大跨“槽型+箱型”连续混凝土梁受力与设计研究

针对某地公轨合建工程35+50+35m大跨“槽型+箱型”组合截面连续混凝土梁结构体系特殊、受力行为不明确，采用ANSYS有限元软件建立三维实体模型，研究其受力行为，并对设计提出建议。研究表明：①“槽型+箱型”组合截面满足平截面假定；②组合截面槽型、箱型部分纵向不同截面、同一截面边/中腹板剪力分布存在显著差异；③槽型部分边腹板与底板衔接处应力集中明显；④槽型部分边腹板与底板衔接处应加强配筋、桥面板悬臂根部及跨中配筋可取包络设计。

Study on Stress and Design of Long-span "Trough + Box" Continuous Concrete Girder

For the study of the special structure system and unclear mechanical behavior of a 35+50+35m long span continuous concrete beam with the "trough+box" combined section, a three-dimensional solid model was established by using ANSYS finite element software. The results show that: (1) The combined section of "trough+box" satisfies the assumption of flat section; (2) There are significant differences in the shear force distribution of the trough and box sections in different positions, as well as the sides and middle webs of 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 of connection of the side web and the bottom plate of the trough part should be strengthened, and the envelope design of the reinforcement of cantilever root and the mid-span reinforcement of the top plate should be desirable.