Behavior Of Steel Joints In Triangular Roof Truss For Hot-rolled Cut T-section

Hot-rolled cut-T-section chords were adopted in the national standard of architecture drawing "Light weight triangular steel roof truss(cut-T-section)" 06SG517-2,together with angle-section web members.The web plate of Cut-T-section chord may be used as gusset plate,and the transmission of force is direct however the load-carrying capability is complex. The paper analyzed the behavior of this new type of joints,which may be referred in design.In this paper,firstly,the model of lower chord panel points was established based on FEA software ANSYS,and was verified by comparison with the result of experiment.On that basis,the behavior on lower chord panel points in mid span of 22 A-truss in the drawing 06SG517-2 was analyzed.The results showed that a small part of gusset in a few of joints developed plastic deformation,but it didn't affect the safety of structure.Because the secondary stress of lower chord is very small,the effect of secondary stress was not remarkable.Secondly,the paper obtained the ultimate bearing capacity,the failure mode and the distributing rules of stress etc by elastic-plastic analysis on lower chord panel points in the mid span of these trusses.The analysis results revealed that the design of the joint in the drawing 06SG517-2 was safe and reliable.The failure mode of joints may be categorized as three kinds:the failure on cross sectional area between middle web member and diagonal web member,forming continuous plastic zone and the failure on middle web member or lower chord.There was no remarkable yield plateau before the failure of joint with a characteristic of brittle failure.Finally,some suggestions were put forward based on the analysis results mentioned above.