Analysis Of Mechanical Behavior Of KT Type Spatial Tubular Joints Of Steel Tube Truss

In recent years,the large-span steel tube truss structure has been widely used in China.With the diversification of structure,the design forms of the large-span steel tube truss structure are becoming more and more complex.The design of the joint with multiple sections and members will appear,which makes the stress at the joints more complex and worse.It is very important to study the mechanical properties of the joints.The research of this paper is centered around the KT type steel tubular joint of Wuhan Moon Bay Outdoor Theater Roof.Firstly,the strength,rigidity and stability of the structure under different load combinations are checked by analyzing the whole structure of outdoor theater roof,and compared with the National Code requirements to verify whether the design scheme satisfies the safety requirements.Secondly,according to the results of the analysis of the whole structure of the outdoor theater roof,the most unfavorable node of the steel tubular truss structure,namely KT type tubular joint,is extracted according to the internal force distribution of each pipe fittings at the intersection of the steel tube truss structure and pipe fittings.According to the analysis of the parameters of the joint,the influence of the parameters such as the stiffener,the thickness of the stiffener and the concrete filling amount on the mechanical performance of the joint is evaluated.The optimization suggestions are put forward for the design scheme of the node.Finally,the failure mode analysis of KT type tubular joints is carried out,and the failure modes of KT type tubular joints under different pipe combinations which are carring force are discussed,and the influence of pipe force and concrete pouring on the failure mode of joints is discussed.The results show that the distribution of stress,internal force and displacement of outdoor theater roof is symmetrical,and meets the National Code requirements,and the structure has a high overall stability safety coefficient;concrete filling and the reasonable design of stiffeners can significantly reduce the stress concentration at the pipe joint line,while the thickness of the stiffener has little influence on the stress concentration;The bearing capacity of main pipe G1 was improved by filling concrete,but the failure mode of G1 was not changed;Under the condition of the main pipe G1,XG1 and SG1 carring forces together,the failure mode of the main pipe G1 changes,and the failure area also deviates,that is,the change of the stress condition has more significant influence on the failure mode of the main pipe G1.