Study On Seismic Performance Of Beam-column Joints Of RC Staggered Column Structure System

The progressive building types have been more and more recognized due to their novel shapes and beautiful forms.The staggered column structure system can not only coordinate with the building appearance,but also make good use of space.It is an ideal structural solution for buildings with indented shapes.As a new type of structural system,the misaligned column system has complex beam and column joints.Many strong earthquakes have caused large casualties and economic losses at home and abroad.Therefore,in order to further promote the RC misaligned column structure system,it is necessary to study the seismic performance of beam-column joints.In this paper,the seismic performance of beam-column joints of RC staggered column structure system is taken as the research object.The main research work is as follows:(1)Based on the research status of new types of structural nodes at home and abroad,and combined with the seismic performance index of the nodes,the research determines about parameters,loading rules,loading methods,and measurement objects of the six groups of test specimens.So according to the existing test conditions,a test device is designed for it.(2)Through pseudo static reciprocating tests of six groups of beam-column joints,the effects of axial compression ratio,misalignment amount,beam longitudinal reinforcement ratio,and additional steel plates on the shape of failure are studied,and the key influencing factors about the weak areas and the mechanism of the misaligned column joints are revealed.The research shows that reasonable design parameters can meet the code’s design requirements for "strong columns and weak beams,strong nodes and weak members".(3)Considering the changes of the research parameters such as the axial compression ratio,the amount of misalignment,the beam longitudinal reinforcement ratio,and the installation of additional steel plates,based on the results of pseudo static reciprocating tests of six groups of beam-column joints,the research carried out a quantitative study on the seismic performance indicators such as the node skeleton curve,bearing capacity,energy consumption coefficient and ductility coefficient.The research has shown that the study parameters have a significant effect on seismic performance indicators.(4)Relying on the advantages of DIC high-speed photogrammetry technology,the surface strain,crack development law and the weak state evolution of the node in the core area of the dislocated column nodes under different parameter changes are studied.The research shows that DIC high-speed photogrammetry technology can measure the high strain state of the structure surface,and combines with the results of the physical test reinforcement strain test.It can provide data support for the study of the failure mechanism of the joint.(5)Based on the ABAQUS finite element numerical analysis platform,the different concrete and steel constitutive models are compared and analyzed,and the numerical simulation method of misaligned column joints is studied in combination with China’s standard material curve formula.Meanwhile,the numerical simulation method of staggered column joints is studied,and the error analysis between numerical calculation results and experimental results is carried out.The research shows that the numerical analysis can better simulate the yield and failure process of beam-column joints,which is in good agreement with the test results,so the calculation results have good reference meaning.