Mesoscale modeling of size effect of BFRP‑reinforced concrete columns under pure torsion

There have been few studies regarding the torsional behavior of FRP-reinforced concrete members. Only the CSA S806-12 and the ACI 440.11-22 codes specify the design criteria for their pure torsional capacities. A meso-scale numerical model of circular/square concrete columns with BFRP bars was developed, in which concrete heterogeneity can be explicitly described. This study evaluated longitudinal reinforcement ratios, stirrup ratios, cross-section shape, and structural size for their effects on BFRP-reinforced concrete column torsional performance. For BFRP-reinforced concrete columns, the nominal torsional strength exhibits a significant size effect, while the longitudinal reinforcement and stirrups ratio cannot suppress the size effect. Furthermore, a modified size effect law was developed to quantitatively reflect the relationship between nominal torsional strength and structural size. BFRP-reinforced concrete columns present a more substantial size effect than steel-reinforced ones. Finally, a modified calculation formula of pure torsional capacity was proposed considering the effect of structural size.

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Opracowanie rekordu ze środków MNiSW, umowa nr POPUL/SP/0154/2024/02 w ramach programu "Społeczna odpowiedzialność nauki II" - moduł: Popularyzacja nauki (2025)