Seismic Behavior of Concrete Columns Reinforced with BFRP, GFRP, Steel, and Hybrid Steel–FRP Reinforcement
Jinliang Liu, Shansong Gao, Hongguang Wang, Jinbo Du
Abstract
Steel-reinforced concrete (RC) columns typically exhibit significant residual displacements and low postyield stiffness when subjected to seismic loads, which may complicate subsequent repairs. This paper investigated the effects of different reinforcement methods on the seismic performance of concrete columns by using glass fiber–reinforced polymer (GFRP) and basalt fiber–reinforced polymer (BFRP) bars. Five samples were subjected to low-cycle horizontal loading tests to compare the corresponding seismic performance indices. The results showed that fully FRP-reinforced concrete columns had a lower energy dissipation capacity and ductility coefficient than RC columns but had other clear advantages in terms of ultimate displacement and a postyield stiffness increase by 100%. Compared to RC columns, the concrete columns with half FRP bars exhibited comparable energy dissipation, greater ultimate displacements and ductility coefficients, and a 60% increase in postyield stiffness. Incorporating FRP bars significantly reduced the residual deformation of FRP-reinforced concrete columns compared to RC columns under the same loading cycle, enabling structural repairs and continued use after an earthquake.