Of Hrb500 Grade Reinforced Concrete Structures By The Mechanical Properties Of The Pilot Study

The standard value of HRB500 steel bar's tensile strength is 5000MPa. It is a new type steel bar which has many merits, such as hi-strength and strong ductility. This kind of steel bar has been used prevalently in foreign countries. But it hasn't been taken in by new Code for design of concrete structures (GB500'10-2002). In order to take the internationalization into reality as soon as possible and popularize this new kind of steel bar in engineering area of our country, the experiment researches should be done on the main characteristic of HRB500 reinforced flexural members.The experiment research shows that the performance of flexural member reinforced with HRB500 steel bar is the same as that of the common reinforced concrete members. It's bearing capacity of flexure member can be calculated by the formula of cross-section in the Code for design of concrete structure (GB50010-2002). The result shows that: whether =fy420MPa orfy=400MPa, the HRB500 steel bar member is safe enough.The research of HRB500 reinforced flexural members shows that the flexural members' width of cracks and deflection under limit state of serviceability can be calculated by formulas in existing Code for design of concrete structures (GB50010-2002),while they should be amended properly.As for the value of deflection, it should be enlarged by a coefficient 1.25. Similarly, the max-width of cracks should be discounted by a coefficient 0.9. Because the HRB500 steel bar's working stress (under the limit of serviceability ) is larger than other bars in existence, we suggest that a checking computation to the width of cracks of the flexural members should be given.The research shows that the performance of shear member reinforced with HRB500 steel bar is the same as the common reinforced concrete members. According to the Code for design of concrete structure (GB50010-2002), the bearing capacity of HRB500 steel bar under shear can be calculated by the formula of bearing capacity in oblique cross-section. Because of its high strength, the HRB500 steel bar cannot reach its max strength, and most of strengths of steel bars are no more than 400Mpa when the member destroyed. So I proposefyv=380Mpaor 360 Mpa.The research shows that HRB500 reinforced continuous beam have enough ductility, "plastic hinge" has full rotation capacity. Continuous beam can implement the plastic internalforce redistribution. This can be take into account when design HRB500 bar reinforced construct.