Description
In contemporary bridge construction, post-tensioned concrete technology stands as one of the prevailing methods. Over the past several decades, it has been extensively employed in the construction of medium-span bridges worldwide. As time has elapsed, many of these structures now demand diagnostic assessments due to their deteriorating technical conditions. A promising approach for diagnosing such bridges involves the utilization of distributed fiber optic sensing (DFOS) technology. DFOS enables continuous measurements to be acquired along the entire length of the structure, which is particularly crucial for these types of bridges. Its advantages have already been demonstrated in civil engineering applications, notably in contexts related to concrete structures. Furthermore, thanks to their construction distributed fibre optic sensors can be used for both new and existing structures. The paper presents research conducted on post-tensioned beams with curvilinear multiwire strands. Optical sensors were installed before and after concreting. The main aims were to measure strains, stresses, cracks, and displacements. It also compared results from monolithic sensors embedded in concrete (for new structures) to sensors in pre-made near-surface grooves (for existing structures) and to detect defects within one beam using sensors inside the cable duct, analysing strain data. DFOS measurements were compared with conventional spot techniques, aachieving very good compliance. This investigation establishes that a well-structured DFOS-based system, encompassing suitable measurement methodologies, optical sensor configurations, installation techniques, and post-processing algorithms, emerges as a relevant tool for the comprehensive diagnostics of post-tensioned concrete bridges.
