| Deformation-based seismic design methods for reinforced concrete frame structures require that the actual deformation capacity of the components is greater than the deformation requirements.The inter-story drift is an important indicator of the overall deformation of the control frame structure,and is the result of the deformation of each component.As a sub-structure in the frame structure,the reinforced concrete beam-column subassemblage consists of three parts:the beam,the column and the core area of the node.Compared with the simple beam or column components,the deformation ability of the beam-column subassemblage more truly reflects The overall deformation ability of the frame structure.Therefore,the study of the deformation ability of beam-column subassemblage under earthquake is of great significance.This paper theoretically analyzed and deduces the ultimate displacement calculation method of reinforced concrete beam-column subassemblage and the contributions of various deformation components to the displacement of the column top.Based on theoretical analysis,ABAQUS finite element analysis software was used to study the influence of axial compression ratio,ratio of column longitudinal reinforcement and beam shear span ratio on the deformation ability of beam-column subassemblage.The main contents and conclusions are as follows:(1)Taking the beam-column subassemblage with the flexural failure of beam end as the research object,the horizontal displacement of the column top of the beam-column subassemblage is decomposed,and the theoretical calculation formula of the ultimate displacement of the beam-column subassemblage is established.The results are more consistent between the theoretical calculation value and the experimental value.(2)The deformation of beam-column subassemblage is divided into two stages of elastic deformation and plastic deformation.The relative stiffness relationship between beam and column is considered separately in the two stages.The contributions of beam and column deformation to the inter-story drift between components are theoretically analyzed.(3)Based on the comprehensive consideration of the factors affecting the shear deformation in the joint area of the beam-column subassemblage.The shear deformation is subjected to regression analysis by using the collected 16 sets of joint shear deformation test data,and the shear deformation estimation formula is obtained.The coefficient of fit(R-square)is used to judge the fitness of the regression formula and R-square=0.78 is obtained.(4)Using ABAQUS as a platform,finite element analysis models of beam-column subassemblage was established using the simplified model of beam element and node area to study the influence of the axial-pressure ratio,reinforcement ratio of column longitudinal bars,beam shear span ratio on deformation ability of beam-column subassemblage.The results show that with the increase of axial compression ratio,the ultimate displacement angle and displacement ductility coefficient of the components decrease gradually,but the bearing capacity increases gradually.With the increase of the ratio of column longitudinal reinforcement,the bearing capacity and ultimate displacement angle of the components increase.And the displacement ductility coefficient increases gradually;with the increase of beam shear span ratio,the bearing capacity and displacement ductility coefficient of the component decrease gradually,but the limit displacement angle gradually increases.(5)The inter-story drifts caused by beam deformation,column deformation,and joint shear deformation during the failure of reinforced concrete beam-column subassemblage model were calculated.The results show that the contribution rate of each deformation component to the inter-story drift is related to its failure mode.The dissertation has completed the research on the displacement and deformation ability of the beam-column subassemblage.The results of the paper have important reference value for the engineering practice. |
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