Abstract:Aiming at the special structural system and the unclear stress behavior of the 35 m+50 m+35 m long-span "trough + box" compound section continuous concrete girder in a highway-rail co-construction project, a three-dimensional solid model is established by using ANSYS finite element software to study its stress behavior, and the suggestions are proposed for the design. The study shows that (1) the "trough + box" compound section satisfies the plane cross-section assumption. (2) There are significant differences in shear force distribution of the side/middle webs of trough and box compound sections in different sections and the same section. (3) The stress concentration is obvious at the junction between the side web and the bottom plate of the trough part. (4) The reinforcement at the junction between the side web and the bottom plate of the trough part should be strengthened, and the envelope design of the reinforcement at the cantilever root and the mid-span of the deck slab can be carried out.