Experimental Investigation of the Confinement of Concrete Columns with Welded Wire Reinforcement

Traditional methods of construction for reinforced concrete columns utilize longitudinal steel bars and transverse ties. Field experience has shown that such a transverse reinforcement method is labor-intensive, time-consuming, and prone to inconsistencies in quality. Welded wire reinforcement (WWR) offers a prefabricated alternative, forming a closed cage that simplifies installation and speeds up the fabrication process. This study investigates the potential of using WWR as a replacement for conventional ties in reinforced concrete columns in pure compression. To achieve this objective, eight one-third-scale columns (1000 mm height, 200 × 200 mm cross-section) were tested under concentric axial loading inside a Universal Testing Machine. Four of the specimens contained WWR, while the other four had conventional ties. The variables that were considered in this study include the concrete compressive strength (34.3 and 43.5 MPa) and the grid size of the WWR (25 and 50 mm). This study investigated the influence of the type of transverse reinforcement on the strength, modulus of elasticity, and ductility of the confined concrete within the core. The findings of the study showed that lateral reinforcement in the form of WWR can increase the concrete core strength by 2.7% relative to corresponding columns employing ties when f′_c = 34.3 MPa was used. Conversely, the utilization of ties proved to be more effective than WWR in improving concrete core strength by an average of 28.8% when f′_c = 43.5 MPa was used. Additionally, WWR reinforced columns demonstrated a marginal 2.0% rise in the modulus of elasticity and a remarkable 21.0% increase in the ductility of the confined concrete core compared with corresponding tied columns. Theoretical predictions of the axial compressive capacity of WWR reinforced columns subjected to concentric loading based on the ACI-318 code provisions underestimated the experimental results by 20%. These findings demonstrate that WWR can serve as an effective substitute for conventional ties, particularly in cases where rapid installation and reduced labor costs are prioritized.