Title:
Glass Fiber-Reinforced Polymer-Reinforced Concrete Columns with Varied Concrete Strength under Combined Bending-Torsion Cyclic Loading
Author(s):
Yasser M. Selmy, Amr E. Abdallah, and Ehab F. El-Salakawy
Publication:
Structural Journal
Volume:
121
Issue:
6
Appears on pages(s):
133-144
Keywords:
circular columns; combined loading; concrete strength; cyclic loading; glass fiber-reinforced polymer-reinforced concrete (GFRP-RC); seismic; torsion; transverse reinforcement
DOI:
10.14359/51740869
Date:
11/1/2024
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.