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Glass Fiber-Reinforced Polymer-Reinforced Concrete Columns with Varied Concrete Strength under Combined Bending-Torsion Cyclic Loading

Research Authors
Yasser M. Selmy, Amr E. Abdallah, and Ehab F. El-Salakawy
Research Department
Research Date
Research Year
2024
Research Journal
ACI Structural Journal
Research Publisher
American Concrete Institute
Research Vol
121
Research Rank
1
Research_Pages
133-144
Research Website
https://www.concrete.org/publications/internationalconcreteabstractsportal.aspx?m=details&id=51740869
Research Abstract

Under earthquake excitations, reinforced concrete (RC) columns could be subjected to lateral drift reversals and a combination of axial forces, bending moments, and torsional effects. This paper investigates the behavior of glass fiber-reinforced polymer (GFRP)-RC columns under seismic-simulated loading, including torsion, which has not been studied previously. Seven large-scale circular GFRP-RC column-footing connections were cast and tested under various combined reversed cyclic loading configurations to examine the effects of torsion-bending moment ratio (tm), transverse reinforcement ratio, and concrete compressive strength. The test results revealed that increasing the tm reduced the lateral load capacity and deformability of the GFRP-RC column, but resulted in a more symmetric torque-twist relationship. Increasing the transverse reinforcement ratio mitigated core damage and provided additional support (for example, spiral turns) for torsion-induced tensile stresses. Moreover, increased concrete compressive strength bolstered torque capacity and torsional stiffness, while, under a tm of 0.4, it resulted in decreased twist capacity. When torsion was present, increasing the concrete compressive strength had an insignificant impact on the bending-shear response, differing from findings for GFRP-RC columns subjected to seismic loading without torsion.

Research Rank
International Journal