Test And Shear Capacity Analysis Of Reinforced Concrete Beams With Diagonal Reinforcement Under Concentrated Load

The study for the shear behavior of the reinforced concrete members have been lasted more than 100 years. Due to the complexity of the shear behavior itself and its numerous influencing factors,the generally accepted theory of shear model is still missing.Currently,the researches about the shear capacity of RC beams are concentrated on the beams without diagonal web reinforcements,few of the beams with diagonal web reinforcements have been reported.According to the 2 beams in the laboratory, which were embedded with longitudinal reinforcements,stirrups and diagonal reinforcements,the shear behavior of the reinforced concrete beams with diagonal reinforcements was studied.The main work can been drawn as following:(1)The general situation of the theoretical study on the shear capacity of the reinforced concrete beams at home and abroad was summarized and the advantages and disadvantages of the different shear models were introduced.(2)The brief introduction of the experiment on the shear capacity of the RC beams with stirrups and diagonal reinforcements was made.The phenomena appeared during the loading process and the results of the experiment,including the width of the crack,the deflection of the beams and the strains of the longitudinal reinforcements,stirrups and diagonal reinforcements,changing as the load increasing,were analyzed.(3) The formulations to calculating the shear capacity of the RC beams listed in both Chinese code and American code were compared.The effort of the important parameters,which were great relative to the shear capacity of the beams,including the strength of the concrete,shear-span ratio,size effort,longitudinal reinforcement and stirrups ratio,were studied.The formulations to transferring the material strength of concrete and reinforcement were proposed.And the minimum stirrup reinforcement ratio expressing both in the Chinese code and American code were calculated and compared.(4) Based on the limit equilibrium theory and the simplified strength criterion of concrete material, which was developed by Rankine’s failure criteria, an analytical model for calculation of the ultimate shear capacity was proposed. Comparing with the beams with diagonal reinforcements and stirrups, it is indicated that the error between the theoretical results and the experimental ones is less than 5%.It is proved that the model proposed in here could apply to the analysis of the shear behavior of the reinforced concrete beams.