Research On Seismic Performance And Design Method Of Steel Beam To Circular Tubed Steel Reinforced Concrete Column Joints With Reinforcement Ring

Tubed steel reinforced concrete structure has high compressive and shear bearing capacity and excellent seismic performance.It is a new type of composite structure with wide application and development prospects.At present,the research of tubed steel reinforced concrete structure mainly focus on axial compression artifacts,and study of beam-column joints are scarce.Therefore,it is necessary to put forward the joint forms with high bearing capacity and clear transmission capacity,and carry out an in-depth and systematic study on them to clarify their stress process and failure mechanism,which is very important to perfect the tubed steel reinforced concrete structure system.Based on the summary of the preliminary test results of the research group,this paper uses a combination of finite element analysis and theoretical research to conduct an in-depth and comprehensive analysis of steel beam to circular tubed steel reinforced concrete column joints with reinforcement ring(CTSRC).The main work is as follows:(1)Three-dimensional modeling and nonlinear finite element analysis were carried out on the test joints.The failure process,hysteretic curve and skeleton curve obtained by finite element analysis were consistent with the test conditions,which verified the accuracy of the models.The stress and strain of the main components of the joints were analyzed in depth to clarify the force transmission and mechanism of them.The structure of the joints used in the test was adjusted and compared with the original models.The failure form,load-displacement curve and ductility energy dissipation of the simplified finite element model were consistent with the original model.Therefore,simplified joints could be used for further analysis.(2)The parameters which have great influence on the mechanical performance of CTSRC were selected,including beam-column stiffness ratio,steel content,axial pressure ratio,strength grade of concrete,steel tube diameter to thickness ratio,width and thickness of the reinforcing ring.In order to clarify the influence of each parameter on the failure mode and mechanical performance of the joints,finite element analysis were performed on ? and ?joints under monotonic load and cyclic load.According to the analysis results,in this paper,the suggested value range of each parameter were as follows: the limit of beam-columnstiffness ratio of ? joints was 1.06.The limit of axial pressure ratio of ? joints was 0.6.The limit of steel tube diameter to thickness ratio of ? joints was 66.7,and it should not be less than 40 when economic benefit was taken into account.The limit of beam-column stiffness ratio of ? joints was 0.60.The limit of axial pressure ratio of ? joints was 0.4.The limit of steel tube diameter to thickness ratio of ? joints was 50,and it should not be less than 40 when economic benefit was taken into account.For both ? and ? joints,it would have better economy when the steel content was within 0.053.The width of the reinforcing ring should not be less than 0.5 times the flange width of the steel girder.The thickness of the reinforcing ring should not be less than that of the flange of the steel girder.(3)According to the results of finite element parametric analysis,this paper integrated and combined the influence curves of various parameters.On this basis,horizontal bearing capacity,flexural bearing capacity and shear bearing capacity calculation method applicable to various parameters ? and ? CTSRC were put forward.The accuracy of the formula was verified by comparing the formula results with the finite element results.The calculation method of bearing capacity could provide reference for engineering practice and the establishment of relevant technical standards.