PSI - Issue 66

Ram Lal Riyar et al. / Procedia Structural Integrity 66 (2024) 181–194 Ram Lal Riyar et. al./ Structural Integrity Procedia 00 (2025) 000–000

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 For all lightly reinforced concrete beams, the charts depicting the relationship between load and CMOD, as well as load and midspan displacement, reveal that the slopes of the beginning segment overlap. This is because the reinforcement has not yet started to work and just the rigidity of plain concrete is represented. The initial load peak corresponds to a notable increase in longitudinal strain and facilitates load transfer to the steel bar. The CMOD and mid-span displacement exhibit a gradual increase at a constant load as the plastic stresses in the reinforcement become more pronounced. This observation suggests a ductile behaviour commonly observed in lightly reinforced concrete beams. With higher reinforcement ratios in these beams, there is an augmented ductility, a greater number of microcracks, and an expanded width of microcracks.  Three sizes of specimens with various reinforcement percentages were used for the size effect experiments. The observations of size effect in RC beams are in the range of the size effect law.  The crack length for larger diameter bars is less compared to low diameter bars, and it requires higher energy, i.e., the reinforcement resisting crack propagation in the beam. For large-sized beams, the crack length is larger, and it requires less energy to expand the crack i.e., crack propagation becomes more favorable as the beam size increases.  The peak load is decreased by 11.5% when the corrosion is 5%, the peak load is reduced by 24.9% when the corrosion is 10%, and the peak load is decreased by 27.14% when the corrosion is 15%.  Corrosion results in material mass loss, which reduces cross-sectional area and weakens the structure. This material loss may lower the material's overall ability to absorb energy, which lessens fracture energy.  Corrosion has a negative impact on a material's fracture toughness, making it more prone to brittle fracture. 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