Ductility Enhancement of High Strength Concrete Columns With Welded Wire Mesh

Abstract

High strength concrete has experienced an increased use by engineers over the last decade due to its large ratio of compressive strength to unit cost, unit weight, and unit volume. However, the gain in strength is achieved at the cost of a loss in ductility of the material. The requirements for transverse steel reinforcement in HSC columns under high shear forces result in high volumetric ratios, which cause reinforcement congestion within the column cross section. An experimental investigation involving the testing of fourteen full-size (355 mm by 355 mm by 1520 mm), high-strength concrete columns in axial compression was undertaken to determine the effectiveness of using Welded Wire Fabric (WWF) as transverse reinforcement in the columns. The performance of columns laterally reinforced with WWF was compared with that of columns laterally reinforced with conventional ties, as well as with unconfined concrete. Axial stress-strain diagrams of the concrete core from the experimental tests showed that substantial gains in strength and ductility of columns laterally reinforced with WWF can be achieved if the volumetric ratio of transverse steel was above 3.5 percent. Strength increases of at least 15 percent were observed, while ductility increases of 250 percent and more were recorded in the specimens with WWF when compared with the corresponding specimens with conventional ties.