Studies On The SCF Of Tubular K-joints By FEM

As the economic fast development and increasing traffic of China, the long span bridge will be used more and more widely. Steel tubular structures are widely used in various long span bridge, since the advantages of the better spanning capacity,the better anti-knock performance, facilitating to construct. Because of Stress concentration on the node and the existence of welding defect, the tubular is subject to fatigue failure under the vehicle load, Fatigue design of tubular joints will turn very important. The common fatigue design method in tubular nod is Hot spot stress method. Therefore, a lot of research was carried out at home and aboard, by summing the research, Stress concentration on CHS node and concrete filled steel tubular node is less studied, and the research of the extent of Stress concentration comparing between CHS and RHS is less.For more in-depth and accurate understanding of square, round steel K-node section of the form of the fatigue performance and stress concentration caused by the difference, using finite element method to analyze stress concentration factor node. In order to study the difference which the fatigue performance and Section of CHS, RHS and K-joints caused, the finite element method is used to analyze stress concentration node factor. This paper introduces the choice of geometric parameters and unit elements in modeling process, and points out what need to note in the mesh and load points to note, which can be reference. Proven reliability in the model, the stress concentration factor node on K-joints of CHS and RHS was analyzed and compared, the node fatigue performance rule with the variation of parameters is acquired Finally, in order to analyze the impact of filled concrete on CHS node, using solid element to simulate the steel tubular and concrete, the stress concentration factors of filled concrete tubular. The study shows that the stress concentration of branch tubular is reduced 57%-75% and the stress concentration of main tubular is reduced 60%-77%,by main tubular filled with concrete. The stress concentration on steel tubular node can be more reduced by main tubular filled with concrete, which is advantage to improve the fatigue capacity.