| Reinforced concrete beam is one of the most basic load-bearing seismic components in the building structure.Its bearing force and deformation damage have a critical influence on the seismic resistance of the frame structure.China's latest "Code for Design of Concrete Structures"(GB50010-2010)clearly stipulates the elimination of HPB235 low grade steel bars,the promotion and use of CRB550 and above the high-strength cold-rolled ribbed ribs.CRB550 grade steel is made of hot-rolled discs through cold-rolled forming and stabilizing heat treatment on its surface to form two-sided transverse ribs and made,the strength was significantly improved,ductility changed little.The kind of steel bar is mainly used in the plate reinforcement,frame tendons,distributed tendons and structural tendons,as the beam,column stirrups are still relatively rare,CRB550 high-strength steel bars in the beam,column components for the application of the main reference Strength of the use of ordinary hot rolled ribbed bar.In the reinforced concrete frame structure,"Building seismic design code"(GB50011-2010 2016 edition)only for ordinary steel bars in the beam end of the hoop reinforcement area length,stirrup maximum spacing and minimum diameter of the structural requirements,Of the cold-rolled ribbed steel bars for the stirrups to make a detailed description,but with reference to borrow,in this proposed for CRB550-class high-strength stirrups in the beam end stirrups to meet the structural requirements of the diameter limit,in order to standardize the cold rolled ribs Application of Reinforcement in Reinforced Concrete Structures.7.Based on the comparative analysis,this paper puts forward the limit of the diameter of CRB550 high-strength steel bars as the stirrup of the stirrups in the beam-end stirrups,and the application of cold-rolled ribbed steel bars in reinforced concrete structures Provide a basis for reference.Therefore,this article "finite element analysis,supplemented by experimental research",through the comparison of test results and finite element calculation results,verify the rationality and reliability of the finite element model used,and then use ANSYS finite element software The seismic behavior of CRB550 high-strength stirrup and HRB335 grade regular stirrups is studied from four aspects: skeleton curve,stiffness degradation,displacement ductility and energy dissipation.It is proved that the reinforcement ratio of small,medium and large longitudinal reinforcement The CRB550 high-strength steel bars with diameters of 6.25 mm,7.75 mm and 9.25 mm can be used instead of the HRB335 grade steel bars with diameter of 8mm,10 mm and 12 mm,which are designed according to the specified limits.Tendons Therefore,on the basis of satisfying the structural requirements of the specification,the limit of the diameter of CRB550 high-strength steel bars as the stirrups in the beam-end stirrups is proposed.The economic benefits of using high-strength steel bars are also very impressive due to the "production capacity" policy of the supply side structural reform.If the steel grades can be widely used and replaced with low strength grades,the amount of steel can be greatly reduced.In the promotion of energy saving and low carbon Today has important practical significance. |
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