Experimental and numerical investigation of the axial compressive behavior of GFRP-reinforced concrete walls under concentric and eccentric loading

This study investigates the axial compressive behavior of reinforced concrete (RC) walls reinforced with glass fiber-reinforced polymer (GFRP) bars under concentric and eccentric loading through a combined experimental and numerical approach. The six RC wall specimens with dimensions of 1000 × 800 × 150 mm were tested and divided into two groups. For Group G1 there were three specimens tested for concentric axial loading and for Group G2 three specimens were analyzed for eccentric axial loading. One control wall in each group was reinforced with conventional steel bars and the rest were reinforced with GFRP bars in vertical and horizontal directions. The experimental program studied first-cracking and ultimate loads, cracking behavior, stress-strain response, ductility ratios, energy absorption capacity, and lateral displacements. The results indicated that replacement of steel reinforcement with GFRP bars decreased ultimate axial capacity; however, GFRP-reinforced walls maintained stable post-cracking behavior and satisfactory ductility performance. When subjected to concentrically loaded specimens, the ultimate load capacity of GFRP-reinforced walls decreased by approximately 10.8-13.3% compared with the steel-reinforced control specimen, while the ductility ratio increased by about 4.4-4.8% points. Under eccentric loading, the ultimate capacity reduction ranged from 6.5% to 14.1% relative to the steel control wall. The energy absorption capacity, assessed from the load-displacement response, was lower for GFRP-reinforced walls compared to steel-reinforced specimens; however, a stable post-cracking response was maintained under both concentric and eccentric loading. In ABAQUS, nonlinear finite element models were generated through the Concrete Damaged Plasticity (CDP) model to emulate the structural response of the tested walls, to be complementary to the experimental study. The numerical results agreed well with the experimental results regarding ultimate capacity, load-deformation behavior, stiffness degradation, and crack distribution. The deviation between experimental and numerical ultimate loads ranged from approximately 0.25% to 11.9%, confirming the reliability and acceptable predictive accuracy of the adopted numerical modeling approach. Therefore, in general, in RC wall systems it is concluded that GFRP bars present a potential viable corrosion-resistant alternative to traditional steel reinforcement. The combined experimental and numerical results yield useful information about the axial behavior of GFRP-reinforced concrete walls under concentric and eccentric loading, that can be useful for making a better design decision in future for durable and sustainable structural wall applications.