Study on the fatigue performance of steel-composite grillage deck of large-span arch bridge

In this paper, based on the finite element numerical method, an arch bridge with a main span of 252m was selected as the engineering background, and three standard grillage segments of the bridge deck in the derrick area were selected to establish a refined finite element model, and the fatigue characteristics of the steel-composite grillage deck were studied. The fatigue calculation mode III in General Specification for Design of Highway Bridges and Culverts (JTG D60-2015) was loaded into the finite element model for calculation, and the fatigue key points were determined, the stress time course curves were extracted, and the fatigue damage calculation was carried out. The results indicate that the most unfavorable stress point of the steel-composite structure model is at the bottom plate (outside) of the intersection of the middle longitudinal beam and the secondary crossbeam under the longitudinal loading of vehicle load in the transverse position; the stress amplitude of the maximum critical point in the longitudinal bridge stress course under the standard fatigue vehicle model is less than the fatigue strength limit of the normal amplitude, which meets the design requirements.