AN INVESTIGATION OF DEFORMATION BEHAVIOR OF BEAMS WITH HIGH DUCTILE CONCRETE IN POTENTIAL PLASTIC REGION

In order to improve the deformability of RC beams, high ductile concrete (HDC) was locally applied in the potential plastic hinge region of RC beams. Six RC beam specimens with a shear span ratio of 3.6 were designed, including five specimens with HDC in the plastic hinge region, and one RC beam designed for comparison. The hysteretic behavior, deformability and energy dissipation capacity were analyzed by using low cyclic loading tests, considering the effect of HDC region length, the reinforcement ratio of the longitudinal reinforcement and the stirrup ratio in the beam ends. The experimental results show that, the failure mode of the beams with HDC in the potential plastic region is changed from bending-shear failure to bending failure with better ductile characteristics and better energy dissipation capacity compared with the RC beams. With identical longitudinally reinforcement arrangement, the displacement ductility factor and ultimate drift ratio in RC beam with HDC in its plastic hinge are increased by 30% and 53%, respectively, while both HDC and stirrup are applied in the plastic hinge region, the displacement ductility factor and ultimate drift ratio are increased by 33% and 76%, respectively. The locally used HDC in the beam end can reduce the amount of stirrups, and the HDC length of the plastic hinge area at the beam end has little effect on the ductility of the specimen. The lateral displacements of the beams at cracking load, yield load, peak load and ultimate load are calculated, respectively, and the calculated values are in good agreement with the experimental values.