is supported by the National Research Foundation (NRF), Singapore, Ministry of National Development (MND), Singapore, and Housing & Development Board (HDB), Singapore under its Cities of Tomorrow R&D Programme (CoT Award COT-V2–2020-2). Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not reflect the views of National Research Foundation, Singapore and Ministry of National Development, Singapore.