Encased Pultruded I-GFRP Beam under Impact Loading

This study experimentally investigated the behavioral impact of composite reinforced concrete (RC) beams that are strengthened with pultruded I-shaped glass fiber-reinforced polymer (GFRP) sections. Six specimens, divided into two categories, were fabricated in different arrangements. Three specimens were subjected to both impact loading and subsequent static loading in the first category to evaluate their residual static strength after impact. The second category, also consisting of three specimens, was tested under static loading only to provide baseline data for comparison. Key variables included the presence of the GFRP I-section, shear connectors, and varying drop heights during impact tests. A 42.5 kg mass was dropped at the mid-span of the beams from heights of 250, 500, 1,000, 1,500, and 1,900 mm. The composite specimens with GFRP I-sections showed significantly higher maximum impact forces, with increases of 19% and 77% for beams without and with shear connectors, respectively, compared to the reference beam under the same drop height conditions. The composite specimens exhibited drops in the maximum deflections at the mid-span compared to the control specimen. These reductions were 9.4% and 21%, respectively, when the drop height was 1,900 mm.