Under the sudden disaster or extreme load, the structure usually causes the direct destruction of local components and further causes continuous collapse events that are not proportional to the initial damage scale. The failure mode is very complex, with dynamic, nonlinear and uncertain characteristics. The study of structural collapse resistance has become the focus of attention of researchers. Most studies that resist continuous collapse are directed at building structures, and there are few special studies on bridges against continuous collapse. In this paper, the large-scale dynamic numerical simulation software ANSYS/LS-DYNA is used to simulate the continuous collapse process of the large-section steel slab-concrete composite girder bridge. The accumulation and failure mechanism of continuous collapse are analyzed. The results show that the initial chord of the steel truss bridge pier is initially damaged, and the upper chord of the nearby area bears a large bending moment due to the action of the large gusset plate, and enters the beam mechanism failure mode. As the deformation increases, the full-span upper chord receives a large tensile stress into the catenary failure stage.In addition, the damage effect of the bridge deck on the steel truss girder is also analyzed. The research table shows that the bridge deck can significantly enhance the ability of the structure to resist continuous collapse. Finally, according to the collapse situation, failure mechanism and maximum stress point of different failure zones, and based on the transformation load path method (AP method), a continuous collapse prevention method for steel truss-concrete composite girder bridge is proposed. Key words: steel truss - concrete composite beam；continuous collapse; LS-DYNA; numerical simulation; failure mechanism; anti-continuous collapse method

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