Study On Caculation Method Of Deformation,Crack And Bearing Capacity Of600Mpa Reinforced Concrete Beam

600MPa high strength reinforcement has the advantages of high strength and good ductility.At present,the United States,the United Kingdom,Japan,South Korea and other developed countries have widely used high-strength reinforcement,but China’s research on the performance of 600 MPa high-strength reinforced concrete components is still in its infancy.In order to bring China’s reinforced concrete research into line with international standards as soon as possible,this paper studies the whole process and calculation method of 600 MPa high strength reinforced concrete beam.The main contents and conclusions are as follows:(1)The sixteen reinforced concrete(RC)beams with 600 MPa steel bars and different concrete strength grade(C30,C40,C50,and C60)were tested to research characteristics of deformation and establish associated calculation method of deformation.The strain variation of concrete along the depth direction and that of longitudinal tensile steel bars,and the complete load-deformation curves of RC beams with 600 MPa steel bars,which were in the normal service stage,were successfully obtained by experiments.The experimental results show that,the strain distribution of RC beams with 600 MPa steel bars can meet plane section assumption,these load-deformation curves are shown as a triangular line.Furthermore,based on the deeply analysis on experimental results of RC beams with 335 MPa,400MPa,and 500 MPa steel bars,and this study on RC beams with 600 MPa steel bar,the applicability of the existing formulas from domestic and foreign codes for RC beams is systematically analyzed.And these uniform models for checking computations of RC beams deformation were proposed.The result of comparing show that the proposed formulas are better with the test data and suitable for these RC beams with different steel bars(from 335 MPa to 600MPa)and different concrete strength(from C30 to C60).(2)In this paper,crack distribution and crack width of reinforced concrete(RC)beams with600 MPa steel bars and different concrete strength were experimental studied.By using statistical analysis on different crack patterns of RC beams with 600 MPa,the feature of main cracks whose crack widths need to be checked in design of RC structures was determined.The methods for determining the depth of effective influence zone of 600 MPa tensile steel bars in RC beams were experimentally obtained.Based on the experimental data of this study and those of RC beams with 335 MPa to 600 MPa steel bars from different scholars,the applicability of calculation formulas from different codes and scholars for determining the average crack space and the maximum crack width of RC beams with 335 MPa to 600 MPa steel bars was analyzed.The methods for calculating average crack space and maximum crack width of RC beams with335 MPa to 600 MPa steel bars were proposed.(3)In this paper,the formulas for calculating the flexural capacity of the normal section of reinforced concrete beams in the existing codes are compared and the applicability of the existing codes is analyzed.The results show that there are slight differences in the strength calculation and the height calculation of the concrete equivalent rectangular stress diagram between the existing codes at home and abroad.The current code at home and abroad is applicable to the calculation of the bearing capacity of 600 MPa reinforced concrete beam,and there is a higher safety reserve for 600 MPa reinforced concrete beam.