Influence of corner radius on the axial compressive behavior of FRP-confined rectangular reinforced concrete columns

Year 2025, Volume: 1 Issue: 1, 26 - 39, 28.02.2025

Ali Juma Noorzad , Hakan Dilmaç

Abstract

The corner radius significantly influences the axial compressive behavior of rectangular reinforced concrete columns externally confined with FRP jackets along their lengths. Fiber reinforced polymer sheets are among the most efficient techniques for enhancing both the strength and ductility of reinforced concrete columns; however, their effectiveness depends on the geometry and edge sharpness. Sharp corners increase stress concentrations and reduce the effective confinement area. This paper analytically investigates the structural behavior of rectangular columns confined with fiber reinforced polymer jackets that experience non-uniform stress distributions at the corners under axial compression. A series of rectangular reinforced concrete columns with varying corner radii were analyzed using reliable analytical models to evaluate the effects on the effective confinement factor, stress-strain response, and axial load capacity. The results reveal that edge sharpness significantly affects the axial compressive behavior of confined rectangular columns. Sections with smaller corner radii behave similarly to unconfined columns and exhibit limited effectiveness from fiber reinforced polymer confinement. Finally, the study concludes that the corner radius is directly proportional to the enhancement of strength and ductility in confined rectangular reinforced concrete columns, playing a critical role in their axial load-carrying capacity.

Keywords

corner radius, CFRP sheets, RC columns, strength, ductility, confinement, axial behavior

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