| The core element of structural steel design is beam-to-column joints.With the wide application of steel structures in high-rise buildings,the traditional T-stub semi-rigid beam-column Joints are not capable of meeting the bearing capacity requirements.Because of the higher load carrying capacity of joints,the stiffeneds T-shaped steel semi-rigid beam-column Joints with stiffeneds between the T-shaped steel web and the flange is gradually used in engineering design.According to existing research,the major cause of failure in stiffened T-stub semi-rigid beam-column joints is bending yield of joints.Up to the present time,there is not sufficient reserch to derive a formula for bearing capacity calculation that can be directly applied to engineering design at home and abroad.The study is focused on analyse the ultimate bearing capacity of stiffened T-stub semi-rigid beam-column Joints with numerical simulation method and theoretical analysis.The results are concluded as follows:(1)The numerical model of T-stub semi-rigid beam-column joints is established by finite element analysis software,ABAQUS.The finite element numerical simulation results are compared with the existing model test data,and the correctness of the numerical model is verified.With the method of finite element numerical calculation,the stiffened arrangement,stiffened thickness,T-stub size,bolt diameter and spacing,beam section size,column section size,column top shaft pressure,friction surface anti-slip coefficient and other factors that affect on the stiffened T-stub semi-rigid beam-column joints are studies in detail.The main failure modes of stiffened T-steel semi-rigid beam-column joints are obtained from the analysis;(2)The sensitivity analysis theory is utilized to analyze the bearing capacity of stiffened T-stub semi-rigid beam-column joints under influencing factors.The main influencing factors of the bearing capacity of the joint are: thickness of T-shaped steel,thickness of T-shaped steel Web,thickness of column flange,height of beam section,and coefficient of friction between bolt and joint;(3)Based on the finite element analysis,the force transmission mode and failure mode of the T-shaped steel members are analyzed,and the contribution formula of the bearing capacity of the stiffeneds is derived.The method of reducing and stacking ribs and T-shaped steel members is proposed,and the formular is provided;(4)Based on the main influencing factors of the flexural capacity and the failure mode of the joints,the material bending theory is utilized to analyze the bending stiffness of each component under the limit of bearing capacity.The bearing capacity of each component is calculated.According to the principle of minimum bearing capacity,the formula of ultimate bending capacity of stiffened T-steel semi-rigid beam-column joints is derived.At the end,combined with the finite element numerical calculation results,the correctness of the ultimate bending capacity of the stiffened T-steel semi-rigid beam-column joint is verified. |
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