A comprehensive nonlinear finite-element analysis (FEA) was conducted to investigate the nonlinear cyclic response of moderate-aspect-ratio (height/length ranging from two to four) concrete bridge wall piers reinforced with steel and glass fiber–reinforced polymer (GFRP) reinforcement. The FEA results were validated based on the experimental outcomes of two concrete bridge pier walls reinforced solely with either GFRP bars or steel bars, as well as three bridge pier walls reinforced with hybrid steel and GFRP reinforcement. A total of 18 cases were studied, featuring various combinations of steel-to-GFRP reinforcement. The investigation focused on several key parameters, including the ratio of effective GFRP reinforcement to the balanced GFRP reinforcement ratio and the mixing ratio between steel and GFRP bars at the wall boundaries. The seismic design aspects examined included strength, stiffness, deformation capacity, damage control, energy dissipation, and equivalent viscous damping. The results of the study revealed that hybrid reinforced concrete (RC) walls exhibited remarkable displacement capacity with controlled residual deformations. Furthermore, the simulated hybrid RC walls demonstrated superior ductile flexural behavior. Based on the findings of this study and within the range of the tested parameters, a preliminary proposal is made for the optimal mixing ratio of steel and GFRP reinforcement to be used in RC walls with moderate aspect ratios. This research provides valuable insights into the design and optimization of hybrid RC walls, contributing to the development of more resilient and sustainable structural systems.
Arafa et al. (2026) studied this question.