International Concrete Abstracts Portal

Title: Exploratory Study of Using Hybrid Glass Fiber-Reinforced Polymer-Steel Bars in Reinforced Concrete Columns to Improve Seismic Performance

Author(s): Anmol S. Srivastava, Girish N. Prajapati, and Brahim Benmokrane

Publication: Structural Journal

Volume: 122

Issue: 4

Appears on pages(s): 229-243

Keywords: design codes; ductility; energy dissipation capacity; glass fiber-reinforced polymer (GFRP); hybrid reinforcement; hysteresis response; quasi-static cyclic load; reinforced concrete (RC) columns; residual deformation; seismic load; stiffness degradation.

DOI: 10.14359/51745488

Date: 7/1/2025

Abstract:
The present study demonstrates the feasibility of using longitudinal hybrid reinforcement in concrete columns in seismic zones. In this research, four concrete columns were constructed and subjected to quasi-static cyclic loading, featuring a combination of steel and glass fiber-reinforced polymer (GFRP) longitudinal reinforcement. Two reference columns were fabricated and reinforced in the longitudinal direction with steel bars. These columns had a 400 x 400 mm (15.8 x 15.8 in.) cross section and 1850 mm (72.8 in.) overall height. All the columns were reinforced with GFRP crossties and spirals in the horizontal direction. The variable parameters were the transverse reinforcement spacing, axial load ratio, and column configuration. The outcomes of this research clearly showed that reinforced concrete (RC) columns that are properly designed and detailed longitudinally with hybrid reinforcement (GFRP/steel) could achieve the drift limitation in building codes with no strength degradation. Further, these hybrid-RC columns displayed enhanced energy dissipation capacity, superior ductility, and improved post-earthquake recoverability compared to columns reinforced longitudinally with steel. The promising results of this study represent a step toward the use of longitudinal hybrid reinforcement in lateral-resisting systems.