Research On Shear Bearing Capacity And Code Formula Reliabilityof Concrete Columns With HRB500Reinforced Bars

With the development of society, the high strength steel and high strength concrete material has more and more riveted people’s attention because of its advantages. HRB500reinforced bars, which possesses a series of advantages such us high strength, excellent ductility, good economic and social profit has been widely used in practical engineering and taken in the newly-revised Code for design of concrete structures (GB50010-2010).Gratifying results about reinforced concrete special-shaped columns structure has been got by the domestic and overseas scholars because of its unique form. But there is little research about it, In order to popularize the application of HRB500steel bar in RC special-shaped column structure, as well as promote the development of the Structural System with Special-Shaped Columns; it is essential and pregnant to carry on the further experiment research on the performance of the specially shaped members with such high strength reinforcement.Base on the experiment of eighteen specimens of T-shaped section concrete columns with HRB500steel bars under axial compression and low cyclic reversed lateral load, the failure mode, bearing capacity, ductility, rigidity degradation, hysteretic behavior, energy dissipation and cumulative damage of the specimens were studied systematically. The effects of reinforcement characteristic value and axial compression ratio on the seismic behavior were discussed deeply in the investigation. The analysis results show that:when the axial compression is small, match hoop increase enhancement to the concrete constraint function and the bearing capacity and deformation ability improved, ductility improved. At the same time the component of the whole stiffness and energy dissipation capacity is improved. With the specimen axial compressive ratio increase, the bearing capacity of member increased but the ductility of the member to reduce. Section form affects its seismic performance, but the impact is small.Furthermore, the shear capacity formulas in Technical specification for concrete structures with specially shaped columns are validated by the experimental data, revealing its applicability and in such structures with high strength reinforced bars. Meanwhile, calculation formula of special-shaped columns oblique section shear bearing capacity has been studied. The results show that the reliability index of shear strength formula is4.03, then shear strength formula is still available to design concrete special-shaped columns with high-strength steel bars.