Effect of Vertical and Horizontal Web Reinforcement on the Strength and Deformation of Concrete Deep Beams Reinforced with GFRP Bars

Abstract

Ten full-scale concrete deep beams reinforced with glass fiber-reinforced polymer (GFRP) with a cross section of 1,200×300 mm were tested to failure under two-point loading. The test variables were the configuration of web reinforcement (horizontal and/or vertical) and shear span-to-depth ratio (a/d=1.47, 1.13, and 0.83). All specimens exhibited sufficient deformation required to develop arch action, which was confirmed by crack propagation and an almost linear strain profile in the main longitudinal reinforcement, in addition to the typical failure mode of crushing in the concrete diagonal strut. The results show that the vertical web reinforcement had no clear impact on ultimate capacity, while the configuration with horizontal-only web reinforcement unexpectedly resulted in a lower ultimate capacity compared to the specimens without web reinforcement. The web reinforcement’s main contribution was significant crack-width control.