| With the continuous development of the construction industrialization in our country,the prefabricated building will have a large scale expansion for its many advantages,such as clean and efficient,the green environmental protection.As an important part of prefabricated steel structure,node plays a key role in the stage of assembling and using.At present,most of the nodes' performance are unable to reach the requirements of industrial production.So the bearing capacity,stiffness and ductility of nodes need to be solved.This paper mainly conducts to study the characteristics of prefabricated trussed beam-steel pipe column connected joints with inclined support.At first,based on the full-scale test of this node in Beijing University of Technology,the finite element software ABAQUS is used to establish the node model which is similar to the test node.The numerical analysis of the moment rotation curve and the failure mode subjected to unidirectional loading are compared with the existing experimental results to verify the rationality of the finite element model.Then the influence factors of the joints stiffness are studied,and the nodes with different angle of inclined support and beam-column stiffness ratio are designed respectively to compare and analyze the hysteretic behavior of joints under cyclic loading with different variables.Then the hysteresis curve,the ultimate bearing capacity of the node,the stress distribution of the node,the skeleton curve and the analysis section are emphatically investigated.The stress and deformation cloud diagram and the bending moment curve of the node are pointed out under cyclic loading.The elastic rotational stiffness of the node is described by the formula of multiple power function product.The formula coefficients are obtained by multiple linear regression analysis after the logarithms are taken on both sides,and then the expression of the relationship between the two parameters and the elastic rotational stiffness of the node is obtained.The main conclusions obtained in this paper are as follows:(1)It shows that the initial rotational stiffness and ultimate bearing capacity of the joints decrease gradually,and the seismic capability of the joints decreases gradually.When the angle of inclined bracing is 30 degrees,the initial rotational stiffness is the largest,the ultimate bearing capacity of the joint failure is the greatest and its seismic capacity is the best.When the angle of the inclined bracing is 45 degrees,the corresponding rotational stiffness and the ultimate bearing capacity are the second.When the angle of the inclined bracing is 60 degrees,the corresponding rotational stiffness and the ultimate bearing force are the smallest.When the diagonal angle is constant,the line stiffness ratio is 0.6 and the line stiffness ratio is 1.0,the situation is basically the same.(2)The smaller the angle between the bracing and the beam is,the more uniform the bracing force is,which can better transmit the load on the beam to the column and reduce the shearing effect on the beam,so that the entire node forms a more reasonable force transmission system.It is recommended to select the type of node with smaller angle between the bracing and the beam to meet the space requirements of the architectural design.(3)When the connection node of the same strut angle,different beam lines of different stiffness(different wall thickness)beam-column joints,which have the same load-displacement curve trend,large bearing capacity of the wall thickness of the connection node of a column is a little more than small connection node.(4)By comparing the calculated results of the two-parameter formula of the joint's elastic rotational stiffness with the calculated values of the finite element,it is found that the error is very small.The formula can accurately calculate the elastic rotational stiffness of the joint between the diagonally supported truss girder and the steel pipe column. |
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