Study On The Relationship Between Bending Moment And Angle Of Semi-rigid Beam-column Joints Connected By Shaped Steel Bolts

In recent years,with the rapid development of national construction industry,precast concrete structure has been paid attention to by the state.At present,the research on the design of new prefabricated concrete beam-column joints and its mechanical seismic performance is a hot topic in prefabricated concrete structures,but there are few studies on the semi-rigid mechanical performance of prefabricated concrete beam-column joints.In this paper,based on the finite element software ABAQUS,the finite element analysis is carried out on the beam and column joints of steel bolt joints and 12 specimens that may affect the bending moment Angle curve of the joints.The bending moment Angle curve of the joints and specimens is obtained,and the semi-rigid coefficient and other semi-rigid mechanical properties of the joints are further analyzed through the curve.On this basis,a mathematical model of bending moment and Angle is proposed,and the calculation method of initial rotational stiffness and ultimate bending capacity is given.The main conclusions are as follows:(1)the skeleton curves of bending moment Angle of joints and all specimens have elastic stage,yield stage and descending stage,which conform to the basic characteristics of semi-rigid joints' bending moment Angle curve.Compared with the semi-rigid coefficient of traditional cast-in-place joints,the semi-rigid coefficient of joints is significantly increased by 19.7%.(2)the semi-rigid coefficient of node and ultimate flexural bearing capacity and initial rotational stiffness on the node related factors(axial compression ratio,steel yield strength,steel strength grade of concrete thickness,bolt diameter,connection column),under the influence of the change,as the growth of the related factors of magnitude,the ultimate flexural bearing capacity of the node and the initial rotational stiffness increases,the strength grade of concrete axial compression ratio and connection column under the influence factors,the increase in particular;The semi-rigidity coefficient of the joint decreases gradually with the increase of related factors,especially under the factors of axial compression ratio,section steel thickness and concrete strength grade of connecting column.However,under the influence of yield strength of section steel,the semi-rigidity coefficient of joint reaches its maximum at yield strength Q345 of section steel.(3)on the basis of finite element and theory analysis,preliminary mentioned apply to this node bending moment corner three line mathematical model,and gives the node initial rotational stiffness and ultimate flexural bearing capacity calculation method,by comparing the simulation results with the results of the calculation of trends,verify the accuracy of the model,provide a reference basis for subsequent nodes design.