Fatigue Properties Analysis Of The Overall Node Of Steel Truss Bridge

As the whole node technology is maturing, and has been adopted in large-span steel truss bridge design, the fatigue of the whole node under traffic loads is gradually aroused attention. However, due to the domestic studies of the fatigue problem start irrelatively late, we also lack effective means to analyze the fatigue performance.This article uses Dalian South Marina Boulevard Bridge as the engineering background to carry out research work. Integrating the existing theories and methods at home and abroad, to explore influencing factor the mechanism and method of calculation on the fatigue damage of high strength bolt connections and welded connections respectively, and propose appropriate methods of analysis.Firstly, this article introduced the basic concepts of fatigue and the basic theory of fatigue strength, including of the fatigue curve (S-N curve) and its influencing factors, comparatively analyzed of linear and nonlinear fatigue damage accumulation theory, explained the concept of fatigue life and its’ analysis methods, and analyzed of the factors that affect fatigue of the steel structures focused and comprehensively, introduced professional software workbench that was used in fatigue analysis in this article.Secondly, analyzed of the factors that affect the fatigue properties of high strength bolts connecting, highlighted the failure mechanism of high strength bolts connecting, which done good theoretical preparation for simulation of the below.Once again, described in detail the modeling process of establishing and treatments of details for the simulation fatigue tests of high strength bolts connecting. The analysis of simulation results show that the simplified model does not occur fatigue failure during normal use, which can be used for the evaluation of the actual bridge fatigue performance. But also, we can obtain the axial force that the experimental model could bear through the simulation. In addition, I also established a series of model to analyze the influence on the fatigue performance when the preload reduced as the bolts loosened.Finally, introduced the technology line of steel bridge welding fatigue simulation study and the nominal stress analysis method that was used in this article. Analyzed in detail for standard fatigue vehicle selection, experimental risk node selection, the experimental fatigue loading and its’ loading modes. Described the establishing process of welding fatigue simulation model, through the static analysis and fatigue analysis of the model, obtained that this bridge was in a safe state in its’ normal life, and fatigue failure did not occur.