| Self-stressing concrete-filled steel tube (SCFST) is a new type of concrete-filled steel tube which adopted self-stressing expansive concrete instead of common concrete. Compared with common concrete- filled steel tube, SCFST fully utilizes the expansion energy of expansive concrete to provide lateral prestressing force for core concrete. At present, the joint fatigue experiment of SCFST is little to carry out at home and abroad. A large number of engineering practice shows that under repeated load, fatigue damage in the steel welding joints happens easily due to the impact of many factors such as welding residual stress, welding defects, the stress concentration and so on, and then, it may lead to catastrophic accidents.Based on the project—Research about node fatigue test in SCFST, which is the crosshead of the western traffic-technology projects-Application-development-test-research project of SCFST(contract No. 200631881422), the following researches have been completed in the dissertation:①Collecting and sorting out the exised research data about the fatigue of SCFST, and formulating the plan of fatigue development of the SCFST joint;②Development joint fatigue experiment of SCFST;③Using the FEM software ANSYS to bulit the fatigue analyzing model, and inquire hot spot stress and stress concentration factor;④Compararing theoretical result with the experimental results, the results indicated that: the theoretical value and the actual value tally well, and at the same time confirmed that the finite element analysis reliable and reasonable;⑤Unifies the domestic and foreign correlation standard about fatigue calculation to evaluate fatigue behavior about region of the collection of the leader tube and the branch tube;⑥Through a lot of numerical analysis, geometric parameters of DY joints and characteristics of fatigue behavior about SCFST section joint were got.
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