Seismic behavior of interior polyvinyl chloride-carbon fiber-reinforced polymer-confined concrete column-ring beam joints

Eleven interior polyvinyl chloride (PVC)-carbon fiber-reinforced polymer (CFRP)-confined concrete (PCCC) column-ring beam joints are fabricated and experimentally investigated. The impacts of axial compression ratio, frame beam reinforcement ratio, CFRP strips spacing, ring beam width and ring beam reinforcement ratio, on seismic behaviors are analyzed. All specimens show obvious failure signs, and the frame beam reinforcement ratio exerts a degree of effect on failure positions, exhibiting different failure modes, such as shear failure in the joint zone, shear-bending failure at the junction and bending failure at the frame beam. The experimental results show that the hysteresis curves are relatively full, which have roughly experienced four stages as elastic, elastic-plastic, stable and decline stages, reflecting that the interior joints have considerable seismic behavior. The increment of ring beam reinforcement ratio or ring beam width enhances the load capacity, mitigates degradation of strength and stiffness. The peak load increases by 38.63% as the ring beam reinforcement ratio increases from 0.88 to 1.5%. When the ring beam width increases from 75 to 125 mm, the peak load increases by 37.24%. Appropriately increasing axial compression ratio can raise the load capacity, alleviate strength degradation, and enhance the initial stiffness. As the axial compression ratio increases from 0.2 to 0.4, the peak load increases by19.41%. The joints with larger frame beam reinforcement ratio show higher load capacity, while the frame beam reinforcement ratio exerts marginal impacts on strength and initial stiffness degradation. The existing classical shear models and specification design formulae are used to evaluate the shear capacity of the interior joints, and the reasons for the deviations of prediction results are expounded, which provides the theoretical basis and useful reference for the subsequent establishment of a new shear capacity formula of the joints.

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Opracowanie rekordu ze środków MEiN, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2022-2023)