EXPERIMENTAL STUDY ON THE SHEAR BEHAVIOR OF HIGH DUCTILE FIBER REINFORCED CONCRETE BEAMS WITHOUT STIRRUPS

In order to improve the shear behavior and deformability of the beams without stirrups, 8 high ductile fiber reinforced concrete (HDC) beams were designed, and 3 reinforced concrete (RC) beams were designed for comparison. The failure mechanism and mode of beams on different shear span ratios and longitudinal reinforcement ratios were studied by static loading tests. The shear failure modes of HDC beams without stirrups are extrusion failure, shear-compression failure, bending-shear failure, and shear-tension failure. The research shows that: all of HDC beams have shown ductility to some extent, which were clearly different from the shear failure mode of RC beams without stirrups; the tensile strain hardening and multiple cracking of HDC can effectively control the development of shear cracks of HDC beams during the failure process, prevent from the crushing and spalling of concrete, and significantly improve the shear capacity and damage resistance ability of HDC beams; comparing with RC beams, the shear capacity and deformability of HDC beams has been enhanced notably, which suggests that the brittle shear failure mode of beams without stirrups can be obviously improved; both the shear span ratio and longitudinal reinforcement ratio have great influences on the failure form and bearing capacity of HDC beams without stirrups. And the shear bearing capacity will be reduced when the shear span ratio is increased, and will be increased with the increase of longitudinal reinforcement ratio.