Research On Deformation Ability And Horizontal Displacement Calculation Of Reinforced Concrete Columns

As the vertical seismic components of the frame structure,reinforced concrete columns are subjected to the compound action of pressure-bending shear in the frame structure,the deformation capacity reflects the damage degree of the components and the collapse resistance of the frame structure.Assuming that the interlaminar stiffness is infinite,the interlaminar displacement of the frame structure is completely provided by the horizontal displacement of the frame column,ignoring the inter-story rotation of the frame beam and the joint.Therefore,the study of the deformability and horizontal displacement of the frame column under earthquake can provide a quantitative reference index for the seismic design of the frame column,which has important theoretical significance and engineering practical value.This paper studies the deformability of reinforced concrete columns under axial load and horizontal load from three aspects of theoretical calculation,data regression and finite element simulation.This article mainly carries out the following work:(1)The horizontal displacement of the column member includes bending deformation,shear deformation and bond-slip deformation,and the theoretical calculation of the horizontal displacement is performed according to the deformation calculation analysis.According to the deformation ratio relationship,a simplified calculation formula for the yield displacement considering parameters such as the axial pressure ratio and the shear span ratio was established.The simplified calculation value are in good agreement with the experimental value,indicating that the simplified yield reliability of the yield displacement is higher(2)The correlation of the influencing factors and displacement ductility coefficient was analyzed.According to the correlation coefficient,the ultimate displacement simplified formula considering the parameters such as axial pressure ratio,shear span ratio and hoop eigenvalue was established.The goodness of fit indicator RNL was used to test the fitting degree,it is 0.812 and the fitting effect is good.(3)The experimental data of 123 reinforced concrete columns were collected from the PEER database.Combined with the experimental data,the failure morphology assessment criteria based on the shear-span ratio and the bending-shear ratio was proposed.According to the correlation between the influencing factors and the displacement angle,the linear equations of various displacement angles under different failure modes were regressed,the significance probabilities of regression coefficients are all less than 0.05,indicating that the regression equation is reasonable.(4)The ABAQUS software was used to verify the correctness and scientificity of the finite element model and material constitutive.Based on this,reinforced concrete column specimens with different shear-span ratios,axial-pressure ratios,reinforcement ratios and stirrup ratios were designed.The simulation results indicate that reducing axial compression ratio and increasing shear-to-span ratio,reinforcement ratio,and stirrup ratio can improve the deformability of components;1/50 is not suitable as an index of limit displacement angle of column specimens with small shear span ratio and reinforcement ratio and large axial compression;Horizontal displacement analog value of the column specimens are in good agreement with the simplified calculation,indicating that the horizontal displacement simplified calculation formula has a wider applicability.The study of the deformation capacity and horizontal displacement of reinforced concrete columns has been completed.The research results have important theoretical significance and engineering practical value.