With Hrb500 Grade Reinforced Tensioned Prestressed Concrete Beams Performance Study

The standard value of HRB500 steel bar's tensile strength is 500MPa. It is a new type steel bar which has many merits, such as high strength and strong ductility. This kind of steel bar has been used prevalently in reinforced concrete structure in developed countries. But it hasn't been taken in by the Code for design of concrete structures (GB50010-2002). Only the mechanical property of reinforced concrete flexural members with HRB500 steel bar was researched. In order to take the internationalization into reality as soon as possible and popularize this new kind of steel bar in engineering field of our country, the experiment researches should be done on the main characteristic of post-tensioned prestressed flexural members with HRB500 steel bar.In this paper, the study about the mechanical property of post-tensioned prestressed flexural members with HRB500 steel bar is carried out to solve the problem on the design of HRB500 steel bar in concrete structures.According to the tests of the mechanical property of three post-tensioned prestressed flexural members with HRB500 steel bar, the stress variation of HRB500 steel bar, strand and concrete have been analyzed, and the result shows that HRB500 steel bar can yield and completely display high strength properties when flexural members are destroyed.In response to the research of the mechanical property of flexural members, the result indicates that the performance of post-tensioned prestressed flexural member reinforced with HRB500 steel bar is the same as that of the common post-tensioned prestressed concrete members, and the bearing capacity of flexure member can be calculated by the formula in existing Code for design of concrete structure (GB50010-2002). The research proposes that: when the design strength fy=450Mpa as HRB500 steel bar is used in post-tensioned prestressed flexural members, it can satisfy the ultimate bearing capacity requirement. Based on the experiments and analysis, the result suggests that crack width and deflection of post-tensioned prestressed flexural members with HRB500 steel bar can be calculated by the formula in existing Code for design of concrete structure (GB50010-2002).