拔出破坏的钢混组合结构栓钉连接件承载力的分析方法

Push-out failure is easy to happen in stud shear connector with small length-diameter ratio of stud. At present, the bearing capacity of push-out failure mode is usually determined by test. In order to extend the application of finite element analysis, the compression strain of concrete near the stud end was taken as a control variable to judge whether the push-out failure happens. Firstly, ABAQUS software was used to create finite element model of standard push-out test. The results were compared with both the reference and design codeand the correctness of finite element model was verified. Then, the influences of length and diameter of stud on bearing capacity were analyzed combined with the method of analyzing the push-out failure. Lastly, the calculation formula of bearing capacity with push-out failure was given. Results showed that the tie constraint between stud and concrete was the upper limit of stiffness for surface-to-surface interaction. Push-out failure was prone to happen with lower concrete strength and it was unsafe to just restrict the length-diameter ratio of stud larger than four to avoid pull-out failure in design code. The degree of increase of bearing capacity caused by the diameter of stud was not affected by concrete strength. When the diameter of stud increased from 13 mm to 22 mm with an increment of 3 mm, the bearing capacity increased by 42%, 31% and 35%, respectively. Eurocode4 was suggested to be followed for design when the diameter of stud was larger than 16 mm, because the value calculated from Code for Design of Steel Structure was a little large. The judgment method and calculation formula of bearing capacity proposed for push-out failure were reasonable and verified by calculated value of design code.