Experemental Study On Shear Capacity Of Reinforced Concrete Beam With 500mpa Hot Rolled Bars Of Fine Grains

500MPa hot rolled bars of fine grains is a new type of fine-grained steels, which is a new research and development of our country according to the technology that control the temperature. It's a new type steel bar which has many merits, such as hi-strength and strong ductility. Now this kind of steel bar has been taken in by《Hot ribbed bar of reinforced conrete》(GB 1499.2-2007), but it hasn't been taken in by《Code for design of concrete structures》(GB50010-2002), because the domestic study of this new king of steel bar strait late and the relevant testing information is absent. The study can provide theoretic and testing bases for the application of 500MPa hot rolled bars of fine grains.Based on the experiments of 16 concrete beams with 500MPa hot rolled bars of fine grains, 1 with HRB400 bars and 1 with HRB600 bars as stirrup under concentrated load. They are observed that the crack, deflection, bearing capacity and failure mode under the different concrete strength, different shear span ratio, different stirrup strength, different ratio of stirrup, different section size. Some comparisons are made between test results and calculated values. The experiment research shows that the performance of shear member reinforced with 500MPa hot rolled bars of fine grains is the same as that of the common reinforced concrete members, the members reinforced with 500MPa hot rolled bars of fine grains work well and have obvious failure marks.The analysis of the experiment results shows that the concrete beams with 500MPa hot rolled bars of fine grains, which test results is in line with the results that is calculated by the the formula in code for design of concrete structures. The test results show that the formula in code for design of concrete structures can be used to calculate its shear capacity, which have enough safety.The analysis of the experiment results shows that under the limit state of serviceability , under the concentrated load the concrete beams with 500MPa hot rolled bars of fine grains as stirrup, which is designed by the formula in code for design of concrete structures meet the request of the width of the diagonal crack. The propositional design strength is discussed when the 500MPa hot rolled bars of fine grains as stirrup. Based on the analysis of experimental results, in the formula in code for design of concrete structures, the propositional design strength of 500MPa hot rolled bars of fine grains is 420MPa.