Experimental and numerical analysis of shear performance of reinforced concrete beams with double openings

In order to study the influence of load position and chamfer opening on the shear performance of reinforced concrete (RC) beams with double openings, five 1/3 RC beams were subjected to three equal point loading tests and ABAQUS finite element analysis. The study revealed that the position of the opening in the structure has a significant impact. When the opening is located in the bend-shearing section, shear force cannot be transmitted, resulting in brittle shear failure of the top chord. In contrast, if the opening is in the pure bending section, bending failure of the specimen occurs. The top chord's cross section exhibits a neutral axis, resembling a short beam, leading to the redistribution of normal stress at the opening. Shear capacity decreases as the loading point moves inward from the outside of the opening. Rectangular openings demonstrate better mechanical properties compared to chamfered openings. The findings from finite element analysis (FEA) suggest that the shear performance of RC beams with double openings is mainly influenced by the length of the opening in the bend-shearing section. The shear capacity relies on the presence of shear stirrups with the same length of the opening in the bend-shearing section. As a result, a revised calculation method for the shear bearing capacity of RC beams with double openings, based on different countries' standards, has been proposed. The revised approach was validated using experimental and FE specimens from this study, along with 32 RC beams with double openings from the previous literature. The calculated results demonstrate a satisfactory level of safety, with the revised Chinese standard deviation within 10%.

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Opracowanie rekordu ze środków MNiSW, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2024)