Bond Performance Of Steel Reinforced Concrete

In the past two decades steel reinforced concrete structure was developed very fast in China, they are more and more widely used in buildings and bridges. Notable benefit of technology and economics have been achieved from engineering practice. Because adequate bond between shape steel and concrete is an essential requirement in the design of steel reinforced concrete structure, the researches on the bond behavior of steel reinforced concrete structure have been widely undertaken in China in the past twenty years. However, none of the numerous investigators has entirely solved the problem of the bond behavior between shape steel and concrete that is significant to engineering practice and theoretical analysis, which prompt the author to carry out experimental study on the bond behavior of steel reinforced concrete.Based on the test of 6 push-out and beam specimens, some analytical model about bond behavior between shape steel and concrete is developed in the paper, on the other hand, the comparison between test results and theoretical study is also presented in the thesis. At first, the bond mechanism between shape steel and concrete compared with that of normal reinforced concrete is analysed. The distribution model of bond stress over the splice length is developed. Then a mathematical model of the relationship between bond stress and slip is established and a r-S curve is plotted, which contribute to the further analysis of nonlinear behavior of the steel reinforced concrete structure by finite Element method. Furthermore, a calculating formula to define the ultimate load is proposed. The influence of several parameters, such as concrete strength, loading method, the thickness of concrete cover and the number of stirrups on the bond behavior is discussed. All the theoretical analysis shows good correlation with numerous test results available in the literature as well as with those obtained from the test in the paper. At last, some problems which are needed to be further studied or revised in the field are pointed out.The results of the experimental study and theoretical analysis in the paper indicate that the bond properties of steel reinforced concrete are different from that of normal reinforced concrete. Some measures to strengthen the bond between shape steel and concrete should be taken in practical projects. The factors affecting the bond behavior of steel reinforced concrete that are noted in the paper should be noticed in design and construction. The results of the research can provide some advice to the design rules.