Seismic Performance And Finite Element Analysis Of Concrete Special-shaped Column Joints

As things stand,the reinforced concrete special-shaped column structure was born at the time of national wall reform.Because of unique structure form,it has achieved good architectural function,and it has been favored and pursued by more and more people.However,it is found that the joint position is the seismic weak point of the special-shaped column structure,which makes the special-shaped column structure fail to be popularized.With a view to improving the seismic performance of special-shaped column joints,many scholars have done a lot of experiments and theoretical research,and found that there are many factors affecting the seismic performance of special-shaped column joints,including axial compression ratio,concrete strength,reinforcement strength,stirrup ratio in the core area of the joint,loading direction and reinforcement form,etc.Due to the cost and time constraints,it is impractical to conduct a lot of structural test research on the influence parameters affecting the seismic performance of special-shaped column joints,which restricts the in-depth research on the seismic performance of special-shaped column joints.However,the development of finite element technology may alleviate this problem.In this paper,Abaqus finite element software is used for nonlinear analysis of T-shaped and cross-shaped column joints.Firstly,the author analyzed the test component and verified its rationality by comparing with the test data,Then,taking axial compression ratio,concrete strength and joint core area stirrup ratio as the influencing parameters,12T-shaped column node models and 12 cross-shaped column node models were designed respectively to carry out finite element expansion analysis.Based on the comparative analysis of hysteretic curve and skeleton curve,the obtained bearing capacity,displacement ductility,stiffness degradation and energy dissipation capacity can be used as the evaluation indexes of its seismic performance.The analysis results show that although increasing the axial compression ratio can improve the ultimate load and equivalent stiffness of the joint beam end,but it will reduce the deformation capacity,stiffness degradation and energy dissipation capacity.Although increasing the concrete strength can improve the ultimate load and equivalent stiffness of the joint beam end,but it will accelerate the stiffness degradation and reduce the energy consumption capacity.For the T-shaped joint,after the concrete reaches C60,the ultimate load of the beam end will be slightly increased,and thedeformation capacity will decreases accordingly.For the cross joint,the C45 concrete model has the strongest deformation capacity,while the others are reduced to different degrees.Also,with the increase of stirrup ratio in the core area of the joint,the ultimate load of the cross joint beam end is better than that of the T-shaped joint,and the deformation capacity of the T-joint is improved.However,for the cross joint,the deformation capacity of the original model is the best.In addition,the stiffness degradation of the two types of joints is accelerated and the energy dissipation capacity is reduced.In the process of finite element modeling,it is found that Abaqus modeling is complex,once the modeling error occurs in the complex model,the cost of modification will be huge.In this paper,C# language was introduced to carry out secondary development of Revit by taking Revit API on Visual Studio 2015 platform,and combined with Python script,to achieve the import of the Revit model into Abaqus,which greatly improving the modeling efficiency of complex structures.