Tests on reinforced concrete deep beams with different web reinforcement types

Abstract

Due to the high depth to span ratio, shear stresses in deeps impose the need for careful design of shear strength. The shear strength of any reinforced concrete beam is the sum of its sectional strength and web reinforcement strength. Steel bar stirrups are the typical reinforcing material up to date for such a purpose; however, many studies were conducted to evaluate the use of other materials or different configurations to increase the shear strength of deep beams. In this research, closed-form steel plates (gagger plates) were used as alternative shear reinforcement in experimental deep beams. Three beams were cast and tested in four-point bending to investigate this possibility. The first was kept as a reference beam as it was reinforced with conventional closed stirrups, while the rest two beams were reinforced with 4 mm thick and 20 mm wide gagger plates. One with in-plane configuration, where the 20 mm side was aligned in the plane of the beam section, while the third beam was reinforced with out-of-plane gagger plates. Based on the test results, the mechanical behavior of beams with steel plates was noticeably improved compared to the reference beam with conventional stirrups. The in-plane configuration was superior to the out-of-plane and reference beams in strength, service stiffness, ductility, and toughness.