Enhanced Shear Performance of Circular Reinforced Concrete Members with Geogrid and Steel Fiber Reinforcement

Abstract

Reinforced concrete (RC) members with circular cross-sections are integral to modern construction, valued for their omnidirectional structural properties, particularly in columns, piers, and piles. This research investigates an innovative approach to augmenting the shear strength and ductility of such members by partially replacing conventional steel stirrups with geogrids and incorporating steel fibers into the concrete matrix. The rationale stems from geogrids' high tensile strength and flexibility, and steel fibers' known efficacy in mitigating crack propagation. An experimental program involving sixteen RC circular specimens was conducted. Key parameters included varying steel stirrup spacing, the use of two concrete types (standard reinforced concrete and steel fiber reinforced concrete with a certain fiber content), and the application of geogrids with distinct tensile strengths. Specimens were simply supported and subjected to a mid-span point load using a hydraulic loading frame. Load-deformation characteristics were meticulously recorded and analyzed to determine ultimate load capacity, secant stiffness, energy dissipation capability, and displacement ductility. The experimental results indicate that the synergistic use of geogrids and steel fibers leads to notable improvements in both the ultimate strength and ductility of the circular RC specimens, suggesting a viable enhancement for shear reinforcement strategies.