Shear Capacity of T-Section Girders Made of Reactive Powder Concrete

Abstract

This study reports the findings of an experimental investigation of the shear behavior of T-section reactive powder concrete (RPC) girders. A total of 12 large-scale girders, each having a depth of 5 mm, were produced to investigate the influence of the shear span-to-effective depth ratio, longitudinal reinforcement ratio, and stirrup ratio on the shear capacity and failure mode. The results show that when the shear span ratio ranged from 1 to 4, the shear failure mode is either shear compression failure or diagonal compression failure, whereas the failure mode of normal concrete (NC) girders is diagonal tension failure when the shear span ratio is higher than 3. The shear span ratio, longitudinal reinforcement ratio, and stirrup ratio significantly affect the shear behavior of the girders. The strains in concrete, transverse reinforcement, and longitudinal reinforcement were analyzed. Four softening coefficients were used to improve the softened truss model. The softening coefficient for RPC was obtained by comparing the analytical shear capacities and the experimental results. The developed softened truss model was then applied in additional experiments, and the verification of the developed softened model was performed. The agreement between the predicted results and the experimental data is sufficient, indicating that the developed softened truss model is suitable for analyzing T-section RPC girders. Through the softened truss model simulation for the shear behavior of RPC girders, the entire shear process could be calculated and analyzed. Finally, a simplified formula for predicting the ultimate shear capacities of T-section RPC girders was derived and verified with the experimental results. The experimental results revealed the shear behavior of large-scale T-section RPC girders with stirrups, including the failure modes, the load-deflection relationship, the concrete strain, and the longitudinal and transverse reinforcement strains. The developed softened truss model provides a powerful tool for the prediction of shear behavior of RPC girders, which would be helpful for the design analysis of RPC girders.