Title: P-M Interaction of Geopolymer FRC Slender Columns Reinforced with Steel, GFRP, or Hybrid Double-Layer

Author(s): Mohammad AlHamaydeh and Fouad Amin

Publication: Structural Journal

Volume:

Issue:

Appears on pages(s):

Keywords: fiber-reinforced concrete (FRC); geopolymer concrete (GPC); glass fiber-reinforced polymer (GFRP) reinforcing bar; hybrid reinforcement; interaction diagrams; slender columns; slenderness ratio

DOI: 10.14359/51740570

Date: 2/14/2024

Abstract:
A numerical integration model is developed to investigate the axial load-bending moment interactions of fiber-reinforced geopolymer concrete (FRGPC) columns reinforced with double layers of steel, glass fiber reinforced polymer (GFRP), or hybrid reinforcement. The model accounts for material and geometric nonlinearities, including the slenderness-induced second-order effects through an iterative layer-by-layer integration scheme of the critical section. Analytical investigations were conducted for various double-layer reinforcement configurations of steel, GFRP, and hybrid. The effect of adding steel/synthetic macro fibers to the concrete matrix was also investigated. Moreover, comprehensive deterministic sensitivity analyses were conducted to assess the influence of the concrete compressive strength (f_co), reinforcement fiber dosage, and the longitudinal/transverse reinforcement ratios on different response values. For the axial load capacity of GFRP-reinforced columns, the longitudinal reinforcement ratio was found to be the most influential parameter, while for the steel/hybrid reinforced columns, f_co, was the most influential parameter. Moreover, for all the simulated configurations, confinement efficiency was most sensitive to f_co out of all the investigated parameters. The longitudinal reinforcement ratio most influenced bending moment capacity and the associated secant stiffness. Lastly, axial load-bending moment interactions were developed for various reinforcement configurations. The interactions included the effects of the slenderness ratio, the macro fiber type, longitudinal/transverse reinforcement type/strength, and the longitudinal reinforcement ratio. The GFRP-reinforced columns showed more sensitivity to slenderness effects than steel-reinforced columns.